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Is there a quick answer to the difference in bike handling and ride characteristics between the tube sizes?
If your building with DO what type of crown and blades are you using to keep the fork from looking anemic?
Are your DO customers most always going with carbon forks, I would assume this..?
85 with 98% humidity and getting ready to fillet braze in a warehouse. Time to sweat it out.
Thanks gents.
i've ridden and raced on the first two options for a long time, and trained on the third, too. according to my opinion, it's a style/fashion thing and what you perceive, if anything at all, comes from the frame design. keep that consistent, and vary the diameters/shapes, and it "feels" like the same bicycle. well it does for me. but as eras changes and visuals do too, folks get used to different things. i can't look at modern parts and shapes on frames made with your first choice. when i went OS full time in the mid 1990s it was for this reason alone. bicycles with "trad" dimensions looked wrong with ergo, and concealed cables, and deep(er) rimmed, low spoke count wheels, and with short stack saddles replacing the rail geometry from the era before - and let's not forget thread-less. the beauty of waiting long enough is that the technology these days allows the frame dimensions to grow with the eras yet not penalize the end user with unnecessarily added avoirdupois. data point: my opinions are only about the ferrous materials. i embrace the look of the bicycles the same way i love to use them - fully. but when my eyes are shut and i'm in the pain cave, as long as the contact points are correct, and my center of gravity is positioned where it should be, i have no clue which tube set the bicycle is made with. the ideal is to take the best characteristics of the past and bring them along with you to the future. in my book, that means frame design and construction quality trump material choice every day of the week. that's been my message going back decades before bin laden's left eye was vaporized. and, all this from a guy who's in the business of selling materials too atmo...
I see this a bit differently than Richard does. While it's true that the larger tubes have a different look I don't see that as a compelling reason to use/not use them. I see it more of a way to match the bike to the rider and less of a way to match the look of the frame to the wheels or components.
When the diameter of a tube changes the bending stiffness of the tube changes too and in a fairly dramatic way. If one considers a pair or top tubes, both with a wall thickness of .6 mm (.023"), and one has an O.D. of 1.125" and the other has an OD of 1.250 (the change that the tubes go through from OS to XL or D.O. tubes) the larger top tube will have 140% the stiffness of the smaller tube. That is a pretty big number that I think most folks would feel. When you go from a 1.250" down tube to one with an OD of 1.375" the larger tube will have 133% the stiffness of the smaller one. The seat tube going from 1.125" OD to 1.250" will give the same results as the top tube - so all three main tubes gain a minimum of 33% in bending stiffness. These numbers are just for simple bending and doesn't factor in torsional resistance. I'd calculate it but for some reason I can't find my spread sheet for it. As I recall the numbers will be even more dramatic but someone smarter than me will find a calculator and post the numbers with any luck.
I own bikes with old school 1" top tubes, new school OS with a 1.125" top tube and a grad school 1.250" top tubes and while I like them all I would say that they lend themselves to different uses and feel a good bit different from one another. They all work well but they work best in different circumstances and certainly have much different flavors to me.
All that said and more to your question of how the tube diameters will affect handling. Generally speaking the larger tubes will of course deflect less when hitting bumps and will not give as smooth a ride. This is not to say that they give an unduly harsh ride but it isn't as buttery smooth as the smaller tubes. At the same time the larger tubed bike will have more torsional stiffness which makes the bike feel more precise on turn-in and it will better hold it's line on rough surfaces as it will not be deflected off it's line as easily.
I see the ride and handling differences being one of degrees. Both can work very well but no doubt some will prefer one over the other - as with all things some will like the change and others not so much.
As for the fork difference and the aesthetics. I build my XL bikes with steel forks and do not offer carbon forks. The steel fork has a 1 1/8" steerer along with it's bigger crown and headset and the only thing staying the same in size are the blades and I don't see the smaller blades being a problem aesthetically - but your taste may be different.
I think there are many ways to make a good bike and tube selection is just one of the many tools the builder can use to truly fit the bike to the rider and the end use. I offer bikes with 1" top tubes to smaller riders, 1 1/4" top tubes to larger riders and 1 1/8" tubes for those in between and it's all good. Goldy Locks had it right IMO.
Dave
http://farm6.static.flickr.com/5020/...5a5ee5eb_b.jpg
http://farm6.static.flickr.com/5293/...7993f936_b.jpg
i agree with dave - the numbers exist and are part of an equation. my reply answers the question
related to ride quality, etc. i can't tell the difference between the options listed in the first post atmo.
it'd be really tough to make a bike that felt "underbuilt" to an athlete richard's size. personally, i can tell you that geometry trumps everything and determines how a bike will ride and also how it will feel. in my experience- you simply need the tubeset to be stiff enough that it doesn't wiggle torsionally- that it won't break in to a million pieces if you eat shit on it, that it's stiff enough that it'll hold its line over crappy road conditions and that it's light enough to be built up to the uci weight limit with normal parts, metal stems and bars and fancy wheels.Quote:
Originally Posted by e-RICHIE
the rest of it is gravy and i am not of the opionion that you can make a bike "too stiff" except when "too stiff" means "too fucking heavy"...but there are plenty of bikes that are too wiggly and underbuilt for many riders.....but it's really tough to do with modern steel tubing.
craig/jerk
it's not size, it's ability atmo. the bicycles are made to order, labeled and all that, too.Quote:
Originally Posted by jerk
ps material has improved exponentially through the years. and better yet, folks who are
still in the game are better at it than many predecessors whose bicycles, the batch built
ones particularly, became the baseline for discussions like this one.
i don't get this.Quote:
Originally Posted by e-RICHIE
i know. what i am saying is that if the wheels are in the right place- any modern steel tubeset is going to be plenty torsionally stiff enough for something 54cm or smaller for most athletes.Quote:
Originally Posted by e-RICHIE
you said you don't notice a difference based soley on tubing diameter. i was agreeing that you shouldn't....how could you unless you were flexing the fuck out of it? if you're not, there's no difference to notice. the bike stays in plane and rides right.
I probably shouldn't be posting here 'cause i'm not a builder,Quote:
Originally Posted by Dave Kirk
but hey, the mod powers let me, so forgive my indulgence....
How common is it to have the same wall thickness in std size tubes as oversize tubes?
I was under the impression most frames built from OS tubes are thinner wall than "std" tubes.
For example, I think a Columbus Spirit Top Tube is 0.4 and say an 'ole SL top tube is 0.6.
This is what I presume E-Richie is saying, the functional differences between tubes of different
diameters has mostly been offset by making the larger tubes thinner.
Is it fair to say the OS tubes commonly used negate most of the change in diameter?
- OS ends up a bit lighter, and that's why it gets used?
This of course leaves the builder the option of larger, stiffer tubes for those who need it.
I'm also a lighter weight rider, and I can say that there is much more "smoothness"
that comes from properly matching the tubes with the rider. I own a steel bike
I would describe as "overbuilt" for my needs, as it is noticeably less enjoyable to ride
over rough surfaces. It's a custom build, so obviously the builder chose the tubes thinking
he was matching them to my needs.... I'd say he missed.
So what does all this mean? I guess it says put me in the camp that says tubing matters...
-g
For the most part the walls of all high end steel tubes are about the same now. It used to be (before the new stronger materials) that the thin walls were left to the bigger tubes and that a larger diameter tube ended up weighing about the same as the smaller tube due to it's thinner walls.Quote:
Originally Posted by GrantM
This changed when the material became strong enough to use thin walls even on the smaller dia. tubes. So now the tube wall thickness is more driven by what the tubing maker can make and less about what is needed to be safe. This ends up being about .5 - .6 for the thick part of the tube. This is why I left the tube wall the same in my example above.
dave
ATMO the chainstays are the main determinant of whether or not a bike feels stiff. When you're out of the saddle flexing the frame, it's the chainstays that are doing most of the work to resist that.
So even though the rest of the frame might be considerably stiffer (as it will be, because stiffness increases with the third or sommat power with increase in diameter), unless we scale the chainstays proportianally, there will be relatively little perceived difference. Not to say there isn't one, but just that it won't be as much as you might otherwise imagine.
I agree. The real difference/benefit in using the larger tubes is making the frame torsionally more rigid. The extra torsional rigidity will make the bike feel/handle better on rough surfaces that might knock a less rigid bike off line. But as you so well said - the big main tube will do little to stiffen the drivetrain.Quote:
Originally Posted by suzyj
dave
So if a lot of perceived stiffness comes from seatstay- chainstay combinations, should we see a much larger variety in available tubing options or is the variation only subtle. I find that wheels, tyres and tyre pressure can play just as big of a roll in ride perception. As Craig said, if you are on the shorter, lighter side, you can pretty well get away with anything, on a larger size frame I would imagine the differences could be exaggerated.
Bill
Dave has explained well
for me
I had this settled 20 years ago
circa 1991.
I have been using XL sized tubes (the term Double over size and any other silly terms are to be banned) since 1991.
(Columbus MAX and Mega tubes)
Big or solid riders like them!
I have been using XL tube with lugs since I designed and produced the first ever XL Compact lugs in 2003
World's First compact angled road bike lug set. The LLewellyn "XLCompact" (Formerly known as "Slant 6")
Album: World's First compact angled road bike lug set. The LLewellyn "XLCompact" (Formerly known as "Slant 6")
"The need for compact angle over size tube lugs got me going. So I set about hand making lug patterns, CAD drawings, with ye old French lug maker "Bocama" influences on the shorelines. My Llewellyn compact angled over size lug set has been a hit with exports around the world. 36 HT 34.9 DT 31.7TT 31.7ST 60* & 79* HT lug angles, 79* ST lug angle"
then in late 2009 (not Feb 2009)
a XL lug set with horizontal top tube
read the story here
The Framebuilders' Collective | Cadenzia Lug Set
and also a prototype XCr for XL lugs tube set in Jan 2010. (I made and took this frame to NAHBS, see FNL #51)
After 16 months the production sets have arrived. (see FNL#112)
This Columbus tube set is driven by Dario Pegoretti with some small inputs from me.
oh and the 30.60mm (which is the correct size for 31.7 .5 tube) seat posts to fit the Columbus 31.7 Life, Cyber, Genius and XCr seat tube with out a sleeve have existed since 2003
So this stuff has been around and well established for TIG and lug builders for many years despite the perception being presented.
and I and others have actually been making frames with these XL tubes for many years.
In my mind it is about correct selection of materials and dimensions for the rider.
One tube set for every size rider and weight of rider is not always going to give the correct result.
This may be of interest
Bici da corsa | bdc-forum.it - Visualizza messaggio singolo - Llewellyn...ditemi un po'
there is no definite line to cross from OS (Custodian) to XL (Cadenzia) size tubes.
I think XL tube sizes are best when the rider
a: the rider is more than 75kgs
and or
b: The frame size is bigger than 58cm seat tube.
c: If the rider is very powerful
d: Some riders want stiffness in the frame to feel confident.
e: Some times the rider's pedaling style and technique is an influence
It is important to match the fork to the rider
The fork blade thickness selection will vary to suit the rider's weight.
I use .8mm for light riders (-65kg) and .9mm (normal) and 1.00mm for heavier riders. +80kg
For very stiff forks I use Columbus MAX fork blades. (+ 95 kg)
It is also important to match the seat stays (posteriore verticale) to the rider and the ride feel desired.
I use 16mm, 17mm and 19mm diameter for the very big riders and track frames.
XL tubes (Cadenzia) is approx 20% greater stiffness then OS tubes (Custodian)
I explain to the client the direction and rational and we confirm so all understand the desired result.
I've got a datapoint in the garage that's been under my own ass. I built it with Dazza's compact lugs, ubersized tubes unfortunately with most of the butts cut out to make it my size, Dazza dropouts which build a stiff rear triangle and 19mm stays that are fastbacked to the seatlug. Matched with a max fork I or another traditional sized steel fork I can tell a difference in ride. I can't tell a difference in performance, but I can tell a difference in ride. My opinion is that if there is any tube matching going on it should be to match what the client likes. 2/3 of what I've been building are cross bikes and frankly its pointless to discuss what i do when we are talking about bikes that often have less than 35lbs of air in the tires.
i have read all the stuff since day one, i make the things, and also use them daily and hard. i'd like to say it's equal parts technology and technique, but i have to draw the short straw and play the alchemy card too atmo. if you guys can feel the numbers and not just quote them, your fingertips are a lot more sensitive than mine. and i mean it with no hint of negativity or sarcasm at all. i've never been on a frame (of mine) and thought, "now this steel (or tubing, or dimension, or shape) really does make it better." the quality of its manufacture* is another subject altogether. some combinations are lighter, some are not. round. oval. seat stays of every known shape. imperial and/or continental blades. cast parts. pressed steel parts. i don't feel it. if the position is correct, the design rational, the center of gravity in the right place, and the paint red, i'm down the road on it.
design > assembly > materials > atmo
* the material's, that is...
I agree with youQuote:
Originally Posted by e-RICHIE
but
Richard, how tall are you?
How heavy are you?
Yes, of course you rode lots of bikes hard
the key point is YOU
You are a good test pilot for a frame that is designed to fit YOU and well assembled with materials selected for YOUR frame.
I raced at 60kg and I am 172 cm tall
my frame was typically 520 x 545
saddle height of 720mm
If I used XL tubes it will be over kill
the bike would shake the fillings out of my back teeth
and rattle any kidney stones loose
but I am not 200cm tall
and weigh plus 90 kg
and have a thresh hold at 400 plus watts
Not many of my clients are built like me
I also will not make a good test pilot for an XL tubed frame
The feed back from tall and heavy riders to all the frame builders I know well is that increasing the rigidity of the frame to match the size and weight and power of the rider yields a frame that is pleasing for them to ride. Maybe not faster, but pleasing, nicer handling, inspiring confidence.
Of course
"design > assembly > materials >" all this has to be in the recipe.
I do plan to make myself an XL frame one day soon with Cadenzia lugs and XL XCr tube set and Dario's new carbon fork when it becomes available , totally just for my own kicks. I do not expect it to handle better or feel faster than my normal OS bikes, it may return negative feed back for a small and feeble rider such as myself. It may well test out my dentist's expensive work in my back teeth:bigsmile: For me it will be interesting and fun project just to find out what it really feels like to a whimp like me
I do not build XL tube frames for aesthetic reasons, I use XL tubes when they are appropriate choice for the client's frame.Llewellyn Custom Bicycles History
I agree with Dazza here and also will add that I've been building XL or DO tubed lugged bikes since Dazza first introduced his Slant-6 lugs (sorry Dazza I still prefer the old name :-) ) way back when...they make for a great bike for the right rider, but frankly these bikes are overkill for most riders (for example...those under about 6'+ and/or 200 lbs IMO). All you are doing is adding weight for very little, if any, performance gain for most, while increasing rigidity to the extent that it can make for a long day in the saddle. Pair a DO tubed bike to a MAX bladed fork and the issue is compounded substancially. Talk about shaking your fillings out! Of all of the "road" forks I have tested (and I do deflection tests on nearly every fork that goes through my shop), none are more stiff longitudinally (front to back, as opposed to side to side), than a max bladed fork....to the extent that there is almost no deflection under normal riding conditions. I suspect some folks will cry foul here, but its true.Quote:
Originally Posted by Dazza
Dave
Yes, but most tube diameters are still available in multiple wall thicknesses, so if I wanted to build a standard tubed bike, I can still use an 8/5/8 or even a 9/6/9, 28.6mm diameter down tube, for example. It's up to the builder really to select tubes that are safe and that's likely going to mean thicker walls on a bike with smaller diameter tubes...all other things, including the rider, being equal. (At least when it comes to a Standard vs OS frame)Quote:
Originally Posted by Dave Kirk
To Grant's question (if I understand it correctly)....in general, yes, thinner OS tubes are used to maintain (increase actually) stiffness, while also reducing weight. However, there is a point of diminishing returns, after which, depending on the rider and the application, you're just adding weight (and stiffness) for no appreciable gain....
I agree Dave.Quote:
Originally Posted by Dave Anderson
I simplified (over simplified?) to make the point easier to make.
Dave
Put me in the camp that believes diameter does make a big impact on ride feel.
I've ridden exclusively OOS bikes and only recently, after connecting with a lot of what DK has written about re:" too much stiffness" and yes I'll admit even some BQ articles !!! I put my money on the line to experience std dia tubing (22.2 chain stays) for the first time. I currently have no shop but had Erik at Alliance build me a STD dia bike for my 155 lbs. The ride behavior of this bike is simply night and day in terms of 'fit' for my weight considering same contact points. I now understand what it feels like to have a bike that works 'with' me. It is more smooth, responsive and enjoyable than ANY OOS tube bike in ANY material that I've been spoiled enough to own.
I think though big tubing is popular for looks (nothing wrong with that!), essential for the right athlete (big dudes), but us lighter dudes should give a skinny tube bike a try. Clients should communicate what they want in terms of performance/feel and not tubing diameters and geometry and leave those two, plus construction of course, to the builder.
i am trying to wrap my head around this stuff because it remains too conceptual based on my experience. if we remove the style/era/trend component out of the equation (mine, at least...) can someone cite an example of what tube diameter substitution in place of another tube yields what difference in feel. is there a moment in a race, or a ride, when you said (for example), "that (tube type goes here ------ > _________ ) changed this (the "this" goes here ------ > _________ ). i am not talking about the frame design or whether the bicycle fit better - the question relates to the OP and the three choices. thanks atmo.
Quote:
Originally Posted by timto
Very cool.
I make a good number of bikes with old school 1" top tubes for smaller lighter riders (typically women) and sometimes it's a bit of a battle to convince them that smaller can be better. But once they ride it they never look back. In some silly ways it's like condoms. The offer standard and 'magnum' but no one offers 'small' and yet I'm guessing small would be a good choice for some. You think the sales of standard size died when magnum was brought to market? I'll bet they did.
dave
I own bikes with all three popular sizes of steel tube - standard, OS and XL - and I like them all. I doubt I'm significantly faster on one than the other two. And yet I feel the difference on every ride, at every corner and going up and down every hill. They are just different. Each one shines a bit more than the others in a given circumstance and falls short of the others in a different setting. But they are all different, all the time. Are they day and night different, black and white, good and bad? No not at all. But they are markedly different. An apt analogy might be comparing a good clincher with a good tubular. Both ride well but they are of course different and most would feel the difference. I think the differences in tube sizes are a bigger deal than the tire analogy but they are similar in concept.Quote:
Originally Posted by e-RICHIE
I'll bet if you built three identical bikes for yourself, with the exception of the tube sizes, that you would feel the difference between them.
As a slight aside - One of the very cool things I got to experience while working at Serotta was riding all different types of bikes, built with different materials or different sizes and of different designs. I rode different bikes all the time and when I finally left the company I had 14 Serottas and no tow were alike. Before this I knew that there were certain bikes I like and others I didn't but I didn't really understand why one felt good and the other didn't. But by riding all the bikes on the same roads with the same fitness and the same fit I was able to learn to feel the differences. I do think it's a learned skill and takes time and a variety of bikes to develop.
During that time I would build a Ti bike without a c-stay bridge and ride it and then bring it in and put a bridge in it and take it right back out and see what the difference really felt like. In some cases there was little difference to be found and in others (like the Ti c-stay bridge) the difference was huge. At the same time I was able to ride many bikes, in my size, built by other companies to put things in perspective. I think you don't really know how good/bad your own work is until you've tried something else. In so many cases rider technique could make up for or mask a shortcoming of a given bike and the rider doesn't even realize it. But when spending time on a completely different design the rider realizes that they can set aside the way they were using the previous bike and let it go and this will open up the performance/enjoyment envelope. One of the things I learned was that in some cases our bikes (Serottas) absolutely kicked ass and in others they were behind the competition. With that experience we were able to make subtle but important changes that made the bike more enjoyable/fun and in some cases faster.
In the end I see this as all being shades of gray and and not black and white and what makes one rider smile will make another unsmile (it's a new word I'm pushing). Vive la Differance. To me tube sizes are just another facet to explore in the quest of make the rider not unsmile.
Dave
data point:
i built richard a gaulzetti with the exact same geometry as the os tubed road bike he'd been riding for years. on paper there shouldn't be two more different riding tubesets.
anyway-
c
like. feel. just different. shines. different. markedly different.Quote:
Originally Posted by Dave Kirk
any or all of these words could be attributed to the weather, or the breakfast meal, or your fitness level.
that's where this started.Quote:
Originally Posted by Dave Kirk
i have. see the above post(s). since the mid 70s i have ridden every conceivable combination, and raced them too. and i haven't said as much already, but while my 'cross career is a hobby at best, i can suffer for an hour if there's a prize list. never have i noticed the difference between the shapes and diameters of the frame parts.
i've had maybe 30 RS frames through the years and the only constant was the design; the pipes, brands, and sizes/gauges varied. that's why my opinions are what they are.Quote:
Originally Posted by Dave Kirk
thanks for the reply. these things you describe are visceral. that's good, too. i was hoping to hear why they felt the way they did, or why you likeed them, or what the difference was, or what makes it shine and how. i understand the math and fully acknowledge the engineering back story. my opinion includes that, while the science exists to explain what a pipe would feel like in different iterations, it's not there to quantify what happens when a set of pipes becomes another item completely. we are talking about the bicycle and its feel, rather than the properties of a pipe. i can't separate design, execution, and materials from each other. i guess shades of gray and visceral will have to be all we have to sink our teeth in for now.Quote:
Originally Posted by Dave Kirk
For grins and giggles, can you tell me the wall thickness of the tubes and fork you built for me?Quote:
Originally Posted by Dave Kirk
I know what SL tubes feel like, i've had many of those frames over the years with very similar geo
to what you made for me, but i also have not known the tube wall thickness on several frames I liked
and didn't like, so i've never been able to narrow that criteria.
-g
ER - like. feel. just different. shines. different. markedly different.
any or all of these words could be attributed to the weather, or the breakfast meal, or your fitness level.
I feel your frustration and understand it. But feelings are all we can have in this. I can say I have more times than I can to remember gone out for a 10 mile loop on one bike and then switched to another and so on and so forth. I can't give anything but subjective feelings because nothing else exists and frankly it's all that matters to me. If you are looking for hard data like 'bikes with XL top tubes are faster by 10%" I can't give that to you and I can't think of anyone else in the biz that can.
ER - that's where this started.
i have. see the above post(s). since the mid 70s i have ridden every conceivable combination, and raced them too. and i haven't said as much already, but while my 'cross career is a hobby at best, i can suffer for an hour if there's a prize list. never have i noticed the difference between the shapes and diameters of the frame parts.
I'm sorry if I didn't understand that you had built with different tube diameters and shapes. I knew you built with 1" top tubes and then switched to 1 1/8" but didn't think you worked in XL or max or tapered tubes.
ER - i've had maybe 30 RS frames through the years and the only constant was the design; the pipes, brands, and sizes/gauges varied. that's why my opinions are what they are.
I assume here you are speaking of the switch from 1" to 1 1/8" top tubes and different walls within those sizes. Do I understand correctly? I think the brands and alloys will have little to no influence over the ride and wall doesn't change it that much either. As we know diameter changes have the biggest effect. So IMO it makes sense that those bikes would feel pretty much the same to you.
I think it would be fun to have bikes in your size magically appear with a wide mix of tubes - XL, MAX, Colorado, aero......etc. It would be fun to have those all in your size to ride back to back on the same afternoon.
ER - thanks for the reply. these things you describe are visceral. that's good, too. i was hoping to hear why they felt the way they did, or why you likeed them, or what the difference was, or what makes it shine and how. i understand the math and fully acknowledge the engineering back story. my opinion includes that, while the science exists to explain what a pipe would feel like in different iterations, it's not there to quantify what happens when a set of pipes becomes another item completely. we are talking about the bicycle and its feel, rather than the properties of a pipe. i can't separate design, execution, and materials from each other. i guess shades of gray and visceral will have to be all we have to sink our teeth in for now.
Again, I, like the rest of the industry, have little in the way of hard numbers but I know what I like. Like I said above I have 3 bikes with different tube sizes and here are the highs and lows of each. I almost always use the same wheels on each bike. FWIW I'm 6'4" and 185 pounds.
Bike #1 1" top tube/ 1 1/8" down tube / 1 1/8" seat tube - Reynolds 725 main tubes and Kirk by Reynolds stays - this bike is very smooth and quiet. It's the choice for a 'day off' ride where I just want to soak up the sun. While I like the smoothness it's not as torsionally stiff as I'd like for hard charging riding and big climbing/descending. If any of the three feels the slowest this would be it by a very small margin. It has a horizontal top tube.
Bike #2 1 1/8" top/ 1 1/4" down tube/ 1 1/8" seat tube - 953 main tubes and same stays as above - The bike feels nearly as smooth as the above bike but it has better responses and jumps more when I want it to. It makes a different noise and has a different feel which seems to boil down to the torsional rigidity of the front end making the bike feel more precise...... like you can aim it better. There isn't much of a downside to this one. If I had to nit pick I'd say it's behavior on bad roads or dirt could be sharper. When going at 10/10ths it can feel a touch vague and harder to keep on line or to hold the exact line of the wheel in front of you. In short it feels like a more precise and 'better' version of the above bike. 5° sloped top tube.
Bike #3 1 1/4" top/ 1 3/8" down and 1 1/4" seat tubes - 953 front end and same stays as above two bikes. This bike's strong suit is holding a line and putting power down. It holds it's line very well on almost any surface and goes exactly where you point it. It's very stiff torsionally and feels 'all of one piece' if you will. It climbs and descends the best of the three. The downsides are that it's a bit heavier and doesn't ride as smooth as the two above. I don't find I use it if I'm going out for an hour of soft pedaling but it is the bike I seem to grab more than any other. 4° sloped top tube.
If I had to give a few word summary -
Bike #1 - a get smelling the flowers bike.
Bike #2 - the best all rounder of the three. what I would choose for a century ride.
Bike #3 - a race bike and the one I would grab if I were going racing.
All this talk of riding makes me want to get out on the bike before the afternoon winds kick in. Have a great weekend and enjoy the spring.
Dave
Quote:
Originally Posted by GrantM
I'd have to go into the way-back machine and look it up but I feel pretty safe in saying the top tube is .8/.5 and the down tube is .7/.4 . The fork blades should be 1.1/.8 .
I hope that helps with the data points.
dave
thanks. that's what i was saying. but, yeah - the frames have also included conical main tubes going back to the mid 90s. i've had columbus air frames, i haven't had full on max or MS frames. i've done the 531, the 653, the 531SL, the 725, the 525, the columbus SL, SP, SLX, KL,, EL OS, LIFE, normal EL, and all the iterations that have followed. i spent 6-7 years using all sorts of true temper cromo. and then there's the deda zero, and deda zero uno, and somewhere in the middle i tried a few SEX attempts too. i vow to continue until at least i feel something. the shades of gray thing is painful. i wanna get to the other side.Quote:
Originally Posted by Dave Kirk
A stiff frame is not faster in the majority of cases.
A flexy frame does not raise one's anaerobic threshold. Sorry Jan, it is not true.
Hundreds and hundreds of riders giving feed back is telling many frame builders that designing a frame with the rigidity to suit the rider size and weight is a good thing. They like it riding them. ( Dave Kirk's post)
I do not believe you go faster until the grunt on the pedals gets to significant levels.
Some A.I.S track testing has shown that this is measurable.
If you putter putter on the pedals it all does not matter if you are 90kg and pedal like a daddy long legs spider and corner like you are on tricycle.
I reckon Richie is fine on OS or Std. They will both be rigid enough for him for his size and weight and horsepower.
But any velocity changes cannot be measured.
read below
I wrote this some where else
yes
and the tests and the science shows that flexy frames do not soak up energy more than stiff frames
they do not heat up dissipating energy, this is a huge myth
but the rigid frame will handle and track better
giving confidence to the rider
thus it feels nice to ride!
but importantly the front wheel and the back wheel stay in better plane/alignment if the frame is rigid under high wattage stress
(Stress = the force, Strain = the deflection)
so rolling resistance of the wheels/tyres is lower as the wheels track better.
If the frame bends a lot the wheels are not in the same plane
and rider counter steers the bike with each pedal stroke
This is what riders call responsive when there is less input to direction/handle bars to the pulse on the pedals.
it feels like the bike jumps to the pedal stroke.
An Extreme example is the kilo rider, when they start they generate over 2,500 watts for a few seconds
and the frame distorts huge amounts, but the wattage drops as the pedal rpm increases but it is still WOW. Still over 1000 watts.
1000 + watts on a frame that is as rigid as over cooked pasta (pasta just like how the French cook pasta )
is terrible.
For a road frame we have to ride for many kilometers for a long time
so harshness must be reduced
All road frames are a compromise of rigidity for good feel and responsiveness with flex for comfort
a good builder designs the frame to find this balance for the particular individual rider
I know steel is the best for this
weight is less important
but the market just sells weight as the most valuable item
Rigidity is about the feel
The correct amount for the rider's size and weight
makes the frame feel nice
In reality not faster, but they rider thinks it is because they like the feel.
Until you do extremes of bike to rider matches then they are all have the same resistance and power transfer
I hate that crap about power transfer. 99% of the time is total bull shit.
I also wrote this some where else
it was a reply about the feel of frame with regards to performance
If we put 300 grams of material in the frame
that extra material will change the way the frame feels.
for example if I make one frame with .7 /.5/.7 mm tubes
and the same frame geomeery and dimensions with tubes .8/.5/.8
then yes the frames will feel different to the rider
It is the extra material, not the extra weight that changes the feeling that the rider is feeling in the frame.
The extra material mass used correctly such as in the frame tubes is a good thing.
The extra weight (Mass) in theory will have effects when changing velocity or working against gravity. In real tests it is never possible to reproduce as the rider's power fluctuates in the tests. And even with SRM measuring data (I was fitting and maintaining the SRM equipment at the Australian Institute of Sport) we can not find the weight against power inputs measurable. In theory it must be there.
With a 75 kg rider and 7kg bicycle = 83 kg then .3kg is not much.
On one climb the rider may perspire .5 to 1.5 kg of water
then air temperature has effects on drag when testing
oh it goes on and on all the problems of detecting 300 grams when riding.
On a calculator it is possible
Out side when riding up mountains science cannot measure as there is so many influences to the measurements. The rider may feel there is a difference, but actual velocity changes is not able to be detected against the input of power. (unless the extra weight approaches 3 to 5kgs, then it shows in the data measurements)
Hookes's law of Springs
Hooke's law - Wikipedia, the free encyclopedia
The same energy is stored in the strain (flex) of the stiff frame tube
as
in the strain (flex) of less stiff tube.
That energy still goes back into the chain as the frame tube returns to normal when the pulse of the pedal stroke reduces at 12 o'clock-6 0.clock
Some say that a flexible frame feels better to pedal on because of this.
I am not sure of this. I like the bike to track smoothly and with out wiggle.
I believe that very flexible frames behave badly when climbing and descending hard in rough corners. (also the fork is very important )
The extra 300 grams is better for performance.
The beautiful part of bespoke custom bicycles, in any material is that a good skilled and careful builder will take appreciation of the rider's circumstances and build a bike to meet the criteria.
There is a limit.
A frame as stiff as Granite is not going to be faster.
Thanks everyone for this discussion - as a hobbyist builder, this is one of the areas that has been most vexing to me as I learn to build... how to select appropriate tube sizes for riders and intended purpose. I am 6'7" tall and weigh 200lbs, and I use myself as the test mule for all my bikes (I don't plan to sell a frame until around #30 or so...). My most recent build was a cross frame based off Dazza's slant 6 lugs. Since I am big and tend to ride my cross big like I am on a downhill mtn course, I felt the larger tubes would be appropriate... so far so good.
Here's my question for Dave - in looking at your three different bikes, how much of the difference in feel is a result of frame design (horizontal vs slanted top tube) vs tubing selection?
The reason I ask is that intuitively I think that a slanting top tube will help stiffen the bike since I am reducing the length of the seat tube, etc... but there are alot of variables to this other than tube selection - in the case of my cross frame, I am using a Thomson seat post in 30.9 size, definitely a stiffer seat post. So as I type this question, the reality of RS's earlier post about what happens when you take a set of tubes and combine them into a completed frame is sinking in... and I have to question the influence of part selection as well.
Again, thanks for this discussion - great food for thought.
Jonathan
Quote:
Originally Posted by Dave Kirk
Thank you everyone for the wonderful thread. Rider weight to me personally determines what butt profiles and tube sets get selected. I've up till this point built with trad. and oversize, never double OS. Thanks for the spirited discussion.
My personal steed is Traditional SL,1" HT, Fastback cluster, Flattop crown oval 1.0 wall blades. I'm 5'9 160lbs. It inspires very fast corner entry and holds the line well on spirited group rides. Looking forward to getting it out in the crits when I come up for air. My butt meter tells me the fastback cluster makes for a much more stiff rear triangle.
Thanks again.. now I'm going out on a ride!
I see it's your first post - cool - welcome to Vsalon.Quote:
Originally Posted by JuanGrande
Thanks for the question. I feel like I'm going to disappoint but to be blunt I have no idea how much comes from the tubes and how much comes from the orientation of those tubes. I could guess.........I'd guess that the tubes themselves have more effect than the slope (or lack thereof) of the top tube but without measuring it I can't say how much stiffness credit should be given to the tubes or the slope. It's pretty damn easy to measure if you have tow frames that are the same geometry but the tubes are different.
This has been a good thread and I feel like I've learned something so that makes it a good deal to me.
Dave
Tubing is like handlebar width, crank length or stem length.
Small people get smaller dimensions, Larger riders get larger dimensions.
Hope that helps.
Now please explain to me why we need 31.8mm H-Bars.
Fuck, they are stiff.
- Garro.
I go this one. Because they don't fit into 26.0 stems without alot of sanding. [blink blink]Quote:
Originally Posted by steve garro
so they can meet stupid CEN impact standards and not weigh a ton.Quote:
Originally Posted by steve garro
and 35mm bars for whom too much is never enough.
dear uncle rich, maybe you ride/race too much cross. i suspect the wide plus low pressure tires, and loose ground muddled your perception about the difference. i bet skinny high pressure tires, long climbs, long twisty descends and >1 hour rides would help you get out of the shades:blink1:Quote:
Originally Posted by e-RICHIE