Likes Likes:  0
Page 2 of 4 FirstFirst 1234 LastLast
Results 21 to 40 of 66

Thread: How does stem length and bar reach effect handling when total reach is held constant?

  1. #21
    Join Date
    May 2008
    Location
    Better to be ruined than to be silent atmo.
    Posts
    18,231
    Post Thanks / Like

    Default

    okay - settled atmo.
    what else hurts?

    ps rename her isisn't.








    Quote Originally Posted by Triskeliongirl View Post
    Thanks, that's my gut feeling too. The set up I have on Isis is just fine for my commute, so I need to be glad for that. As I said, this bike is just one of those 'mistakes', and while its hard to admit a $2000 mistake, throwing more money at it isn't gonna fix it.

    Basically, buying Rhea was the best thing I could have done. In defense of Georgena, at least she made the first bike with brake levers I could reach, and enabled me to ride. Yeh, now I know there are better ways to build a small framed bike. Heck, even Georgena builds bikes w 650c wheels now, and that's the irony of my mistake. If I just bought Isis in the next larger size she did have 650c wheels, but I was afraid I couldn't get set up on the 74 degree STA that all her 650c wheeled bikes are spec'd with (combination of long femurs and short rails on my brooks finesse, so its struggle for me even with a 73 degree STA). The guy who fit me on my Cervelo (Matt at Bicycle Heaven) did it with the Look ergo post 2, a $200 post he threw in to make the sale. Too bad the boys at Harris Cyclery that sold me Isis didn't give me better advice.

    I always thought I had bad bike handling skills, but now I realize I just had badly handling bikes.
    0
     

  2. #22
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    Quote Originally Posted by swoop View Post
    I think 'up stem' might mean a lot of the lentgh is going to elevating the bars? Stephen wonders as well.
    Yes, by up I meant +, sorry, I should have written +17 degrees (I said up since the stem can be mounted in either orientation). According to the stem chart at habanero cycles, my 11 cm +17 degree stem has a horzontel reach of 10.5 cm. The 13 cm +17 degree stem should have a reach of 12.4. That is how I did all my calculations.

    And that is the problem with the bike. I ride with my bars just slightly lower than my saddle (2 cm). The cervelo, with sloping top tube and the tall head tube is designed for that, but the terry has a horizontel top tube, so I have to jack the bars up a lot with a highly angled stem to get my bars the right height.

    But the problem is more than that. I also have a 48 cm terry (I've been discussing my 44 cm). And that handles poorly too compared to the cervelo. If I run the numbers through the trail calculator that is the biggest different. Trail is just too small on the terrys.
     
    0
     

  3. #23
    Join Date
    Jun 2008
    Posts
    1,861
    Post Thanks / Like

    Default

    Quote Originally Posted by Triskeliongirl View Post
    But the problem is more than that. I also have a 48 cm terry (I've been discussing my 44 cm). And that handles poorly too compared to the cervelo. If I run the numbers through the trail calculator that is the biggest different. Trail is just too small on the terrys.
    One of the nice things about the RS is that Cervelo worked on improving the handling of the smaller sizes. Longer front centre, decent trail. I owned a Cervelo Soloist in a 51cm and it had a ludicrously tight front centre, overlapping a third of my shoe. Not the case with a Cervelo RS in 51cm when I test rode that.

    Unless you're putting a heavy load on the front (big handlebar bag, or a front rack with panniers), a decent amount of trail is key to have nice handling. The last couple of custom bikes (no front load), I asked for a trail around 5.7cm to 6.2cm range. That is, just a hair on the stable side of neutral at speed. I find that yields a nice handling bike for me.

    On the other hand, I had a stock Colnago Master X-Light which had a trail of 6.89cm. Too much of a good thing. That was overly stable to the point where I had to be really deliberate in guiding the bike.
     
    0
     

  4. #24
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    I hear you. I know much more than I really care to about all of this in my quest for a decently handling 48 cm bike. The trail on Gerogena's are too small, don't remember exact numbers but pretty close to 5, so the steering is too quick, especially on fast descents. At the other extreme, I test rode a 50 cm trek madonne that handled like a mach truck, so stable it could barely turn. Here they tried to push the fork too far out to avoid TCO. I like cervelos approach, accept TCO and buy an R3, or don't accept it and buy an RS, but whichever way you go, you can count on the bike handling well. That's what blows me away about my RS. I never knew a bike could be BOTH stable and responsive. By that I mean, it does what I ask it to do, it accelerates well, power transmission is just amazing, it turns if I ask it to turn, etc., but on a fast descent its stable as a rock.

    Its funny, I could tell from the geometry chart how she would ride, but when she was first introduced I couldn't justify dropping that much cash on a new bike after my 2,000 'mistake', and I am putting 2 kids through college. But, my LBS ran a 2008 closeout to get rid of one of those 'awful bikes with 650c wheels' so I took her off their hands for a deep discount. I also loved the shop. First of all, when I went in, the owner didn't hesitate to install my custom crank set for the test ride. THe mechanic looked at him strange, and he said, its the only way she can evaluate the bike. He put my saddle on too, and even tweaked the fit to match isis.

    Then he sent me out the door on a real ride with a real climb. THe bike sold itself. I don't know why more shops don't do this. By the time I was back she was mine, I even cried on the test ride, and had to pull over and call my husband and tell him how she felt. Back at the shop he further tweaked the fit, making a recommendation for some subtle changes in position and a bar change. He didn't mess around with my saddle height, or set back, since that was all set by Tom when he built my crank set. But, he recommended the compact bar, and brought my reach in a tad. I also thought I should ride as stretched out as possible, its more aero, but he said my elbows were too locked, and wanted them a little more bent. He said if I was more comfortable I'd ride better, and he was right. I have never felt more powerful on a bike. My average speed instantly went up 2 mph, which is quite remarkable. I really had hit a wall, in that I lost all my excess body weight, but was still getting dropped on climbs by gals on feather light carbon bikes. Now I am dropping those same girls that were dropping me. I never thought the bike could make that much difference, since I don't race.
     
    0
     

  5. #25
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    Can you explain how a handlebar bag stabilizes a bike with too small a trail? I noticed this, and in fact prefer to do this on my commuter (isis) because I've noticed she feels more stable, but don't know why, and perhaps its why I don't mind her as a commuter.

    Also can you explain what you mean about the longer front centre, how does this value effect handling?

    Quote Originally Posted by fixednwinter View Post
    One of the nice things about the RS is that Cervelo worked on improving the handling of the smaller sizes. Longer front centre, decent trail. I owned a Cervelo Soloist in a 51cm and it had a ludicrously tight front centre, overlapping a third of my shoe. Not the case with a Cervelo RS in 51cm when I test rode that.

    Unless you're putting a heavy load on the front (big handlebar bag, or a front rack with panniers), a decent amount of trail is key to have nice handling. The last couple of custom bikes (no front load), I asked for a trail around 5.7cm to 6.2cm range. That is, just a hair on the stable side of neutral at speed. I find that yields a nice handling bike for me.

    On the other hand, I had a stock Colnago Master X-Light which had a trail of 6.89cm. Too much of a good thing. That was overly stable to the point where I had to be really deliberate in guiding the bike.
     
    0
     

  6. #26
    Join Date
    Jun 2008
    Location
    dirtphalt
    Posts
    1,019
    Post Thanks / Like

    Default

    BigMac come in, BigMac come in
     
    0
     

  7. #27
    Join Date
    Jun 2008
    Location
    South of No North
    Posts
    4,652
    Post Thanks / Like

    Default

    Quote Originally Posted by Triskeliongirl View Post
    ...

    Also can you explain what you mean about the longer front centre, how does this value effect handling?
    There is a lot out there on the topic and perhaps others here can point to more detailed/better descriptions, but this is a pretty concise description imo:

    http://www.calfeedesign.com/frontendterms.htm
     
    0
     

  8. #28
    Join Date
    Jun 2008
    Posts
    1,861
    Post Thanks / Like

    Default

    Quote Originally Posted by Triskeliongirl View Post
    Can you explain how a handlebar bag stabilizes a bike with too small a trail? I noticed this, and in fact prefer to do this on my commuter (isis) because I've noticed she feels more stable, but don't know why, and perhaps its why I don't mind her as a commuter.

    Also can you explain what you mean about the longer front centre, how does this value effect handling?
    Happycamper's link to the Calfee site is an excellent tech explanation.

    I tried to search for dbrk's superb description of the different types of bikes that he liked on the Hampsten blog, but it was from a few years ago and I couldn't find it. It included a few sentences on low trail bikes with a front load. Prof. Brooks, perhaps you can re-post here?

    I don't write as well as dbrk, but I'll try to explain what I mean by the stabilizing effect:

    As you've experienced, a low or short trail (let's call it sub-5cm) without a load is very quick, twitchy. Breath on the handlebar and you're changing direction.

    Putting a substantial front load increases the inertia. If you're going in one direction, it's a bit harder to change direction, when you increase the load. Having a short trail plus a noticeable load gives you nice handling - the load slows down the twitchy feel of the short trail.

    Two decades ago (!) I had a custom touring bike with 26" wheels made in this manner. Trail was in the 4cm range (can't remember exactly) and I always had two front panniers and a low rider rack on the fork. It handled just fine with the load, very twitchy without.

    Front Centre: Besides improving toe clearance, any increase here also helps with tracking straight. My shortest front centre currently is a stock Merckx MX Leader. It has relatively long chainstays (for a racing bike) coupled with a short front centre (the reverse of my lost Colnago). While it has a decent trail, I find the shorter front centre seems to keep the handling quick. It's not scary twitchy, but I do have to pay attention more than my Hampsten.

    My Hampsten Strada Bianca has a front centre about 1.5cm longer than the Merckx with about the same trail. While it's never a good thing to "fall asleep at the wheel" when cycling of course, the SB doesn't need me to be paying close attention to the steering. It's very stable, almost takes care of itself. FYI chainstays are also about 1.5cm longer than the Merckx.

    At the other extreme, I had a box-stock Fuji touring bike for winter riding two years ago. That thing had a ridiculously long front centre and drove like a truck! Combine it with marathon-length 44cm chainstays, it handled about as well as the Titanic.

    I don't own a Cervelo RS, but I liked its handling during test riding, more so than their stock racing geometry (Soloist or S series, R series). Longer stays, front centre is longer, headtube angles went slacker on the smaller sizes, and they spec'd different fork rakes for different sizes, which is nice on a production bike.
     
    0
     

  9. #29
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    Thank you guys. Those posts were highly informative.
     
    0
     

  10. #30
    Join Date
    Jul 2008
    Location
    Seattle area
    Posts
    1,202
    Post Thanks / Like

    Default Stem Chart

    I have found this chart to be very helpful in trying to decipher reach in stem sizing:

    http://www.habcycles.com/fitting.html
     
    0
     

  11. #31
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    Indeed, this is how I calculated the reaches I reported in this thread, and indeed it is correct when I order this way and then measure it on the bike.

    Quote Originally Posted by Gradient View Post
    I have found this chart to be very helpful in trying to decipher reach in stem sizing:

    http://www.habcycles.com/fitting.html
     
    0
     

  12. #32
    Join Date
    Jan 2009
    Location
    CA
    Posts
    1,857
    Post Thanks / Like

    Default

    Quote Originally Posted by nerdwin View Post
    While we're on the naming thing, can we stop calling them "steeds" too.
    "whip" is also terrible. it's terrible for a car as well. then again i would never call a vehicle a "ride", either.

    and a "quiver" of bicycles? that one takes the cake. gimme a break!
     
    0
     

  13. #33
    Join Date
    Jul 2008
    Location
    Seattle area
    Posts
    1,202
    Post Thanks / Like

    Default My sympathies

    Quote Originally Posted by Triskeliongirl View Post
    Indeed, this is how I calculated the reaches I reported in this thread, and indeed it is correct when I order this way and then measure it on the bike.
    At 5'7" and a 28' inseam, long torso and short arms I am probably a good candidate for a compact designed frame. I'm just to cheap and old to experiment with it. I generally just ride a "standard" 50cm/52.5cm (cc) horizontal top tube frame after experimenting with some smaller ST horizontal frames. Geometry on frames smaller than 50cm seem to be a pandora's box of compromises, and that is why those 650c (and 24") wheels start getting used. But trying to grock those frame angles to fore/aft seat and stem lengths is a PITA. I'm with Swoop, add in the lighter material mix, wheelset, wheelbase, along with the angles and the resulting trail, is just a witches brew of problems to overcome. Even Mr. Sachs alludes to his "inner fitter" which to me translates into "this is more art than science". So measurements just sometimes don't 'splain the problem.

    My sympathies also for how this thread devolved from stem length to photos of Fabio, LOL! Love this place....
     
    0
     

  14. #34
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    Even though this thread morphed a lot from the original question, in many ways it didn't. The real question in my head was what could I do to make my terry handle like my cervelo. The answer is absolutely nothing. The problem with riding in the drops on the terry isn't the bar, its a lack of stability. It freaks me out to put my hand there cuz the front end goes all wobbly on me.

    This thread also helped me understand more why my cervelo handles so much better.

    So, instead of putting any more money into the terry, I'll just keep her set up as my dedicated commuter with a handle bar bag and carradice sqr slim bag, and that way she is still wicked fun to ride to work. The noodle gives me lots of hand positions, I like that position right behind the hoods which I'd have to give up on a short reach bar, and its got lots of room for a handle bar bag.

    For the fast stuff, the cervelo still blows me away. It just spoiled me a little but there is no way in hell I am riding the cervelo to work. I had a locked bike stolen there, a bike (and me) totalled when an SUV hit me on the way in, etc. So, the cervelo lives in my living room until its the weekend or vacation.
     
    0
     

  15. #35
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    Quote Originally Posted by Gradient View Post
    Geometry on frames smaller than 50cm seem to be a pandora's box of compromises, and that is why those 650c (and 24") wheels start getting used. ...
    No kidding, which is why if anyone remembers anything from this thread its that Cervelo got it right with the 48cm RS, and that in the smaller frame sizes, 650c wheels rock!
     
    0
     

  16. #36
    Join Date
    Jun 2008
    Posts
    665
    Post Thanks / Like

    Default

    Quote Originally Posted by Triskeliongirl View Post
    No kidding, which is why if anyone remembers anything from this thread its that Cervelo got it right with the 48cm RS, and that in the smaller frame sizes, 650c wheels rock!
    Someone ask SteveP if it's OK to use an 11 with a 650 wheel :D
    Sharp as a lemon, with the zest of a knife
    0
     

  17. #37
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    Quote Originally Posted by RudAwkning View Post
    Someone ask SteveP if it's OK to use an 11 with a 650 wheel :D

    What do you mean? The stem on the cervelo with the 650 c wheel is only 9 cm and its great.

    The stem on the terry w a 24" front wheel is the one that is 11 cm. I am sure that is part of the problem, as I said before the frame is too small for me, but the trail is also too small even on next size up.
     
    0
     

  18. #38
    Join Date
    Jun 2008
    Location
    los angeles
    Posts
    635
    Post Thanks / Like

    Default

    this thread is making my stem hurt
     
    0
     

  19. #39
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default

    FYI, this is what Rhea looks like, the cervelo. I don't have a pic of the terry in her current set up.

    Since I took this pic I put a new sleeker saddle bag on, and shimmed the brake levers, but other than that, this is my current set up on the cervelo, the bike I love, w 650c wheels.
     
    0
     

  20. #40
    Join Date
    Mar 2009
    Location
    San Antonio, TX
    Posts
    331
    Post Thanks / Like

    Default Rhea

    Try the pic again.....
    Attached Images Attached Images
     
    0
     

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •