Medium weight rider + double oversize tubes + comfortable geometry = ?

[txsimple]

I hope this is the right place to ask this. I really like the look of double oversize steel tubes. I weigh 165 lbs and the roads around here are *horrible* chip and seal (think gravel, except stuck to the roadway). I really want a comfortable bike and am willing to have a comfortable geometry (longer chainstay and wheelbase) and am willing to run 28c tires. Would it be a mistake to have a frame built up with very large diameter tubes? Would it be too stiff and jarring to be comfortable? Thanks for any feedback!

TX

[Bobqzz]

The tube size will make 0 difference in vertical compliance

[Dallas Tex]

@TXsimple. Nearly all my bikes are double OS. Folks of all weights ride them comfortably on Texas chip seal. Your builder can design in as much comfort or stiffness as you need. gt

[Lionel]

Ask the builder his opinion. OOS is stiffer than OS everything else being equal.

[suhacycles]

FWIW, I'm 140 and ride a frame with 31.8 tubes throughout the whole main triangle and round, 420mm chainstays. Stiff and smooth, feels great.

[Andrew R Stewart]

I've always felt that on buzzy chip n seal the tires had far more effect on ride feel then the frame does. Maybe the fork is second but the frame is pretty well triangulated for much vertical shock absorption to happen. Andy.

[Dallas Tex]

Ask the builder his opinion. OOS is stiffer than OS everything else being equal.

Everything else is never equal.... ;)

[txsimple]

Thanks for all the replies so far. I am thinking of working with a frame builder who has only 1-2 years of experience, so I wanted to solicit other opinions. The replies so far are very useful. I would be eager to hear any additional ones. Thanks!

[Amaro Bikes]

I really like the look of double oversize steel tubes....
....willing to run 28c tires...

to me, you've the answer yourself ;)

It will be perfectly ok, as using longer chainstays together with the 28c tyres will give as much confort as you might wish on bad roads, and then the OS main triangle tubes will not only give you good performance but also will be the ones making you look to your bike with desire (a must for a long term relationship!)

[fpavao]

The tube size will make 0 difference in vertical compliance

Really. Zero zero? Why not make all bikes oversized then?

[Bobqzz]

Really. Zero zero? Why not make all bikes oversized then?

Weight? Aerodynamics? Stiffness in other dimensions? The vertical compliance of a conventional diamond frame bicycle for all intents and purpose=0. Damon Rinard conducted the tests showing show many years ago now. IIRC- average compliance of the frames was less than .030". Now think about how that compares to the compliance of the tires, the seat rails, the seat padding, yours shorts padding, and your ass.

[fpavao]

Weight? Aerodynamics? Stiffness in other dimensions? The vertical compliance of a conventional diamond frame bicycle for all intents and purpose=0. Damon Rinard conducted the tests showing show many years ago now. IIRC- average compliance of the frames was less than .030". Now think about how that compares to the compliance of the tires, the seat rails, the seat padding, yours shorts padding, and your ass.

How about wall thickness? I'm not sure as I've never compared directly two frames with the same geometry, but I still have the idea that the bike will feel different with diferent diameter tubing, including comfort related. Maybe vertical compliance wasn't the term I was looking for...

[Andrew R Stewart]

How about wall thickness? I'm not sure as I've never compared directly two frames with the same geometry, but I still have the idea that the bike will feel different with diferent diameter tubing, including comfort related. Maybe vertical compliance wasn't the term I was looking for...

Bingo! The discriptive attempts of what we feel when riding are so wide ranging... Very few people really have a grasp on how to discribe what they feel and then to take the next step and attribute that feeling to a certain frame spec... Bike riding is never a double blind experience. Andy.

[Dallas Tex]

..................Now think about how that compares to the compliance of the tires, the seat rails, the seat padding, yours shorts padding, and your ass.

^^^^^^ this is the right answer.


also, wheels/spokes, tire pressure, handlebars, stem, seatpost, etc.

[txsimple]

Again, thanks for all the replies. One more related question given the comments about the tube diameter mattering less. Is there really a noticeable difference in comfort between a 27.2 seatpost and a 31.6 seatpost? I have only ridden on 27.2s my whole life. It seems like a 27.2 seatpost would look weird with a very large diameter seat tube, is that right?

[Z3c]

[QUOTE=Andrew R Stewart;506133]I've always felt that on buzzy chip n seal the tires had far more effect on ride feel then the frame does.

I think this holds true in all conditions esp. if you factor in tire air pressure.

[shiggy]

[QUOTE=Z3c;507203]

I've always felt that on buzzy chip n seal the tires had far more effect on ride feel then the frame does.

I think this holds true in all conditions esp. if you factor in tire air pressure.

You have to factor in tire pressure. Does not matter how big the tire is if it is inflated to the same pressure as a smaller cross section tire.

High volume tires have a smoother ride (and more grip) because they let you run lower pressures, and only if you use lower pressure.

[Dornbox]

When I lived in Austin Spinergy wheels were a God sent. 25 Mich Pros or 27 tubies or 28s with 90 psi are where your comfort is at, esp on chippy.

If your ST is a 31.8, a 27.2 post is great. That is pretty much 99% of what I build for both my brand and my contract brands. The difference in marginal. Jump up to a 34.9 ST and then you've got the proverbial Orange on a toothpick.

OOOOOOS tubes rock ATMO 42mm DTs are the new black in my shop.

[suhacycles]

Vertical compliance differences may be nil when comparing OS to OOS but I don't think you can say the same when it comes to torsion with out of saddle efforts or leaning into a not so smooth turn.

[Bobqzz]

Vertical compliance differences may be nil when comparing OS to OOS but I don't think you can say the same when it comes to torsion with out of saddle efforts or leaning into a not so smooth turn.

1. Yes
2. Unlikely