Framebuilders - Wheelbase

I was wondering if you guys had any insight to share about wheelbase, especially when it comes to larger (58-62cm TT) bikes.

I'm playing with a design in bikecad, and right now my wheelbase is around 105cm, which seems to be quite long according to what I'm reading...

It really depends on what type of riding you want to do. My Waterford with a 59cm top tube has "road-sport" geometry for stability and comfort on long distance rides and has a wheelbase of 103cm. A racing frame with steeper angles and shorter chainstays would have a shorter wheelbase.

http://i32.photobucket.com/albums/d7/k4drd/Bicycles/Waterford%20B07014/WaterfordB07014ProductionDrawingONLY.jpg

I'm aiming for the same thing. Steep angles, low BB and long chainstays for a long distance but still nimble feel. I've tried looking for more info on wheelbase here, on frameforum and velocipide. Should I focus mostly on angles, trail and the TT needed for my height and let the wheelbase just fall into place?

Right now I'm using 430mm chainstays for added comfort, as I've seen it recommended for taller folks.

Should I focus mostly on angles, trail and the TT needed for my height and let the wheelbase just fall into place?

Yes, but I wouldn't go steeper than ~73° on the STA and HTA. It'll be plenty nimble enough (yet not so twitchy you'll get tired on long rides) if you have the right trail (~55-60mm).


Right now I'm using 430mm chainstays for added comfort, as I've seen it recommended for taller folks.

That should be fine.

You might want to read Dave Moulton's blog entries on Trail, fork rake, and a little bit of history (http://davesbikeblog.squarespace.com/blog/2007/5/4/trail-fork-rake-and-a-little-bit-of-history.html) and Head angles and steering (http://davesbikeblog.squarespace.com/blog/2007/4/9/head-angles-and-steering.html).

Just as an "outlier" data point, my Eisentraut Rainbow (63cm) has a 98.5cm wheelbase. Probably the best-handling bike I've ridden in 35 years at this game, but definitely not an LD bike - more of a crit rocket. Rock solid all the way up to 50 mph tho... And I wouldn't trust a less-experienced builder to make a bike that big and that short.

SP
Bend, OR

Another thing I notice in at least some of the designs I follow, is that the wheelbase can be a fixed number across the whole size range, with the angles the same, so it's just a number for show. If you looked at those numbers you would be inclined to see really large frames as being too long when you generated real numbers.

I respect Jobst Brandt to the extent that while I may on not believe/understand everything he says, I am willing to swallow it whole when it follows what I want to hear. :) I understand that even though he is more into road geometry than I am that he is a believer in the longest rear end wheelbase possible. I tend to agree, and would wonder whether there are any real points for riders outside the top few in the world in some of the designs that are out there. But if nothing else I am willing to believe it isn't worth worrying about a few fractions of an inch, unless you have very specific needs. I don't design around a number, I just design the rest of the bike and let the wheelbase take care of itself.

Thanks for the feedback guys, I'll just let the wheelbase result from the other design decisions.

@bobbycorn: that sounds like a sick bike man, any chance for a pic and geo details?

Thanks for the feedback guys, I'll just let the wheelbase result from the other design decisions.

@bobbycorn: that sounds like a sick bike man, any chance for a pic and geo details?

No pics, unfortunately. "Kilgore" is hanging up in the garage, awaiting "reconstructive surgery", thanks to an "improper right turn" by a pickup truck driver 10 years ago.

Geometry is:
ST 62cm c-c
TT 59cm c-c
SA 72 deg
HA 74.5 deg
Rake 4.2cm
CS 40cm
Drop 6.5cm

Tubing is Albert's "secret blend", rumored to be Columbus and Ishiwata. It's an amazingly smooth ride on coarse surfaces, tho' it tends to "hobbyhorse" on big bumps (no surprise). I'm really looking forward to getting this'n back on the road!

SP
Bend, OR

ps - if you google Eisentraut Rainbow, there are pics of a few out there. Definitely enuf to show the short wb.

Thanks Bobby, hope you get it restored soon, sounds like a crazy ride!