TruF 

I read in this forum recently that some classic and vintage bikes that are really, really nice in larger sizes may not be as nice in smaller sizes. I want to start looking for a nice old road bike in a 51. Advice or suggestions? Thanks in advance for your two cents!

RobbieTunes

There's a 51cm Centurion Lemans in the For Trade section, I think. He's looking for a rare bike he likely won't find, but he may want to sell the Lemans RS.

I think there are just fewer of them, that's all.

wrk101

+1 They are every bit as nice.

The problem is they are rare/extremely hard to find. I have only found four decent small road bikes in the last year. All were OK bikes, but lower end bikes (cromoly Schwinn World Sport was one).

If you can find a higher end vintage bike in a small size, buy it, pay full market OR HIGHER if you have to, as you are not likely to find another one anytime soon. And if you do happen to get lucky and find more than one, then they are very easy to sell.

Almost everything I find is either a 21 inch, 23 inch or 24 inch frame. Anything larger or smaller is scarce. Small ones sell quick, big ones (larger than 24 inch) take a while.

TruF 

Thanks, RobbieTunes! I see you're a fan of the Centurions. I found the post and also see that you've already PM'd the poster. I'm in no hurry and just starting my research, but if you don't mind, I'll PM him(?) too.

TruF 

Thanks, wrk101! Appreciate the advice.

Picchio Special

It's not just about availability. It's also about geometry - some manufacturers significantly altered their geometry in smaller sizes, in particular to avoid toe-clip overlap. Toe-clip overlap is a bete noir to folks who know little or nothing about racing bike handling. Some builders compromised the handling in smaller sizes; some didn't.

TruF 

Ahh! So are you saying that novices freak about toe-clip overlap because they don't know about counter steering? And that this concern when they test ride a bike drives the manufacturers to make the frame too long (??) to avoid losing sales? (Excuse my noob-ness...)

TejanoTrackie 

I don't think it has anything to do with countersteering, but toe to front wheel overlap when making sharp turns at very slow speeds. What manufacturers of small frames often do is make the head tube angle smaller to bring the front wheel forward while making the seat tube angle greater to bring the cranks back, thus increasing the distance between the cranks and front wheel. This also shortens the top tube, such that a short person does not require a super short stem. This is really not an issue on a touring bike, however, it matters on a racing bike because it makes the bike steer more slowly.

Road Fan

TruF, what the range of sizes or characteristics that will work for you?

Picchio Special

In addition to the good information provided already, I'll add that some builders that provided a full range of seat tube sizes used a much more limited range of top tube sizes. It almost seemed as if they used the same top tube length regardless of the size of the bike. Some older Raleighs show this characteristic, if I recall correctly. Smaller riders without long torsos would not find a good fit. This tendency seems to have become less prevalent by the 80's as proportional geometry was widely adopted. So it depends on the era of the bike to some extent whether or not this is a potential issue.

Road Fan

TruF, I have a 51 cm c-c US Masi, that has considerable toe overlap. It doesn't bother me particularly. It also has fantastic handling, with nearly the same front end geometry as frames 56 cm and up. I believe Masi built this as a custom for a woman who wanted a great racing bike. It seems to differ from stock small Masis. Brian Bayless, one of the great modern framebuilders trained at Masi, has complained in print how many small Masis do not handle well, because of the compromises required to eliminate overlap. Mine has the tradeoff the other way.

I also have a Mondonico, similar size but different geometrically, that has radically different front geometry. Its handling is very acceptable IMO, but its also very different from this Masi. It has no overlap.

Basically the change is to move the front wheel out away from the bottom bracket. This is done using two adjustments, once the seat tube angle is set. Lengthen the top tube, and slacken (less vertical) the head tube angle. The most key dimension in the front end is trail, which depends on angle and on fork offset aka rake. If the angle is slackened, the rake is increased to get the same trail, so frame designers go for that. But other keys to comfort and handling, like weight distrubution between the tires and of the rider on the bike can be compromised. Terry Cycles used small wheels for small womens' bikes to resolve these conflicts.

noglider 

Right, toe overlap is not that hard to deal with, but the makers avoid it anyway, which is a shame, though it's also understandable.

TruF 

Thanks everybody. Still gathering information before taking another plunge. This is very helpful.

Road Fan, I ride a Ruby Specialized in a 51. Fits me like a glove. Hard to translate the geometry of that bike to a classic ride because it has "compact" geometry. (And I'm not even sure what that means!) I had a computerized bike fitting done before getting my Ruby, and it suggests a 513 c-c seat tube and 521 c-c top tube. (I'm long-limbed with a short torso...)

cyclotoine

Hey TruF, I have a 51cm GIOS professional from the early to mid 1980s... it's a beautiful machine but my girlfriend has no interest in road riding so I've decided to part with it. I can sell the frame set or the complete bike with a very very excellent condition first generation chorus group... Let me know if you are interested and I can provide more details.

Road Fan

Several measurements could be used to build a comparison. The overall criteria in matching up the frames are BB height (or, given the same wheel size, BB drop), height of the top of the headtube above ground, and top tube effective length (distance from top of head tube to the axis of the seat tube, measured parallel to the ground plane).

I don't know if you're interested in a classic Masi, but mine might be your size and is on offer. We can talk more on PM or email if you like. Same for my Mondonico.

The Masi grew up in SoCal, and would be happier to live in the warm weather of his youth.