Cyclocross v. Road Fitting: Has the traditional wisdom gone by the wayside?

[caleb]

The traditional wisdom (as I've inherited it), is that a cyclocross bike should be one size smaller than a rider's road bike. I think the idea was that the lower top tube on the smaller bike compensate for the taller tires on a cross bike to maintain standover height. Also, I think it had something to do with a shorter bike handling better.

Perhaps this wisdom made sense when everyone was riding big bikes with level top tubes on the road, but now they're not. Most guys are racing as small of a frame as possible on the road and using a long stem to compensate for the lack of top tube length. I'm a case in point: my current road bike has a 53cm top tube and a 140mm stem. A larger frame would put my bars too high. Standover is a non-issue.

The pro road peloton definitely seems like they're on some pretty small bikes with long stems, too.







Lots of small frames and long stems.

On the other hand (and counterintuitively), top 'cross riders actually seem to be riding bigger frames than their roadie counterparts. When I say that they're riding "bigger" frames I mean that they're riding less stem and seatpost, and that the frame accounts for a larger portion of the bike.

Some examples from the 2007 World Cup:





I'm sure there are exceptions, but it seems that there are far fewer 140-160mm stems being run in 'cross.

Maybe cross racers prefer a shorter reach.

Or, maybe the traditional wisdom of downsizing one's cross frame has been inverted so that cross frames are actually larger than road frames.

Your thoughts?

[Too Tall]

I use 1 cm shorter TT and let the builder decide what I should ride. No really, that's what I did!!!! Keep in mind that your racing position will be from the drops so plan accordingly.

[caleb]

Too Tall,

Does the 1cm shorter top tube shorten your reach, or do you run your stem 1cm longer to compensate?

[Mr.President]

I asked a similar question here on the differences between road and cross. I cannot find where it is, but e-richie sent me here to find some answers. don't know if it will help you also.

[Sasha]

I'm going to start working on my 'cross position for this year in the coming weeks, so any resources are welcome. Here's an interesting post from molly cameron about 'cross fit.

http://www.mollycameron.com/2008/06/...e-of-bike-fit/

[dbohemian]

Most guys are racing as small of a frame as possible on the road and using a long stem to compensate for the lack of top tube length. I'm a case in point: my current road bike has a 53cm top tube and a 140mm stem. A larger frame would put my bars too high. Standover is a non-issue.

The pro road peloton definitely seems like they're on some pretty small bikes with long stems, too.

Your thoughts?

For what they are worth....-.02c... Some of the pro peloton have ill-fitting frames. We all know the reason. They ride what they are paid to ride and have to make due with modifications like crazy long stems.

You answered your own question without really knowing it. That is that handlebar offset is extremely important (the height between the seat and handlebar drop). When designing a custom frame this can easily be addressed while keeping the overall reach the same and not resorting to very long or very short stems which affect the feel of the bicycle. (I.e a very long stem will make a bike fell like it steers slower because of the larger moment between the handlebar and the fork steerer)

There is lots of good stuff about cyclocross sizing as has been mentioned with the link from eRichie, but generally the increase in tire size increases the standover and one wants to sit up a little more than on a pure road bike to be better able to handle the terrain (better weight distribution) so when designing the frame is technically sometimes a small size, but has a similar standover and less offset between the bars and the seat.

There are instances that long stems are warranted. For instance when a person has extremely long arms and that would cause the top tube to grown in length to the point that it would undermine handling but I consider very long stems on average sized bikes to be less than an ideal solution to the problem of plopping everyone on 3-5 sizes.

All the best,

[Too Tall]

Caleb, infact the stem is same length as my road race bike 140 the 1 cm shorter TT and a taller headtube gets the bar drops exactly where I want them for cross...it's GENIUS I tell yah :)

[agilismerlin]

my boss/owner came in today, late, after putting her dog down. Besides being glum, she got a notice from one of her dealers, on a smoking deal = alum. cross frame/fork/headset/seatpost - i could not pass up. It made her day i said "yes. We had been going back and forth over this conundrum since April, on all diff options........................and she was way past, hearing me back down week after week looking.

psyched.....................

52cm when i usually ride 54 tt's



the price

[Too Tall]

Nice Agillis, Camels or Marlboro's?

[jsf]

I thought the slightly smaller size of a cross relative to a road bike had to do with a higher BB. The higher BB compensated for stuff one might hit on the ground with your pedals. Anyway my 54 st cross has the same standover height as my 56 road (coincidently).
Right?
-Jon

[agilismerlin]

masi = chiawanese

the price


when i am drunk enough camel lights............couple times of year...............just the way i roll.............. :)

[Catulle]

That I can recall, cyclists have preferred smaller frames since the times of Coppi, and probably earlier. Back then the weight issue was more critical than it is now as materials were heavier. I've learned to let go of that idea only in my old age.

Regarding cross, I ain't got the slightest idea.

[agilismerlin]

catulle,

neither do i :cheers:

[ghsmith54]

For what they are worth....-.02c... Some of the pro peloton have ill-fitting frames. We all know the reason. They ride what they are paid to ride and have to make due with modifications like crazy long stems.

Not sayin' you're wrong, but I'm curious about this.

As near as I can tell, the average protour rider is just that - average - with respect to body type. Sure, they're skinny as all get out but there aren't a whole lot of short torsos, super long legs with short arms or other weirdo body types in the pro peloton.

If that's the case, why would they need whacked out stems to get an off the shelf bike to fit?

[dbohemian]

you are absolutely correct. Most of those guys fall into the bell curve and they do fit quite well on the stock frames that are offered them.

Even though that is the case, individuals have different morphology, flexibility and different riding styles. (i.e. some like only to use the tops of the bars some like the drops)

The bikes themselves are fairly similar but often differ amongst brands with top tube length, seat angles and the like and this could cause a difference that may mean a rider has to use a long or short stem on one brand when a previous brand was just right for them.

I will say too that many non-pro riders do not really IMHO have the flexibility to reach some of the extreme positions they emulate from pros. A case where frames have gotten too small for some.

[jerk]

whatever...most cyclocross guys who are any good are belgian....belgians set up their road and cross bikes like belgians....the front ends are higher and there's more setback designed into the frame to compensate. has to do with their morphology...they tend to be broader shouldered and bigger framed than their italian compatriots; who in turn tend to run their road bikes with more drop and longer stems....but i know shit about cross. myerspace jazzy for the real scoop.

as for that one italian guy who races cyclo-cross; i think he's currently undergoing a uci mandanted drug suspension and currently on the verge of elimination on the italian version of the tv program "american idol"....called "saccheto del doccia vaginale che cantano come merde"...so i've no clue what his bike looks like; but if he don't beat that pornostar/member of parliment he's up against i'm boycotting the program next season.

jerk

[e-RICHIE]

called "saccheto del doccia vaginale"...

jerk

please go to the penalty boxmo.

[jerk]

please go to the penalty boxmo.

come on. that's some of my finest work.

[e-RICHIE]

come on. that's some of my finest work.

sorry
'still in PEI in a ghetto called murray's harbor.
cannot think straight atmo.

later.

[davids]

sorry
'still in PEI in a ghetto called murray's harbor.
cannot think straight atmo.

later.

No one can think straight in Canada. Why do you think they call them the Maritime Provinces?