Jsiegs

I tried searching - couldn't find much. Sorry if this is an often asked question.

I'm looking to get a cyclocross bike on the cheap (i.e. used) and thus don't want to waste a shops time asking fit questions and trying out stuff since I don't intend to buy there. I figure I can get into the ballpark based on my road bike size/geometry. What I'm not really sure is the cross riding position (I'm a noob to cross, looking to get started).

I currently ride a Cervelo S2, 56cm bike with a stack of 560mm and reach of 394 mm (i'm 6-1 for reference). It's very aggressive with a lot of drop for me, with a few spacers and a 110 stem. I also ride an older Bianchi steel frame in 57 (stack and reach unknown) with a 110.

I'm looking at a Specialized Tri cross in 58 that is stack of 611.7mm and reach 382mm. So it's 5 cm taller (though I use spacers on the Cervelo) and about 1 cm shorter. Should that be in the ballpark of the right size/position for me? Obviously, there is adjustability in stem length/angle and spacers.

Thanks.

Sawtooth

Although many chose to go down a size, both of my crossers are 54, just like my Tarmac. Although I do race occaisionally, I use them for a lot of things other than cross racing so I like my fit to be perhaps a bit more stretched out than your average cross racer. I tend to like my top tubes on my cross bikes to be about the same length as my road bikes. My crossers even feel a bit larger than my road bike but I am fine with that.

Barrettscv 

I would use reach as your best guide. I'm 6'0" and ride a 60cm size.

Sawtooth

Update, I just completed my 14 mile commute in to work on my JTS. I noticed that the reach on the JTS feels significantly shorter than it does on my Major Jake. The only real difference is in the handle bar. I am running an FSA pro-wing compact on my JTS and a Ritchey WCS ergo on my Major Jake. The reach to the hoods and in the drops is SIGNIFICANTLY greater with the Ritchey ergo bar. I say this because it is something to consider...even with a relatively limited frame (as long as it is within a decent range of fit), you have a lot of sizing variables for adjustment with components as well.

mahijiru

I'll go the opposite of conventional wisdom: my roadie is smaller than my CX.

I bought my 57cm CX (Felt F1X) w/o having much of a clue about what size I was. Picked up a 56/54cm (top tube/seat tube) Cannondale R800 for a quick road bike.

Both work. Since the road bike is smaller, it feels even quicker to handle. I put a short (85mm) stem on the CX and it feels fine.

I ride almost exclusively on the tops, not on the hoods or drops. Cross-top brake levers essential for riding in traffic (Seattle). I even put 'em on the roadie.

fietsbob

you building a Cross race bike or just a commuter on a cross bike platform?

Jsiegs

I plan to race.

simonaway427

For reference, I'm 6'0 - I ride a 56cm S1 (same geometry as your s2) with a 110 stem. I ride a 57cm Felt F75x with a 90mm stem. The reach (measured) is identical they way they are set up, but the cross bike definitely feels bigger. In retrospect, I would have been better off with a 55cm cross bike.

Tricross tends to fit big in my opinion. My first bike was a 58cm Tricross and it was way too big for me. The long chain stays make it feel even more sluggish compared to the bikes I own now. If you're looking at getting into racing, I'd looking into something a little more aggressive than Tricross.

fietsbob

Simon Burney, UK Coach to the young Pros, whose Books on the subject of cyclocross,
are in their 3rd edition,
says take off a CM from seat tube length and reach. to the bars..

Abu Jack

I bought a Motobecane Fantom Cross last year in the same size as my speciaized roubaix. It fit fine. I'm very happy with the fit.https://www.bikesdirect.com/products/...ross_ti_xi.htm