Gravel/endurance v race frame sizing and geometry (Focus Paralane v Cervelo C3 v Look 765 content).

[feckless]

Does the sizing of gravel/endurance bikes differ much from race bikes all that much?

My current bike has a relatively compact road geo, with 490mm seat tube and 545mm top tube (plus 95mm stem), so fairly stretched out for the frame size.

When I look at the specs for most gravel/endurance bikes, the top tube lengths all seem very short for the frame size.

So the Look 765 has a 524mm TT in its small (490mm) frame size and the Focus Paralane 526mm in the 485 frame size. The Cervelo C3 is similar, with a 531mm TT for the 510 size frame.

All three manufacturers suggest that at 1.73m (5’8” for the old gits) I should be in the small frame size. Alas I haven’t been able to sit on any of these yet so I have no idea whether this is even remotely accurate.

Oddly, the Specialized guys were adamant I should be on a 54cm frame on the Roubaix (545mm TT). This did feel a bit tall for me when I sat on it, but not unmanageably so.

I know the “right” answer is to try all four and get properly fitted, and that I surely will do. But at this point I’m just trying to work out whether I should be reading the numbers the same way I would for a standard road frame.

Thanks

f

 

[Slick]

Everyone is different and I'm sure there will be a few who will be able to discuss the technical nuances between manufacturers and frame types but personally I'd be very wary of a salesman telling you what size you should 've on when your mind already knows it's probably not true. My LBS tried it and for a split second I listened to him tell me the current fashion is now smaller frames and longer stems which may be true in the TdF but not for my 100 9dd miles a week.

You have probably answered your own question, try them all and see what feels best without making too many drastic adjustments or alterations.

 

[Joffey]

I ride a Cervelo R3 but have ridden a C3 and on both bikes the 56 frame fitted me perfectly.

 

[MichaelW2]

Do you want to replicate your current points of contact (Pedal/saddle/bars) ?

 

[feckless]

Do you want to replicate your current points of contact (Pedal/saddle/bars) ?

Hmmm ... good question.

I guess the only answer is: no, not necessarily. I'm just using my current bike as a reference point.

As it turns out, it may not be a very good reference, being a bit long for its frame size. Then add in that more modern endurance style bikes are supposed to be more upright anyway, and the difference is only about 20 to 25mm so maybe I'm worrying about nothing.

f

 

[feckless]

I'd be very wary of a salesman telling you what size you should 've on when your mind already knows it's probably not true.

Indeed. I've made that mistake before, which is kinda why I want to get my basic research straight before taking my credit card into a hostile environment

f

 

[MichaelW2]

Hmmm ... good question.

I guess the only answer is: no, not necessarily. I'm just using my current bike as a reference point.

As it turns out, it may not be a very good reference, being a bit long for its frame size. Then add in that more modern endurance style bikes are supposed to be more upright anyway, and the difference is only about 20 to 25mm so maybe I'm worrying about nothing.

f

Then you should measure up the Points Of Contact (POC) on your bike in [X,Y] corrdinates, from the bottom bracket [0,0].
You will then be able to deduct the required amount off your bar position and see if your new bike can be adapted to that POC fit.
Using [X,Y] eliminates frame angles from your assessment of fit.
In my case, I find that +-25mm in the bar position is something to address. That is quite a distance in stem length or rise. You can also address the saddle position with posts of different layback if you run out of saddle rail adjustment.

 

[bpsmith]

Sound advice above. I would only suggest positioning the bike on a known flat surface up against a known vertical wall. Then measure the required positions from the wall and ground. That way you can accurately ascertain each point relative to the bottom bracket. Trying to measure accurately from the BB isn’t ideal and from the wall and ground makes it so much easier and more accurate.

 

[MichaelW2]

. Trying to measure accurately from the BB isn’t ideal and from the wall and ground makes it so much easier and more accurate.

I measure and mark x=0 on the top tube the measure the bars and saddle from that mark.

 

[bpsmith]

I measure and mark x=0 on the top tube the measure the bars and saddle from that mark.

Whatever works for you. Personally would rather not mark my toptube.