choosing the correct frame size cyclocross bike

Especially for light weight issues concerning cyclocross / touring bikes & parts.

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Enda Marron
Posts: 345
Joined: Sun Nov 10, 2002 6:03 pm
Location: Belfast

by Enda Marron

Please advise as soon as possible.
I have the opportunity to pick up a Cannondale CX9 its a 56cm frame, and on the road I ride a 56cm frame, the Cannondale website advises to take one size smaller for a cx bike
THE QUESTIONS ....
1. Why do Cannondale suggest a size below road size
2. Would it matter to my performance if I took a road size frame (planned use - to train for and race the long distance 3 peaks cyclocross race in UK)
3. If I did take a 56 frame what changes to stem seat post saddle setup could be made to make it more cx friendly

Thank you

xcfisher
Posts: 488
Joined: Fri Jul 23, 2004 7:48 pm
Location: All over....
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by xcfisher

top tube length on the CX9 is 2cm longer.

I ride a 52cm SuperSix, and a 50cm CX9. The geometry is almost identical.
11' Flash Ultimate, 1x10 - 15.7
11' SuperX Single Speed - 13.0
12' SuperX Geared - 15.3
12' Scalpel Ultimate, Wireless SRM - 18.3

Enda Marron
Posts: 345
Joined: Sun Nov 10, 2002 6:03 pm
Location: Belfast

by Enda Marron

Thanks for the reply.
What are you comparing the CX9 with? My current road bike is a Cervelo R3SL which has a top tube length of 56.5cm.
My torso is slightly short and my legs are slightly long.
Is there a CX size guide available anywhere?

xcfisher
Posts: 488
Joined: Fri Jul 23, 2004 7:48 pm
Location: All over....
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by xcfisher

You'll need to cross reference the measurements on your Cervelo... Cannondale recommends (on their sizing) that you downsize 1 size based on the standard road bike sizing. They assume you are riding a SuperSix, Caad9, etc. I'm not sure how this sizing corresponds to Cervelo.
11' Flash Ultimate, 1x10 - 15.7
11' SuperX Single Speed - 13.0
12' SuperX Geared - 15.3
12' Scalpel Ultimate, Wireless SRM - 18.3

kervelo
Posts: 294
Joined: Wed Jan 21, 2009 6:58 am
Location: Finland

by kervelo

When I was choosing the frame for my cx bike, I found this article quite useful: http://www.cyclocrossworld.com/Tech.cfm ... Disabled=0.

kiwirider
Posts: 16
Joined: Fri Jun 19, 2009 1:12 am

by kiwirider

It's a good article Kervelo, but I would only add that the comments about frame size should be subject to specific comments from any given manufacturer.

I ride Cannondale road and cross and I can tell you that their "down one size" advice works for me - the 54 crosser is too long in the top tube, whereas the 52 lets me get the exact same position as my roadie ... :)

nitropowered
Posts: 1146
Joined: Fri Jul 17, 2009 4:10 am

by nitropowered

Your reach should be about 2 cm shorter. So select a frame a stem that will be 2cm shorter than your current road bike.

Enda Marron
Posts: 345
Joined: Sun Nov 10, 2002 6:03 pm
Location: Belfast

by Enda Marron

Thanks for all the advice, I also got some good advice from Toby at Wheelbase in Cumbria.
Basically the rule of thumb is sit on the bike with saddle centralised & adjusted to desired height then grip the hoods and if your elbows are bent then its good.
I also got the advice about the 10cm stem.
The Cannondale advice re go for a frame size smaller is good - but only if your road bike is a Cannondale.
Another interesting thig was the derivation of the term "rule of thumb" - in ancient times it was ok for a chap to beat his wife as long as the stick he used was no thicker than his thumb!!!

backflat
Posts: 111
Joined: Sat Jan 15, 2011 5:13 am

by backflat

i have a canondale with headshock
size 52

feels a little big

thinking of buying trek 50 cm cyclocross bike

is this a bad idea ?

no shop has one in stock to see actual fit

backflat
Posts: 111
Joined: Sat Jan 15, 2011 5:13 am

by backflat

right now on the canondale.
the seat post is all the way down in the frame.

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euan
Posts: 1494
Joined: Sat Sep 05, 2009 11:20 am

by euan

Trek has stack and reach for working out your current fit on their bikes. Is your current fit actually suitable?
"Step forward the climber and all those who worship at the altar of lightness" - R. Millar

backflat
Posts: 111
Joined: Sat Jan 15, 2011 5:13 am

by backflat

the canondale is too big

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euan
Posts: 1494
Joined: Sat Sep 05, 2009 11:20 am

by euan

Get a professional fit. Buy bike that matches fit.

But in Trek CX geometry the main different between the 50 and 52cm frames is the stack height with it being 2cm higher. If you cannot get a fit, I'm 5'6 and ride the 52.
"Step forward the climber and all those who worship at the altar of lightness" - R. Millar

backflat
Posts: 111
Joined: Sat Jan 15, 2011 5:13 am

by backflat

the trek comes in a 50 or a 54

backflat
Posts: 111
Joined: Sat Jan 15, 2011 5:13 am

by backflat

i took the bike out of the shed
and see it has speed max 30 c tires on it.

i wonder if canondale makes stem that is really short
i am going to guess it has around a 90 on it now.
stem that fits old headshok fork diameter

i tried to post a pix
but says file too big

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