Cervelo R5 - disc vs rim

Discuss light weight issues concerning road bikes & parts.
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cshong88
Posts: 4
Joined: Fri Jan 16, 2009 4:49 am

by cshong88

Hi guys, would appreciate some third party input to help me decide on this next purchase. Cat 1, former UCI conti pro who has been a loyal Cervelo R5 rider for the past 5 years. In the market for a new Cervelo R5 and now having to consider for the first time whether or not to purchase a disc brake bike as this was never an option before. Some riding habits about myself.

1. Current/lifetime job (medicine) means 80% of riding is indoors on my Wahoo Kickr
2. Performance-oriented - goals of riding/training are still to go fast and if job permits, compete in local races and hill climbs in next couple years - as such wheel compatilibity in races (neutral support etc) is a factor for me. As a side note, I've been reading the rear 142mm axle is fast becoming the standard for discs. Supposedly the Cervelo R5 disc is a 135mm standard? Is this true? And if so, will this cause issues if I had a disc version for races?
3. Hard to predict but I'd like to have a bike that is in keeping with the times, both now and in the next couple years. Would be a bummer to invest in a rim bike and see the pro peloton and racing scene transition to disc brakes full time in the next year or so.

Ultimately, I anticipate buying another bike in 3-4 years but I want my next purchase to be performance oriented and in line with the standards of contemporary bike racing now and for the next few years. I know it's a hotly debated topic but any thoughts on rim vs disc for my situation? Thanks for all input, much appreciated.

by Weenie


wingguy
Posts: 4042
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

First, not sure what you’ve been reading but the R5 disc is a 12x142 rear end, just like everything else. It has a proprietary keyed thru axle system rather than threaded but that doesn’t change wheel compatibility at all and it works fine with a Kickr - IF you have the latest 2017/18 version. Older kickrs (v1/v2) are not compatible with the keyed axle.

Second, what do you want out of the disc? Tyre clearance is much bigger, you could get a measured 35 or even close to a 40 in the Disc R5, but that’s not really race relevant. The Rim version still clears a 30mm anyway. Wet weather performance is obviously better too, but if most riding is on the turbo that probably doesn’t matter.

The rim version, well the whole thing builds lighter, obviously, and there are no compatibility issues with anything.

Maybe the disc version would have slightly better resale but honestly all high end road bikes depreciate like rocks so it’s probably gonna be more even than you might think.

cshong88
Posts: 4
Joined: Fri Jan 16, 2009 4:49 am

by cshong88

Hm, I have the original Wahoo Kickr. Is the Cervelo R5 disc not compatible with this model/no adapters I could get to make it work? Might be a deal breaker otherwise...

What I mainly want out of disc vs rim is a choosing a technology that is not obsolete in a few years and one in which the local/national/international racing scene adheres to if/when I get back into elite level racing. I've always been used to rim but this whole disc bike trend now making its way into high level racing has me pause to consider buying a disc bike if this is where racing is heading in the next few years. Likewise, for current purposes, despite riding mostly indoors due to the job, I'm after a performance oriented set up that is most optimal for the fast group ride and to be competitive at the local hill climbs. Thanks in advance for your input.

Mr.Gib
Posts: 3144
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

Welcome to the clusterf**k that is the changing state of cycling technology.

When everyone else is on discs you'll think you should have 'em. When your on the limit in an uphill finish of some race trying to recapture some of your former glory you'll wish you didn't.

The fact that you're even wondering about this suggest to me that you should just get discs. This sport won't go backward in that regard so you will be more future proof. Shame to add at least a pound to what could easily be a very light bike.

As for not fitting on your Kickr etc., that might be the least of your worries. How pairs of nice wheels to you have in your basement that you will never be able to use?
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

stevod
Posts: 17
Joined: Tue Aug 18, 2015 8:09 am

by stevod

wingguy wrote:
Fri Jun 29, 2018 3:01 pm
Tyre clearance is much bigger, you could get a measured 35 or even close to a 40 in the Disc R5, but that’s not really race relevant. The Rim version still clears a 30mm anyway.
I didn't realise this - thought they were both the same re the frame - officially a 28mm although as you say a bit more in practice.

I can see the clearance in the fork without the caliper, but could a 35-40 really fit between the chainstays or behind the seat tube?

S

wingguy
Posts: 4042
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

Ah good call, not between the chain stays no. Measured 32mm for sure though, and maybe even a bit bigger than that.

On the rim model the seat stay bridge is the limiting factor, and the disc model doesn’t have one. The disc fork clearance is monstrous.

by Weenie


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