Cervelo R5 - disc vs rim

Discuss light weight issues concerning road bikes & parts.
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Lewn777
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by Lewn777

To the OP.

A smart move would be to wait until after the 2019 Giro. That way you can see how the pro peloton has changed, maybe most riders will have been forced on to disks by next year with a dominant axle and disk rotor size standard, or maybe it will be just like this year.

by Weenie


MoPho
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by MoPho

asiantrick wrote:
Tue Oct 02, 2018 11:12 pm

But isn't this exactly what I was saying though. The brand is pushing disc brakes in Pro Peloton to increase sales in disc bikes. You have to admit that part. I understand we're not talking about the EXACT bike the pro are riding. I'm just talking about the same frameset. If Sagan is riding the tarmac disc, I can bet you Joe Schmoe wants the disc over caliber.
If they were really pushing disc on the pros in order to sell disc brakes, they would all be on disc brakes already, that's their job. I also think pros are resisting it because they are still afraid they are going to get cut up by the rotors ( a retired pro I talked to also suggested this) and they believe unless everyone is on disc, no one should be on disc.

At this point, people either want disc or they don't, and if they do, they would buy the disc even if Sagan, etc. is riding the rim brake version or vice versa, The main issue as I see it with the pros not using disc is it provides fuel for the anti-disc crowd argument on the internets, but they aren't going to change their minds even the pros addapt them.

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C36
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by C36

I keep saying the same 2 things over and over
1) disc frames don’t behave as well (reactive, « alive ») as rim brake discs. It may change on the future but now it’s just a fact for whoever really had the opportunity to compare. Since I push on the pedals 99% of the time and brake 1%...
2) do you need discs?
- do you plan to have a single pair of wheels with basic brake surfaces?
- do you ride in mountain under the rain and insist in using your carbon wheels even under Armageddon weather?
- do you have long tough descents that impose to really squeeze the brakes till it cause pain and that’s really an issue?

Thinking « i need to invest in the new norm » won’t change the two points above. If you don’t need discs today... what would it bring you ?


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Andres
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by Andres

cshong88 wrote:
Fri Jun 29, 2018 1:54 pm
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.
I rode an R5 disc for a bit, enjoyed it quite a bit. I would say if you're planning on using mechanical shifting, don't to the disc brake version as the cabling is a bit of an afterthought. That frame seems to be optimized for electronic in the disc configuration.

The weight will be lighter in the rim version, tire clearance marginally better, not as drastic as the person who said you might be able to clear nearly a 40. I was pushing it with a 30mm Schwalbe.

Both have a seatpost clamp mechanism that doesn't lend itself to much adjustment unless the saddle has extra long rails, and it's not replaceable. There's really not a ton of fore-aft adjustment and depending on your saddle position/size, you may have to opt for a zero offset or if you're on a smaller frame that comes with a zero offset, purchase a 25mm offset post.

The R5 is essentially a rim brake bike with discs, if you don't care for the disc brake performance, don't need to run a 30mm tire, want the lightest bike you can build (this is WW after all), the rim brake version is the one to go with. If you want your bike to be performance oriented and in line with the standards of contemporary bike racing now and for the next few years, get a BMC SLR01/TMR01, a new Venge, a Madone Disc, or even the new S5 though I think it looks hideous.

cshong88
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by cshong88

Well I've had the chance to ride both and the rim feels a bit snappier and nimbler to ride. And the disc ocasionally rubs, more so in wet conditions, which is annoying. That being said, my times up local climbs and loops are no different between the two so despite the different feel of the bike, I doubt there is any significant speed difference.

The notion that discs are here to stay and will be "the future" makes me hesitate to stick with rims. I don't plan on buying another bike for a few years and don't want to be on out-dated technology in 2-3 years. Curiously, Sunweb stuck with rims for the R5 bikes this year which makes me question whether rims will truly be phased out for the GC/climbers.

Somebody help sway me one way or the other!

TiCass
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by TiCass

cshong88 wrote:
Fri Mar 22, 2019 2:55 pm
Well I've had the chance to ride both and the rim feels a bit snappier and nimbler to ride. And the disc ocasionally rubs, more so in wet conditions, which is annoying. That being said, my times up local climbs and loops are no different between the two so despite the different feel of the bike, I doubt there is any significant speed difference.

The notion that discs are here to stay and will be "the future" makes me hesitate to stick with rims. I don't plan on buying another bike for a few years and don't want to be on out-dated technology in 2-3 years. Curiously, Sunweb stuck with rims for the R5 bikes this year which makes me question whether rims will truly be phased out for the GC/climbers.

Somebody help sway me one way or the other!
Well, it's not really curious. Rim brakes are still lighter, more aero and more "race ready" then disc brake. It makes sense that the GC rider will stay on rim for a while.

Kazyole
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by Kazyole

cshong88 wrote:
Fri Mar 22, 2019 2:55 pm
Well I've had the chance to ride both and the rim feels a bit snappier and nimbler to ride. And the disc ocasionally rubs, more so in wet conditions, which is annoying. That being said, my times up local climbs and loops are no different between the two so despite the different feel of the bike, I doubt there is any significant speed difference.

The notion that discs are here to stay and will be "the future" makes me hesitate to stick with rims. I don't plan on buying another bike for a few years and don't want to be on out-dated technology in 2-3 years. Curiously, Sunweb stuck with rims for the R5 bikes this year which makes me question whether rims will truly be phased out for the GC/climbers.

Somebody help sway me one way or the other!
I mean there are a ton of advantages race-wise to still running rim brakes, but easy wheel changes is probably the biggest. Things may change in the future but right now rim brake bikes are also lighter and more aerodynamic. While disc brakes are inarguably better brakes.

But, whether or not you need disc brakes is really dependent on how you ride. Because in the dry there's not much between them. Discs really come into their own on wet or broken road surfaces.

GCN did a good "Does science" video comparing discs and rim brakes in wet and dry conditions:

https://www.youtube.com/watch?v=t0hKMgUEku4

And another one where they compared stopping distance on a variety of road surfaces:

https://www.youtube.com/watch?v=uHFSSXOSnxs

My takeaway is that for me and the way I ride, rim brakes are plenty good enough. And what I trade off in terms of braking performance in situations where I typically don't ride is outweighed by the aero and weight advantage in every ride I do. I ride mostly on decent roads, don't do a ton of huge alpine descents where I'd be worried about my hands fatiguing, and tend to stay inside on days where it rains. And I'm a very lightweight rider who doesn't really need a ton of power to stop. So I wouldn't really see 95% of the advantage of discs. So I'm sticking with rim brakes for now. At least until discs get lighter.

Personally I don't really worry about riding something "outdated." Rim brakes have been around for too long and too many people still prefer them for them to die overnight. I think we'll see discs grabbing more and more marketshare over the next several years, but there are still issues to be worked out on that side.

rollinslow
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Joined: Fri Dec 21, 2018 2:25 am

by rollinslow

cshong88 wrote:
Fri Jun 29, 2018 4:03 pm
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.

I'd argue that rim brakes have proven themselves for about 100 years while discs keep changing. All comes down to what you want out of your ride. The pro peloton will always do whatever the big sponsors tell them needs to be marketed to consumers. Why pay more for extra weight, extra maintenance, new wheels, new standards etc? I think if you need big tires (>30mm) and ride in the wet/mud frequently or want to ride some gravel discs make sense. For a true race bike I would vote for rim brakes.

On a side note, I ride almost only big mountains. Last year rode over trail ridge road in Colorado which is the highest continuously paved road in north america (13000ft). Rims brakes are great. If if was raining or snowing, the road would be closed so the wet/dry arguement is rarely relevant on some of the highest peaks.

kode54
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by kode54

The 135mm width came with QR and seemed like it was the transition to the 142mm thru axle version.

Measure will still be the same. Inside.
Rim rear width: 130mm
Disc with quick release (and most likely post mount calipers): 135mm
Disc with flat mount and thru axle: 142mm

AJS914 wrote:
Tue Oct 02, 2018 4:23 pm
No one should have fear of buying rim brakes. If you buy a frame today you'll be able to ride it for decades if it lasts that long. There will always be a way to get parts. The only reason to get discs is because you want them.
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?
I don't know specifically about this bike but 142mm thru axel is 135 inside diameter on the rear dropouts. It's just that they measure outside to outside on thru axel.
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gurk700
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by gurk700

If resale value is a thing to consider for you, go with discs. Rim brake bikes, wheels, framesets etc are already crazy low price compared to 2 years ago.
If you are not comfortable descending 10%+ grades on rim brakes, go disc.
If you have to bomb down hills on rainy days, go disc.

For everything else, rim for me.
Below are my reasons and may not apply to others.

-So much lighter when all else is equal. It may not improve the performance on paper by much but lightness of a bike is the easiest you can feel and as we are humans, not robots, feel is important to us.
-Discs have very annoying aspects. The rub doesn't matter to some but hearing that disc rub every time I get up and sprint or go up a hill off the saddle just kills my mood. I love a dead quiet bike.
-Being able to buy a dream wheelset that normally costs $2500 - $3000 for $600 cause they are out of fashion is pretty much the best feeling.
-You look at your bike weird and it requires bleeding brakes. Exaggerating ofcourse but especially with fully integrated invisible brake lines, where all bikes are headed, adjustments are a pain and big adjustments may require rebleeding the system. Also you flip the bike upside down and your brakes need bleeding. What? No thanks.

I went rim > disc (for a month and a half before I hated it) and back to rim now. Should've never bothered. Discs are amazing. But they are also very annoying.

Again, YMMV.

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wheelsONfire
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by wheelsONfire

Buy the bike you feel for and stick to that feeling.
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TurboKoo
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by TurboKoo

Once you bleed the brakes correctly you can flip the bike as you wish and brakes are good. At least on mine they work when bike is upside down.
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cshong88
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Joined: Fri Jan 16, 2009 4:49 am

by cshong88

Well, about to bite the bullet on rim vs disc version of the R5. Having had a chance to extensively ride both, I'm still on the fence and looking for suggestions/advice. Sorry to bring up again as I know the whole rim vs disc debate has been discussed extensively. To rehash my situation, I'm a cat 1 racer and do pay attention to what the pros ride. Have always been firmly in the rim brake camp but with more and more disc bikes showing up in the pro/elite peloton, I've been contemplating switch to disc to stay with current trends. A lot of pros still on rim bikes this year but I wonder what 2020 season will bring - disc brakes for GC contenders? Sunweb switch to all disc including cervelo R5 disc? If this happened, I think I'd switch to disc pretty readily.

Rim bike considerations:
The rim still feels a bit nimbler but times up local climbs do not seem to suggest one bike is faster than the other (not surprisingly).
The rim bike has an annoying chirp with the front braking and obviously not as smooth braking as the disc bike.
No obvious need for discs based on where I live (don't ride in rain too often, no big descents).
Gut instinct says ride quality of rim bike is smoother, more agile, more enjoyable to ride than disc bike.

Disc bike considerations:
The disc bike has an annoying creak everytime I get out of saddle (it's not disc rub) - wheel/hub related or perhaps the house rattling in fork?
Ride feel is dead/mute compared to rim bike - don't think it's slowing me down but it does feel less fast/enjoyable to ride compared to rim bike quality.
I've ridden it enough now to appreciate smooth modulation and silence of discs in dry. In wet, brakes still work but they make a lot of annoying noise when braking and even when just riding, perhaps from contamination of discs from road grit.
Again, despite occasional disc rub, out of saddle creaks, mute/dead feeling ride quality, I don't think the discs are slowing me down.

If you are so inclined to give your input, would be much appreciated. Help an undecided fellow weight weenie out :) Thanks all.

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Calnago
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by Calnago

Go with your instincts. Keep in mind that if it weren’t for the manufacturers pushing the discs and needing the pros to be riding them for marketing purposes, I doubt there would be a single team on discs today at the pro peloton level. The pro peloton is the prime playground where on balance a rim brake road race bike is the superior choice. But the reality is it exists for marketing purposes. If nothing else, consider the 500gram weight penalty for discs then consider you’re on the margins of the weight limit. You’re at the weight limit and someone says, ok... you can ride this bike at the weight limit with disc brakes or rim brakes. But there’s no free lunch. If you want to ride the disc brakes at that weight, then we’re taking 500g out of the frame, cuz it’s gotta come from somewhere. No thanks, I’ll keep the stronger frame please and the rim brakes. Losing more than 50% of the material in the most structurally significant part of what’s keeping my head off the pavement on a gnarly descent is not an option.

Then you have the reality that the manufacturers have succeeded in pretty much pushing the rim brake road race bike to the side. Make no mistake, they “pushed” it aside. Trek just finished its offer that they would give you a healthy trade-in value for your rim brake bike, provided you used that trade on a disc brake bike. And only a disc brake bike. Want another rim brake bike. Sorry, no deal for you. Specialized finally got fed up with their pros parading around before the big races on the latest disc bike, then showing up on the starting line with the rim version. Solution... take the choice away. Job done.

When people ask me about discs or rims now, I always ask “why?” first, out of curiosity. And one of the most common reasons I get from experienced riders for thinking about going discs on their next purchases is not because they think they’re so much better for their needs, but rather that they don’t want to be getting something that the manufacturers are clearly trying to obsolete. I think we’ve seen the pinnacle of design of the road racing bicycle, and it’s in the rear view mirror, for now. That may change again down the road, but for now it’s past tense.

But basically I think you will end up with disc, and you’ve already stated the reason.... you are influenced by what the trend is, despite knowing it’s a manufacturers trend first and foremost. Big time. You follow the trends even though your gut tells you the rim brake bike feels more nimble, etc. It is. Yet, the power of marketing is great, and hence manufacturers have pulled the time plug on the pros. The production plans have been in place several years before now. Discs are on the shop floors. And so too must they be in the pro peloton. Time has run out for the pros to be allowed to willingly adopt discs. Willful adoption simply did not happen. So, at least for SpecialIzed sponsored teams, the choice is gone. And so too with Trek, although I think if I was on a Madone I would choose disc brakes too just because the rim brakes are so poor. And the Emonda frame is so light that they have to slap on discs to be at the weight limit. And guess what, all of a sudden the pressure to reduce the UCI weight limit is gone. Just like that. Not hard to figure that one out.

So, my opinion is that you should get the disc brake bike, not because it is better for your needs, but because you want to follow the trend and not be left out. I’m ok with staying on rims for all the reasons you stated. They work and the bike looks and feels more nimble than a disc brake road bike. I think rim brake road bikes also just look miles sexier than disc road bikes. Can’t help it, just do. I’m good, despite the trend. When I see discs in the pro peloton, I understand why and how they got there. It’s business. But my playground is all about the high end road bike. Discs are surrounding the fence but I’m not letting them in just yet. They’re too ugly. Ha. It just feels better this way.

[edit]: just realized that you started this thread some time ago. Got a bunch of responses, mine included. And have now resurrected it. Why? It’s time for you to make your own decision. But I’ll leave what I wrote, just cuz I wrote it. And it felt good. Lol. Enjoy whatever you get.
Last edited by Calnago on Thu May 09, 2019 1:09 am, edited 3 times in total.
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Mr.Gib
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by Mr.Gib

Ha, you really are having trouble making up your mind - I feel for you.

My two cents: I have both options and perhaps my preferences might help you decide. If I am heading out with a fast group, I always grab my lightest, fastest rim brake bike with carbon wheels - no hesitation. On many other days when I am just training on my own, or the the group is taking it easy, I prefer the disc bike. There is something really nice about just not giving a damn about what is happening to the rims when I hammer the brakes. I find myself frequently testing the limits of the braking just 'cause it's fun. I live in a hilly area with some steep technical bits and the discs are superior in this terrain.

I also deal with some really bad surfaces - very rough and cracked chip seal. And that brings me to the second thing I like about the disc bike - I can run big soft tires (30mm @ 65psi) and just ride over everything and not give a shit. So, so comfortable. Of course if your focus is racing, none of this is relevant to you.

Another thing I have to admit is that I also have a rim brake bike that can take 30mm tires, and I prefer this setup most of all, but only with alloy rims. Once you get to comparing rim brakes with carbon wheels (even with the best braking surface) against disc, my preference goes back to disc for most situations, except the fast group or racing scenario.
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.

by Weenie


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