Disc vs Rim brakes

Londonirish72 · 20-01-2017 7:21pm #1

[font=arial, sans-serif]Some advice needed on the benefits of one over the other. I am considering buying a new road bike and I cannot decide between disc vs rim brakes. I am a nervous descender so I reckon disc brakes might give me more control and perhaps even increased confidence. However, I don’t know how much work is involved in maintaining disc brakes on a road bike. I am a reasonably competent mechanic and I tend to take good care of my bikes. However, would I need to take a bike with hydraulic disc brakes to a mechanic in the event of a problem? Also, I would expect to have to remove the wheels a lot for storage and transportation are the difficult to put back on with disc brakes? Do you need to align them exactly or do they just slot into the mechanism? Anything else (bar the weigh penalty) to consider?[/font]
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07Lapierre · 20-01-2017 8:31pm

Disc Brakes are UGLY!
Decision made

Londonirish72 · 20-01-2017 9:16pm

I dunno. The wheels look cleaner with less clutter where rim brakes would have been. I guess I just need to spend more money on the frame and wheels so no one notices!

rollingscone · 20-01-2017 10:29pm

Discs may not be what you expect on descents.

I've got them on one bike (mechanical so not the best example) and there have been times I've been extremely grateful for them (cycling a flooded N11 with luggage for example.)

Buuuut I still feel like I know what's going on with my wheels more on my rim brake bike and the absolute stopping power feels greater on rims (again hydraulic brakes are reputedly more powerful and less fiddly).

xxyyzz · 20-01-2017 10:47pm

Mountainbiker here, I've been riding with disc brakes for years and there is no comparison, they are equally good in the wet or dry, superior stopping power, don't rub if the wheel has a slight buckle and most importantly, far superior modulation.

07Lapierre · 20-01-2017 11:34pm

To improve your descending skills, you've got to learn NOT to use your brakes. IMO Overuse of the brakes (rim or disc) will not improve your descending.

This is me descending Col De Galibier....https://youtu.be/jHL45P1w45g

I'm not the fastest descender but you'll note that I don't brake too often...the trick is to try and NOT use your brakes.

smacl · 20-01-2017 11:36pm

Had rim brakes on the old bike, disc brakes on the new one (cx). For a road bike my personal preference would be rim brakes. Easier to fine tune to suit your needs. I find i can adjust the cables on rim brakes to feather nicely. Feck all adjustment on hydraulic disc brakes, up to you to get used to how they work. Also standard qrs make buying wheels easier with rim brakes. Big advantage of discs for me is being able use wider tyres without cantis. Better off road too where mud clogs up v-brakes. I'd recommend try before you buy to see what suits you.

crosstownk · 20-01-2017 11:53pm

I made the decision recently to buy a bike with rim brakes simply because my wheels would be interchangeable between bikes.

The decision was easy because like 07Lapierre, I don't like the look of disc brakes. Too asymmetrical for my liking.

OleRodrigo · 20-01-2017 11:54pm

Disc brakes, electric gears, power meters... all expensive distractions from rule no.5

diarmaidol · 21-01-2017 9:24am

Bigger tyres will give more confidence, get a bike that will fit 28mm-32mm tyres ... this will probably come with disks.

Brian? · 21-01-2017 10:26am

diarmaidol wrote: »

Bigger tyres will give more confidence, get a bike that will fit 28mm-32mm tyres ... this will probably come with disks.

Why would you want 32mm tyres on a road bike? Has the world gone crazy?

Brian? · 21-01-2017 10:27am

07Lapierre wrote: »

To improve your descending skills, you've got to learn NOT to use your brakes. IMO Overuse of the brakes (rim or disc) will not improve your descending.

This is me descending Col De Galibier....https://youtu.be/jHL45P1w45g

I'm not the fastest descender but you'll note that I don't brake too often...the trick is to try and NOT use your brakes.

What he says. Descending is about knowing when not to break and braking smoothly.

diarmaidol · 21-01-2017 11:20am

Brian? wrote: »

Why would you want 32mm tyres on a road bike? Has the world gone crazy?

I mentioned fit / clearance... a 28mm GP4000 on a c17 rim is about 30mm wide

I'm making the assumption that the OP isn't talking about an actual active race bike considering the hole "rotor" thing.

Having both a bike with 23mm tires and 32mm (really 30mm wide) and comparing descending on both, I'm a lot more confident on the wider tires.

Crazy was thinking 20mm tires @ 120psi were fast.
Crazy is getting hung up on minor aero effects of a bike when theres a lump of a human on it and your not actually in a race.

Londonirish72 · 21-01-2017 1:23pm

thanks all for the advice. i appreciate all the additional advice on descending. I have ridden the Tape twice and know all about hand cramps and over braking when coming down those mountains. I guess I need to practice more but anyone who has cycled in an event like this knows how hairy descending with thousands of others is.
For the record i am looking at a Rose marathon bike with Sram groupset and disc or rim brakes.

Tenzor07 · 21-01-2017 5:59pm

Londonirish72 wrote: »

However, would I need to take a bike with hydraulic disc brakes to a mechanic in the event of a problem?

Also, I would expect to have to remove the wheels a lot for storage and transportation are the difficult to put back on with disc brakes?

Do you need to align them exactly or do they just slot into the mechanism?

Anything else (bar the weigh penalty) to consider?

1. No, just buy a bleed kit and fluid
2. Couldn't be easier
3. The disc/wheel slots in very easily, no adjustment needed
4. Yes, they are awesome

rollingscone · 21-01-2017 6:06pm

Brian? wrote: »

Why would you want 32mm tyres on a road bike? Has the world gone crazy?

I remember a lengthy thread on here poo-pooing the idea of electronic shifting where many used similar language about Di2.

Fast forward 12mths and there were days where I seemed to be the only forum regular who didn't have EPS.

Lumen · 21-01-2017 6:45pm

This is all just total bull****.

Before disc brakes and carbon rims were introduced to road bikes nobody thought braking was a problem. If you wanted great brakes you bought Ultegra or Chorus, and if you wanted lighter great brakes you bought Dura Ace or Record.

Then we had deep carbon rims for improved aerodynamics and braking went to hell, and ride quality went to hell. And there was year after year of fancy new pads and braking surfaces to fix the carbon rim braking problem, and fancy new frames to fix the terrible ride quality.

And then...da-da! Disc brakes to the rescue! And there was muttering about aero, and muttering about more terrible ride quality from forks that were too stiff, and muttering about loads of spokes despite the fact that we'd spent 20 years shedding spokes for aerodynamics and lightness, but the magazines and the websites kept the muttering to a minimum because they won't bite the hand that feeds them.

So where are we now? We now have disc brakes on bikes that have shallow section aluminium rims, for "modulation" reasons! Never have I ever had a problem "modulating" rim brakes on alloy rims. They just worked!

But people who don't remember that rim braking on road bikes is a solved problem, coming from MTBing or from motorbikes or from cars, they love the discs, because descending in lycra is scary and more braking is obviously going to help, right?

Electronic shifting is genuinely pleasurable to use. Disc brakes are not. They are similarly effective at doing a very boring thing in a slightly different way, but a bit heavier and less aerodynamic and harder to service.

On a typical Sunday ride I need to brake to the limit of grip about zero times. Hour after hour of not really needing brakes at all. If I do need to brake hard my brakes work, whether they are rim brakes or disc brakes.

The only time disc brakes are genuinely useful is in emergency braking in the wet in heavy traffic when I'm drafting a car. That's because I don't want to wait 2m for the pads to clear the rims of water.

rollingscone · 21-01-2017 6:50pm

#Istillpreferrimbrakes and I'm not a great descender, albeit my top speed (best descent) was on my rim braked single speed (old 10spd era Ultegra calipers) possibly because when I did brake I felt confident that I knew what was happening with the bike.

With discs all I ever feel is the bike slowing down.

harringtonp · 21-01-2017 10:16pm

xxyyzz wrote: »

Mountainbiker here, I've been riding with disc brakes for years and there is no comparison, they are equally good in the wet or dry, superior stopping power, don't rub if the wheel has a slight buckle and most importantly, far superior modulation.

In my mountain biking days I pulled brakes all the time (so much so that I often didn't get more than 2 long mucky Ballyhoura rides out of a set of pads). I wouldn't contemplate mountain biking on rim brakes.

On road bikes I rarely use brakes, I can easily get 2 years out of a set of pads. When commuting around Dublin years back on a crappy bike in crappy weather without any mechanical knowhow braking was always iffy. Since I've become a roadie and bought decent bikes and built up a basic service knowledge I've never ever had problems with or felt uncomfortable with rim brakes. I just don't get disc brakes on road bikes unless those bikes also had minor mods to allow them be used off road (and I've just moaned about this 30 mins ago on another thread). People talk about wet weather rim braking but this generally works good too unless your picking up a huge amount of grit which generally means you're not on a road.

saccades · 21-01-2017 10:19pm

Discs are ace for commuters in heavy traffic (and bad weather) and mtbers in mud.

Anywhere else and the Pros/Cons ratios starts to shift, although I raced down from our ladies view doing the ROK with an alfine & disc equipped bike (relatively low geared) and raced against a serious whippet looking fella who was taking racing lines over both sides of the road (it was a closed road before anyone getting their knickers in a twist) and was able to brake way later than him into the bends and keep up despite spinning out out like crazy until the lower longer stages where I couldn't spin any faster.

cdaly_ · 21-01-2017 10:34pm

Brian? wrote: »

Why would you want 32mm tyres on a road bike? Has the world gone crazy?

1. Fast
2. Comfy
3. Comfy

37mm Vittoria Voyager Hyper...

Londonirish72 · 22-01-2017 2:09pm

i just need to pluck up the courage to buy the bike now. thanks.

Lumen · 22-01-2017 3:32pm

cdaly_ wrote: »

37mm Vittoria Voyager Hyper...

Are they really better than 28mm Conti GP4000S II ?

200g ish heavier per tyre. That's a lot of spinning mass. I make no claim about whether that matters for performance, but it must have a noticeable effect on handling.

smacl · 22-01-2017 5:50pm

cdaly_ wrote: »

1. Fast
2. Comfy
3. Comfy

37mm Vittoria Voyager Hyper...

Question so. If you're running wider tyres, do you prefer disc brakes or cantis on the assumption that these are your only options? Or do you have some very long armed caliper brakes?

Usjes · 22-01-2017 6:20pm

One more question about disc vs rim brakes, do disc brakes require a change to the frame geometry ? ie. does the rear fork need to be wider and have longer skewers to accommodate the disc ? I'm just wondering if I buy a bike with disc brakes and really dislike them could I just remove the disc brakes and buy new wheel to convert back to rim brakes or would the rear fork be too wide for a wheel that is intended to be used with rim brakes ?

Thanks,

Usjes.

cython · 22-01-2017 6:28pm

Usjes wrote: »

One more question about disc vs rim brakes, do disc brakes require a change to the frame geometry ? ie. does the rear fork need to be wider and have longer skewers to accommodate the disc ? I'm just wondering if I buy a bike with disc brakes and really dislike them could I just remove the disc brakes and buy new wheel to convert back to rim brakes or would the rear fork be too wide for a wheel that is intended to be used with rim brakes ?

Thanks,

Usjes.

I don't think there's an appreciable (if any) difference in the axle lengths of disc braked road bikes vs rim braked ones, but for the vast majority of disc braked bikes, switching back to rim brakes is not an option as the frame simply does not have mounting points for rim brakes.

Lumen · 22-01-2017 6:29pm

Usjes wrote: »

One more question about disc vs rim brakes, do disc brakes require a change to the frame geometry ? ie. does the rear fork need to be wider and have longer skewers to accommodate the disc ? I'm just wondering if I buy a bike with disc brakes and really dislike them could I just remove the disc brakes and buy new wheel to convert back to rim brakes or would the rear fork be too wide for a wheel that is intended to be used with rim brakes ?

There are some frames that take disc and rim brakes, but it's quite rare. I would try to discount this as an option cos you'll unnecessarily limit your choices.

xxyyzz · 22-01-2017 8:54pm

http://www.cyclingnews.com/news/boonen-to-race-on-disc-brakes-throughout-2017/

They work better, they're easier to control, they lock out less fast than normal brakes. Of course I can control normal brakes but with disc brakes you have so much more feeling. It's the biggest improvement I've seen in my career – I don't know what all the hassle is about."

Change give roadies a nosebleed

magicbastarder · 22-01-2017 9:11pm

Usjes wrote: »

One more question about disc vs rim brakes, do disc brakes require a change to the frame geometry ?

on my bike, apart from the obvious mounting points for the brakes, the fork is a different shape:
6034073

Lumen · 22-01-2017 9:15pm

xxyyzz wrote: »

Change give roadies a nosebleed

Boonen is a roadie. He's comparing carbon rim breaking with disc brakes.

xxyyzz · 22-01-2017 9:18pm

Lumen wrote: »

Boonen is a roadie. He's comparing carbon rim breaking with disc brakes.

I'm aware of that. The nosebleed point was a general observation. Boonen is the exception to the rule.

Borderfox · 22-01-2017 9:37pm

I recently changed to a cx bike for winter and changed to wheels to Askium Disc. I changed the rear caliper to a Trp hy/Rd and find it much better than the bb7 brakes. Running 28mm conti gp4000 and the soak up so much on the bike, the ride is so comfortable but can go fast when you want to

magicbastarder · 22-01-2017 11:22pm

i'm currently getting my head around hy/rd brakes. i think i have them fixed...

'think' is always good when you're dealing with brakes.

smacl · 23-01-2017 8:44am

Borderfox wrote: »

I recently changed to a cx bike for winter and changed to wheels to Askium Disc. I changed the rear caliper to a Trp hy/Rd and find it much better than the bb7 brakes. Running 28mm conti gp4000 and the soak up so much on the bike, the ride is so comfortable but can go fast when you want to

I found with the full hydraulic disc brakes on my CX bike that as shipped the rear brake was far more responsive than the front brake, which led to quite a few skids. Balancing them took a fair bit of mucking about, specifically loosening the lever adjustment screws all the way out, doing a bleed, and then resetting them. This was after already changing the pads and doing a regular bleed. Adjusting cables is so much easier. They work great now, but were such a pain to setup to my liking.

nordicb · 23-01-2017 11:35am

Other than rim wear... Are there any more benefits of disc brakes?

Yes, they are more powerful, but what's the point locking your wheels on a road bike. With this little amount of road contact, locking wheels will not slow you down faster, in fact this most likely will lead to a fall, fast and sharp. They are a must on a mountain bikes, undoubtedly, as locking wheels aids the turning and stuff.

Rim brakes give this very wide range of feel of what's going on under you, and the fact it takes more effort to lock the wheel is actually a good thing. Ability to read the road ahead is the skill that keeps us safe and less on brakes. Just my thoughts.

cdaly_ · 23-01-2017 11:38am

Lumen wrote: »

Are they really better than 28mm Conti GP4000S II ?

200g ish heavier per tyre. That's a lot of spinning mass. I make no claim about whether that matters for performance, but it must have a noticeable effect on handling.

I've never run GP4000s so I cannot say. They're certainly nicer than the 25mm Gatorskins I ran on the Giant.

As for extra weight, I suspect that I have a much greater effect on handling than any weight of tyre I might use. That said, I don't do racing so I'm not after super acceleration. They certainly roll fast and I keep up with the bunch no bother.

smacl wrote: »

Question so. If you're running wider tyres, do you prefer disc brakes or cantis on the assumption that these are your only options? Or do you have some very long armed caliper brakes?

On the advice of Andy Thorn, I run a rear disk brake (avid BB7 mechanical) and a front canti (avid Shorty Ultimate). Thorn reckons you cannot make a light, springy steel fork that will take disk brakes. You have to beef up the fork too much for the forces involved and you lose the springiness.

I'm really liking the setup. Rear brake is a proper stopper alone and the front is needed mostly for emergency stops or steep descending. Reduces rim wear also.

xxyyzz · 23-01-2017 1:27pm

nordicb wrote: »

Other than rim wear... Are there any more benefits of disc brakes?

Yes, they are more powerful, but what's the point locking your wheels on a road bike. With this little amount of road contact, locking wheels will not slow you down faster, in fact this most likely will lead to a fall, fast and sharp. They are a must on a mountain bikes, undoubtedly, as locking wheels aids the turning and stuff.

Rim brakes give this very wide range of feel of what's going on under you, and the fact it takes more effort to lock the wheel is actually a good thing. Ability to read the road ahead is the skill that keeps us safe and less on brakes. Just my thoughts.

It's not about the extra power, it's about how they allow you to apply that power. You can lock up the wheel with a rim brake, that doesn't mean you do it all the time. Good hydraulic disc brakes allow far better modulation ie from the point that the pad makes contact with the rotor to the point you lock up the wheel gives you a lot more sensitivity to play with.

Also they give far better wet weather performance, in fact there is no drop in performance in wet weather

Tenzor07 · 24-01-2017 8:30pm

Disco's in the pro ranks

Boonen to race on disc brakes throughout 2017

'It's the biggest improvement I've seen in my career' says Belgian

boonen-to-race-on-disc-brakes-throughout-2017

Zen0 · 24-01-2017 9:37pm

One advantage of disc brakes which I have not seen mentioned here, and I realise I'm open to being called a wuzz on this one, disk brakes are a lot cleaner. After a long spin on wet roads with lots of braking, I just have to clean off road spray from the rims, not that awful black gank that brake pads leaves. I'll happily embrace my inner wuzz for that.

youtheman · 24-01-2017 9:59pm

Zen0 wrote: »

One advantage of disc brakes which I have not seen mentioned here, and I realise I'm open to being called a wuzz on this one, disk brakes are a lot cleaner. After a long spin on wet roads with lots of braking, I just have to clean off road spray from the rims, not that awful black gank that brake pads leaves. I'll happily embrace my inner wuzz for that.

I actually consider this a big advantage. I can clean my disc brake bike in less than half the time it normally takes. Plus I'm not wearimg the rims so the wheels will last longer.

boege · 24-01-2017 10:14pm

Road biker here and normally use rim brakes.

Hired a bike in Nice last summer (Giant Defy) and was pleasantly surprised to find it had disc brakes, thinking I could really evaluate disc brakes as I am looking at new bike soon.

Did an 80/90km route up by Col d'Èze and Col de la Madone and descended off the Madone into Monaco. I am an experienced descender, and comfortable at speed on long alpine descents.

I wont exclude the possibility that i had a duff bike setup but I hated the disc brakes. Lack of feel was a big issue but more uncomfortable was the inertial mass of the dics/brake/fork (fork is heavier) which made sudden change of directions slow. I was extremely uncomfortable descending as a result and yeah descending off the Madone the way I did is hairy even with good brakes.

Have taken up MTB lately and would not argue against discs but for road biking I will be slow to change.

I could see Boonan using them in Spring Classics for sure (close to MTB conditions) but will be interesting to see if he persists throughout the year. Cav tried discs for a while but reverted back to rims.

Tenzor07 · 25-01-2017 9:21am

Ah the first Pro race win on Discs... I guess they are here to stay now!

tech-milestone-boonen-wins-first-race-with-disc-brake-bike

nordicb · 25-01-2017 11:43am

Just love the clean sharp finesse look of hubs and exposed cassette.

07Lapierre · 25-01-2017 11:49am

Tenzor07 wrote: »

Ah the first Pro race win on Discs... I guess they are here to stay now!

tech-milestone-boonen-wins-first-race-with-disc-brake-bike

I assume Tom won the race by NOT using his brakes as much as everyone else?

Tenzor07 · 25-01-2017 12:24pm

07Lapierre wrote: »

I assume Tom won the race by NOT using his brakes as much as everyone else?

Nah, they were just more aero than caliper brakes...:pac:

wanderer 22 · 25-01-2017 12:50pm

07Lapierre wrote: »

I assume Tom won the race by NOT using his brakes as much as everyone else?

Exactly - who came last? That guys brakes are the ones we want :pac:

xxyyzz · 25-01-2017 1:38pm

Tenzor07 wrote: »

Nah, they were just more aero than caliper brakes...:pac:

Nah, they let him off because all roadies know that if you get to close to disc brakes then this in inevitible. If I had a euro for every time it happens on a mtb spin...

Tenzor07 · 25-01-2017 2:10pm

xxyyzz wrote: »

Nah, they let him off because all roadies know that if you get to close to disc brakes then this in inevitible. If I had a euro for every time it happens on a mtb spin...

Lovely, makes great lunchtime viewing!

xxyyzz · 28-01-2017 1:28am

If only poor Simon knew how wrong he was about disc brakes https://www.youtube.com/watch?v=8Il8XV61yLQ

Cookie_Monster · 29-01-2017 9:17am

Discs without question. Rim on the road bike, discs on the cyclocross. I hate using the road bike now after a week of commuting on the cycloX, it feel like it has no stopping power. My next road bike without question will have discs, for me the single best improvement on bikes in recent years.

xxyyzz · 29-01-2017 12:22pm

Something that's not mentioned often is that disc brakes allow wheel makers to build rims without having to compromise by putting in a braking strip. It gives them more leeway to design more aero rims, also with the trend towards wider tyres, you can now have a wider rim which gives the tyre a better profile and makes it less likely to roll off the rim.

Disc vs Rim brakes

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