Owners of disc brake road bike vs rim. To bike harsh or same

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mtnbikerva1
Posts: 16
Joined: Wed Jul 22, 2015 11:02 pm

by mtnbikerva1

Do you find the front and rear disc brakes it inherently changes the ride qualities of the total bike and if so how so. Disc=harsher! better handling! fatigue...? Do you think Road disc brakes are coming on hard into thousand 2016 or do you think they will never take over the sport due to the weight issue.
In reality how much more Do the disc brakes weight versus rim breaks as a total package of wheels, brakes and mounts and all the rest of it?
Do the brakes change the total package of the bike as far as ride quality on non smooth surfaces? Does it make stability of the bike any different? Since the strength of the frame and fork must change, is this a noticeable change at all or only on longer rides?
Thank you.
Last edited by mtnbikerva1 on Thu Jul 23, 2015 1:15 pm, edited 1 time in total.

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ergott
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by ergott

I have both.

(Hydro) Disc offers better feel and modulation in all conditions, wet or dry.

Rims brakes still have a place and I'm not selling mine off anytime soon.
Last edited by ergott on Thu Jul 23, 2015 12:11 am, edited 1 time in total.

LionelB
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Location: Aix en Provence

by LionelB

I have both as well. Prefer the rim brakes.

MichaelB
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Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

I haven't ridden a disc/rim bike from the same model/manufacturer, so can offer a specific answer, but .....

I reckon it would be almost impossible to tell the difference in a blind test (hard to do properly). The braking would be the big difference.

Just try a few bikes and see how YOU find it. They work great, much better than rim brakes !!

0psi
Posts: 32
Joined: Tue Jun 16, 2015 1:07 pm

by 0psi

LionelB wrote:I have both as well. Prefer the rim brakes.

+1.

The only difference between disc and rim is the braking, ride qualities are exactly the same. As for the weight, you can still build a disc brake road bike down to 6.8kg if you wanted to so it's a non issue really. If discs take off in the coming years we'll see an improvement in disc specific rims which will be lighter as heat won't be an issue and more aero as we don't have to worry about brake tracks. That alone should outweigh the small weight penalty of a disc over a rim brake.

As for the actual braking. Being someone who spends a lot of time on a mountain bike I expected more from road discs. I suspect they've deliberately dumbed down the power of road discs so that the difference is a bit more manageable for those who own both disc and rim brake bikes and when riding in a bunch. Stopping power in the wet is better but otherwise I didn't notice a massive difference. I'd liken the difference between a good caliper and a Shimano hydro disc to that of a good caliper and an average caliper. Certainly noticeable but not game changing.

pamountainbiker
Posts: 83
Joined: Mon Jan 12, 2009 3:49 am

by pamountainbiker

I have both, the disc bike is about 1 pound heavier, actually a tad more - i never pulled off all the parts though to do a gram by gram comparison. The weight isn't really noticeable. Braking performance wise, discs as you can imagine are absolutely consistent in wet or dry - for me, however, I rarely ride in the wet so that benefit at least for me is mitigated. Modulation is very good, like a mountain disc brake. Honestly though, in the dry my Dura Ace 9000 calipers on a dry carbon rim are not that far behind modulation wise. In both scenarios power builds linearly and whereas at 30+ MPH / 50+KPH you're going to have to use two fingers on the DA brakes you can get away with just one on the discs. Again, in the wet, totally different story, but I rarely ride in the wet and frankly I'm going a lot slower anyway in any scenario that requires braking whether I'm on discs or not, call me cautious. In other words, I'm not going to bomb downhill in the wet even with discs, great modulation and all.

Here's what I don't like about the disc bike and it has nothing to do with the brake performance, but moreso the rotor. I live near a waterway and there is always wind. I'm also a lightish rider (145 pounds). My disc bike wears ironically custom H Plus Son Alu rims and I run 140MM rotors (non ice tech Shimanos) and the wheels are much more susceptible to cross wind stability issues. There are times I can actually hear the wind through the rotors not to mention feeling it at the wheel. Conversely, the DA caliper bike has carbon rims, blunt nose rims and the affect of crosswinds is really fairly negligible and highly manageable. This is completely anecdotal but the disc bike also feels slower in a variety of wind situations. I say feel because I don't have a wind tunnel, I only have my legs. Again, it's not a scientific experiment here as the disc bike has different geometry etc. Lastly, he disc bike has 135MM spacing, which while practical is a heel knocker for me, as I already frequently rub heels on my 130MM caliper bike. Again, more annoyance, but it happens.

Which bike do I typically reach for? The rim brake bike. It's lighter, visually more simple ( I like that). Has racier geometry, so it feels a little different and It cross chains better. And yes I cross chain all the time, sorry. Does this mean I'm getting rid of the disc bike? Not at all, in fact I'm doubling down and getting a new one most likely in early spring next year. And what's more I'm going for the freak bike - the Cannondale Slate. So lest anyone think I'm a luddite, I'm actually going for the franken bike with discs and suspension! I'll continue to ride my disc road bike more as a winter bike.

kulivontot
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Joined: Sun May 16, 2010 7:28 pm

by kulivontot

I rode a Specialized E5 Crux Disc for about 6 months as a road bike while my Addict was in storage in another state. I have it equipped with Sram Red Levers and used both cable-actuated Avid BB5 and Shimano CX75 (currently) brakes. I find the overall braking power between the the Crux and my Addict to be pretty close, I can lock up the wheels pretty easy in either case. What's different between the two is really the feel and the modulation.
There's no question that the discs give you better control and modulation. But for whatever reason I cannot set them up properly to not rub without pushing the engagement point way down the bar. I have to pull the lever basically 2-3 times farther on the disc setup than the rim brake setup to get the brakes to really bite. This means that to lock up my wheels, I basically have to pull the lever all the way to the bar. This is fine, it's just different. The only time this was an issue for me was after a long 'cross race where I had been doing a lot of hard braking going up and down steep dirt hills. My hands had started to cramp up after 50 minutes of racing. Maybe I've set up something wrong? I don't know. This is my experience, no mechanic has been able to really set them up better. This also means that the braking power is more progressive as compared to the rim brakes. It's much harder to skid a tire in a panic situation than the rim setup. The result is that overall I'm more confident on descents and muddy conditions.
But this comes with some downsides. They squeal like crazy. Frighteningly so in the wet. Even if they do brake better when the road is soaked, the noise it makes is so ear-piercing that it messes with your confidence because you have to assume that something is going very very wrong to make that sound.
And then the weight penalty is very real. I upgraded the stock components to Sram Red and 1500g carbon clinchers thinking I'd be around 17-18 pounds since that's around what a Sram equipped CAAD10 would be. Actual weight was above 20 pounds. Now maybe the E5 Crux is just a heavy frameset, but I have a hard time believing any other alloy bike with Sram Red and carbon clinchers would weigh that much. The math for disc penalty is something like this, at least +200g for the frame and fork to support disc braking forces, +100g for disc brake calipers, +50-100g for disc brake hubset, +225g for the addition of disc rotors and bolts, and +??? for thru axles.
So is it worth it for road? I'm not really convinced. For cross, definitely. I think I would need to ride a bike with hydro disc to really make a judgment. But if given $5000 today to go out and buy a new road bike, I think I'd stick with regular caliper brakes.

pamountainbiker
Posts: 83
Joined: Mon Jan 12, 2009 3:49 am

by pamountainbiker

@kulivontot

+1 on your mechanical disc experience. I had a Trek built up with CX-77 brakes which I ended up selling awhile ago, but the same issues you list are my experience on mechanicals. They were very finicky to set up such that the rotor was not pinging the pads and then once done the engagement point at the lever was about 1/2 inch from bottoming out. Power was adequate but lever engagement point was far different that rim caliper action. And there's really no good way to change it save with cable tension or by minutely moving the fixed caliper (we're talking fractions of a millimeter here) toward the rotor (without making it ping) then using the movable calibers set screw ever so slightly to dial in pad to rotor clearance. Hugely frustrating. Hydro's at least let you monkey with the engagement point, but out of the box, the levers still were much more similar in action / engagement to the mechanical discs then traditional calipers. Shimano (I don't have SRAM) does this on purpose I believe for issues of rider safety i.e. not grabbing a handful of your new hydro and face planting.

kulivontot
Posts: 1163
Joined: Sun May 16, 2010 7:28 pm

by kulivontot

pamountainbiker,
Good to know that I'm not crazy. The issue is that the rotors are not perfectly true either, so even if you could dial in the tension/pad spacing perfectly, the imperfections in the rotor will still prevent you from really bringing it in. Rotor truing is the equivalent of taking an out of true wheel and banging it on the ground at the bent spot, not the most precise adjustment.

grover
Posts: 1302
Joined: Mon Jul 26, 2004 1:06 pm

by grover

My rim brake bike is an Emonda SL. My disc brake bike is a Domane 6 series. As expected the Domane is the more comfortable bike. I've not ridden the rim brake Domane to compare but my disc version is a very smooth ride.

Overall weight difference is around 500 grams with fairly comparable builds.

I find the Emonda more responsive/maneuverable. But I think that is mainly due to bar shape and hood shape. The bulky hydro hoods don't fit as nicely in the hand, and they're on a Bontrager bar that has no outward slant to the drops which points the hoods straight up. While the Zipp bar on the Emonda has an outward slant to the drops which slightly angles the hoods in putting my wrist in a better position.

As for the braking, I far prefer the discs (hydro, not cable actuated). The Emonda has eeCycleWorks brakes. In the dry I could live with the rim brakes but the disc brakes are less effortful and if I want to I can pull up quicker in the bunch than those on rim brakes (as in you have to be aware not to brake too quickly and have the guy behind you run into you). In the wet the initial responsiveness makes a massive difference. When you apply rim brakes in the wet nothing happens for a couple of wheel revolutions. I do a lot of commuting. In traffic, on wet roads, when a car pulls out in front of you or merges in front of you, wiping off speed the instant you apply the brakes is the difference between an increased heart rate and sprawling across a bonnet.

As an aside, coming from mountain bike and cyclocross disc brake use I would never use cable disc brakes again. Only one pad moves (TRP Spyre excluded) which means every time you brake you are pushing the rotor sideways rather than just clamping onto it. In my mind that doesn't result in straight rotors long term. It also means having to pull cable to not only push the pad to the rotor, but then also over to the fixed pad, which is why so much lever throw is required on cable actuated discs. Then there's the issue of pad wear not self adjusting like hydro brakes meaning the cable pull increases as the pads wear (like rim brakes but the effect is multiplied for discs, and not as easily remedied).

If I had my way I'd have an Emonda with discs and a slight sort out to the ergonomics of the shifterhood (hopefully SRAM wireless electronic can make the hood shape smaller). I'd negate most of the aerodynamic and weight drawback of discs by using carbon wheels (which I'm not happy to do daily on rim brakes).

mtnbikerva1
Posts: 16
Joined: Wed Jul 22, 2015 11:02 pm

by mtnbikerva1

kulivontot wrote:I rode a Specialized E5 Crux Disc for about 6 months as a road bike while my Addict was in storage in another state. I have it equipped with Sram Red Levers and used both cable-actuated Avid BB5 and Shimano CX75 (currently) brakes. I find the overall braking power between the the Crux and my Addict to be pretty close, I can lock up the wheels pretty easy in either case. What's different between the two is really the feel and the modulation.
There's no question that the discs give you better control and modulation. But for whatever reason I cannot set them up properly to not rub without pushing the engagement point way down the bar. I have to pull the lever basically 2-3 times farther on the disc setup than the rim brake setup to get the brakes to really bite. This means that to lock up my wheels, I basically have to pull the lever all the way to the bar. This is fine, it's just different. The only time this was an issue for me was after a long 'cross race where I had been doing a lot of hard braking going up and down steep dirt hills. My hands had started to cramp up after 50 minutes of racing. Maybe I've set up something wrong? I don't know. This is my experience, no mechanic has been able to really set them up better. This also means that the braking power is more progressive as compared to the rim brakes. It's much harder to skid a tire in a panic situation than the rim setup. The result is that overall I'm more confident on descents and muddy conditions.
But this comes with some downsides. They squeal like crazy. Frighteningly so in the wet. Even if they do brake better when the road is soaked, the noise it makes is so ear-piercing that it messes with your confidence because you have to assume that something is going very very wrong to make that sound.
And then the weight penalty is very real. I upgraded the stock components to Sram Red and 1500g carbon clinchers thinking I'd be around 17-18 pounds since that's around what a Sram equipped CAAD10 would be. Actual weight was above 20 pounds. Now maybe the E5 Crux is just a heavy frameset, but I have a hard time believing any other alloy bike with Sram Red and carbon clinchers would weigh that much. The math for disc penalty is something like this, at least +200g for the frame and fork to support disc braking forces, +100g for disc brake calipers, +50-100g for disc brake hubset, +225g for the addition of disc rotors and bolts, and +??? for thru axles.
So is it worth it for road? I'm not really convinced. For cross, definitely. I think I would need to ride a bike with hydro disc to really make a judgment. But if given $5000 today to go out and buy a new road bike, I think I'd stick with regular caliper brakes.

Did you try different pads? Centered vs organic? Centered/metallic brakes better I think. Also the hydrolic seems to be far better than mech/cable pull, due to parallel push/squeeze, self aligning and ease of actuation.
Last edited by mtnbikerva1 on Thu Jul 23, 2015 8:48 pm, edited 1 time in total.

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Powerful Pete
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Location: Lima, Peru and the Washington DC area - it's complicated.

by Powerful Pete

What ergott said.

I have (one month old bike and about 1200km of riding) a new supercommuter with Shimano hydro discs. Fantastic modulation and power. This bike will get ridden year-round, rain, snow, ice (yup, studded Nokians) and nice weather. The performance of discs is very nice and useful.

Sunday nice ride is a Cervelo R3 with Campagnolo Chorus rim brakes. Great for my "serious" rides. Different needs, different equipment, both have their place.

Having said all of this, waiting for disc technology to settle for my next specialissima... which I would expect to be a Campagnolo full group with discs... 8)
Road bike: Cervelo R3, Campagnolo Chorus/Record mix...
Supercommuter: Jamis Renegade...
Oldie but goodie: De Rosa Professional Slx, Campagnolo C-Record...
And you can call me Macktastik Honey Pete Kicks, thank you.

mnmasotto
Posts: 581
Joined: Mon Jun 06, 2011 7:16 pm
Location: Irvine, CA

by mnmasotto

I have a 2015 Specialized Tarmac S-Works Disc and a 2014 Tarmac S-Works with rims brakes. The Disc brake bike is about 1.5 pounds heavier than the rim brake bike despite spending about 4K on the disc bike for weight savings! The disc brakes work better in every way but are not absolutely necessary. The bike handle and ride the exact same in every way. Both bikes have Enve 3.4 SES wheels. I cannot tell any difference in wind resistance, stiffness, or cross wind susceptibility. I am convinced disc brake bikes are here to stay in a big way but mostly for marketing reasons. I believe disc brakes are a big improvement on mountain bikes but not road bikes.

weenie
Posts: 88
Joined: Mon Nov 11, 2013 6:48 pm

by weenie

One thing i notice is that full-time road bikers, with no experience of discs don't always see how its a benefit. they don't do "precision" braking. they "just brake". Once you get used to the amount of precision its pretty great.

Another thing is that mechanical disc brakes are pretty poor - and that both decent rim and disc brakes can instant-lock-wheels so its not about power. Finally, for the ones that do mtb a bit and like disc brakes - they often find the road discs aren't very powerful. its not the disc or calipers dummy (hint - they're the same). you can lock the wheel remember? The tires are 2 to 3 times narrower. That's what.

Stueys
Posts: 673
Joined: Sat Nov 22, 2014 1:12 pm

by Stueys

I've both, SRAM hydro discs and DA9000 rim brakes. The discs braking performance outperforms the rim brakes in every situation, especially on carbon rims. Can't really comment on whether there's a speed disadvantage to discs as my disc bike is set up as my wet weather ride (guards, cheaper components, heavier Alu frame, etc).

Currently I wouldn't buy a disc frame for my nice ride, the standards are moving around a bit and the wheel manufacturers haven't really started engaging. I think it will get really interesting over the next couple of years though when we start to see wheels fully aero shaped to the rim lip and properly lighter rims.

by Weenie


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