crankarmbreaker

Hi, I'm 39 years old, weigh 350 pounds and am 6 feet 9 inches tall. I have a 20-year-old custom bike, and it's time for a new one. One question that's come up is what kind of brakes to get. The fit specialist tried to steer me towards rim brakes, saying large people warp their disc brakes fast. I've never had disc brakes, but I'm drawn to the idea for their better stopping power. Anyone large person here have experience with the disc brakes vs rim brakes?

p.s. my name is Eric but I thought crankarmbreaker was a cool handle just because it's what I do about once per year. I break pedals two or three times per year.

katsup

What is your old bike and what is wrong with it to make you want a new one? You can post a photo of if once you make 10 posts.

sdmc530

crankarmbreaker

@katsup: The old bike was originally built as a mountain bike and some modifications were made to turn it in to a road bike, but it's got some issues that are still a little weird, for example, it's quite hard to get large chain rings on the front. Also, I'd like to see if I can get a more comfortable setup with a new bike.

crankarmbreaker

@sdmc530: How much do you weigh?

brawlo

I have used both on my road and mountain bikes. I've 'only' been up to around 140kg (310lb). I don't think that there was any real difference in performance TBH, but I will say that I am a big guy at 6'5" (you are bigger) and I have the hand strength to really yank on the road rim brake levers and pull up quickly.

What kind of roads are you riding and what conditions. When you're descending long switchback downhills and in wet conditions, discs win hands down. I would much rather warp a disc than blow a tyre due to rims overheating! If you're like me, and don't really do much if any of that sort of riding, then it really just comes down to what you want/prefer. You can improve rim brakes with different calipers, pads and even rims, just as you can improve discs with pads, levers and disc diameter.

jsigone

likely need a top pull front D, different pull ratio then a bottom pull found on most road builds.

Get disc brakes if you can afford it on the widest hubs possible (future proof)
Get them if you don't ride in tight packs all the time (brake modulation is different and the rim brake guy behind you might rub your wheel since he can't stop as fast)
Get them if you ride in mixed weather/mixed surfaces.

sdmc530

as high as 336, down to around 290 now. I go up and down like a yoyo...

MattTheHat 

A vote for disc brakes here. Disc brakes will generally allow you to run larger tires for a smoother ride. I haven't yet warped a rotor, but I was closer to 265 when I started riding. If you do warp a rotor, you can always straighten it. If it's beyond straightening, you can always replace it.

-Matt

HIPCHIP

Not as big as you, but unless you are going downhill at major speeds I would imagine either brakes would be fine. While a little bit of weight here and there shouldn't matter, I'd say a disc is going to be heavier, so if you can find a good pair of rim brakes it shouldn't matter. Unless you are in a wet area with lots of downhills and have had problems in the past with rim brakes, they should be fine.

69isfine

Gerry221

I am a larger gent too. I have used both. To be honest, not really noticed much of a difference.

If I was pushed, I would say I prefer rim brakes. Much easier to maintain. It's mainly road I ride on, so rim is fine.

jpescatore

I bought a new road bike early last year, my first with disc brakes. I weigh 230 and they are big time better stopping at the bottom of downhills. I don't ride in the rain much, but on a 60 mile ride a few weeks ago an unforecasted rain storm moved in and for 20 miles I got to see how much better disc brakes are than rim brakes.

Years ago when I weighed closer to 270 and was biking in Vermont, I got a few flats from heating up my rims needing to use (pumping) the brakes on long gravel downhills. I think that would happen roughly as often as actually warping disc rotors - haven't had that problem at all.

bikingbill

I live at the top of a long steep climb. At the bottom of the descent, there is a traffic light. I've hit 53mph on this hill.

With Rim brakes, I was taking the temper out of the rim and I'd end up with cracked rims every few 1000 miles. I put on Velocity Chukkers and that solved the problem.

Then I replaced the bike with a similar model, but with discs. Other than having to use bi-metallic rotors to prevent warping, this has worked out quite well.

tyrion

If you're getting a custom build, I think downhill mountain bike disc brakes would be the best. The bigger rotors provide both increased braking power and better cooling.

Note there are 3 general categories of disc brakes: road (160mm discs), mountain bike (180mm discs), and downhill (200mm+ discs). The extra stopping power of mountain or downhill brakes will certainly be safer than rim brakes.

travbikeman

I've never heard of disc brakes warping because of clydes being rougher on them. Not sure if that is really true or not. Had my disc brakes for several years and no warping, their even the Tektro's not the more expensive brands.

Now I have heard and did warp the rear wheel on my bike which would have caused issues braking then if I had rim brakes.

But I like disc due to the sometimes muddy and wet trails I ride on.

fietsbob

Unknown is where you, OP, ride.. hilly or flat, long rides or JRA around locally..

I have 1 heavy load bearing Touring bike with Cantilever brakes , another with Hydraulic rim brakes ..

my Heavy rider option Bike Friday Pocket Llama has Disc brakes, in 20" wheels .. 32 spoke
(BMX rims can be found with as many as 48 spokes.. )
just switched it to a TRP cable operated hydraulic caliper..
I must be careful, these stop me very fast..

[door # 3 ] Drum brake hubs , these are good for year round commuting
near zero service, as their brake shoes are a much larger surface area than rim or disc pads..
none over the past 3 decades..

base2 

Pretty much what has already been said. Both work, are effective, and mature technologies. It is true that disc's warp if over heated & I've personally seen melted IceTech rotors from a tandem. The thing to keep in mind is the heat load. A rotor with more mass/cooling area is going to take a much harder duty cycle in stride while a smaller rotor is going to suffer. Wheel diameter in relation to rotor diameter is going to affect the brake calipers leverage & that is inversly related to modulation.

Say for example: Short reach calipers on a 700c disc. You are at a 1:1 ratio wheel size to rotor size. Your heat load is distributed evenly over nearly 60 square inches of brake track. It takes a lot to get it to blow, but the foul weather performance suffers because of relativly squeeze low pressure and amount of area to clear.

The brake track of a 700c wheel is 7.2 times the area of a 180mm rotor so for the same stop many times more force must be applied and many more times heat is caused in 1/7th of the area (8.27 square inches). The difference is how much input at the lever results in output at the caliper. 7.2 times the range of modulation means you have that much more control. The brake force on discs is simply on a different scale than rim brakes. 7.2 times the force in 1/7th the area causes ~50 times the heat load than rim brakes...assuming my math isn't buggered. Road rotors are designed for higher heat loads.

Beware of the forks maximum rotor size recommendation. I broke a fork once with a rotor that was too big. I've warped plenty of rotors that were too small.

My personal preference on 700c wheels is 180mm IceTech or 180mm Avid rotors and Avid BB7's or TRP Spyre calipers. Both seem to be in the sweet spot for my uses. My commuter + myself is 260 pounds. I have a bike with a 26 inch wheel with the above 180mm&TRP combination and it is TOO touchy for my taste. So there is a such thing as too much of a good thing. I've never warped a centerlock type design, but that may be coincidence. 160mm rotors had more modulation, but faded to uselessness too easily.

Hope I helped.

radroad

I haven't been following disc brake development in bikes very closely. Is the trend towards larger rotors, or has the industry settled on a standard for skinny tire bikes? I like the idea of access to wider tires with discs, along with a little bit of an edge in wet/rainy conditions over rim brakes, but a 1 or 2 lbs weight disadvantage on an expensive, higher end road bike would grate at me a bit if one of the benefits is supposed to be lighter weight.

OP, if you do go with rim brakes, go with established higher end brakes: 105 on up in Shimano for example. Avoid the generics such as tektro's or "axis" (relabeled tektro) brakes.

Seattle Forrest

Stopping power is mostly limited by your tires. I'm good conditions, you'll have the same power with either type of brake, on the same tired. But disc brakes give you better control over how much power to use (better modulation). In the wet, discs win hands down.

I've warped a rotor once, I think it happened transporting the bike. A rotor truing tool is $10 or so. I've cooked my hydraulic fluid twice, both times descending a high mountain pass on hot days with car traffic. Only the rear brake, and it costs about $40 to have a brake line bled. I've also had rim brakes fade, descending on a hot day on black carbon rims.

I prefer disc brakes for safety reasons, and because they don't chew my rims up.

xraydog

Another vote for disk brakes with one caviat..... pneumatic disk brakes.

I am a large guy (265lbs) and live in the mountains of Northcentral PA. I have had bikes with cable disk brakes and were not impressed with their stopping power. My latest bike has pneumatic disk brakes that make me feel very secure and have great modulation and stopping power matched with appropriate tires as mentioned previously.

fietsbob

air brakes are on heavy goods, trucks,
pedal bike brakes are hydraulic , cable mechanical or cable pulled hydraulic..

crankarmbreaker

I ride in Western Washington state, which frequently involves long descents of 2000' of elevation loss when riding in the mountains. My idea behind getting this bike is to use it on the Ride Around Mt. Rainier in One Day, which involves two big mountain passes and one small one over the course of 154 miles. So, being huge, I'm afraid I'll warp the disc. I asked about the drum brake, which my parents have on their tandem, but fit guy at the shop looked at me funny and said that I wouldn't have enough hands to operate it.

How much do hydraulic or pneumatic brakes cost?

StephenH

My preference is disk brakes.
One thing to note in relation to weight: Either type of brake is commonly used on tandems, with two people on there. So there's not many 350 lb people out riding, but probably the majority of the tandem teams riding are around that weight together. So it's not so much a weight issue.
One difference is that a typical road bike with disk brakes may have 140mm disk on back, 160 on front, whereas the tandem may have 160 front and rear. So they can be beefed up a bit. That would mainly be a matter of what disk size the frame was intended for. You may find mountain/gravel/cyclocross bikes set up for better brakes than just a road bike.
I've ridden close to a 100,000 miles with disk brakes. I've read lots of arguments for and against them, and with all that, see very little reason to use them or to avoid them. There's advantages and disadvantages, and it all turns into a Ford vs Chevy type of argument. If you find a bike you like that has disks, great. If you find the bike you like and it has rim brakes, great. Either will get you stopped if it's set up right and maintained, either can have some issues if not.
I've used Avid BB5 brakes, didn't like them. Used Avid BB7 brakes, DO like them. Have some kind of Shimano brake on my current bike, don't care for them. The "like/dislike" factor is based on easy of adjustment, not so much the operation. I've never used hydraulic disk brakes, and can't comment on them.

OneIsAllYouNeed

Hey Eric,
Lots of tandem teams that weigh around 350lb together are using 203mm disc rotors front and rear with good success. I've been experimenting on my tandem with different brake rotors to find which are least susceptible to warping. The best rotors are 2-piece rotors that fully float, such as these:
https://www.dp-brakes.com/Shop/p-24-B...ece-rotor.html
https://www.discobrakes.com/?s=0&t=4&c=55&p=1750&tb=006
The next best option are plain steel disc rotors. The other 2-piece rotors (such as Shimano Ice Tech, TRP 33) bend to one side while they're hot.

Note that you'll need most likely need a custom fork for 203mm rotors, as most road/CX forks have 160 or 180mm maximums.

Drag brakes are typically operated by a bar-end shifter. You set it to "on" near the beginning of a long descent, then set it to "off" when your'e ready to start pedaling again.