Tell Me About Disc Brakes

[97CSI]

Am starting to look at the design for a custom bike. Want a touring machine that can 'do it all'. Fully lugged steel, of course. Couplers to make it easy to travel with. But, am thinking that I want disc brakes. What, if any, are the drawbacks when using disc brakes on the road? Is there a constant drag? Am using Avid mechanical disc brakes on my MTB and would use the same on the new bike. Thanks.

[Smiley]

Check out my co-mo tandem in the photo gallery, It is a coupler with front and rear disc's, Dwan talked me into it. Like you I was reluctant but now that we have them BOY DO THEY Work great. Stop you on a dime and give you 7 cents change in return. We have the Avid BB7 with the largest rotors. Glad I did it cause with pads I used to glaze them over with very fast decents and moduating the brakes.

no squeal and no issues about 100 miles so far and the work better with break in

http://forums.thepaceline.net/showthread.php?t=36795&highlight=tandem

[Lazy Bill]

willy in pacifica has disc (front only?) on his Vanilla randoneur, you might ask him. That is one sharp bike! Maybe search for his pics.

[dbrk]

My Tournesol 650B uses disk brakes. They are remarkably powerful and reliable, plus we designed the bike so that you could use either a 650B wheel or 700c since the overall diameter once you add tires is the same. Unfortunately when this bike was reviewed the reviewers didn't understand dik brake set up and complained that they were ineffective. Anyone who can set up disk brakes properly knows otherwise. They are a good choice especially on tandems but they are sort of overkill on any "regular" unloaded road bike, imho.

dbrk

[samtaylor1]

I have disc breaks on my cross bike (the avid road discs- 2 years ago), work well after you break them in, though it takes a bit. The only problem with disc breaks is that there is often some noise (like a rubbing). Even if they are aligned perfectly there can still be some noise (e.g. there is no resistance when there shouldn't be), which can be annoying, especially if you are used to the quite smooth ride of your road bike. Just something to think about.

[Blue Jays]

My mountainbike has Magura Marta SL hydraulic disc brakes and they are absolutely fantastic. Performance is predictably powerful wet or dry.

I was considering cable-actuated discs for my next roadbike but I understand the arrangement can become a tad challenging when incorporating fenders, lighting, racks, and all that kind of stuff.
As mentioned by dbrk, they are supremely reliable.

[cak]

Disc brakes will work fine, with a few things in mind. Get Avid BB7 for road levers or the Shimano mechanicals for road (BR505). Whichever ones you get, I would highly recommend getting the Shimano centerlock rotors. they actually come straighter than any others I have seen, stay straighter and you still have a good choice on hubs. Don't bother with any others. Setup is easy on both of these, power is wonderful, and I think the biggest benefit of disc brakes on road bikes is the fact that you dont gt the black brake/rim dust that can be so nasty (esp if you ride in the rain).
Andrew

[willy in pacifi]

willy in pacifica has disc (front only?) on his Vanilla randoneur, you might ask him. That is one sharp bike! Maybe search for his pics.

Mine has discs F&R and they are fantastic. I have a Taylor cross bike with discs F&R as well. The Vanilla has the Avid 7's which allow micro adjusting on the caliper both inboard and outboard, whereas, the Taylor's Avid 5's only allow adjusting on the outboard side. Get the Avid 7's as they will allow you to get the brakes tighter.

[97CSI]

Very nice! Looks very much like what I'm am having built by Harry Havnoonian in Media, PA. We live 'down the shore', but our house in Media is literally across the street from Cycle Sport, which is Harry's LBS. I placed my order about three hours ago. Thanks for the tip on the 7s vs. 5s.

Another question. Why couldn't the rear caliper be mounted on top or below the chainstay rather than the seatstay? Any reason(s)?

[willy in pacifi]

Another question. Why couldn't the rear caliper be mounted on top or below the chainstay rather than the seatstay? Any reason(s)?

The only compromise I made on the bike was the rear caliper mounting. My full intention was to have the rear mounted on top on the left chainstay so the cable could run down the downtube and keep the top tube and left seat stay nice and clean. But the Vanilla "V" stainless disc dropouts would not allow it so it was either the drop out or the mount and I wanted the SS V Dropout. But I would have him do it on the chain stay if I were you to keep it nice and clean.

I would guess your builider has built bikes with disc brakes but depending on where the caliper is mounted you have to worry about being able to remove the rear wheel easily. If he has not built a bike with the caliper on the chain stay he would jsut have to be sure you can remove the rear wheel from the drop out easy enough.

Me, I need to be able to remove the wheel in the dark at 3am if need be.

willy in pacifica

[Blue Jays]

willy in pacifica, that is beautiful and well-executed for sure! Congratulations on a fantastic bike.

[xjoex]

I have them on my cros bike, I love them.
http://i62.photobucket.com/albums/h85/boulderjoe/bikes/100_0563.jpg

[97CSI]

Willy - What hubset are you using in order to fit the disc? I will also be running a Campy group. That is a nice bar with the tight bend. What is it?

Am pleasantly surprised to see a bike so close to what I am having built. One major difference will be that I'm having mine built with S&S couplers. HHR had a 51cm touring with S&S couplers on the shelf. The lugs for the couplers matched the rest of the lugs on the bike. Very nice, indeed. I'll probably go for Ferrari red, though.

[willy in pacifi]

Willy - What hubset are you using in order to fit the disc? I will also be running a Campy group. That is a nice bar with the tight bend. What is it?

I am running Chris King hubs. You are going to have a hard time finding Campydisc hubs. I wanted campy shifters to get both a clean look and to get the cable out of the way to allow for the bar bag.

Other than the campy shifters I am running shimano everywhere else. But, if you want to run Campy you will still want to run a Shimano compatible 135mm rear hub so be sure to have the builder make the rear 135mm. I am sure he is aware of this. campy does make a 130mm disc hub but you would be hard pressed to find one and probably do not want one.

What you need is a Jteck gizmo. It will change the Campy rear shifter cable pull to Shimano cable pull and works like a charm. I have it on a couple of bikes and it is very popular amongust tandem riders.

I also like the Ritchey WCS Ergo bars as they are very comfy. And when I say comfy I mean comfy as I ride my bke upwards of 300-400 miles a day and the whole bike works and fits like a glove.

willy in pacifica

[Blue Jays]

/\/\ 400 miles in a day? Holy cow!

[97CSI]

Don't see anything on this or any other bike I own being Shimano. Am thinking of a set of Mavic disc wheels. May have to be relaced to Open Pro CD rims, or something similar to carry the tires I want. Will take some investigation to decide what, exactly.

Why the 135mm spacing? Is that required for the disc?

Are you riding brevets?

Thanks for the info.

[willy in pacifi]

/\/\ 400 miles in a day? Holy cow!

I rode the Vanilla on PBP this past year which is 760 miles in about 3 days. The 600k's (375 miles) I can get done around 30 hours and I have a 24 hour TT in a few months and hope to get 350ish. The TT is a ***** because of course you have to ride along and no drafting.

There is a time trial in Sept which is 516 miles I plan to do. They allow a follow van but no drafting. I plan to do it in a different kind of division where you do not even get a follow van so have to ride on your own with no assistence for the whole ride. They will allow a drop bag around 100, 200 and 400 miles which should help alot so I do not have to carry so much food. Not sure if I will use the disc Vanilla or one of the other Vanillas I have. The disc Vanilla would work great due to the bags and the generator hub but it is a bit heavier and I would not be able to put aerobars on it with the bag. I may grab my road Vanilla and use the aerobars. On the Davis 24 hour TT I will use the aerobar'd Vanilla and see how comfy it is for 24 hours. I know the disc Vanilla is comfy forever...or at least 760 miles so far.

willy in pacifica

[willy in pacifi]

Don't see anything on this or any other bike I own being Shimano. Am thinking of a set of Mavic disc wheels. May have to be relaced to Open Pro CD rims, or something similar to carry the tires I want. Will take some investigation to decide what, exactly.

Why the 135mm spacing? Is that required for the disc?

Are you riding brevets?

Thanks for the info.

Almost all of the disc hubs are built for Mt Bikes so 135mm spacing. You can run all your Campy stuff as long as you use the Jtek gizmo and you will have to run a "Shimano" compatible hub since campy does not make a disc hub. Besides this way you can use any disc hub. The hub does not have to be Shimano only Shimano compatible. Then you have to use a shimano compatible cassette but you can get a Sram if you do not want
Shimano. Both of my disc bikes use Record 10 speed shifter but I run shimano compatible 9 speed cassettes. The gizmo will allow you to use the Record 10 speed shifter with either 9 or 10 in the rear.

Yes, the Vanilla was built for PBP last year and I ride brevets. We just started the season and I am riding a 200k tomorrow then a 300k in a couple weeks. I love the 400k and 600k the best since we get to ride a lot in the dark. Very peaceful riding in the dark at 3am. Not a lot of traffic to worry about.

willy in pacifica

[Orin]

Am starting to look at the design for a custom bike. Want a touring machine that can 'do it all'. Fully lugged steel, of course. Couplers to make it easy to travel with. But, am thinking that I want disc brakes. What, if any, are the drawbacks when using disc brakes on the road? Is there a constant drag? Am using Avid mechanical disc brakes on my MTB and would use the same on the new bike. Thanks.

I have two things to say about disc brakes on a (single) road bike.

1. A complete waste of time on the rear.

2. A good idea on the front if you ride in the wet. Discs are a lot easier to replace than rims.

For tandems, 1 doesn't apply. Put the biggest disc back there that you can.

Orin.

[Blue Jays]

Orin, what kind of setup do you run with that combination? Avid front and Paul rear, or something like that?

[palincss]

My Tournesol 650B uses disk brakes. They are remarkably powerful and reliable, plus we designed the bike so that you could use either a 650B wheel or 700c since the overall diameter once you add tires is the same. Unfortunately when this bike was reviewed the reviewers didn't understand dik brake set up and complained that they were ineffective. Anyone who can set up disk brakes properly knows otherwise. They are a good choice especially on tandems but they are sort of overkill on any "regular" unloaded road bike, imho.

dbrk

We were discussing disk brakes on road bikes the other day on the KOG list. Here's what some posters had to say::


It's the levers and brakes. The brakes are simply a modified MTB design and such were never designed for road use. A road specific disc should, IMO, have a smaller rotor (since road tires have a smaller contact patch) and a cable pull optimized for STI, DoubleTap and Ergo levers. The brake should have less overall stopping power than a MTB disc as well as more modulation. Of course it would be even better if they were hydraulic but that's still a ways off. Hydra road brakes would be very low maintenance. Pads can be changed in seconds without any tools, adjustments are rarely needed since there are no cables to stretch. There's a reason why motorcycles and cars use them (even racing models where weight IS a big concern just as it is with bicycles)

and:


With a mechanical disc like the BB7, proper setup and stiff housing
make all the difference in performance and feel. Avid markets a
similar "flak jacket" product which I've had good experience with.

I've owned a set of first generation Avid discs since 2001 or 2002,
and I've spent a far amount of time with other (specifically hydraulic
setups) and for my purposes, you'd be hard pressed find a better brake
than the BB7.

I've never run Road BB7s or used MTB BB7s with long-pull levers like
the Dia Compe 287-V, but I've heard good things about pairing a
quality road lever with Avid's short-pull calipers and generally
ambivalent reviews w/ the 287-V. I've also heard drop bar disc setups
are particularly sensitive to lengthy housing (run for instance under
bar tape) and minimizing your cabling is key to alleviating mushy discs.

Running a standard flat/mtb bar lets you use hydros (they're a closed
system) or run standard disc specific mountain levers as they were
intended. (I run XTR v-brake levers.) With a little tuning, they
should run wonderfully.

[ericspin]

This is very interesting to me and I hope this thread gets worn out with much info. I am a big fan of discs from MTBing and had BB7's on the TiMax which I loved. I love canti's but hate all the fidgeting required to solve the squeal. The tire size possibilities with discs seem endless also. I no longer am uptight about weight as I have found with the proper motor I can push what I need to as long as I am COMFORTABLE. I am intrigued by Willy's setup and can envision such a setup on my upcoming Kirk. I am most interested these days with time in the saddle rather than max. speed at the end of the ride.

Please continue.

Eric

[palincss]

I love canti's but hate all the fidgeting required to solve the squeal.


If it's squeal you're interested in, by far the worst shrieking I've ever heard from a bicycle brake was from the rear disk on a tandem. No idea what was wrong with it, if anything; but this squeal felt as though it could shatter glass. It wasn't the "oh my god, an accident is happening" squeal of Mafac centerpulls, or the howl of a cantilever; this actually made your body hurt.

[97CSI]

Sounds (pun intended) as if the pads/rotors are glazed. Time to get out the crocus cloth and do a bit of tune-up.

My plan is for BB7 road models with a 203mm rotor up front and 160mm in the rear to reduce the power back there. With my 200 pounds and 30 pouinds of cargo I am not worried about 'too much brakes'. Especially rolling off the longs hills I will be riding in VT, VA, CO, down the west coast, etc. and using 28 and larger tires. Might even go crazy and pull a small trailer on some rides. My biggest question is flat bar or drop. The WCS that Willy is using looks to be an excellent compromise.

Another question - while it is obvious that I'll be running a Shimano freehub, is the JTeck gizmo that Willy mentions needed if I simply use Campy spacing in the cassette?

[ericspin]

. My biggest question is flat bar or drop. The WCS that Willy is using looks to be an excellent compromise.




I have a hell of a time getting comfortable on flat bars after years of drops. I never can get it so that I don't end up with _locked_ elbows. The drops just offer so many positions to switch up. I agree with Willy, I use the same Ritchey's and love them.

[gdw]

You might be able to use a Hugi 240s disk rear hub. I believe that you could simply swap the Shimano freehub for a Campagnolo one and be ready to roll without special adaptors like the JTEK. Contact DT Swiss at 970 242 9232 to see if there are any potential problems. The 240s is available in both center lock and standard six bolt pattern

[paczki]

Has anyone tried a randonneuring setup with disc brakes and a Rohloff hub? Or is the Rohloff just too drop bar unfriendly.

[goonster]

Has anyone tried a randonneuring setup with disc brakes and a Rohloff hub? Or is the Rohloff just too drop bar unfriendly.

It's been done. (Well, no disc brakes here, but it's a rando-specific rig from ANT)

The shifting options for the Rohloff are a bit kludgy, but I guess it's a question of priorities.

http://www.antbikemike.com/images/Bikes/Rohloffbig.jpg

There was a Rohloff-specific bike at PBP, but I can't remember the details. Perhaps someone can find a picture.

[97CSI]

OK.....now that my questions have been answered concerning disc brakes for the road, am wondering about wheels.
- Who makes 700 size wheels for the road that are set up for international standard disc rotor? Or, does one have to build the wheels?
- Does anyone know anything about Bell Pro II hubs? The seller tells me that they are excellent quality and made in the UK and parts are readily available. I wonder?

[T-Crush]

I picked up a pair of Mavic Speed City wheels for my Cannondale 'Cross Disc so I could ride it on the road without changing times. They are nice, not Ksyrium ES or handbuilt nice, but they do the job without complaint and make the bike that much more versatile.

[willy in pacifi]

[QUOTE=gpdavis2]OK.....now that my questions have been answered concerning disc brakes for the road, am wondering about wheels.
QUOTE]

I forgot to mention one important detail. Have the rear and front fork, if he is building you one, also built to take the long reach brakes. If you do not like the discs or decide in years to come to go with a traditional set up you are set to go. Mine is built for both and the brake mounts are used to mount the fenders anyways.

Also if you notice on my Vanilla, Sacha built a "light rack' to mount my lights where I like them and to house the wiring. Very clean and with three screws the whole set up comes off and I lose a couple pounds by putting on a regular front wheel instead of the Schimtt hub.

Also, I wanted my bike to look super clean. By having disc brakes I can use the non-machined Velocity rims with the black sidewalls and do not have to worry about rim brake pads wearing the black off. So a disc in the front rim in the back would work fine but it would ruin the look I was going for. Just something to consider and the disc brakes work great Front & rear.

You can buy generic Shimano disc 700c wheels on Ebay for a couple hunderd bucks new. There are a lot of item like this due to the 29ers. May be a bit tougher than you need but would make a great back up set. Otherwise jsut buy a couple of hubs and rims and have the bike shop build you a set you like. WTB has some nice black very light hubs that are lighter than Chris King and inexpensive. Since they are built for MT bike they should be very durable for a roadbike.

willy in pacifica

[Orin]

Orin, what kind of setup do you run with that combination? Avid front and Paul rear, or something like that?

My experience is with an Avid BB7 8" rear disc on a tandem with a junk Shimano canti on the front. It's major function seems to be to make noise. The disc does almost all of the braking and I hardly use the front brake. Note that I run my single bikes with front brake on the right. The tandem is rear disc on the right. I hardly ever use my left hand for braking on either.

I'm looking to run an Avid front on one of my road bikes, but I haven't found a suitable fork. Plenty of cross forks around, but they are too long.

Orin.

[97CSI]

Orin - have a fork built to your spec.

And, my crow is tasting pretty good. Just bought a set of XT hubs with the ISO 6-bolt disc pattern. New for under $100 seemed like a good place to start on building wheels. Will have them laced to a set of Mavic rims.

And, yes.....definitely having the bike built with the fork crown/rear brake bridge so can use long-reach pivoted brakes should I wish to do so.

[97CSI]

OK.....another question. Does anyone know the difference between Avid's road and MTB disc brake systems? They are listed as different on their website, but they no longer have any method for direct contact for questions on same. Thanks.

[gdw]

The MTB version were designed to work with v brake levers which pull more cable than road levers. The road version are modified to work with both standard road and cantilever levers.

[97CSI]

Thanks. Just ordered the road set with a 203mm front rotor and 160mm rear rotor. Stock-piling of parts for the build kit has begun (have the hubs, headset and, now, brakes).

[97CSI]

Wonder how much of this applies and is real for road bikes with disc brakes? http://www.ne.jp/asahi/julesandjames/home/disk_and_quick_release/index.html

[rudetay]

If you're worried about the disk pulling the QR out, just run a bolt-on skewer or the DT Swiss RWS skewers.

I haven't had any issues with my QR front on my cross bike with a 160mm disk, but I haven't had it for too long. I could see it being more of an issue with a larger rotor. The DT Swiss ratcheting skewers seem like a very good idea, more solid mounting and no need for an extra tool or taking more time to swap wheels.

I like the center lock system for road/cross disk wheels, as the hubs themselves are similar in weight and style to standard road hubs, and you can even put the rubber shield over the CL section when using rim brakes on non-disk bikes for a clean look. I've heard mixed reviews of compatibility between XT/XTR centerlock rotors and BB7s though. Xjoex doesn't seem to have any issue. I have only used an adaptor to a normal Avid 6 bolt rotor (similar in weight to a 6 bolt hub or CL+CL rotor with the DT Swiss adaptor)

I'm running a BB7 in the front and an older Avid Shorty 6 in the rear with Record 10 levers. I'd like to upgrade to a Paul in the rear, but it works fine as it is.

I just prefer disks for the smooth, predictable, brake response in all conditions. Once the pads wear in mine have been silent, and I've had no issues with rubbing, the BB7s are very easy to fine tune.

[WadePatton]

i've lived happy with BB7's for off road for years now. try different pads for more/less bite. wonderfully simple and effective.