Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  

Go Back   > >

Classic & Vintage This forum is to discuss the many aspects of classic and vintage bicycles, including musclebikes, lightweights, middleweights, hi-wheelers, bone-shakers, safety bikes and much more.

User Tag List

Thread Tools Search this Thread
Old 06-20-08, 01:53 PM   #1
Thread Starter
Haptown's Avatar
Join Date: Feb 2007
Location: Nashville, Tn
Bikes: Cannondale F500, Mid 80's Fuji Touring Series III, 1979 Raleigh Sports 3spd, 1995 Schwinn Traveler
Posts: 107
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Odd Brake Caliper Placement on old Trek?

I have a friend who has an old Trek 800 series mountain bike (maybe from the '80's?) and it has a set of brake calipers on the rear wheel that are mounted under the chain-stay! Some of you have probably seen this brake design before but I never have. Does anyone have any information about this brake design? It seems a bit odd to me and my friend says that it's a pain in the neck when he rides through mud or snow - the caliper tends to collect the aforementioned like a beaver dam.
Haptown is offline   Reply With Quote
Old 06-20-08, 05:08 PM   #2
Senior Member
Join Date: Apr 2006
Posts: 2,790
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 92 Post(s)
They take a special brake called a "U" brake that that is different from both cantilevers and V brakes. The bosses are in a different place. The theory with the placement was the chain stays are bigger and stronger than the seat stays. This would give you less brake flex. The problem with them is because of the location they filled up with mud and you ended up with no brakes. Roger
rhenning is offline   Reply With Quote
Old 06-20-08, 05:27 PM   #3
Grand Bois
Senior Member
Grand Bois's Avatar
Join Date: Mar 2005
Location: Pinole, CA, USA
Posts: 17,282
Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 359 Post(s)
Just about every mountain bike built in 1987 had them. Those bosses will also take a roller cam brake. I have a Japanese-made Peugeot with the rear brake under the chainstays. It had a Suntour roller cam, but I switched to a Capagnolo Euclid U brake. The brake won't get clogged so badly if you run a fender all the way through it.

Grand Bois is offline   Reply With Quote
Old 06-20-08, 05:28 PM   #4
Bill Kapaun
Senior Member
Bill Kapaun's Avatar
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Bikes: 86 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.
Posts: 10,122
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 403 Post(s)
As mentioned, they are U brakes.
Common from about 87-89.
Bill Kapaun is offline   Reply With Quote
Old 06-20-08, 07:38 PM   #5
Senior Member
Join Date: May 2008
Location: SoCal
Posts: 1,246
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s) brakes from hell. Clog with mud....they attracted mud like Trailer parks and Tornados
merlin55 is offline   Reply With Quote
Old 06-21-08, 07:18 AM   #6
John E
feros ferio
John E's Avatar
Join Date: Jul 2000
Bikes: 1959 Capo; 1980 Peugeot PKN-10; 1981 Bianchi; 1988 Schwinn KOM-10;
Posts: 18,253
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 404 Post(s)
My mountain bike (see signature) has an under-chainstay U-brake and a RollerCam in front. Yes, the rear brake does tend to pick up dirt, but the brakes provide me plenty of easily modulated stopping power. Yes, I would have preferred a more conventional location for the rear brake, but the system I have is not bad.
"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324
Capo: 1960 Sieger, S/N 42624
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1981 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
John E is offline   Reply With Quote
Old 06-22-08, 06:04 AM   #7
Senior Member
Join Date: Nov 2004
Posts: 14,837
Mentioned: 226 Post(s)
Tagged: 1 Thread(s)
Quoted: 1310 Post(s)
There's is another reason for the lack of flex of the U-brake. The mounting studs are are above the rim, as opposed to below it, as in cantilevers or V-brakes. With the studs farther up the stays and closer to the bridge, the stays are more resistant to outward flex in response to braking force.

There was another advantage to the U-brake. Early ATBs had very long chainstays. By the late 1980s, these had shortened considerably and the geometry become more agressive in general. With ther shorter stays, some riders would contact the cantilvers with their heels, dislodging the yoke cable and resulting in no brake. The narrow profile of the U-brake prevented this.

U-brakes are still common on BMX bicycles.

My 1988 GT Karakoram had the best of both worlds. It had a rear U-brake that was mounted on the seat stays.
T-Mar is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -6. The time now is 02:04 PM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.
  • Ask a Question
    get answers from real people!
Click to start entering your question.