Go Back  Bike Forums > Bike Forums > Classic & Vintage
Reload this Page >

U brake questions

Notices
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.

U brake questions

Old 06-28-20, 08:07 PM
  #1  
bikemig 
Senior Member
Thread Starter
 
bikemig's Avatar
 
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 17,032

Bikes: A bunch of old bikes and a few new ones

Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 4523 Post(s)
Liked 820 Times in 581 Posts
U brake questions

I'm fixing up a 1989 Specialized rockhopper (I think it's an '89, late 80s for sure with the u brake) for my nephew as a commuter/college bike. It's around 10 years older than he is so he thinks it's seriously vintage.

The u brake isn't working right. The left arm (on the non drive side) has weak spring action. The right has a very strong spring action. I took the arm apart and the spring on the left side looks great. Put it back in and no joy.

So I think these are my options:

(1) Buy a new u brake. They're easy to find but they all have pretty short reach since they're designed for bmx bikes (30-50 mm); the u brake on this bike has a reach of 90 mm. Or am I just measuring this wrong? Is there a new u brake that will work on an old mountain bike?
(2) Find a used MTB u brake.
(3) Replace the spring? The spring looks a lot like the spring you would find on a cantilever so maybe I can track down an old canti and just rob the spring.

Any other options? The bike looks pretty good and it's ready to go once I get the u brake working.




Last edited by bikemig; 06-28-20 at 08:12 PM.
bikemig is offline  
Old 06-28-20, 08:42 PM
  #2  
Miele Man
Senior Member
 
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,054

Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1084 Post(s)
Liked 631 Times in 438 Posts
On the chainstay U-brake mount, is there more than one hole that the spring can fit into? No?

Is there a bolt on the side of one of the caliper arms? If yes, then turn that bolt in or out to increase/decrease spring tension.

Some of the videos I've watched show a flat on the U-brake spring holder. You turn that flat and hold it in position and then tighten the retaining bolt that holds the brake arm to the brake stud.

Cheers
Miele Man is online now  
Old 06-28-20, 08:45 PM
  #3  
bikemig 
Senior Member
Thread Starter
 
bikemig's Avatar
 
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 17,032

Bikes: A bunch of old bikes and a few new ones

Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 4523 Post(s)
Liked 820 Times in 581 Posts
Originally Posted by Miele Man View Post
On the chainstay U-brake mount, is there more than one hole that the spring can fit into? No?

Is there a bolt on the side of one of the caliper arms? If yes, then turn that bolt in or out to increase/decrease spring tension.

Some of the videos I've watched show a flat on the U-brake spring holder. You turn that flat and hold it in position and then tighten the retaining bolt that holds the brake arm to the brake stud.

Cheers
Yeah there's a tensioner but only on the right side, cheesy. And there's only one hole. I thought about trying to tighten up the action on the spring; so I'll do some digging for some videos!
bikemig is offline  
Old 06-28-20, 09:18 PM
  #4  
dddd
Ride, Wrench, Swap, Race
 
dddd's Avatar
 
Join Date: Jan 2010
Location: Northern California
Posts: 7,342

Bikes: Cheltenham-Pederson racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.

Mentioned: 100 Post(s)
Tagged: 0 Thread(s)
Quoted: 846 Post(s)
Likes: 0
Liked 255 Times in 196 Posts
I am remembering some versions of the rear Shimano U-brake where one had to remove the pivot bolt and then insert a 6mm hex key to wind the spring, followed by holding it (the arm) in place and then re-installing the bolt.

I also recall that perhaps the correct direction to turn the hollow hex was not so intuitive. I found it maddening at first, and with time having passed I vowed to never mess with these unless absolutely necessary!

The parts are robust so not prone to failure in this area.
dddd is offline  
Old 06-28-20, 09:25 PM
  #5  
TenGrainBread 
Senior Member
 
TenGrainBread's Avatar
 
Join Date: Sep 2015
Location: Madison, WI
Posts: 2,550

Bikes: Cherubim, Alps, a few Schwinns

Mentioned: 51 Post(s)
Tagged: 0 Thread(s)
Quoted: 1054 Post(s)
Liked 358 Times in 237 Posts
If you get to the point where you need to replace the brake, Dia Compe still makes their AD-990 brake and it should have pretty similar specs to the Shimano brake. Plus the spring adjustment is super easy with the BMX-style spring tension nuts on each pivot. And at $30 a piece, pretty well-priced.
TenGrainBread is offline  
Old 06-29-20, 04:52 AM
  #6  
John Nolan 
Senior Member
 
Join Date: Apr 2007
Location: Ottawa, Canada
Posts: 526

Bikes: Raleigh Classic 15, 84; Miyata Ridge Runner SE, 85; Miyata 610, 86; Miyata 100M, 86; Miyata Valley Runner, 88; Miyata Triple Cross, 89; GT Karakoram, 90; Miyata Elevation 300, 91; Marinoni Touring, 95; Long Haul Trucker, 2013

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Liked 28 Times in 19 Posts
Forgive me if I'm stating the obvious, but just to be sure:

Have you read Sheldon's instructions for u-brakes or Park Tools' instructions?

You know how the tension is set, right?

"Install the arms with them at their maximum spread and tighten the bolts that hold them to the frame. This is how you set the springs."

Last edited by John Nolan; 06-29-20 at 04:55 AM.
John Nolan is offline  
Likes For John Nolan:
Old 06-29-20, 09:45 AM
  #7  
bikemig 
Senior Member
Thread Starter
 
bikemig's Avatar
 
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 17,032

Bikes: A bunch of old bikes and a few new ones

Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 4523 Post(s)
Liked 820 Times in 581 Posts
Originally Posted by dddd View Post
I am remembering some versions of the rear Shimano U-brake where one had to remove the pivot bolt and then insert a 6mm hex key to wind the spring, followed by holding it (the arm) in place and then re-installing the bolt.

I also recall that perhaps the correct direction to turn the hollow hex was not so intuitive. I found it maddening at first, and with time having passed I vowed to never mess with these unless absolutely necessary!

The parts are robust so not prone to failure in this area.
Agreed these are not parts prone to failure so I need to do some homework on installing this correctly. These are a pita to work on but once they are dialed in, they are very reliable. It will make a good college bike for my nephew.
bikemig is offline  
Old 06-29-20, 09:46 AM
  #8  
bikemig 
Senior Member
Thread Starter
 
bikemig's Avatar
 
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 17,032

Bikes: A bunch of old bikes and a few new ones

Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 4523 Post(s)
Liked 820 Times in 581 Posts
Originally Posted by TenGrainBread View Post
If you get to the point where you need to replace the brake, Dia Compe still makes their AD-990 brake and it should have pretty similar specs to the Shimano brake. Plus the spring adjustment is super easy with the BMX-style spring tension nuts on each pivot. And at $30 a piece, pretty well-priced.
Cool. That is one possible solution.

Do you know the reach on this? Or have you installed this on a MTB with a u brake?

This is the manufacturer's site on the u brake but it does not provide the specs. The u brakes I have found online are, I think, too short to work on this bike.

https://www.diacompe.com.tw/product/ad990/

Last edited by bikemig; 06-29-20 at 09:50 AM.
bikemig is offline  
Old 06-29-20, 09:53 AM
  #9  
bikemig 
Senior Member
Thread Starter
 
bikemig's Avatar
 
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 17,032

Bikes: A bunch of old bikes and a few new ones

Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 4523 Post(s)
Liked 820 Times in 581 Posts
Originally Posted by John Nolan View Post
Forgive me if I'm stating the obvious, but just to be sure:

Have you read Sheldon's instructions for u-brakes or Park Tools' instructions?

You know how the tension is set, right?

"Install the arms with them at their maximum spread and tighten the bolts that hold them to the frame. This is how you set the springs."
Oops, I should have used google first,

Thank you for this post. The brakes worked perfectly before though (I've had the bike for a few years) and the tension proved insufficient when I fixed the bike up to ship to my nephew. I assumed that this was due to a parts failure which is why I was thinking about a replacement in my initial post. Still I need to try this out and see if it solves the problem!

Last edited by bikemig; 06-29-20 at 09:56 AM.
bikemig is offline  
Old 06-29-20, 09:58 AM
  #10  
dddd
Ride, Wrench, Swap, Race
 
dddd's Avatar
 
Join Date: Jan 2010
Location: Northern California
Posts: 7,342

Bikes: Cheltenham-Pederson racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.

Mentioned: 100 Post(s)
Tagged: 0 Thread(s)
Quoted: 846 Post(s)
Likes: 0
Liked 255 Times in 196 Posts
Those directions from park and from Sheldonbrown.com may not apply to the OP's U-brake.
There are some huge variations in the sprung pivot design on some Shimano U-brakes that require certain knowledge and/or experimentation/research to assemble properly.
Fear not though, it's doable!
dddd is offline  
Old 06-29-20, 09:59 AM
  #11  
John Nolan 
Senior Member
 
Join Date: Apr 2007
Location: Ottawa, Canada
Posts: 526

Bikes: Raleigh Classic 15, 84; Miyata Ridge Runner SE, 85; Miyata 610, 86; Miyata 100M, 86; Miyata Valley Runner, 88; Miyata Triple Cross, 89; GT Karakoram, 90; Miyata Elevation 300, 91; Marinoni Touring, 95; Long Haul Trucker, 2013

Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Liked 28 Times in 19 Posts
I have those brakes, and those instructions seem appropriate.
John Nolan is offline  
Old 06-29-20, 10:45 AM
  #12  
tricky
Senior Member
 
Join Date: Oct 2005
Location: Upper Left, USA
Posts: 1,260
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 340 Post(s)
Liked 92 Times in 72 Posts
I replaced the Shimano U-Brake on my 87 Fisher Hoo-koo-E-Koo with this and it worked well after I replaced the pads. https://www.modernbike.com/diatech-g...-black-u-brake

I can't vouch for your exact situation but your u-brake looks very similar to the one I replaced. I bet a new u-brake would work, but if you go that route, buy from a shop that allows returns just in case.
tricky is offline  
Old 06-29-20, 11:05 AM
  #13  
fleslider 
Senior Member
 
fleslider's Avatar
 
Join Date: Feb 2014
Location: Fort Collins, CO
Posts: 1,381

Bikes: 1974 Paramount ~ 1974 Raleigh Pro ~ 1977 Pro-Tour ~ 1978 TX900 ~ IronMan 85,87:E/M,88:M/Pro,89:E ~ 98 Peugeot Festina Replica

Mentioned: 85 Post(s)
Tagged: 0 Thread(s)
Quoted: 433 Post(s)
Liked 67 Times in 37 Posts
I have the same Shimano Deore UBrake on my 1988 GT Karakoram. the instructions noted above worked perfect for me
__________________
fleslider is offline  
Old 06-29-20, 12:07 PM
  #14  
bikemig 
Senior Member
Thread Starter
 
bikemig's Avatar
 
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 17,032

Bikes: A bunch of old bikes and a few new ones

Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 4523 Post(s)
Liked 820 Times in 581 Posts
Originally Posted by tricky View Post
I replaced the Shimano U-Brake on my 87 Fisher Hoo-koo-E-Koo with this and it worked well after I replaced the pads. https://www.modernbike.com/diatech-g...-black-u-brake

I can't vouch for your exact situation but your u-brake looks very similar to the one I replaced. I bet a new u-brake would work, but if you go that route, buy from a shop that allows returns just in case.
Yeah I've been wondering how to measure the reach on a u brake. If I measure from the "center" of where the two arms cross, I get a reach of a bit over 90 mm. With caliper brakes you measure from the bolt hole brake center but of course there is no center bolt with a u brake.

So I guess with u brakes, you measure from the bolt hole which the arm is screwed into. If that's the case, then the reach on my bike is 44 mm and this brake will work perfectly. I may give this a try since Modern Bike is a few blocks from my house which makes returns easy as pie.
bikemig is offline  
Likes For bikemig:
Old 06-29-20, 12:45 PM
  #15  
tricky
Senior Member
 
Join Date: Oct 2005
Location: Upper Left, USA
Posts: 1,260
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 340 Post(s)
Liked 92 Times in 72 Posts
Originally Posted by bikemig View Post
Yeah I've been wondering how to measure the reach on a u brake. If I measure from the "center" of where the two arms cross, I get a reach of a bit over 90 mm. With caliper brakes you measure from the bolt hole brake center but of course there is no center bolt with a u brake.

So I guess with u brakes, you measure from the bolt hole which the arm is screwed into. If that's the case, then the reach on my bike is 44 mm and this brake will work perfectly. I may give this a try since Modern Bike is a few blocks from my house which makes returns easy as pie.
Yeah, that's also what I was thinking regarding how to measure the reach on these. Keep us updated on your progress. There isn't much info out there on upgrading u-brakes on vintage mountain bikes despite their being lots of u-brakes on the market. The more documentation, the better.
tricky is offline  
Old 06-29-20, 08:48 PM
  #16  
TenGrainBread 
Senior Member
 
TenGrainBread's Avatar
 
Join Date: Sep 2015
Location: Madison, WI
Posts: 2,550

Bikes: Cherubim, Alps, a few Schwinns

Mentioned: 51 Post(s)
Tagged: 0 Thread(s)
Quoted: 1054 Post(s)
Liked 358 Times in 237 Posts
Originally Posted by bikemig View Post
Cool. That is one possible solution.

Do you know the reach on this? Or have you installed this on a MTB with a u brake?

This is the manufacturer's site on the u brake but it does not provide the specs. The u brakes I have found online are, I think, too short to work on this bike.

AD990 | DIA-COMPE
While I won't guarantee 100% that it will fit your bike, the Dia Compe 990 u-brake was specced on many mountain bikes in the late 80s and should be fine for your bike. The reach was the same for all of the variations of the brake so I'm pretty sure it will reach your rims. These brakes are designed for BMX bikes which generally have tires in the 2"-2.2" range, just like mountain bikes.

By the way, I see someone else posted a Dia Compe Diatech 996 brake ("Gordo"). Be aware that this model is die-cast instead of forged, which is a weaker production method. The 990 model is forged and only $10 more. Plus I much prefer the adjustability of the post-mount brake pads on the 990 than the threaded mount of the 996.
TenGrainBread is offline  
Old 07-10-20, 10:05 AM
  #17  
bikemig 
Senior Member
Thread Starter
 
bikemig's Avatar
 
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 17,032

Bikes: A bunch of old bikes and a few new ones

Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 4523 Post(s)
Liked 820 Times in 581 Posts
I ended up having to replace the rear u brake. I couldn't get the tension right and I didn't want this to fail down the road. I bought a black ops rear u-brake mainly because it was available locally. The price wasn't bad at $20. It is melt forged.

It's as easy as pie to adjust the spring tension on these brakes. I learned a few things. One is that the reach on u-brakes is measured from the frame braze on to the opening on the brake. That makes sense but I wasn't certain of that before buying one. The other is that the brake pad that came on the new u-brake was too long. To work right on an old MTB with the u brake under the chain stays, I needed to replace them with the shorter brake pads and holders found on road bikes. U-brakes are a pain to work on and a stand is a big help.

In my experience, u brakes are a solid design. They did not work well for mountain biking because they got gunked up. But they are fine for road riding which is what this bike is going to be used for. I've been riding the bike around and everything is working well. I'll ride it a few more times over the weekend and then ship it off to my nephew who is looking forward to his new old bike.



Last edited by bikemig; 07-10-20 at 10:29 AM.
bikemig is offline  
Likes For bikemig:
Old 07-10-20, 10:18 AM
  #18  
clubman 
Youngman Grand
 
clubman's Avatar
 
Join Date: Jan 2010
Location: Nova Scotia
Posts: 6,465

Bikes: roadsters, club bikes, fixed and classic

Mentioned: 92 Post(s)
Tagged: 0 Thread(s)
Quoted: 1381 Post(s)
Liked 400 Times in 277 Posts
Pretty bike! Love yellow and blue.
clubman is offline  
Old 07-10-20, 10:39 AM
  #19  
John E
feros ferio
 
John E's Avatar
 
Join Date: Jul 2000
Location: www.ci.encinitas.ca.us
Posts: 19,844

Bikes: 1959 & 1960 Capo; 1982 Bianchi; 1988 Schwinn KOM-10;

Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 815 Post(s)
Liked 172 Times in 138 Posts
Does anyone else with a U-brake in back have a U-brake or SunTour RollerCam (same above-rim pivot mounting) up front? Your Rockhopper has a regular cantilever (pivots below rim) up front, as do the other Project KOM-10s I have seen. Is mine that unusual?

For the record, I am extremely pleased with both brakes on my KOM-10.
__________________
"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 (2), S/N 42624, 42597
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069
John E is offline  
Old 07-10-20, 10:55 AM
  #20  
clubman 
Youngman Grand
 
clubman's Avatar
 
Join Date: Jan 2010
Location: Nova Scotia
Posts: 6,465

Bikes: roadsters, club bikes, fixed and classic

Mentioned: 92 Post(s)
Tagged: 0 Thread(s)
Quoted: 1381 Post(s)
Liked 400 Times in 277 Posts
Nishiki had Rollercams front and back as well as High Sierra's.
clubman is offline  
Old 07-10-20, 11:13 AM
  #21  
madpogue 
Senior Member
 
Join Date: Jan 2004
Location: Madison, WI USA
Posts: 4,737
Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 1492 Post(s)
Liked 565 Times in 434 Posts
Most of what you describe about working with the u-brake has nothing to do with it being a u-brake. A u-brake mounted on the seat stays or the fork does not present these problems, including those related to riding in dirt/mud.

I see your new u-brake has flats for adjusting the tension on each arm individually. That design does make balancing the brake a LOT easier.

I have been able to use long-ish brake pads on u-brakes in a couple cases. The end of the pad hits the stay / fork when the brake is released for wheel removal, but it still releases enough to allow the wheel to be removed. A wide tire might need to be deflated first.

John E , my GT Outpost has u-brakes mounted on the seat stays and fork. My Schwinn High Sierra has roller-cam brakes mounted on the seat stays and fork.
madpogue is offline  
Old 07-10-20, 04:48 PM
  #22  
bikemig 
Senior Member
Thread Starter
 
bikemig's Avatar
 
Join Date: Apr 2012
Location: Middle Earth (aka IA)
Posts: 17,032

Bikes: A bunch of old bikes and a few new ones

Mentioned: 140 Post(s)
Tagged: 0 Thread(s)
Quoted: 4523 Post(s)
Liked 820 Times in 581 Posts
Originally Posted by madpogue View Post
Most of what you describe about working with the u-brake has nothing to do with it being a u-brake. A u-brake mounted on the seat stays or the fork does not present these problems, including those related to riding in dirt/mud.

I see your new u-brake has flats for adjusting the tension on each arm individually. That design does make balancing the brake a LOT easier.

I have been able to use long-ish brake pads on u-brakes in a couple cases. The end of the pad hits the stay / fork when the brake is released for wheel removal, but it still releases enough to allow the wheel to be removed. A wide tire might need to be deflated first.

John E , my GT Outpost has u-brakes mounted on the seat stays and fork. My Schwinn High Sierra has roller-cam brakes mounted on the seat stays and fork.
Right, the design is solid. The problem was locating the u brake on the chainstay. I like the brakes.
bikemig is offline  
Old 07-10-20, 06:08 PM
  #23  
Miele Man
Senior Member
 
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,054

Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX

Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 1084 Post(s)
Liked 631 Times in 438 Posts
bikemig

One nice thing about under the chainstay mounted brakes (not that you seem to need it) is that there's nothing to snag on a pannier that's mounted far forward. Especially the old straight arm cantilever brake arms that stuck straight out were prone to getting snagged on a pannier and holding the brake pad(s) against the rim. Not nice if it happened going up a hill.

I had an old Bianchi MTB that had lots of clearance between the rear of the seat tube and the tire even with fenders on. I used to carry an extra water bottle there. It was a 750ml (20 oz) one complete with cage.



I think U-brakes or roller-cam brakes under the chainstays are great for a touring bike.

Cheers
Miele Man is online now  

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.