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


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 10-01-12, 10:54 AM   #1
sub-atom
Sub10 Rider
Thread Starter
 
sub-atom's Avatar
 
Join Date: Mar 2008
Location: Finland
Bikes: Scott Sub10 2004
Posts: 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Replace v-brakes by u-brakes on a frame designed for 28'' wheels.

Hi guys,

is it reasonable to exchange v-brakes for u-brakes in order to adapt a 26'' wheelset to a frame that was made for 28'' wheels? I would like to make a touring bike.

thanks.
sub-atom is offline   Reply With Quote
Old 10-01-12, 11:35 AM   #2
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Good question; NFI.
Kimmo is offline   Reply With Quote
Old 10-01-12, 11:44 AM   #3
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 18,067
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 233 Post(s)
Quote:
Originally Posted by sub-atom View Post
Hi guys,

is it reasonable to exchange v-brakes for u-brakes in order to adapt a 26'' wheelset to a frame that was made for 28'' wheels? I would like to make a touring bike.

thanks.
U-brakes don't use the same brake studs as linear/cantilever brakes. The diameter of the stud is different and the location of studs is wrong.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Old 10-01-12, 11:52 AM   #4
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by cyccommute View Post
The diameter of the stud is different and the location of studs is wrong.
Wrong for the same wheel size, or what's proposed here?

Which uses the larger stud? Any idea by how much? Maybe it could be sleeved.

I like a challenge
Kimmo is offline   Reply With Quote
Old 10-01-12, 12:02 PM   #5
himespau 
Senior Member
 
himespau's Avatar
 
Join Date: Jun 2008
Location: Louisville, KY
Bikes:
Posts: 9,602
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 119 Post(s)
There was a thread here not too long ago where someone was able to use the hole in the fork and bridge to mount dual pivot (I think) brakes and go from 26" to 700c wheels, but he said he had a big drawer of brake calipers to choose from and he had to try most of them to find some that'd fit.
himespau is online now   Reply With Quote
Old 10-01-12, 12:06 PM   #6
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
There's always hub brakes...
Kimmo is offline   Reply With Quote
Old 10-01-12, 12:20 PM   #7
sub-atom
Sub10 Rider
Thread Starter
 
sub-atom's Avatar
 
Join Date: Mar 2008
Location: Finland
Bikes: Scott Sub10 2004
Posts: 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I see... maybe I need to try to find a place from where to try several models until I have a match. But looking at the placement of the studs and their diameters... it looked feasible to me. I will get back if I succeed...
sub-atom is offline   Reply With Quote
Old 10-01-12, 12:41 PM   #8
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 18,067
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 233 Post(s)
Quote:
Originally Posted by Kimmo View Post
Wrong for the same wheel size, or what's proposed here?

Which uses the larger stud? Any idea by how much? Maybe it could be sleeved.

I like a challenge
The U-brake stud is larger in diameter.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Old 10-01-12, 12:45 PM   #9
mconlonx 
Nobody
 
mconlonx's Avatar
 
Join Date: Jun 2007
Bikes:
Posts: 7,175
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 702 Post(s)
Quote:
Originally Posted by cyccommute View Post
The U-brake stud is larger in diameter.
I believe 9mm vs 8mm stud for regular cantis/v-brakes. Not an easy mod. Suggest OP looks into Sturmey Archer drum brake options...
__________________
I know next to nothing. I am frequently wrong.
mconlonx is offline   Reply With Quote
Old 10-01-12, 12:54 PM   #10
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
0.5mm sleeve sounds possible... what about the other aspect; the height?
Kimmo is offline   Reply With Quote
Old 10-01-12, 01:08 PM   #11
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 18,067
Mentioned: 11 Post(s)
Tagged: 0 Thread(s)
Quoted: 233 Post(s)
Quote:
Originally Posted by Kimmo View Post
0.5mm sleeve sounds possible... what about the other aspect; the height?
You are going the wrong way. The U-brake stud is 9mm. The cantilever stud is 8 mm. You'd have to drill out the brakes to make them fit.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Old 10-01-12, 01:18 PM   #12
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Um...
Quote:
Originally Posted by sub-atom View Post
exchange v-brakes for u-brakes
Anyway, drilling out the brake would be easier, if the brass bushing was thick enough.
Kimmo is offline   Reply With Quote
Old 10-01-12, 01:31 PM   #13
mconlonx 
Nobody
 
mconlonx's Avatar
 
Join Date: Jun 2007
Bikes:
Posts: 7,175
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 702 Post(s)
Quote:
Originally Posted by Kimmo View Post
Anyway, drilling out the brake would be easier, if the brass bushing was thick enough.
It's not.

However, OP should see if the studs are removable and if they can be replaced with appropriate studs. There, of course, still might be rim alignment issues...
__________________
I know next to nothing. I am frequently wrong.
mconlonx is offline   Reply With Quote
Old 10-01-12, 01:42 PM   #14
sub-atom
Sub10 Rider
Thread Starter
 
sub-atom's Avatar
 
Join Date: Mar 2008
Location: Finland
Bikes: Scott Sub10 2004
Posts: 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by cyccommute View Post
You are going the wrong way. The U-brake stud is 9mm. The cantilever stud is 8 mm. You'd have to drill out the brakes to make them fit.

i've tried out an old shimano and the stud is actually larger, so the U-brake would fit with an adapter althought not an ideal solution...
sub-atom is offline   Reply With Quote
Old 10-01-12, 01:43 PM   #15
sub-atom
Sub10 Rider
Thread Starter
 
sub-atom's Avatar
 
Join Date: Mar 2008
Location: Finland
Bikes: Scott Sub10 2004
Posts: 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Kimmo View Post
There's always hub brakes...
hub brakes would indeed be awesome. Just a rather expensive mod... need to change the entire gear system as well...
sub-atom is offline   Reply With Quote
Old 10-01-12, 01:57 PM   #16
dabac
Senior Member
 
Join Date: Mar 2008
Bikes:
Posts: 5,509
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 46 Post(s)
Why can't you tour on 28" wheels?
And why would you need to change the entire gear system if you went to hub brakes?
And what would the difference be, as you're already considering getting new 26" wheels?
dabac is offline   Reply With Quote
Old 10-01-12, 02:11 PM   #17
sub-atom
Sub10 Rider
Thread Starter
 
sub-atom's Avatar
 
Join Date: Mar 2008
Location: Finland
Bikes: Scott Sub10 2004
Posts: 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I didn't say I couldn't tour on 28'' wheels. They are actually totally awesome. I'm just worried about not being able to mount tougher tyres (wider, buffier). The hub brakes I have checked have in-hub gears, so I would need to dump the whole shimano business, no? I didn't say I was going to get new 26''... more like second hand. But as my first sentence suggest, I would like to see if it's reasonable to switch brakes (the main issue), and since the studs ain't the same size, it probably ain't reasonable.
sub-atom is offline   Reply With Quote
Old 10-01-12, 02:14 PM   #18
sub-atom
Sub10 Rider
Thread Starter
 
sub-atom's Avatar
 
Join Date: Mar 2008
Location: Finland
Bikes: Scott Sub10 2004
Posts: 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by himespau View Post
There was a thread here not too long ago where someone was able to use the hole in the fork and bridge to mount dual pivot (I think) brakes and go from 26" to 700c wheels, but he said he had a big drawer of brake calipers to choose from and he had to try most of them to find some that'd fit.
Well, given that I would like to fit a smaller wheel, that would place the rim even farther from any hypothetical hole in the fork/bridge than with a 28'' wheel. So it goes one way,not the other ;-)
sub-atom is offline   Reply With Quote
Old 10-01-12, 02:18 PM   #19
himespau 
Senior Member
 
himespau's Avatar
 
Join Date: Jun 2008
Location: Louisville, KY
Bikes:
Posts: 9,602
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 119 Post(s)
Ah, I must have misread your first post. I thought it said you wanted to go to 28" from 26" with cantilever brakes. Guess a couple of us thought that.
himespau is online now   Reply With Quote
Old 10-01-12, 02:53 PM   #20
sub-atom
Sub10 Rider
Thread Starter
 
sub-atom's Avatar
 
Join Date: Mar 2008
Location: Finland
Bikes: Scott Sub10 2004
Posts: 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by himespau View Post
Ah, I must have misread your first post. I thought it said you wanted to go to 28" from 26" with cantilever brakes. Guess a couple of us thought that.
oops. Sorry if that wasn't clear enough! Indeed. I want to replace 28'' wheels with 26''!
sub-atom is offline   Reply With Quote
Old 10-01-12, 03:03 PM   #21
DannoXYZ 
Senior Member
 
DannoXYZ's Avatar
 
Join Date: Jul 2005
Location: Saratoga, CA
Bikes:
Posts: 11,606
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
The other issue with this conversion is the 31.5mm drop in the radius from the axle to ground will decrease trail by a significant amount. The bike will be very twitchy and hunt/dart around after hitting bumps in the road. It gets tiring riding such a thing because you have to keep your hands on the bars all the time and keep it on track.
DannoXYZ is offline   Reply With Quote
Old 10-01-12, 03:10 PM   #22
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: copy/paste links: http://velospace.org/node/36949 http://velospace.org/node/47746 http://velospace.org/node/47747
Posts: 7,099
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Not to mention BB height...

But I'm tipping it's nowhere near as much as 31.5mm, since the OP said the point is to fit bigger tyres.
Kimmo is offline   Reply With Quote
Old 10-01-12, 04:07 PM   #23
Airburst
Senior Member
 
Join Date: Oct 2009
Location: England, currently dividing my time between university in Guildford and home just outside Reading
Bikes: Too many to list here!
Posts: 1,921
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by sub-atom View Post
The hub brakes I have checked have in-hub gears, so I would need to dump the whole shimano business, no?
Sturmey-Archer make a drum brake hub with a freehub, and also one that's threaded for a freewheel.

As for the u-brake thing, I've done it while trying to put a 20" wheel on a 26" fork to make a chopper. I can confirm that, with a sleeve (I used brass stock I had lying about), a u-brake will fit a cantilever brake boss. The different wheel size didn't work out on that bike, so I never actually used the brake. To be honest, it's not enough of a decrease in diameter going from 28" to 26", you'll probably put the cantilever boss about level with the rim, when it needs to be above it for a U-brake.
Airburst is offline   Reply With Quote
Old 10-01-12, 05:41 PM   #24
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Rock Springs, WY
Bikes: My War
Posts: 26,866
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 307 Post(s)
BB and axle height will be about the same if 2" tires are going to be used and 23mm tires were being used.

Seems like long reach BMX calipers would be an easier swap.
LesterOfPuppets is offline   Reply With Quote
Old 10-09-12, 01:49 AM   #25
dabac
Senior Member
 
Join Date: Mar 2008
Bikes:
Posts: 5,509
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 46 Post(s)
Quote:
Originally Posted by sub-atom View Post
I didn't say I couldn't tour on 28'' wheels. They are actually totally awesome. I'm just worried about not being able to mount tougher tyres (wider, buffier).
For tire availability, check out cyclocross tires and 29er MTB tires. They'll both fit a 28" / ETRTO 622 mm rim. Might be something there that'll give you an acceptable tread pattern as well as clearing your fork/frame.

Quote:
Originally Posted by sub-atom View Post
The hub brakes I have checked have in-hub gears, so I would need to dump the whole shimano business, no?
Well, if you're running external (shimano) gears now, and is considering going to IGH, then you will need a new shifter.
If the current setup is brake and shifter lever in one assembly, I'd advise replacing that one too.
You might get away with using the brake lever, but it'll probably steal the space where you'd otherwise would have liked the shifter to go.

There might be chainline issues when going from EGH to IGH. Nothing that can't be fixed, just don't expect stuff to play nice at first assembly.

Quote:
Originally Posted by sub-atom View Post
The hub brakes...
I'd be a bit wary about touring on hub brakes if you're heading into truly mountainous areas. There is a risk of overheating.
dabac is offline   Reply With Quote
Reply


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 07:09 PM.