Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

what is a "Tire Guide" screw?

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.

what is a "Tire Guide" screw?

Old 06-10-07, 05:23 AM
  #1  
thefsb
Tom
Thread Starter
 
Join Date: Jun 2007
Posts: 80
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
what is a "Tire Guide" screw?

the brake shoe holder on my shimano brakes has a mysterious screw. in the exploded view it is labeled number 12 and listed as "Tire Guide": http://bike.shimano.com/media/techdo...9830609104.pdf

but the service instructions don't mention it at all: http://bike.shimano.com/media/techdo...9830604299.PDF

what's it for? how does one use it?
thefsb is offline  
Old 06-10-07, 06:31 AM
  #2  
vpiuva
*
 
vpiuva's Avatar
 
Join Date: Jan 2007
Posts: 3,458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time in 1 Post
The Tire Guides are those little wings that hang down from (sometimes molded into) the brake pad holder. Maybe some of that model brake come with a separate screw that hold them on. Usually they are held on by the shoe fixing bolt.
vpiuva is offline  
Old 06-10-07, 06:46 AM
  #3  
2manybikes
Dog is my co-pilot
 
2manybikes's Avatar
 
Join Date: Jun 2003
Posts: 17,563

Bikes: 2 many

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 1000 Post(s)
Liked 17 Times in 14 Posts
It's to guide the tire in between the brake shoes as you put the wheel on.
2manybikes is offline  
Old 06-10-07, 07:29 AM
  #4  
thefsb
Tom
Thread Starter
 
Join Date: Jun 2007
Posts: 80
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by vpiuva
The Tire Guides are those little wings that hang down from (sometimes molded into) the brake pad holder. Maybe some of that model brake come with a separate screw that hold them on. Usually they are held on by the shoe fixing bolt.
on these brakes the "wing" is indeed a part of the shoe holder. there is a threaded hole through this wing with a screw in it that can be removed. this screw is what shimano's exploded view calls labels a "tire guide". and i've no idea what it's for.
thefsb is offline  
Old 06-10-07, 07:39 AM
  #5  
2manybikes
Dog is my co-pilot
 
2manybikes's Avatar
 
Join Date: Jun 2003
Posts: 17,563

Bikes: 2 many

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 1000 Post(s)
Liked 17 Times in 14 Posts
Originally Posted by thefsb
on these brakes the "wing" is indeed a part of the shoe holder. there is a threaded hole through this wing with a screw in it that can be removed. this screw is what shimano's exploded view calls labels a "tire guide". and i've no idea what it's for.
The head of the screw is what hits the tire in this case not the wings. So it guides the tire into the center between the brake shoes. Making it a "tire guide".

The idea is very old. The wings on other brake shoes are only there to guide the tire into the center as you install the wheel. Guiding the tire in to the middle helps as the wheel goes on helps prevent some people from getting the tire stuck and knocking the brakes out of the center position.
2manybikes is offline  
Old 06-10-07, 07:52 AM
  #6  
Stacey
Non Tribuo Anus Rodentum and off to the next adventure (RIP)
 
Stacey's Avatar
 
Join Date: Dec 2002
Posts: 9,161
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
The dumbing down of bicycles. Sheesh!
__________________
Stacey is offline  
Old 06-10-07, 08:00 AM
  #7  
2manybikes
Dog is my co-pilot
 
2manybikes's Avatar
 
Join Date: Jun 2003
Posts: 17,563

Bikes: 2 many

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 1000 Post(s)
Liked 17 Times in 14 Posts
Originally Posted by Stacey
The dumbing down of bicycles. Sheesh!
They had it in the 1970's. The old red square brake blocks sometimes had wire under the shoe that is the shape of the wing on that shoe.
Most of the time when someone needs to re center caliper brakes it's because they knocked them off center when putting the wheel on, but don't know it. There's really nothing else to do that unless the mounting bolt is loose.

Like the hundreds of people that have a computer not working because they moved the sensor when they put the wheel on. Many think it is a complicated computer problem.
They think I'm a miracle worker when I just move the sensor back where it was in three seconds!

Last edited by 2manybikes; 06-10-07 at 08:07 AM.
2manybikes is offline  
Old 06-10-07, 09:38 AM
  #8  
vpiuva
*
 
vpiuva's Avatar
 
Join Date: Jan 2007
Posts: 3,458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by 2manybikes
The head of the screw is what hits the tire in this case not the wings. So it guides the tire into the center between the brake shoes. Making it a "tire guide".

So we have a tire guide mounted in the tire guide. Boy, must have been a bad day for Shimano's Italian/Japanese translator when deciphering calipers.
vpiuva is offline  
Old 06-10-07, 02:37 PM
  #9  
thefsb
Tom
Thread Starter
 
Join Date: Jun 2007
Posts: 80
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by 2manybikes
The head of the screw is what hits the tire in this case not the wings. So it guides the tire into the center between the brake shoes. Making it a "tire guide".
fair enough. but why would one need to adjust it? without such a need i don't see a motive to go to the trouble to drill and thread the hole and insert a screw.
thefsb is offline  
Old 06-10-07, 06:17 PM
  #10  
2manybikes
Dog is my co-pilot
 
2manybikes's Avatar
 
Join Date: Jun 2003
Posts: 17,563

Bikes: 2 many

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 1000 Post(s)
Liked 17 Times in 14 Posts
Originally Posted by thefsb
fair enough. but why would one need to adjust it? without such a need i don't see a motive to go to the trouble to drill and thread the hole and insert a screw.
The only thing I can think of is that it narrows the slot the tire goes into, also the head of the screw lets the tire slide by better than the plastic wings, and makes for a faster wheel change? That's just a guess, I can't think of anything else it could do. For some reason they thought it improved the tire guiding function. Otherwise the name would be different.
2manybikes is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
seypat
Classic & Vintage
62
12-31-18 06:08 PM
Hatsuwr
Bicycle Mechanics
28
12-22-18 11:47 AM
GlennR
Northeast
1
01-10-17 09:39 PM
GeraldChan
Road Cycling
1
02-03-07 10:32 PM

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

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