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

How bad is a bad rim?

Notices
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.

How bad is a bad rim?

Old 05-08-19, 07:28 PM
  #1  
Full Member
Thread Starter
 
Join Date: Aug 2012
Location: Rochester, NY
Posts: 428
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 77 Post(s)
Liked 20 Times in 12 Posts
How bad is a bad rim?

I just pulled 2 rims off of a set of hubs. The wheels were running straight when assembled. Laid flat on a table now the rims are clearly a little bent.
1) Is it fine to just reuse them and let spoke tension fix the issue?
2) Is there a way for me to bend them back by hand (and lots of weight) before install?
3) How much wobble would you allow for when using a vintage rim?
The_Joe is offline  
Old 05-08-19, 07:35 PM
  #2  
Senior Member
 
mrrabbit's Avatar
 
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,503

Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 144 Post(s)
Likes: 0
Liked 34 Times in 29 Posts
1. yes (judgement call though on how much range in relative tension per side you'll allow)
2. yes
3. +/- .003 to .004 in. for high end stuff. But to be honest, one person's wobble isn't the same as another's.

=8-)
__________________
5000+ wheels built since 1984...

Disclaimer:

1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:

Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
mrrabbit is offline  
Old 05-09-19, 12:23 PM
  #3  
Full Member
Thread Starter
 
Join Date: Aug 2012
Location: Rochester, NY
Posts: 428
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 77 Post(s)
Liked 20 Times in 12 Posts
Originally Posted by mrrabbit
1. yes (judgement call though on how much range in relative tension per side you'll allow)
2. yes
3. +/- .003 to .004 in. for high end stuff. But to be honest, one person's wobble isn't the same as another's.

=8-)
Ok thanks. I guess it doesn't hurt to give it a try then.
The_Joe is offline  
Old 05-09-19, 12:40 PM
  #4  
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 30,225

Bikes: Catrike 559 I own some others but they don't get ridden very much.

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 642 Times in 363 Posts
1. Try to figure out where the bend is. Once you find it, you can usually take most of the wobble out by holding the bend against something solid like a post or a door. Be careful not to push too hard or you can make it even worse going the other way.
2. Building a wheel takes more work with a crummy rim than with a good rim.
3. You'll get a better result if you start with good components.
__________________
My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.
Retro Grouch is offline  
Old 05-09-19, 12:48 PM
  #5  
Full Member
 
Kovkov's Avatar
 
Join Date: Nov 2017
Location: Switzerland
Posts: 390

Bikes: 1957 Alpa Special, 1963 Condor Delta, 1967 Tigra Sprint, 1977 Oltenia, 1987 Mondia, 1965 Staco de luxe, 1969 Amberg

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 117 Post(s)
Liked 76 Times in 43 Posts
I once bent back a tacoed rim over the edge of a table. It laced back up pretty fine but i still don‘t have the courage to ride it
Kovkov is offline  
Old 05-09-19, 01:04 PM
  #6  
Senior Member
 
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702

Bikes: old clunker

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 104 Times in 82 Posts
Originally Posted by The_Joe

How bad is a bad rim?

. . . the rims are clearly a little bent. . .
How bent is a little bent?
AnkleWork is offline  
Old 05-09-19, 01:07 PM
  #7  
Full Member
Thread Starter
 
Join Date: Aug 2012
Location: Rochester, NY
Posts: 428
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 77 Post(s)
Liked 20 Times in 12 Posts
Originally Posted by AnkleWork
How bent is a little bent?
If it's sitting on a flat surface it has less than a quarter inch of lift. In two spots, 180 degrees out. So if noon and 6 are on the table then 3 and 9 bend up.

It was running true on the bike previously.
The_Joe is offline  
Old 05-09-19, 01:08 PM
  #8  
Expired Member
 
shelbyfv's Avatar
 
Join Date: Jun 2007
Location: TN
Posts: 11,423
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 3626 Post(s)
Liked 5,286 Times in 2,685 Posts
Originally Posted by Kovkov
I once bent back a tacoed rim over the edge of a table. It laced back up pretty fine but i still don‘t have the courage to ride it
That's the problem, isn't it? I bent one back by standing on it, it tensioned reasonably well, but it still makes me nervous. I'd replace it if a new one was available.
shelbyfv is offline  
Old 05-09-19, 01:33 PM
  #9  
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 13,765

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1749 Post(s)
Liked 1,188 Times in 827 Posts
Originally Posted by The_Joe
If it's sitting on a flat surface it has less than a quarter inch of lift. In two spots, 180 degrees out. So if noon and 6 are on the table then 3 and 9 bend up......
It sounds like a good candidate for a bit of manual bending over the edge of the table.
You don't have to get ALL of the warp out, but it appears you can make this rim "better" without too much effort.
Bill Kapaun is offline  
Old 05-09-19, 10:19 PM
  #10  
working on my sandal tan
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Posts: 22,609

Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)

Mentioned: 98 Post(s)
Tagged: 0 Thread(s)
Quoted: 3867 Post(s)
Liked 2,547 Times in 1,568 Posts
You may be surprised at how little weight/force may be needed to bend the unlaced rim. Start somewhat gently, and check your progress often.

With a good attitude, fixing bent old wheels can be a fun project, but if you are working in a shop or have other time constraints, I can see why others would prefer to start with straight new parts.
__________________
Originally Posted by chandltp
There's no such thing as too far.. just lack of time
Originally Posted by noglider
People in this forum are not typical.
RUSA #7498
ThermionicScott is offline  
Old 05-10-19, 11:37 AM
  #11  
Full Member
Thread Starter
 
Join Date: Aug 2012
Location: Rochester, NY
Posts: 428
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 77 Post(s)
Liked 20 Times in 12 Posts
Originally Posted by ThermionicScott
You may be surprised at how little weight/force may be needed to bend the unlaced rim. Start somewhat gently, and check your progress often.

With a good attitude, fixing bent old wheels can be a fun project, but if you are working in a shop or have other time constraints, I can see why others would prefer to start with straight new parts.
I've got nothing if not a good attitude. Thanks for the encouragement!
The_Joe is offline  
Old 05-10-19, 04:56 PM
  #12  
Friendship is Magic
 
3alarmer's Avatar
 
Join Date: Nov 2010
Location: Sacramento, CA
Posts: 22,780

Bikes: old ones

Mentioned: 304 Post(s)
Tagged: 0 Thread(s)
Quoted: 26071 Post(s)
Liked 9,987 Times in 6,937 Posts
Originally Posted by The_Joe
I just pulled 2 rims off of a set of hubs. The wheels were running straight when assembled. Laid flat on a table now the rims are clearly a little bent.
1) Is it fine to just reuse them and let spoke tension fix the issue?
2) Is there a way for me to bend them back by hand (and lots of weight) before install?
3) How much wobble would you allow for when using a vintage rim?
...I don't do this much any more, because as a wealthy retiree, I've decided to build my wheels with newer rims. But back when I was doing a lot of "period correct" rebuilds, I straightened a lot of rims. The ones that are not box section are easier to work with in terms of bending, but anything is worth trying if you've got the time and patience. I used a couple of sawhorses a lot, and a flat glass top of a display case to check for flat.

We also had a Rube Goldberg wheel straightening machine that was once made and sold commercially at the bike co-op. It was mostly a coiuple three rollers on bearing shafts, with one of them adjustable up and down so you could use it to push down on the high spot while running the rim back and forth through the rollers. It, too, had trouble with box section alloy rims.

Originally Posted by mrrabbit
But to be honest, one person's wobble isn't the same as another's.

=8-)
...testify !

Originally Posted by The_Joe
Ok thanks. I guess it doesn't hurt to give it a try then.
...you should try it, if for no other reason than the learning experience. Sometimes a rim will come back pretty flat in plane with minimal effort. There are also some specific tools for working out flat spots in the circumferential direction. They have pretty much disappeared as more and more people just give up and buy new wheels or rims.
3alarmer is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Kilroy1988
Classic & Vintage
22
06-14-17 08:26 AM
hj630
Bicycle Mechanics
13
03-10-16 02:32 AM
ClarkinHawaii
Bicycle Mechanics
4
07-26-15 05:33 PM
velorider562
Bicycle Mechanics
11
05-26-12 12:56 AM
MPC Biker
Bicycle Mechanics
10
05-25-12 09:04 AM

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.