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 06-28-07, 12:14 PM   #1
C_LOGAN
Hammer Time
Thread Starter
 
C_LOGAN's Avatar
 
Join Date: Mar 2007
Location: Australia
Bikes: Paconi, Hillman, Sun Tourer + Mongoose Tetra SX
Posts: 258
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Frame misalignment. What to do?

I have a steel road bike with a misaligned rear wheel. I measured the rear with a piece of string running from both rear dropouts to the head of the frame - the difference between both sides of the string to the seat post is 5mm. Measuring from the head to each of the rear dropouts, the difference is around 3mm. The wheel is slightly to one side, but the bike seems stable - except that the wheel moves out of place and rubs sometimes. The rear dropout spacing is also around 5-7mm larger than the rear axle.

Is there an easier method to fix this problem, rather than bending the frame? Is it possible to get a longer rear axle, and align the wheel by using spacers? I am not experienced with frame bending and I really don't want to mess the frame up... If bending is possible, what approximately would be the cost of rectifying the problem?

Thanks.

Last edited by C_LOGAN; 06-29-07 at 06:34 AM.
C_LOGAN is offline   Reply With Quote
Old 06-28-07, 12:37 PM   #2
well biked 
biked well
 
well biked's Avatar
 
Join Date: Jul 2005
Bikes:
Posts: 7,065
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
You may have already seen this, but here's some very useful info regarding dropout spacing, frame alignment, etc.: http://sheldonbrown.com/frame-spacing.html

Are you saying the frame is 5mm out of alignment at the seat tube when you do the string test? If so, it sounds like that fact combined with the fact that the dropout spacing is approx. 5mm too wide is a solution waiting to happen. You'll simply need to use Sheldon's instructions (which will involve a two by four, a ruler, string, etc) to cold set one side of the rear triangle 5mm inward, and you'll then have it aligned and you'll also have approximately the correct dropout spacing as well. Work slowly, carefully, read the instructions thoroughly. It's not very difficult, really. I recently cold set an old steel frame for the second time using Sheldon's method, it was originally spaced at 126mm, I had cold set it to 130mm, and then I bought a wheelset with "mountain" hubs, 135mm axle spacing. When I spread the frame to fit those hubs, I fine tuned the alignment down to the millimeter using Sheldon's instructions, the frame's probably better aligned now than it was when it was new. Since the dropout spacing was originally at 126mm and I went all the way to 135mm, I also aligned the dropouts when I was done.

In regard to your wheel, you might want to check the dish, to make sure the rim is centered properly. It might bug you to get the frame aligned and then have a wheel that's not dished properly, which would still put the rim off center in the frame-
well biked is offline   Reply With Quote
Old 06-28-07, 12:48 PM   #3
C_LOGAN
Hammer Time
Thread Starter
 
C_LOGAN's Avatar
 
Join Date: Mar 2007
Location: Australia
Bikes: Paconi, Hillman, Sun Tourer + Mongoose Tetra SX
Posts: 258
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by well biked
You may have already seen this, but here's some very useful info regarding dropout spacing, frame alignment, etc.: http://sheldonbrown.com/frame-spacing.html
Hi,

The wheel is okay - I was using it on another bike and it was straight. I suppose I will look into 'doing it myself' in regards to frame bending - but I have an unfortunate knack of messing such things up.

In the instructions it says to remove the wheels, mud guards, etc.. So I suppose everything else could stay on the bike except for maybe - pedals?

And is this a permanent fix, or does it have to be repeated sometimes?
C_LOGAN is offline   Reply With Quote
Old 06-28-07, 01:34 PM   #4
well biked 
biked well
 
well biked's Avatar
 
Join Date: Jul 2005
Bikes:
Posts: 7,065
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Quote:
Originally Posted by C_LOGAN
Hi,

The wheel is okay - I was using it on another bike and it was straight. I suppose I will look into 'doing it myself' in regards to frame bending - but I have an unfortunate knack of messing such things up.

In the instructions it says to remove the wheels, mud guards, etc.. So I suppose everything else could stay on the bike except for maybe - pedals?

And is this a permanent fix, or does it have to be repeated sometimes?
The middle and rear section of the frame is off the ground during the procedure, so you should be able to leave the pedals on without a problem, I did the last time I did it.

As for it being a permanent fix, yes, you're bending the tubing, not just flexing it, so it's not going to bend back on its own. Steel is the only frame material that's suitable for this.

If you really don't feel confident about such things, you might ought to just take it to a shop and see if they can do it or if they know someone who can. As Sheldon says in his article, it's not for everybody. Good luck with it-
well biked is offline   Reply With Quote
Old 06-28-07, 01:36 PM   #5
C_LOGAN
Hammer Time
Thread Starter
 
C_LOGAN's Avatar
 
Join Date: Mar 2007
Location: Australia
Bikes: Paconi, Hillman, Sun Tourer + Mongoose Tetra SX
Posts: 258
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by well biked
The middle and rear section of the frame is off the ground during the procedure, so you should be able to leave the pedals on without a problem, I did the last time I did it.

As for it being a permanent fix, yes, you're bending the tubing, not just flexing it, so it's not going to bend back on its own. Steel is the only frame material that's suitable for this.

If you really don't feel confident about such things, you might ought to just take it to a shop and see if they can do it or if they know someone who can. As Sheldon says in his article, it's not for everybody. Good luck with it-
Thanks. I will definately give it a try - I am sure it is not too hard. I suppose it is good to try these things to gain experience.
C_LOGAN is offline   Reply With Quote
Old 06-28-07, 03:28 PM   #6
well biked 
biked well
 
well biked's Avatar
 
Join Date: Jul 2005
Bikes:
Posts: 7,065
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Quote:
Originally Posted by C_LOGAN
Thanks. I will definately give it a try - I am sure it is not too hard. I suppose it is good to try these things to gain experience.
Couple of other things have come to mind. When you get ready to cold set the frame, make sure you double check the alignment before you start, so you'll know exactly what your goal is. Also, just to clarify, you are checking the alignment with the rear wheel removed, right? The reason I ask is that since you say the dropouts are currently spaced 5-7mm too far apart for your hub, you may be affecting the alignment when you squeeze the dropouts inward to secure the wheel.......Out of curiosity, what's the axle spacing of the hub and what's the current dropout spacing?
well biked is offline   Reply With Quote
Old 06-28-07, 06:37 PM   #7
C_LOGAN
Hammer Time
Thread Starter
 
C_LOGAN's Avatar
 
Join Date: Mar 2007
Location: Australia
Bikes: Paconi, Hillman, Sun Tourer + Mongoose Tetra SX
Posts: 258
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by well biked
Couple of other things have come to mind. When you get ready to cold set the frame, make sure you double check the alignment before you start, so you'll know exactly what your goal is. Also, just to clarify, you are checking the alignment with the rear wheel removed, right? The reason I ask is that since you say the dropouts are currently spaced 5-7mm too far apart for your hub, you may be affecting the alignment when you squeeze the dropouts inward to secure the wheel.......Out of curiosity, what's the axle spacing of the hub and what's the current dropout spacing?
Thanks for the advice. Yes the measurements were taken with the wheel off the bike - the LHS rear fork was the culprit, and when I tightened the wheel the LHS pulled the wheel out of centre. The hub measurements? Didn't get those, I just measured the error differences. I think possibly 126mm? And the dropouts around 5mm more than that. It is a standard hub with a 6 speed freewheel.

Anyhow, I just completed the process to around 1mm of error. The wheel space is now narrower by around 1mm but the rear wheel is straight so I am happy with it. I just took off both wheels, put a blanket on the grass so that the bike's components were not damaged by a hard surface and bent the frame with a large piece of wood - with cloth wrapped around it so as not to damage the paint.

I have now completely finished the build of my bike.

C_LOGAN is offline   Reply With Quote
Old 06-28-07, 07:34 PM   #8
well biked 
biked well
 
well biked's Avatar
 
Join Date: Jul 2005
Bikes:
Posts: 7,065
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Quote:
Originally Posted by C_LOGAN
Thanks for the advice. Yes the measurements were taken with the wheel off the bike - the LHS rear fork was the culprit, and when I tightened the wheel the LHS pulled the wheel out of centre. The hub measurements? Didn't get those, I just measured the error differences. I think possibly 126mm? And the dropouts around 5mm more than that. It is a standard hub with a 6 speed freewheel.

Anyhow, I just completed the process to around 1mm of error. The wheel space is now narrower by around 1mm but the rear wheel is straight so I am happy with it. I just took off both wheels, put a blanket on the grass so that the bike's components were not damaged by a hard surface and bent the frame with a large piece of wood - with cloth wrapped around it so as not to damage the paint.

I have now completely finished the build of my bike.
Hey, that's a beautiful bike, congratulations on the build-
well biked is offline   Reply With Quote
Old 06-29-07, 04:03 AM   #9
C_LOGAN
Hammer Time
Thread Starter
 
C_LOGAN's Avatar
 
Join Date: Mar 2007
Location: Australia
Bikes: Paconi, Hillman, Sun Tourer + Mongoose Tetra SX
Posts: 258
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by well biked
Hey, that's a beautiful bike, congratulations on the build-
Thanks for that. I took it for a ride before - a lot better. The wheel was slipping slightly and rubbing on the chain stays - but the bending has fixed this problem.
C_LOGAN 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 07:10 PM.