sp4ce4lien

no, I mean the vertical space of the drop out... where the axle rests. it's a random thought but worth a quick look if you haven't already.

sp4ce4lien

No, I mean the vertical space of the drop out where the axle would rest. It's just a random thought but worth a quick look if you haven't already.

rothenfield1

I hadn’t thought of that, and will take a look at it this weekend when I’m home.

Thanks man for your thoughts. As you can see, I’m getting close to completion of the build. I think I’m going to have to ride it as-is for now. That damned off-set is going to bug me though. All I know is, it’s either the frame or the wheel.

sp4ce4lien

Cool man, best of luck!!!

Bill Kapaun

So there's 6-7 people that suggest flipping the wheel in the frame to see if the offset reverses and you still won't try it.

Why not?

rothenfield1

I will take a look at that when I see the bike again this weekend. The reason I don't feel that that will do anything is because my first reaction when I saw it was to try and put the spacer from the left to right side by threading the axle through. It resulted in the offset being exactly wrong on the left side as it was the right. Go figure.

Bill Kapaun

Maybe you need 2 spacers with 1/2 the length of the one you have.
One on each side?

rothenfield1

That Sir, is exactly my impression from the get-go. But I'm a backyard wrencher, and I thought I'd ask better minds then I.

IthaDan 

So the lesson here is really that you shouldn't post a help thread when you're not near the bike in question.

Remind me again, how does this wheel line up in other bikes?

Bill Kapaun

I have messed up "official" hub spacing to use a 130MM replacement wheel off a junked bike in an old 10 speed (which got turned into a 21 speed at the time) with 126MM spacing.
It's been too long to remember exactly what I did, but it did involve swapping spacer(s?) and some re-dishing.
I remember having to do it twice because I had the top cog rubbing the chainstay the first attempt. I do remember adding the thinnest locknut I had out of the "parts pile" to use as a spacer on the DS and then using a shorter spacer on the NDS.

I imagine if somebody else ended up with that wheel, they might be scratching their head??

reddog3

Well... looking at the pic it shows that the wheel is indeed offset in the frame. It's offset from the seat tube as well, and closer to the DS chainstay. Since the cassette to dropout spacing looks about right you can rule out axle spacing. It's either the frame or the wheel. It's really easy to check both.

To check the wheel (yes, I'll join all the others) install it backwards in the frame. If offset to the other side- it's the wheel. You haven't done this yet? Should have been the first check when you noticed the misalignment.

To check the frame there is good info right here sheldonbrown.com/frame-spacing.html

jack002

I'd like to know how it looks in there backwards too. Seems a long time to wait to hear how it looks when you do. We'll see.

cny-bikeman

It does not matter what a mechanic told you, regardless of his experience or reputation. There are only three possible causes for what you describe, and you can determine with a fair amount of accuracy which is the case.

1. The wheel is not dished to the outer locknuts on the hub. Whether one can correct that by moving spacers is determined by how much space is available between the outer cog and the inner surface of the right dropout, and less commonly by how far outboard the derailleur can move. If you reverse the wheel as explained previously, with it mounted in the same position in the droopouts, and it shifts in the other direction then the dish is the problem - period. If it's in the same position then it is a frame/rear triangle problem.

2. The rear triangle is not aligned properly. You do not need a mechanic to determine that either. Just run a taut string from the outside of one dropout, around the head tube, and then back to the outside of the other dropout. Measure the gap between the seat tube and the string on both sides - the distances should be equal to each other. If the rear triangle is off to the left that side will of course show a larger gap.

3. The dropouts are out of alignment. This is the one problem that is somewhat more difficult to determine at home, but you can get a good idea by putting the bike upside-down on a stand or with a friend holding it, and sight along both sides of the front wheel toward the rear wheel. You should be able to see the same amount of wheel on both sides and neither should be tilted in relation to the other when you look over the top of the wheels.

I should note that the only way the dropouts could be out of alignment in a way that would cause the problem would be either an original frame defect or damage to a seat stay. I don't see any indication of damage, so it would have to be a frame defect - very unlikely to have not been detected and addressed previously to you owning the bike.

bobotech

I'm new at this whole bike thing and I even managed to redish my rear wheel when I upgraded the cassette from a 7 speed to an 8 speed. My wheel was doing the same exact thing. i thought I had a bent frame and it was suggested to me that I redish the wheel. All has been well with the world ever since.

And i would LOVE to know what happens after you mount the rim in the dropout reversed. Sounds like a very logical troubleshooting step.

rothenfield1

Sorry to start the question without having the bike in hand, but I’m working out-of-town and will be back Friday. I will remount the wheel backwards and take a pic. I imagine the idea is that if the wheel is off-set the same amount to the other side when reversed, it's the wheel; but if it's off-set to the same side, it's the frame.

Thanks for your interest and advice. It’s much appreciated.

saddlesores

got access to another bike with a centered wheel?

why not just switch rear wheels and compare?

SBinNYC

There is one other caveat. The assumption is that the wheel is placed in the same position in the dropouts in each instance. This is fairly automatic with vertical dropouts. There is the possibility for operator error with horizontal dropouts.

Your picture did not make it clear which you had. Here's a link that shows the differences: https://www.sheldonbrown.com/gloss_dr-z.html . Horizontal dropouts sometimes have adjusting screws to insure that wheels are inserted straight. Otherwise, it's important to make sure the wheel is all the way back in the dropouts on both sides.

jack002

For horizontal dropouts I just pull it back as far as it can go and check the alignment of the wheel inside the chainstays and center it there. The alignment between the seatstays is usually not that adjustable with them.

I'd never thought to mount a wheel reversed to see if it's dished right, I usually sight along the side of the rim to the other side on both sides or try to pull a string along both sides of the rim from one side to the other to see where the center of the rim lies on the hub. That should tell you if the dishing is right. If its way off you can tell somewhat by looking. Normal wheels look very flat on the drive side.

cny-bikeman

That's not really going to do it very well, unless you measure from the string to the locknut on both sides, which is a bit labor intensive when it's much quicker to use the frame.

Chris Chicago

if he reversed the axl, and it flipped the problem to being off center the other way. than doesnt that mean it's wheel dish, or an axle spacing problem?

and given it looks like the spacing between the small cog and dropout is pretty good (imo), wouldnt that eliminate axl spacing and designate dish as the definite issue?

gyozadude

You need to do this first and double check the approx. frame alignment. See this link on frame alignment using just simple twine. https://sheldonbrown.com/frame-spacing.html

Next, check the dish as others have suggested. Reverse the wheel in the rear drop outs. Remember to use the chain adjuster screws on the dropouts to achieve the best center in the rear triangle you can, then remove wheel, flip and insert until the axle hits the chain adjuster screws.

Logically, a frame can NOT be aligned AND the rear wheel properly centered/dished with your situation. One thing or another is out of alignment. This is a ogical fact, unless you're doing something totally bizarre with your chain adjuster screws. This will root-cause what's going on and you can then proceed to complete the build on your bike.

rothenfield1

That’s an amazing Sheldon link. I don’t think that I have ever had a bike related question that someone didn’t provide a Sheldon link to. That guy was amazing.

I get home tomorrow evening and will reverse the rear wheel. If it appears to be the frame alignment rather than the wheel, Paul Sadoff of Rock Lobster bikes said that he would take a look. Paul is one of the best frame builders in the West, and if he can’t figure it out, it probably can’t be figured out.

I’ll get a picture up tomorrow showing the result of reversing the wheel.

jack002

and given it looks like the spacing between the small cog and dropout is pretty good (imo), wouldnt that eliminate axl spacing and designate dish as the definite issue?

I think so. A post earlier pointed that out. If you focus on getting the tire and rim to center in the seatstays by moving axle spacers around you'll find the small cog either jammed against the dropout or way off away from it. Not good.

rothenfield1

I reversed the wheel with the same result. The offset is still about 3mm to the right. This leads me to believe that it is the frame. The rear triangle spread originally was 126mm and cold-set to 130mm, and I have recently learned from the seller that he had been running a 135mm hub on it. My conclusion is that the rear is sprung out to the right. I’m taking the frame to Rock Lobster bikes to see if Paul can sort it out.

fr333zin

Yes I agree, jamming a 135mm hub in there has caused an additional offset it seems. You could take a go at cold-setting it back again; Sheldon Brown's legacy to us all once again contains simple instructions on how to do this. Going to Rock Lobster sounds like a good idea though, you now need to know how it is currently aligned before making any adjustments. Does beg the question how your LBS thought things were OK!

Out of interest does it seem 'sprung' when you put the rear wheel in place, and what's the measurement across the inner faces of the dropouts when the wheel is removed?

Look forward to seeing pics of your Trek when it is finally built :O)