Relevant Information:
I have a 2002 Trek 5200 (history unknown). I got the bike in what I would consider very nice condition. It does not seem to have been abused and the frame appears intact and solid. There are no scratches or apparent disturbances to the rear dropouts. When I received the bike I had the rear wheel trued. The bike has what I would consider close to vertical dropouts.

Problem:
When (any) rear wheel is installed and positioned securely up against the dropouts the wheel points about 3-4mm towards the drive side chain-stay. The wheel is not parallel to the frame. The tire clears the chainstay but it's a little too close for comfort and I'm prevented from using anything larger than a 25mm tire. When I position the left side of the axle up against the dropout the wheel will be centered. But then, when I pull the right side of the axle up against the dropout (appox 2mm of play) the wheel is off centered.

Question:
Is it dangerous or ill-advised to ride the bike with one side of the axle not securely up against the dropout? I can tighten the QR just fine. Is it possible to purchase a shim that would fit inside the dropout? Is filing down one of the dropouts by approximately 1mm a possible solution or will I been degrading the integrity of the dropout? I'm sort of leaning towards the filing solution.

Let me know if you need any more info or if I may have not described something clearly.

TMT

Cant see a thing..bring it to a bike shop, get it fixed-up there..

Filing down drop out slot surfaces is a time honored method to correct less then best alignment. Done this many dozens of times, many dozens. Al long as the QR will keep the axle in the location you initially set it at, to attain wheel/frame coplaneness (alignment) there is no real issue. The phrase "don't fix what's not wrong" comes to mind. A QR with steel serrated drop out contacting faces and having an internal cam with NO plastic goes a long way to insure axle placement. Really this is what we did when horizontal drop out slots were the norm.


Having said that my sensibilities would want the wheel to fit in the aligned arrangement with only gravity to make quick reinstalls easy. On road flat repairs go faster and with led fiddling about this way. But my sensibilities don't ride or steer the bike. Andy

Before taking a file to your dropout it would be wise to figure out what, exactly is wrong. You mentioned recently having the wheel trued. What made you thing that needed to be done? I'd be in favor of doing some more exploration before doing something that can't be undone.

Put the wheel in backwards to insure that it is actually the frame that is wrong.

And that's assuming you are taking these measurements with the QR closed.

I should have added that this condition isn't what's usually considered to be a drop out parallel issue, but is a stay length one. Andy

The wheel was definitely out of true when I obtained the bike. Also, I have installed 2 other compatible wheels on the bike and they all exhibit the same behavior

Thank you and understood. I'm leaning towards some touch and go filing.

I will give that a try in my effort to cover all my bases.

Don't pick up a file until you've confirmed that the frame is otherwise straight. It doesn't need to have strange marks on it for the chainstays to be bent a little to one side or the other.

can you make some alignment test tools? 2 straight axles and 4 nuts is not a great expence

I would check the alignment of the whole frame. Seems to me if both halves of the rear triangle (in other words, both the drive and non-drive chain/seat-stays) were bent to the same side, this could happen.

It's a full carbon frame, which can't bend. I would guess it has been like this from the moment the dropouts were bonded in.

Take a frame alignment guage to it. Could be asymmetrical stays. Is the wheel actually off-axis to the centerline of the bike? Or is the stay spacing the only bug?

Good point.

There are a few quick and dirty things you can do if you don't take it to an LBS to check the alignment. Take some measurements of the chainstay, from the BB, to see if there is a pretty obvious difference. Install the wheel and see if the rear derailleur is parallel with the cassette or is it at a slight angle. If the derailleur is parallel the hanger/dropouts might be tweaked. If you do file, alter the non-drive side.

John

+1 It is indeed a carbon frame so bending really isn't an option and perhaps filing isn't a good idea either.

That does sound like a possibility. But, with an impact that would move them both that much I would have expected some of the carbon around the dropouts to have been cracked. The bike does not appear to have been abused.

I was able to get about 2mm of movement where I needed it by filing down the one dropout just slightly. I don't want to spend top much effort and the filing seems to be the quickest means to my end. I appreciate everyone's input and there are a lot of suggestions and ideas to keep me thinking about this problem.

TMT

With a carbon frame the most one can do is to get the rear wheel relatively centered by filing the drops. Remember that theres about a 3 or 4 to 1 ratio of wheel shift to filing amount. Go slow and check. I usually file on the slot's forward slot first so any QR slippage is negated by the axle's butting against this surface. Then I go to the seat stay centering being careful to not change the chain stay centering, easier said then done though. Know that the if the rear drops are not centered WRT the mainframe plane all you end up with is a wheel that looks centered in the frame but will be actually steering the bike from the rear as it's contact patch with the ground won't be centered WRT the main frame (or ft wheel).


Again doing less is often the greater good. Andy

Why would filing the aluminum dropouts be a bad idea?

Agreed, but others with different frames need to know that not all carbon frames use AL drops. Andy

Yeah, but I don't know why anyone would assume that all bikes are identical - carbon bikes have been made with four different dropout materials. The OP identified the model in the first post - I sometimes find it frustrating that people like to give technical advice when they don't understand much about the problem.

I thought that was the norm here Andy (who also gets frustrated)

Filing dropouts on a modern carbon frame?

Just because a wheel is true doesn't mean it is properly dished....did you even check this?

=8-|

Seems like it.

Who knows, maybe all his wheels are zero dish wheels (which of course do not exist for symmetrical frame based bikes which 99.99% of us ride.)

I kinda wonder too if the frame in question has a bond that has come loose or slipped. I've seen it happen on a late 90s Vitus? - and you couldn't tell with a cursory look cause it somehow looked clean even when slipped. (Left chainstay into dropout.)

Either way - when trouble shooting frames:

1. Properly dished wheels.
2. Dropout alignment.
3. Frame alignment check / Fork alignment check.
4. Then elsewhere....including fixes.

Jumping to #4 without any dead obvious "wrecked exotics" like damage / oddities is not how you go about stuff like this.

=8-P

Are the dropouts aluminum? Many carbon frames have carbon dropouts too. If they really are aluminum, by all means file away.