3Roch

The frameset in question is a ~1979 Motobecane Grand Touring; not MB's best but not their worst. Vitus 888. Built into bike with "modern" groupset

The issue is that when the rear wheel( at the rim) is centered in the chainstays it can not be centered in the seatstays...by about 3/8 of an inch. Before you leap to conclusions please read the below!!

1) the wheel ( new DT Swiss rim on 9 speed hub) dish is dead on.
2) the wheel is true+- .004" lateral runout
3) the axle is not bent broken

4) the dropouts .are spaced to 130
5) the dropouts are aligned dead on
6) don't have a surface plate etc but running a thread (not a rope) from dropouts around head tube and measuring ( with dial calipers, not a yardstick)..distance to seat tube is identical. Same result using straight edge against head tube and seat tube and measuring to dropouts
7) when the dropout adjust screws are set so wheel is centered in chainstays the screws are not same distance into dropouts by about .060"...humm

8) frame is in really nice shape.no evidence of crash damage/bend/dents/ kinks etc

Any suggestions, I'm beginning to think guy who built frame had too much vin rouge for lunch

Thanks

unterhausen

I'll take your word on all the tests. But I would flip the wheel just in case.

The only reasonable thing to do is file the low dropout. Pick a wheel location.

3Roch

I assume your concern is the dish. If my trusty Hozan dish tool is happy, I'm happy. But thanks for the reply

unterhausen

I would see if there is some obvious misalignment of any of the parts. The way they build production bikes, this defect is somewhat unlikely, but if there was a problem part or a bad subassembly it's always possible someone just forced things together so they could move on to the next frame. Look at dropout parallelism, how far they are inserted into the stays, seat stays of different lengths or attached to the seat lug differently, that sort of thing.

It doesn't take much misalignment at the dropout to get a wheel off by 3/8"

duanedr 

Are the horizontal dropout slots the same width on both sides all the way back? If one opened up and you're installing the wheel while the frame is in a stand, the axle is resting on the lower bent portion, not the top. Weird that the adjusters aren't equally inserted. Pictures?

unterhausen

I would also like to see pictures

3Roch

At the moment the bike and my camera are in 2 different places but with all due respect( I do appreciate the replies ) pictures of what?

The dropout slots are pretty snug on the axle, there is really no vertical play when the axle is in the slot(s) and the QR is not latched. As far as the dropout adj screws are concerned if you set them up so the rim is centered in the chainstays with the wheel pulled hard back against the screws and a bit of weight on the bike to ensure the axle is against the tops of the slot ..the wheel is not centered in the seat stays and the one adjust screw is about .060" "out" (towards the axle) then the other.

I'm sorta beginning to suspect one or the other dropout is not where it's supposed to be. re the stays

,

unterhausen

I would like to see pictures of both dropouts and the seat stay attachment.

I doubt we would see anything that would help with a fix, I think a file is called for

squirtdad

No answers but could something have been tweaked.twisted during cold setting? 130mm dropout space implies cold set as a 1979 almost certainly have been 126. Not sure is this an area to look into or not?

unterhausen

1979 French bike was almost surely 120mm. I don't think that spreading it would change the way the wheel sits. We're going to have to trust the OP that the bending was done symmetrically.

Andrew R Stewart 

Sounds like one seat stay is longer/shorter then the other. Don't worry about the axle position in the slots as that's one reason why horizontal slots are used, to allow centering with less then best construction. Also don't worry about where the rim sits between the SS at the brake bridge. It's where the rim sits WRT the main frame (as usually seen by the ST/rim alignment). Foe a 3/8" off center rim placement a 1/8" dropout "offness" is expected, that's a lot of stay length difference. Could be the SS's/brake bridge hole are not in line too. Andy

Canaboo

Just file the top edge of the offending dropout and call it good. It won't tale much..

3Roch

If I'm doing my mental math correctly it would take about 1/8" of dropout filing to move the rim 3/8". No way am I filing 1/8" of the load bearing surface of a dropout away. If you filed a notch in it, that's what called a stress riser.

If anything it would make more sense to shim the other side down (steel feeler gauge stock or similar) but there isn't enough room to accomplish much.

unterhausen

I get 2mm, but that is quite a bit. Somebody lived with it for 40 years, I guess you can live with it too. Unless it needs a paint job. But fixing it with fire is not an easy job. What kind of dropouts does this thing have?

Andrew R Stewart 

I do find these threads about a frame's alignment interesting, most have little follow through after the real understanding and corrections are done to know what was actually going on.

One correction I have thought of is to cut a section (perhaps the blade's width only) and then splice back together with an internal sleeve.

Drop outs are pretty substantial and generally have a lot of meat. They also tend to not be made of brittle alloys, especially after brazing heat. I would have very little concerns about a "stress riser" in a drop out's slot's upper surface, unless done by a hack. I've filed away, maybe, a third/half of that amount before. IMO the real issue is the loss of the axle lock nut and QR end cap contact with the lower edge of the slot. Andy

unterhausen

Looks like it possibly had suntour dropouts? https://www.equusbicycle.com/bike/mot...moto197906.pdf
I'm a bit surprised it has heat treated tubing. I don't think you could get Vitus tubing in the U.S. back then and nobody would have wanted it anyway. It's a pity.

3Roch

The "1979" is based on the color and the components ( triple crank, etc) that were on it when I found it at a thrift shop for $18; it was in super shape but my days of living with friction shifting on downtubes and 5 speed freewheel are long over; it now has 8 speed cassette, brifters, and has shed some pounds.

The rotting Vitus 888 stickers are still on the fork and seat tube.

The thing rides OK, not desperate to fix the alignment; when I really want a nice, fast ride use my Reynold 531 Le Champion...it's now 9 speeds and no frame issues

Note: I saved all the original parts of the GT and the Le Champion was only a frameset when I got it so no museum pieces were destroyed in the process.

Andrew R Stewart 

I frequent a forum (Lightweight Classic Vintage bicycles) where some insist that a bike remain in show room spec to be valuable. Others say just ride the bloody bike. I am of the second camp. Back in the day we had no qualms about changing out components to better suit the bike for our rising. It's a rare bike, IMO, that should remain as it was. Andy

Road Fan

It sounds to me that your wheel is canted in the frame, so that the rear wheel is not in the plane of the seat tube, assuming the seatstays are straight. I had that problem on my Trek, and Ron Boi rectified it by milling the dropout surfaces to rotate teh wheel so it sav perpendicular when the BB axis was level to the ground. Hel also aligned the entire frame, not just the back end.

Canaboo

A compromise would be to file the whole flat surface a few strokes and do a test fit and repeat to achieve a correction that can be lived with visually and structurally..