Abe_Froman

So...I've got a Marin steel cyclocross/touring bike I've had since 2011. I'm honestly not sure if I bought it like this, or managed to bend the frame somehow myself at some point, but the rear dropouts are definitely not aligned. The leading edge of the tire sits noticeably left of the center of the seatpost...I'd say by a few millimeters. It's not drastic.

Also...the dish of the wheel is not off, as I'm sure that will be the first question. I rebuilt it myself and checked the dish, it ended up being within 0.5mm of dead on when I was done, and still sat off center in the frame. The bike rides fine, and has for the last few years since I noticed the issue when I put wider tires in. Now I'm thinking of going even bigger, or getting tires that have similar volume but a few knobs, and am worried about clearance by the left chainstay.

So...finally to the actual question. Is this something you would recommend undertaking myself to fix? If not...how difficult will it be to find a shop that can do it competently?

xenologer

This has to be my favorite tool in the shop
https://www.parktool.com/product/fra...ightener-ffs-2

one point to check though
with the wheel off the bike, turn the axle by hand. does it stay centered in the hub, or do the ends noticeably wobble?
sometimes even if a wheel is true, a slightly bent axle will mess up where the wheel sits when mounted...

Crankycrank

Here is a good start. https://www.google.com/search?q=how+...ialgle&ie=&oe= Lots of tutorials available. I've always been a little measurement challenged when trying to determine if everything is aligned on a bike but maybe that's just me so I just gave two of my bikes to the local frame tweaking specialist to straighten. You also need to check if the dropouts are parallel to each other independent of any other bends in your rear triangle and tutorials are also available on how to check and make your own inexpensive tools. Many people do it themselves but there is the possibility of cracking tubes and joints if you go overboard.

Binky

If the bike was OK before and nobody except you has been riding the bike, I would doubt very much that the frame is bent from having been damaged. Possibly it was built that way. Either way, I have encountered a few instances in which it was necessary to move the rear rim left or right in order to accommodate vagaries of rear drop out misalignment. If you have to move the rim and tire back into the centre of the bike by forcing it to the right a few mm, just do it. Leave the wheel on the bike. Loosen all of the spokes on the left side of the wheel by half a turn, and tighten all of the spokes on the right side by the same amount. Then true the rim again and see where it is. You have plenty of thread contact remaining so losing half of a thread in the nipples will not be a problem.

If the bike was not brand new when you got it is possible that the rear wheel was replaced at some time... or you or the previous owner may have accidentally moved a washer or spacer from the left end of the axel to the right end or vice versa when lubricating your bearings and displaced the entire wheel to the left in the process.

Bink.

Andrew R Stewart 

I'm not sure if what you describe would be what I call "misaligned dropouts" in the usual reference. Dropout alignment is generally considered to be their being parallel to each other and no other aspect. What you describe, a wheel that sits cocked in the frame, is usually due to a chain stay or seat stay effectively being longer the it's mate is. Bikes with horizontal/slotted drop outs have the ability to change this to a degree by sliding the axle back and forth in the slots till the wheel is as centered as possible. Vertical/through axle drop outs have no ability. Very minor stay length miss matches can be corrected by filing the slot a bit, there's about a 1:3 ratio of drop out slot changes and the "movement" of the rim WRT the frame. So a .5mm filing of the drop out will result in about a 1.5mm rim shift. This is best to be done by someone who has some experience as whenever you remove material you commit to a path that you'd better know where it ends up at. Andy


xenologer makes a very good point to check the rear axle for it's being bent.

Abe_Froman

Nope, axle is fine. Replaced bearings and spent a bunch of time fine tuning the bearing adjustment when I build the wheel. Axle is definitely straight as an arrow.

Andrew R Stewart 

So when you flip the wheel around and reinstall it you see the same cocked position as before? To the same side? Andy

Abe_Froman

I've actually not done that. But I'm 100% certain that will be the case. The dish on the wheel is perfect.

Abe_Froman

And wow, thanks for the fast responses. You guys are on the ball in the mechanics section lol

Abe_Froman

Honestly...it really is not that far off. I think I'd rather have it off a bit, but keep the dish correct for a stronger wheel.

berner

I've had a similar problem with my bike. The result of axle misalignment was poor tracking. After much measuring I determined the problem cold be cured by filing the rear dropouts just a tiny bit. The geometry is such that a misalignment at the axle of 1/2 mm results n the rim being off center about 5 times as much, say 4mm. After some serious contemplation I went ahead with the filing. The result was much improved tracking. I was even able to ride hands.

davidad

Run a string from one dropout around the head tube back to the other dropout and measure the distance to the seat tube from both sides. This will tell you if the misalignment is in the rear triangle. If it's off you can bend one side to make both equal. Steel is very forgiving.

cny-bikeman

The symptom you see could be incorrect wheel dish (result of improper truing or moved/missing axle spacers) a bent rear triangle, or just not mounting the wheel properly. It would be difficult for misaligned dropouts alone to cause the problem. As for your specific question, given dropout alignment tools it's not a challenge at all to align them. Unless you have a stable of bikes and work on them for others there's no percentage in purchasing expensive tools that will seldom be used.

Andrew R Stewart 

Let's see, a common rear drop out width is 135mm. A common cyclecross wheel has a brake track/rim bead radius of 311, and I don't use the tire as it's run out can be large. 311/135=2.3. 2.3x.5mm=1.1+mm. A far cry from 4mm.


When I suggested a 1:3 ratio of axle end repositioning and resulting rim shift I was wrong. It's about 1:2.3 or less.


Why does this mater? I just like to read real math and go by rear numbers when I can. Andy

Andrew R Stewart 

cny- has a good point. I'll add that having a qr spring on backwards can produce a cocked wheel. It's such a no brainer that I forget about this possibility often yet see it often enough on customer bikes. If the large end of the spring overlaps the axle end it will keep the axle from fully settling into the dropout by at least the thickness of the spring. Everything else, dish, dropout and frame alignment, brake adjustment/centering can be spot on and the wheel will sit crooked. Andy

fluffylama31

so I think what you’re describing is my problem. I’ve got an 89 rockhopper. The tire hits the drive-side chainstay when the axle is fully seated.

ive checked the:
1. Rear dropout alignment.
2. Frame alignment (string method)
3. Wheel is dished and true (threw on multiple rear wheels to assess my sanity).

I’m convinced the rear dropouts were welded out of alignment (right side further back than the left).

so my question is that you would true the wheel with the axle fully seated in the dropouts as opposed to just offsetting the wheel so it runs straight?

mind you, the tire “rub” isn’t even a rub. The wheel straight up won’t spin if the axle is fully seated. It’s way, way off.

Your post was a few years ago. Hopefully you’re still active!

sweeks

If the wheel is true, then the axle is perpendicular to the plane of the rim. There's no way you would be able to adjust the alignment of the rim by "truing", since the axle of the mounted wheel is (apparently) not perpendicular to the fore-aft axis of the frame.

Mr. 66

Fluffylama31 you may have some front triangle issue, sideswiped frames came give misleading measures in checking the rear triangle.

unterhausen

Put the wheel in wrong way around, gears on the non-drive side. I don't understand how a bike can leave a bike shop with the wheel hitting. Plus, was it totally unused for 30 years?

Except just doing a quick search, it looks like this is one of those bikes that has horizontal dropouts. The answer is not to fully seat the axle. If it had vertical dropouts, then the answer would be different.

fluffylama31

Thanks, I agree. I was just asking for clarification because I didn’t fully understand what he was suggesting would fix the problem.

fluffylama31

I hear you. But there is no sign of trauma to this bike. It has been ridden well, but no signs of trauma and has been taken care of overall.

fluffylama31

I flipped the wheel and it still hits on the same size.

oh. Honestly I thought ‘horizontal dropouts’ were totally horizontal, but I suppose they are. So adjusting the axle so the wheel is centered and then clamping down is considered normal in this case?

I tried posting a photo of the dropouts. Not allowed here?

unterhausen

A 30 year old rockhopper is not worth the surgery/paint it would take to move the wheel over if it really were a dropout problem. This is still true for me, and I can do the work myself. On some bikes with vertical dropouts, it's close enough that you can file off the front of one side of the dropout and move the wheel over. But if your bike has horizontal dropouts, they didn't really intend for you to pull the wheel all the way back on both sides. My '85 rockhopper is like that. I has a filler web on the drive side and a longer slot on the left side. You could easily pull back the wheel until it hits the chainstay, but I prefer bikes that have freely moving wheels.

Some of those horizontal dropouts they used had filler webs on both sides. I still wouldn't pull the wheel back until it hit the chainstay.

You can upload a picture of the bike to an album in your gallery, and we can rescue it for you so everyone can easily see it.

You can't bend a frame so that it fixes this problem unless it is visibly bent.

unterhausen

I guess we were posting at the same time.

Those dropouts are maybe a little more tilted than some horizontal dropouts, but they aren't tilted as much as some of the ones I would call "semi-horizontal." And they definitely aren't vertical. A wheel should stay in place if clamped a little forward. You might have to find a full closed-cam quick release if you have open cam quick releases now.

Upload a pic to an album in your gallery and let us know. We can post it here for you. I thought they were changing the rules for newbies to post pics to 5 posts, but maybe not.

fluffylama31

This is great to read. Here I though I had a dud. I was ready to scrap it. Thanks.

The photo is just of the dropout. Clearly ya'll know what kind of dropouts my bike has, but here it is anyways

..... tried to insert an outside URL and it told me I have to make 10 posts before I can even do that.......

I'll expand my senses in terms of what is called 'horizontal.'