Changing tire on old mountain bike - can't get wheel back between forks?
May 17, 2023 10:56 AM Subscribe
I am awful at fixing bikes, but I thought I could manage to change a couple of tires. Overconfidence got the better of me, so I didn't even bother to take a photo first. I am simply trying to put the front wheel back on the bike, but the black bits here and here (sorry don't know what they are called) are not leaving me room to get the wheel back on. The back wheel has similar black bits, but the wheel slots between them no problem. Am I supposed to force the forks apart to give me room? It really doesn't feel like that's the right idea. I can't get the black bits closer together, but I could loosen them to put them farther apart - but that would make it worse? How do I fix this?
Video here if it helpful.
Video here if it helpful.
Best answer: Yes, just spread the fork ends apart. And just to forestall further frustration, you may have issue fitting the fully inflated tire between the brake pads too. So, fully inflate the tire after the wheel is installed….
posted by TDIpod at 11:26 AM on May 17, 2023 [4 favorites]
posted by TDIpod at 11:26 AM on May 17, 2023 [4 favorites]
Deflate the tire and it should fit, then reinflate once the wheel is on.
posted by cmm at 12:09 PM on May 17, 2023 [2 favorites]
posted by cmm at 12:09 PM on May 17, 2023 [2 favorites]
I have never had to push fork ends apart to reinstall a wheel. Did you have to pull hard to remove it? If not, then the width of the fork is not the issue.
Deflating the tire often works. The brakes almost certainly have some kind of release that allows the calipers to be spread wider.
posted by Caxton1476 at 12:38 PM on May 17, 2023 [1 favorite]
Deflating the tire often works. The brakes almost certainly have some kind of release that allows the calipers to be spread wider.
posted by Caxton1476 at 12:38 PM on May 17, 2023 [1 favorite]
I think this is worthy of a bit of investigation.
First of all, yes, it is fine to pull the fork ends/dropouts of a steel frame apart by a few millimeters when you're reinstalling a wheel. However, like Caxton1476, I've virtually never had to do this with a fork--and I worked at a bike shop for several years!
It's fairly common for rear wheels to be slightly off, because the standards for the distance between dropouts, where you put the rear wheel, have gradually been creeping upwards over the last 4-5 decades as the length of the axle clamped between the dropouts (referred to as the over locknut distance or OLD) has grown to accomodate more gears and different riding styles. As a result, it's extremely common to put a newer/wider wheel in an older/narrower frame, because you almost always replace wheels before a frame breaks or becomes totally obsolete. Also, rear wheels are normally asymmetrical, and there's often a bit of washer and spacer rearrangement that goes on when assembling a rear wheel's axle in order to get everything aligned correctly, all of which can lead to not-quite-spec OLDs. There's even a standard bike shop service where they'll permanently bend your rear dropouts apart and then coax them back parallel with each other (called "cold setting" the rear triangle) to permanently re-space a steel frame's dropouts.
But none of these things are going on in the front. Fork ends have been 100 mm apart on most bikes for a very, very long time (iirc, with the exception of a downhill bike standard which is 110 mm, and if you had one of these you'd know it). The shop I worked at regularly cold set rear dropouts, but in my memory we never did a fork. Because 99% of the forks and front wheels out there are 100 mm and just fit without any fuss.
So, I think it's worth measuring both the distance between the dropouts and the OLD of your front wheel. You can just stick a ruler in the dropouts, actually, and if it's 100 mm or very close to it, you can assume the wheel's OLD is too large for some reason. You can definitely measure the wheel's OLD too but you might need set up some makeshift calipers.
If your front wheel's OLD is dramatically >100mm, there's probably an extra washer or something in there...but fixing the problem may not be as simple as removing it, as the location of the washers, locknuts and cones (the things that thread or slide onto the axle) serves to center the wheel. If you can take two equally thick washers off each side you're golden, but if you take a spacer off of one side only you'll need to shift EVERYTHING over in that direction by a distance equal to half the thickness of the spacer. If you don't, the hub will be off-center and the tire may rub the inside of the fork blades at the top. So you may want to carefully stretch the fork blades now, and then have a bike shop look at it at some point in the future.
One last unlikely possibility is that the wheel is like this intentionally because your fork is itself asymmetrical, and the wheel is intentionally wonky to match. But that's also a question for a shop.
posted by pullayup at 1:11 PM on May 17, 2023 [1 favorite]
First of all, yes, it is fine to pull the fork ends/dropouts of a steel frame apart by a few millimeters when you're reinstalling a wheel. However, like Caxton1476, I've virtually never had to do this with a fork--and I worked at a bike shop for several years!
It's fairly common for rear wheels to be slightly off, because the standards for the distance between dropouts, where you put the rear wheel, have gradually been creeping upwards over the last 4-5 decades as the length of the axle clamped between the dropouts (referred to as the over locknut distance or OLD) has grown to accomodate more gears and different riding styles. As a result, it's extremely common to put a newer/wider wheel in an older/narrower frame, because you almost always replace wheels before a frame breaks or becomes totally obsolete. Also, rear wheels are normally asymmetrical, and there's often a bit of washer and spacer rearrangement that goes on when assembling a rear wheel's axle in order to get everything aligned correctly, all of which can lead to not-quite-spec OLDs. There's even a standard bike shop service where they'll permanently bend your rear dropouts apart and then coax them back parallel with each other (called "cold setting" the rear triangle) to permanently re-space a steel frame's dropouts.
But none of these things are going on in the front. Fork ends have been 100 mm apart on most bikes for a very, very long time (iirc, with the exception of a downhill bike standard which is 110 mm, and if you had one of these you'd know it). The shop I worked at regularly cold set rear dropouts, but in my memory we never did a fork. Because 99% of the forks and front wheels out there are 100 mm and just fit without any fuss.
So, I think it's worth measuring both the distance between the dropouts and the OLD of your front wheel. You can just stick a ruler in the dropouts, actually, and if it's 100 mm or very close to it, you can assume the wheel's OLD is too large for some reason. You can definitely measure the wheel's OLD too but you might need set up some makeshift calipers.
If your front wheel's OLD is dramatically >100mm, there's probably an extra washer or something in there...but fixing the problem may not be as simple as removing it, as the location of the washers, locknuts and cones (the things that thread or slide onto the axle) serves to center the wheel. If you can take two equally thick washers off each side you're golden, but if you take a spacer off of one side only you'll need to shift EVERYTHING over in that direction by a distance equal to half the thickness of the spacer. If you don't, the hub will be off-center and the tire may rub the inside of the fork blades at the top. So you may want to carefully stretch the fork blades now, and then have a bike shop look at it at some point in the future.
One last unlikely possibility is that the wheel is like this intentionally because your fork is itself asymmetrical, and the wheel is intentionally wonky to match. But that's also a question for a shop.
posted by pullayup at 1:11 PM on May 17, 2023 [1 favorite]
Might be the brakes. I can pull my wheel off without loosening the brakes but I can’t put it back on.
posted by kerf at 3:30 PM on May 17, 2023 [1 favorite]
posted by kerf at 3:30 PM on May 17, 2023 [1 favorite]
Best answer: I've had to push front forks apart slightly in order to get a front wheel in before. This is not a big deal and I give you permission to just pull them apart, slip the wheel in there and not think about this any more. It'll be fine.
This has nothing to do with the brakes or the tire.
posted by ssg at 9:17 PM on May 17, 2023
This has nothing to do with the brakes or the tire.
posted by ssg at 9:17 PM on May 17, 2023
Yep, I would just bend the forks out slightly by putting one side of the axle in the slot, then pull the other fork out by hand until the wheel drops in (only use just enough force to get it in). It's probably been bent at some point.
You may then find you can't get the tire to fit in between the brake pads and that's usually solved by deflating the tire first.
posted by dg at 4:58 PM on May 18, 2023
You may then find you can't get the tire to fit in between the brake pads and that's usually solved by deflating the tire first.
posted by dg at 4:58 PM on May 18, 2023
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Those nuts should be tight but not too tight. If they are too tight the wheel won't spin freely. If they are too loose, then the bearings will be too loose which could cause more problems. The silver axle part should spin pretty freely and not shift around if pulled/pushed.
posted by jclarkin at 11:07 AM on May 17, 2023 [3 favorites]