Bicycle Mechanics - Ride is kinda bumpy, I think its the tires

So, last night, riding home from work, when switching to my largest chain ring, my chain fell off. Now, I know that is due to a poorly adjusted limit screw. I can fix that.

However, instead of stopping immediately to put the chain back on, I decided to just coast until I stopped. Not pedaling allowed me to feel a bump.

It feels like I'm riding on a rumble strip, that is very spread apart. It feels like one bump per rotation of the wheel. I feel it in my butt, so I believe its the rear wheel. I know its not the road, because I intentionally rode slow / coasted on quite a few different roads (maybe 1/2 mile) and it occurred on all of the roads, some of which are quite new roads.

While pedaling quickly, I don't notice the bump - probably because of all the movement that's going on involved in pedaling. The bump feeling is more pronounced when I am rolling faster (coasting down a hill), which leads me to believe it is based on rotations of the tire. I do not need to be pedaling to make this happen. I do not hear a noise, I just feel it.

Any ideas?

Bulge in the rear tire. Get a new tire.

Take the wheel off the bike and spin it while holding with your hands.
Look for the bulge as it rotates.

Spin the wheel while holding a finger near the tire and see if the gap gets larger and smaller. If so, the next step is watching the rim in the brake shoes to see if it too rises and falls.

If the rim isn't round, you need a wheel alignment. OTOH if the rim is true or has much less eccentricity than the tire then you have a tire problem. Often it's a matter of poor seating, with on section deeper or higher in the rim. Confirming by spinning the wheel slowly and watching the molded lines nearest the rim. If the seating is OK but the tire isn't round or has a local bump, it's a warning sign that the cord is fractured and beginning to let go. This isn't repairable and calls for a new tire.

So I bought a new tire... but it seemed like my tube was too big for it. It folded on itself inside the tire. Is this normal?

A single size of tube is able to accommodate many sizes of tire. Sometimes the tube is folded and sometimes it is stretched inside the tire. As long as the tube is not pinched between the rim and sidewall of the tire then there will not be a problem.

Try to figure out why your old tire was having problems. Sometimes it is caused by a brake pad hitting the tire and cutting the threads. If this was the cause of the first tire failure, it is likely to be the cause of a second.

Also, an out-of-true rim is much less likely to be felt in the saddle than a bulge in a tire.

It feels like I'm riding on a rumble strip, that is very spread apart. It feels like one bump per rotation of the wheel. I feel it in my butt, so I believe its the rear wheel. I know its not the road, because I intentionally rode slow / coasted on quite a few different roads (maybe 1/2 mile) and it occurred on all of the roads, some of which are quite new roads.


Unseated tire (fix this before it blows off), broken cords (replace the tire), or flat spot in the rim (replace it).

So I bought a new tire... but it seemed like my tube was too big for it. It folded on itself inside the tire. Is this normal?

No, a tube should never fold on itself inside the tire. I've seen a few that were marginally long and had to be slightly compressed, but like a roundworm, not folded.

Take it out put some air into the tube and stuff it into the tire spreading it evenly all the way around. Then finish mounting the tire, letting the air back out of the tube if it helps.

The only way I could see a tube folded in on itself inside a tire is if you had, for example, a 700c tube in a 26" tire. In hindsight, maybe that's what was wrong with your prior lumpy tire.

No, a tube should never fold on itself inside the tire. I've seen a few that were marginally long and had to be slightly compressed, but like a roundworm, not folded.

Take it out put some air into the tube and stuff it into the tire spreading it evenly all the way around. Then finish mounting the tire, letting the air back out of the tube if it helps.

The only way I could see a tube folded in on itself inside a tire is if you had, for example, a 700c tube in a 26" tire. In hindsight, maybe that's what was wrong with your prior lumpy tire.

Disclaimer: I bought this bike at a Walmart-type store, and it is a piece of crap

I've never even taken the rear wheel off once it was assembled. After noting the tube was "too big," I put the old tire back on. I don't ride THAT much, figure it won't hurt. The two tires APPEAR to be the same diameter, but the tube is perfect size for the old tire, but too big for the new tire.

I wasn't able to figure out what was wrong with the old tire either. No apparent physical damage, the seating of the tire seemed fine. I tried to eyeball it, but couldn't see anything. I did re-mount the tire, twice, and the bump seems to be less pronounced, but I still feel it.

Disclaimer: I bought this bike at a Walmart-type store, and it is a piece of crap

I've never even taken the rear wheel off once it was assembled. After noting the tube was "too big," I put the old tire back on. I don't ride THAT much, figure it won't hurt. The two tires APPEAR to be the same diameter, but the tube is perfect size for the old tire, but too big for the new tire.

I wasn't able to figure out what was wrong with the old tire either. No apparent physical damage, the seating of the tire seemed fine. I tried to eyeball it, but couldn't see anything. I did re-mount the tire, twice, and the bump seems to be less pronounced, but I still feel it.

The tires should have the size printed on the sidewall, for example 26 x 1.25, 26 x 1.5, 26 x 1.75. Those are all 26" tires, but differnt widths.

By the way, next time your chain comes off, try gently pedaling and shift it back onto the chainring instead of stopping. Works quite often.

The tires should have the size printed on the sidewall, for example 26 x 1.25, 26 x 1.5, 26 x 1.75. Those are all 26" tires, but differnt widths.

By the way, next time your chain comes off, try gently pedaling and shift it back onto the chainring instead of stopping. Works quite often.

The box said it was good for 26", and listed a bunch of widths. The thing is, the tube seems to be a larger diameter than the new tire, but it fits in the old tire. Which is funny, because both tires look the same size....

Also, the chain fell off and was hanging around where the crank meets the chainrings... I don't think I can pedal the chain back up there?

... The two tires APPEAR to be the same diameter, but the tube is perfect size for the old tire, but too big for the new tire. ...


The tires should have the size printed on the sidewall, for example 26 x 1.25, 26 x 1.5, 26 x 1.75. Those are all 26" tires, but differnt widths. ...


The box said it was good for 26", and listed a bunch of widths. The thing is, the tube seems to be a larger diameter than the new tire, but it fits in the old tire. Which is funny, because both tires look the same size.... ...

Ignoring the tube, what is printed/written on the sidewall of the tyres? If the truly are the same size I don't understand how the tube should fit one an not the other.