hit a pothole, hard.

[Returnformer]

i hit a pothole pretty hard the other day, hard enough to slightly dent the rim. (see pic.) didnt see it coming until i was on it. i got the front up and over it, but the back wheel took a hit. i thought the dent was the extent of the damage, but ive been feeling a thump-thump-thump as i ride, i think since then. i doubt its from the rim, though, thats barely noticeable. any ideas? i tried lifting the back and pulling the throttle to see if i feel anything without the wheel on the ground, and i think its not as pronounced, but still there. when riding, its noticeable most at medium speeds. at slow or high speeds its not so noticeable. seems to ride fine otherwise. is maybe the wheel out of alignment or something and im feeling a wobble? something bent by the axle inside the motor? any other ideas?

thanks.

 

[Balmorhea]

It’s a flat spot bashed into the rim. Under other circumstances, it could be a bulge in the rim making contact with the brake pads, but judging from the photo it looks like you don’t have rim brakes.

The remedy is to relace the wheel with a new rim. The best future preventive is a bigger tire with more pressure in it, and standing up off the seat when you know you’re going to hit a road hazard. Slowing down helps too.

i once nailed a nasty deep pothole spanning across the entire bike lane, that was full of water so it didn’t look like a big deal. It was my first e-bike, with SLA bricks hard mounted on top of the rear rack. I had a 700x38 tire with 100 psi in it(which didn't pinch flat), but the rim still bent inward and caused a noticeable bump once per rotation. I took 15 years getting around to relacing the wheel, but it’s good as new now.

 

[AHicks]

Anything is possible, but my vote would be the tire. Same thing happened to me (hard hit on a pot hole) and within about 50 miles or so the bulge in the sidewall became apparent. Didn't like the "hum" from those tires anyway......was easy to say good bye to them!

 

[Returnformer]

even such a slight dent with a fairly large tire over it would cause a noticeable thump?

it annoying, but not annoying enough to replace the rim unless its dangerous...

 

[MadRhino]

I guess the rim is cracked, unless it is dirt or surface damage that I am seeing under the C of the tire name. So, maybe it has to be replaced. The tire might have damage to the canvas fibres inside the rubber, and that alone is enough to make it spin unbalanced, even if the rim is goid and true.

 

[Returnformer]

I guess the rim is cracked, unless it is dirt or surface damage that I am seeing under the C of the tire name. So, maybe it has to be replaced. The tire might have damage to the canvas fibres inside the rubber, and that alone is enough to make it spin unbalanced, even if the rim is goid and true.

thats rubber from the tire sticking down, theres one under "original", too.

 

[99t4]

If we're still playing "find the defects in this picture," what about the apparent crack there under the "B," on the inner surface of the rim at the nipple? Or is that the joint seam? At any rate, looks like it has opened up?

 

[docw009]

You're the only one that can tell, but is there a slight dent under the "LB"? You could loosen the spokes 1/4 turn there amd tighten the opposite ones, It won't remove the dent, but the wheel might spin more rounded.

 

[Balmorhea]

You're the only one that can tell, but is there a slight dent ubder the "LB"?

That’s the flat spot I’m talking about. It looks like the rim buckled badly enough to bulge the sidewalls out.

The spoke under the buckled section is probably loose.

 

[Returnformer]

If we're still playing "find the defects in this picture," what about the apparent crack there under the "B," on the inner surface of the rim at the nipple? Or is that the joint seam? At any rate, looks like it has opened up?

it looks like a crack in the pic, but in person it looks more like a scratch. doesnt seem to be cracked.

You're the only one that can tell, but is there a slight dent under the "LB"? You could loosen the spokes 1/4 turn there amd tighten the opposite ones, It won't remove the dent, but the wheel might spin more rounded.

yes, thats the slight dent that the pic is meant to show, presumably where it hit. i dont think its out of true, though, its dented on both sides. very very slight, though.

That’s the flat spot I’m talking about. It looks like the rim buckled badly enough to bulge the sidewalls out.

The spoke under the buckled section is probably loose.

there was a few spokes loose in the vicinity, just tightened them. perhaps that was the cause of the thump? ill find out next time i ride...

 

[Returnformer]

i think tightening the spokes might have lessened the thump a bit, but its still there. i tried watching the back wheel as it spins slowly, and i do think i see a bit variance as it spins. hard to tell when i have to use one hand to hold the bike up and one to make it spin. i dont have a repair stand that can support such a heavy bike. any idea how to lift up just the back so i can checkthe wheel out easier?

 

[fechter]

I turn my bikes upside down to work on the wheels. I place some foam pipe insulation around the grips so the brake reservoirs and display don't hit the ground and wrap a towel around the seat to prevent dirt/scratches.

If you can get the wheel up so it spins easily, you can make a pointer out of a piece of wire and place it near the edge of the rim to check for trueness.

 

[Returnformer]

I turn my bikes upside down to work on the wheels. I place some foam pipe insulation around the grips so the brake reservoirs and display don't hit the ground and wrap a towel around the seat to prevent dirt/scratches.

If you can get the wheel up so it spins easily, you can make a pointer out of a piece of wire and place it near the edge of the rim to check for trueness.

yeah, i do that when fixing flats, i was hoping there was an easy way to just lift it up a bit, maybe a milk ccrate under the bb or something.

 

[fechter]

yeah, i do that when fixing flats, i was hoping there was an easy way to just lift it up a bit, maybe a milk ccrate under the bb or something.

That can work too if you have something the right height.

How heavy is the bike?

 

[Returnformer]

yeah, i do that when fixing flats, i was hoping there was an easy way to just lift it up a bit, maybe a milk ccrate under the bb or something.

That can work too if you have something the right height.

How heavy is the bike?

i think its about 60 overall.

 

[dogman dan]

Sure, you can keep running that, with at least some permanent thump. But nothing will ever straighten that rim, its toast.

Not dangerous really, unless you go very fast, but trying to pull that thump out will start breaking spokes, or ripping out nipples. Waste of time and effort compared to a new rim. Lacing and truing one may be hard for you, or not. Just depends on how experienced you are. If you have messed with spokes some, relacing is easy, truing it a bit harder, but not as hard as trying to true a bent rim. That's IMPOSSIBLE.

I like the zip tie trick. Put a zip tie on the frame where its near the rim. cut to length, and adjust to make a truing stand out of your upside down bike. Cut off too much, easy to try again. But again, waste of time to try to straighten a bent rim. It won't straighten without extremely over tight spokes somewhere on the wheel.

 

[fechter]

That's not too heavy. Either way will work. There are some good online tutorials about wheel truing. I have a dial gauge now, but I used to just tape a piece of copper wire to the stay or fork and bend it so it almost makes contact with the rim and you can visually see how much runout there is.

 

[Returnformer]

Sure, you can keep running that, with at least some permanent thump. But nothing will ever straighten that rim, its toast.

Not dangerous really, unless you go very fast, but trying to pull that thump out will start breaking spokes, or ripping out nipples. Waste of time and effort compared to a new rim. Lacing and truing one may be hard for you, or not. Just depends on how experienced you are. If you have messed with spokes some, relacing is easy, truing it a bit harder, but not as hard as trying to true a bent rim. That's IMPOSSIBLE.

I like the zip tie trick. Put a zip tie on the frame where its near the rim. cut to length, and adjust to make a truing stand out of your upside down bike. Cut off too much, easy to try again. But again, waste of time to try to straighten a bent rim. It won't straighten without extremely over tight spokes somewhere on the wheel.

how fast is very fast?

ive changed the rim on a regular wheel, and trued a couple wheels, so its not completely foreign to me, although i wouldnt say im an expert at it.

(i just use my thumb as a gauge, which is what i saw a guy do in a shop once.)