Bicycle Mechanics - Rim flat spot fix?

The rear wheel of my newly acquired PUCH has a flat spot- not horrible, but you can feel it. Any ideas on how to fix or at least lessen the feel? Apply pressure in the opposite direction? It is a 36 spoke Weinmann rim, and I want to keep it original. Thanks

The only way I've seen recommended to improve a flat spot is pretty crude. You loosen the spokes, then "wack" the rim inside of the flat area with a piece of wood to bump the flat out to the correct contour, then retension and true the wheel.

I use a flat spot tool....looks like a piece of arched steel rod with two puller plates...however it is primarily intended for use with box and semi box rims.

Works best when the flat spot is simple - i.e., no twist or side bend in the flat spot.

=8-)

This is unacceptible and should be replaced under warranty.

Al

This is unacceptible and should be replaced under warranty.

Al

Good luck with that.

:D

Good luck with that.

:D

I had an out-of-round Specialized wheel replaced under warranty.

OP said "newly aquired", not "new" ..... so I assume that means a used bike.

Anyway, little flat spots can be improved by loosening the spokes at the flat spot and 1 or 2 more on each side, then tightening the 2-3 spokes beyond those on either side. That will force out the flat spot. This works best for more "out-of-round" situations than dent type flat spots, so the rim puller may be a better option. Otherwise, rim replacement is fairly easy if the spokes & nipples are in good shape.

Any chance of a picture of the flat spot tool? Homemade or bought?

Thanks,

DPN


I use a flat spot tool....looks like a piece of arched steel rod with two puller plates...however it is primarily intended for use with box and semi box rims.

Works best when the flat spot is simple - i.e., no twist or side bend in the flat spot.

=8-)

I use a flat spot tool....looks like a piece of arched steel rod with two puller plates...however it is primarily intended for use with box and semi box rims.

Works best when the flat spot is simple - i.e., no twist or side bend in the flat spot.

=8-)

1+ I recovered a bicycle that was stolen from me. I discovered that both rims had "flat spots" from whatever the theif did. My LBS had tools as described, the rims were box type. The process was 50% successful. The front rim was fixed the rear could not be fixed sufficiently. I rode the front wheel for many (1000's) of miles but it eventually developed rim cracks around the spokes where the flat spot was. The cost of the repair was well worth it if you can find a shop with the right tools.

I would take this Puch to your bike shop and have them do it. a flat spot is best left to a Pro. OH where do you live? is the Puch that was on CL in Deleware county PA? if so it was a real nice bike.

Yeah.... I have the same issue on an otherwise perfect 25-year-old rim.

Any chance of a picture of the flat spot tool? Homemade or bought?

Thanks,

DPN

Darn...just dropped it off back to the shop a couple days ago. No pictures...however it is a well known tool...available from bicycle tool catalogs. Wouldn't be surprised if on online tool supplier has a pic of it.

=8-)

No problem...I'll look around.

I did see a tool that looked like a jack that had a base that sat on the hub, and the jack plate applied pressure to the inside part of the rim. I guess you'd just jack your way back to roundness!




Darn...just dropped it off back to the shop a couple days ago. No pictures...however it is a well known tool...available from bicycle tool catalogs. Wouldn't be surprised if on online tool supplier has a pic of it.

=8-)

No problem...I'll look around.

I did see a tool that looked like a jack that had a base that sat on the hub, and the jack plate applied pressure to the inside part of the rim. I guess you'd just jack your way back to roundness!

That's one style, but I don't like the idea of using the middle of the hub body for leverage. I prefer the other tool that goes on the outside of the rim & pulls outward.

The sidewalls are often flared out at the flat spot. Bending them back in to match the rest of the rim will reduce the size of the flat spot.

That's one style, but I don't like the idea of using the middle of the hub body for leverage. I prefer the other tool that goes on the outside of the rim & pulls outward.

Yep...that's the one...curved rod on the outside with two pivoting seats...rectangular plate with bolts on the inside...

=8-)

I had an out-of-round Specialized wheel replaced under warranty.

Specialized is still around.

I'm skeptical any company bought and sold like 20 years ago is going to be responsible for their products. Most Puch bicycles in the US are the old company, the new ones are rare even in Europe.

puch.at

Yep...that's the one...curved rod on the outside with two pivoting seats...rectangular plate with bolts on the inside...

=8-)

I've seen this tool in parts and tools catalog available only to dealers, but our service manager quit and took the catalog with him. There's also a slightly less expensive tool that pushes the rim outward from the hub. I would not use this one with super-lightweight hubs, though.

http://www.biketoolsetc.com/index.cgi?id=98212742410&d=single&c=Tools&sc=Wheel-and-Rim&tc=Rim-Repair-Tools&item_id=CU-030

Not cheap at $148, but maybe worth a group buy if you're part of a club or know other owners who might need it from time to time.

http://www.biketoolsetc.com/index.cgi?id=98212742410&d=single&c=Tools&sc=Wheel-and-Rim&tc=Rim-Repair-Tools&item_id=CU-014

This one, too. That catalog had them both for about 2/3 the cost. We're supposed to get an account.