dents in american classic mtb

[wapad]

I have four dings in my rear american classic mtb tubeless can these be straightened, they still seal perfect I think its maybe 1-2 mm off true are their any specialists out there. I'm from Cape Town.

 

I've been running my tyre pressure to low and realised this after finding my floor pump gauge was dodgy and a few dings to in my rear wheel.. love the wheels though

 

Any advice appreciated

[Brighter-Lights]

I would advise to be VERY VERY careful when bedning the tubeless AMC rim... they are very soft, but also very thin. I straightened my AMC tubeless rim about 10 months ago and it bent so easily it felt like I was bending a piece of cheese, the problem is, because it's so thin, bending it just a little too much could result in that section of the rim wall cracking and seperating from the rest of the rim.

 

Tape the section you want to bend with some sort op PVC tape to prevent it from getting scratched. Then take a shifting spanner and close the jaws over that section and use it as a lever and bend little by little. Sometimes it's best to leave it like that if it's better than it was, because bending it that 0.5mm further might result in a crack...

 

The type/size of tool/clamp you need obviously depends on how long the dent is, and how deep it is...

 

Take the tyre off, re-fit it and see how the dent affects the seating/sealing first. Sometimes a fitted tyre will hold a seal because the sealant has glued the tyre to the rim, but when fitting a fresh tyre, it may not seal or seat properly. You want to be sure it seals, but more important, make sure it seats properly, or snap/pop onto the rim hook. If not, the tyre could come off/burp at lower pressures, because the total rim wall height on these rims are lower than one a STD rim, (almost like on a stans rim) so tyres, once off the rim hook, can very easily be put on, or taken off the rim. I never have to use tyre levers, but once the tyre has popped into place, it's secure...

 

Good luck!

[Flea]

I had the same - ran my tyre too soft and hit a curb - lost tyre pressure. When trying to fix, the sides looked like cracking -probably just the paint, but enough to worry me. Unfortunately I only had 2 daays to fix, so had to go with a different rim as I could not get AC in time, so that meant a whole new set of spokes as the new rim thickness was less. Now I have to decide if I go back to AC?

By the way this was on a 29er

[Lucky Luke.]

I have four dings in my rear american classic mtb tubeless can these be straightened, they still seal perfect I think its maybe 1-2 mm off true are their any specialists out there. I'm from Cape Town.

 

I've been running my tyre pressure to low and realised this after finding my floor pump gauge was dodgy and a few dings to in my rear wheel.. love the wheels though

 

Any advice appreciated

 

Try Lance at Epic Bike Shop, he's good with wheels. 087 802 5959. 39 Contstantia Road, Plumstead http://www.epicbikeshop.co.za/

[EasyBike]

Ditto exactly what Brighter-Lights said: the tape, the adjusting spanner, and carefully.

 

And DON'T run your tyre pressure too low.

[Johan Bornman]

May I advise against the shifting spanner method. A shifting spanner creates a sharp, localised bend where it creates a fulcrum against the outer wall of the rim. The results are almost always unsatisfactory.

 

What you need is

 

1) A flat anvil - something like a piece of thick U-channel or even a proper anvil with a perfectly flat surface.

2) A buddy

3) A nut whacker*

4) A ball-peen hammer

 

Locate the dent (they're almost always from the outside to the inside.).

 

Lay the dent on the anvil and get your buddy to lower/raise the wheel until the flat edge of the rim is perfectly parallel with the anvil and right against the edge of the anvil. If you bend down and look flat-on at the envil's top, you'll see light between the rim and anvil 'cause the dent makes a gap.

N

 

Now, with the nut wacker in one hand, place its tip carefully on the dent and whack it with the hammer so tha you flatten the dent against the anvil. Do not use a piece of wood. It will give and bend the rim to the other side.

 

Continue with gentle but smart smacks on the nut wacker. Often you'll actually ahve to press against your buddy with the wacker so that it lines up well for the smack.

 

You'll end up with a 99% perfect rim.

 

Some rules:

 

1) Don't use wood. It gives way too much.

2) Be patient.

3) Dont ever hit the rim on its hollow inside.

4) Never strike the rim directly with a hammer or mallet. Always work though a nut whacker.

 

* Nut Whacker - those of you who attend my fork courses and DIY classes know this usefull tool all too well. It is merely a nylon rod 25mm thick, 200mm long. It is soft enough not to create sharp dents, yet is is hard enough not to split or flatten with a hard knock. These are very, very useful tools.

[wapad]

May I advise against the shifting spanner method. A shifting spanner creates a sharp, localised bend where it creates a fulcrum against the outer wall of the rim. The results are almost always unsatisfactory.

 

What you need is

 

1) A flat anvil - something like a piece of thick U-channel or even a proper anvil with a perfectly flat surface.

2) A buddy

3) A nut whacker*

4) A ball-peen hammer

 

Locate the dent (they're almost always from the outside to the inside.).

 

Lay the dent on the anvil and get your buddy to lower/raise the wheel until the flat edge of the rim is perfectly parallel with the anvil and right against the edge of the anvil. If you bend down and look flat-on at the envil's top, you'll see light between the rim and anvil 'cause the dent makes a gap.

N

 

Now, with the nut wacker in one hand, place its tip carefully on the dent and whack it with the hammer so tha you flatten the dent against the anvil. Do not use a piece of wood. It will give and bend the rim to the other side.

 

Continue with gentle but smart smacks on the nut wacker. Often you'll actually ahve to press against your buddy with the wacker so that it lines up well for the smack.

 

You'll end up with a 99% perfect rim.

 

Some rules:

 

1) Don't use wood. It gives way too much.

2) Be patient.

3) Dont ever hit the rim on its hollow inside.

4) Never strike the rim directly with a hammer or mallet. Always work though a nut whacker.

 

* Nut Whacker - those of you who attend my fork courses and DIY classes know this usefull tool all too well. It is merely a nylon rod 25mm thick, 200mm long. It is soft enough not to create sharp dents, yet is is hard enough not to split or flatten with a hard knock. These are very, very useful tools.

 

to everybody thanks for all the usefull advice now I just have to build up the courage to do it

 

Thanks

[brussel]

I have done exactly the same on my AC rim, the issue is that my ding is so bad there is a noticeable dent in the rim bed as the impact happened exactly on a spoke hole. Also the hollow body of the rim has bulged quite noticeably.

 

I have managed to gently get the dent on the lip of the rim mostly out. but I am concerned about the bend in the bed and sidewall.

 

So when does one consider the rim as toast?

[wapad]

I have done exactly the same on my AC rim, the issue is that my ding is so bad there is a noticeable dent in the rim bed as the impact happened exactly on a spoke hole. Also the hollow body of the rim has bulged quite noticeably.

 

I have managed to gently get the dent on the lip of the rim mostly out. but I am concerned about the bend in the bed and sidewall.

 

So when does one consider the rim as toast?

 

 

if it still seals with the tubeless then thats step one

 

step two would be how out of balance it feels if it's a no with wheel balancing then its time to rebuild I saw a price of about R900 for a rim and then there is rebuild labour R300 + maybe spokes

 

but they are great wheels I would go with a rebuild these wheels definitely need to run at higher pressures though

[SURFER]

if it still seals with the tubeless then thats step one

 

step two would be how out of balance it feels if it's a no with wheel balancing then its time to rebuild I saw a price of about R900 for a rim and then there is rebuild labour R300 + maybe spokes

 

but they are great wheels I would go with a rebuild these wheels definitely need to run at higher pressures though

 

What is your weight and what pressure is to "low"?

 

I also have AC MTB, weigh 85kg, back wheel pressure at about 2 and front 1.9