How to straighten a wobbly rim

[juniormarbles]

My son has a Manco 285 Go Kart with wobbly rear rims (the drive axle is not bent but straight.) Manco has discontinued this type of rim, and I am trying to either straighten the rim myself or find a specialist in the Portland, OR region who can do this.

The exact problem: the axle-mounted rim (one big bolt, rather than several like on a car's rim) has been moderately bent off its true axis at the center, where it's mounted on the drive axle, probably after an impact.

If I had a very large vise to hold the rim, and a very long lever to stick into the rim's center hole, to bend the center hole back into the same plane as the rest of the rim's plane, where the tire is seated, I would be done. (The wheel is not bent anywhere at its outer edges.)

What is the proper method to fix this? And do you know the kind of specialist who attends to these kind of rim repairs?

Thanks,
JM

 

[bighead]

Is the hole in the wheel round or the octogon shape?

Your plan may work but you might need some heat to heat it up? Not sure for I never tried it. I guess the wheel is shot.

A vice to hold a wheel? I would figure out another way to hold it tight. Perhaps a car on top of the wheel. Who knows.

 

[anderkart]

You might try leaving the rim mounted on the kart and very carefully using a come-a-long to pull between the rims 'bent out' portion and a strong part of the frame. Just keep in mind that to remove dents/bends you simply need to re-create the exact-opposite force that caused the problem.

Be careful you don't bend or break something else though, You could first slide a wood 2x4 or something between the 'bent-in' half of the rim and the frame to tightly shim it and hopefully lower the stress on the axle/bearings/lock-collars, etcetera.

On the other hand, you probably could find a pro to fix your rim.
You could research here:--> http://www.google.com/search?source...gc.r_pw.&fp=19a92025165ef437&biw=1007&bih=646

 

[Odonnellp24]

You could cut a wood block the right size so that you could lay the wheel flat on top and hammer the other side flat against that block. Kinda hard to explain but the pic should help. Just make sure to use a hammer with a poly face or another piece of wood to keep from marring it up.

 

[fowler]

can we see a pic

this sounds like the kinda thing that sounds very simple till u try it


the problem i see is damageing the tube where the bearings go

the pole is likely to just force out the edges

 

[number 37]

can we see a pic

this sounds like the kinda thing that sounds very simple till u try it


the problem i see is damageing the tube where the bearings go

the pole is likely to just force out the edges

qft.

 

[sexyvicta]

easiest thing to do would be take it to a wheel repair specialist. The kind of place that repairs buckled and curbed alloy wheels etc

or if there isn't one in your town then take it to somewhere where they work on speedway cars. They bend wheels every day

 

[bighead]

can we see a pic

this sounds like the kinda thing that sounds very simple till u try it


the problem i see is damageing the tube where the bearings go
the pole is likely to just force out the edges

I think the dingos use an octogon axle shaft as well. So finding a pole will not be easy. No bearings in the dingo rear wheels. Solid to axle.

Here is the only shot of a dingo wheel I have. Mine were octogon axles. I am also in Portland. So if you find a shop post the info.

Have you tried looking for a used wheel?

 

[bighead]

If it is the hex pattern style here is a new one for $30. This is the first time I seen one for sale. I would jump on it even though it has more than 10 listed.

http://cgi.ebay.com/Go-Kart-Cart-14.../190498584405?pt=Go_Karts&hash=item2c5a99b755

Here is the hex hubs. But you would need new wheels. More options with these.

http://cgi.ebay.com/Go-Kart-Cart-Ma.../320312621833?pt=Go_Karts&hash=item4a941ebb09

 

[juniormarbles]

Well, guys, I am overwhelmed with your generosity to help!

I will provide several close-up photos of wheel and axle details, as soon as it has stopped raining here. Then you may know a bit better what might work and what might not.

So, for now: thanks a bunch!

JM

 

[fowler]

what is qft mean?

 

[number 37]

Quoted For Truth

= agreement

 

[South Kart3377]

those wheels are sold by bmi, why not buy direct from bmi????

 

[fowler]

Quoted For Truth

= agreement

ahh right
thanks

 

[juniormarbles]

The sun came out in Oregon today, and I took pictures:

* Go-Kart, full side view w/youthful driver
* Left wheel with axle, brake, frame, and clutch
* Axle w/o wheel showing bearing mounted to frame
* Wheel view
* Wheel center, outside view, showing keyway
* Reference piece of wood against rim at largest gap
* Reference piece of wood against rim at minimum gap
(difference between the two gaps = more than 3/8" at the rim's edge as shown)


Attachment of the wheel is via center nut. Keyway on axle and woodruff key (located inside wheel) keep the wheel fixed to the rotating axle. The axle shafts themselves are fairly well centered and wobble-free, on both sides.

Both rims have a significant wobble (shown in pics #5 and #6) which gets worse, the further out you get from the wheel's centers. At the contact point of the tire I measure about a 3/4" difference between the two extremes which happen to be on opposite ends of the wheels (maybe that's good.) The wobble makes the cart unsafe on smooth pavement at speeds faster than, say 15mph.

A couple of comments about some of the suggestions so far:

The "Come-Along" method of straightening the wheel seems good in theory but may be hard to execute, as I cannot find an attachment point on the rim' s edge to hook the Come-Along to.

The idea of pounding the wheel against a flat piece of wood is scary to me, because I may over-whack the rim, creating a worse wobble.

I may have to resort to new wheels, but then they may be hard to find, because they need to have the same woodruff keyway, and most likely will not be gold in color (minor deal).

Anyway, your suggestions are welcome!

Thanks,
JM

 

[Russ2251]

Any reputable machine shop can repair it in minutes.

 

[porsche930dude]

im having a hard time believing its not the axle. did you confirm its the wheels by spinning it on the axle without the keyway in or on a different dummy axle? if your sure its the wheels i would try and clamp the whole tire assembly down and use a bar to bend the center back straight. maby jack up your car and set it down enough to clamp it in place or use boards somehow so you can lay it down flat. or just strap it down like hell to something solid

 

[juniormarbles]

im having a hard time believing its not the axle. did you confirm its the wheels by spinning it on the axle without the keyway in or on a different dummy axle?

This was a brilliant idea: stop the axle from spinning, spin the wheel on the fixed axle, and see whether the wheel still wobbles on the (straight) axle, or whether the wheel stops wobbling, pointing to a bent axle.

It was the former: The wheel had the same wobble when it was turned on the fixed axle. And to confirm: moving the other wheel to that axle cured the wobble.

There you have it. Considering the cost, I am going to replace both rear wheels:
http://www.bmikarts.com/item/8-Rim-w-1-Bore-260081-6219
rather than dicking around with this any longer.

Thanks again for all your helpful hints!

JM



and ask myself: why the hassle?

 

[juniormarbles]

Two new wheels from BMI arrived yesterday. After transferring the tires, it turns out that one of the wheels is perfectly round and straight, the other is wobbly- as bad as my old wheel. So much for quality control at BMI.

 

[sexyvicta]

haha yeh all wheels are a little wobbly

take it to a tyre/tire shop and get them to put on their balancing machine. they will stick some lead on to even out the wobblyness