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Old 04-11-2005, 09:26 PM   #1
txrider OP
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Tire Balance

I got a little question on my 620,

My ktm has a rim lock front and rear and I've never balanced my tires, and they weren't balanced when I bought the bike, obviously the front is gonna be way out of balance with that rimlock in there.

Ive also had a head shake at about 75-80mph always.

Could the balance issue be responsible for the head shake? Anyone ever run a wheel with a rimlock unbalanced and balanced and seen a big difference?
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Old 04-11-2005, 09:44 PM   #2
meat popsicle
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they say that it does on pavement, even makes your tires last longer. go for it!
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Old 04-12-2005, 09:27 AM   #3
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TX-

You can get in the ballpark by supporting the wheel on it's axle between two uprights - jackstands will work. See how quickly it turns to the heaviest point- is it overshooting, then heading back? The amount of overshoot, and how fast the wheel accelerates from rest tells you how bad it is out. Add weight opposite the lowest point at final rest (probably rimlock) until the wheel doesn't stop near the rimlock anymore.

For the street, I use a balance stand that has a ground rod that spins on low friction discs, but this will do you fine. Improvement is what you are after.
I use stick on weights on my street bike, but I would try to find the sort that clamp to the spokes in your case.

J
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Old 04-12-2005, 09:38 AM   #4
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TX, please post a report if you do this

TX, I'd love to hear a reoprt if you decide to try and balance the front. I have a major wobble at about 70mph on my RXC. To the point that I will not go any faster than 65-70 since it just gets scarry. I'd love to hear how things change for you if you do the balance thing.

JOsh.
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Old 04-12-2005, 09:51 AM   #5
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Well I went and got some stick on wheel weights, I took the front caliper off and spun the wheel and with almost 2 ounces it seems pretty close. Close enough I can't tell there's any imbalance with the wheel bearing drag.


If it was balance screwing with my front end it should definately see a difference, gonna ride it after work today and I'll report back what I find.

I went ahead and added weight to the rear as well, but about 3 ounces.

That's a little less weight then Creeper said the locks were, but if it works I'll be pulling the wheels and balancing the right way so I'm not to concerned.
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Old 04-12-2005, 10:09 AM   #6
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"but if it works I'll be pulling the wheels and balancing the right way"

You didn't take the wheels off? Tell me you took the chain off at least?
If there are external sources of drag, it won't work. Or at least won't be very accurate.

J
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Old 04-12-2005, 11:07 AM   #7
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Worked for my DRZ40S

I have two sets of wheel for my S but riding to the trails with the Knobbies on was a bitch because of the bouncing and wobbeling at anything over 40mph so I bought one of those simple shaft type balancers. It took over 20 ounces to get the back done and about 10 on the front. The differance is amazing. It now rides straight and true. I didn't think it could be that far off. I thought that I had laced the rim wrong. But they feel great now. I think they even feel better off road but that's hard to tell. If you ride at all on the street you need to do it, imho.
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Old 04-12-2005, 11:33 AM   #8
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Quote:
Originally Posted by eaglej
"but if it works I'll be pulling the wheels and balancing the right way"

You didn't take the wheels off? Tell me you took the chain off at least?
If there are external sources of drag, it won't work. Or at least won't be very accurate.

J
The front is what I'm really worried about, I got that close removing the caliper. I basically about doubled what I put on the front on the rear, across from the rim lock without removing brake or chain.

I should feel a big difference in the front at least when I test ride it this evening, if so I'll pull both and balance em off the bike.

Though with all the feedback here and on other boards I asked on, it seems that front rimlock can indeed cause a lot of grief and I ought to do it anyway.
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Old 04-12-2005, 11:47 AM   #9
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Quote:
Originally Posted by MrMike
I have two sets of wheel for my S but riding to the trails with the Knobbies on was a bitch because of the bouncing and wobbeling at anything over 40mph so I bought one of those simple shaft type balancers. It took over 20 ounces to get the back done and about 10 on the front. The differance is amazing. It now rides straight and true. I didn't think it could be that far off. I thought that I had laced the rim wrong. But they feel great now. I think they even feel better off road but that's hard to tell. If you ride at all on the street you need to do it, imho.
Mike, was the set of tires already worn when you did the balancing? I figure if they were out of balance and the tires had a good chance to wear really unevenly then it might take a lot more weight to get em straight again. I am wondering though b/c I want to balance mine and my tires are both about 50% tread left.

Josh
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Old 04-12-2005, 01:12 PM   #10
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I don't know dude... If it took 20 oz to balance your rear wheel (you realize that is 1.25 POUNDS, right?) you should take the tire off, and sell the cocaine that the drug smuggler you bought the bike from is hiding in there. Or- you should stop doing rear wheel lockups from 150mph

I won't tell.

J
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Old 04-12-2005, 02:13 PM   #11
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Ok, I ran 250 miles of Interstate tonight, the balancing helped a lot, the bike is pretty smooth.

It will still get all sloppy at 80+ and try to headshake if I get into any winds etc. but it rides much better at 75 an more stable. 90 is no sweat if I shift enough weight forward to keep the forks loaded, otherwise it headshakes.

I'm thinking a front tire that has a straight knob pattern instead of the side to side shifted pattern of the Karoo front might help. With knobs offset in one direction for 4-5 knobs then back the other way for 4-5 looks like it's just asking to headshake.

BTW TKC 80's seem to be decent road tires on the rear, felt very good with a nice round profile. Best street handling knobs Ive tried.

Gonna take em off the bike and balance em right tommorrow.

Leaving on a 1500 mile round trip to Big Bend Thursday afternoon, hope this old LC4 makes it in one piece.
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