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Old 07-01-2009, 02:35 PM   #316
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Question for all you pan gurus. I notice that when I hold my car off the ground, and give it the throttle, somewhere between 30% and 60% throttle the rear shaft generates a bit of a vibration and resulting noise. I first noticed the sound watching all the WGT cars go down the back straight... and saying to myself "man.. all the pan cars make a strange grinding/wirring noise as they take off". Well.. mine does the same thing.

What causes this? Is there any way to dial it out?
i have a similar problem. when the car moves you can hear like a gritty sound or clicking if you will. diff seems ok and car rolls freely. i am using 48p gears if it makes a difference.
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Old 07-01-2009, 05:13 PM   #317
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i have a similar problem. when the car moves you can hear like a gritty sound or clicking if you will. diff seems ok and car rolls freely. i am using 48p gears if it makes a difference.
Yep... every WGT car at my track makes the identical noise... what is that? You would think such a direct drive system would be SUPER smooth and quiet.. but they aren't.
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Old 07-01-2009, 05:21 PM   #318
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[QUOTE=Cpt.America;6011538]Yep... every WGT car at my track makes the identical noise... what is that? You would think such a direct drive system would be SUPER smooth and quiet.. but they aren't.[/QUOTE]

exactly. the car is super smooth but it does make the noise.

you know if every other car sounds like this then maybe we're doing something right
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Old 07-01-2009, 05:36 PM   #319
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Yep... every WGT car at my track makes the identical noise... what is that? You would think such a direct drive system would be SUPER smooth and quiet.. but they aren't.
It's the tire on the spur side that causes this. I have replaced everything including tires, hub, bearings and ride height adjusters and it is still there. And it is there on different brands of cars. It is also not present on the 12r5 so it has something to do with the rotating mass of the tire.
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Old 07-01-2009, 05:43 PM   #320
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i was curious about that because i never heard a 12th scale sound like that.

on a side note i had a speedmerchant 1/10 scale using 2.250" bsr tires and i didn't have the noise, now with the ae i'm using 2.100" jaco tires and the noise is there.
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Old 07-01-2009, 05:59 PM   #321
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It's the tire on the spur side that causes this. I have replaced everything including tires, hub, bearings and ride height adjusters and it is still there. And it is there on different brands of cars. It is also not present on the 12r5 so it has something to do with the rotating mass of the tire.
Interesting... I can duplicate the vibration/noise even when I hold the car up in the air. I wonder if it would still happen if I take off the wheels, which if your theory is right, it would. BTW, you going to the freedom fair race? We will be there with bells on.

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Old 07-01-2009, 07:17 PM   #322
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Interesting... I can duplicate the vibration/noise even when I hold the car up in the air. I wonder if it would still happen if I take off the wheels, which if your theory is right, it would. BTW, you going to the freedom fair race? We will be there with bells on.

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Just tested my car and with the tire off and there is no vibration. Also switched tires from side to side and there still is a vibration of the spur side and not the other side. Makes you go Hmmmm

The only other thing to check is to see if most of the tires are out of balance.
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Old 07-02-2009, 08:46 AM   #323
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Yep... every WGT car at my track makes the identical noise... what is that? You would think such a direct drive system would be SUPER smooth and quiet.. but they aren't.
i have many pan cars in my "garage" and the sound normally happen if i dont rebuild my diff when it is time to. Sometimes my diff ring has a small groove from the ball bearing. Sometimes my bearing is out. It can also happen if i dont apply diff grease. Try tighten up your diff slightly tighter but if it does not help, it is time for a rebuild
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Old 07-02-2009, 09:46 AM   #324
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i have many pan cars in my "garage" and the sound normally happen if i dont rebuild my diff when it is time to. Sometimes my diff ring has a small groove from the ball bearing. Sometimes my bearing is out. It can also happen if i dont apply diff grease. Try tighten up your diff slightly tighter but if it does not help, it is time for a rebuild
That's not it. It happened on my WGT car the day I put it together, and every WGT car at my track makes this noise... it has nothing to do with how tight, loose, or dry the diff is. Were talking about something different.

If I examine my axle REALLY closly, it appears to be an issue with how the right hub is mounted to the axle. it looks like it is slightly out-of-balance. Mike, I bet if you mount your wheel to your truer and get it spinning, it would look perfectly balanced. Now, put the same wheel on the right hub and it will appear to have a SLIGHT wobble to it. That tiny wobble, combined with a certain RPM... and vuala.. you get your "wuuuurrrring" noise at some particular frequency. Is there a way to dismount and reattach the right hub? I betchya thats it.

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Old 07-02-2009, 10:17 AM   #325
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That's not it. It happened on my WGT car the day I put it together, and every WGT car at my track makes this noise... it has nothing to do with how tight, loose, or dry the diff is. Were talking about something different.

If I examine my axle REALLY closly, it appears to be an issue with how the right hub is mounted to the axle. it looks like it is slightly out-of-balance. Mike, I bet if you mount your wheel to your truer and get it spinning, it would look perfectly balanced. Now, put the same wheel on the right hub and it will appear to have a SLIGHT wobble to it. That tiny wobble, combined with a certain RPM... and vuala.. you get your "wuuuurrrring" noise at some particular frequency. Is there a way to dismount and reattach the right hub? I betchya thats it.

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You are right about the tire. On the truer there is no wobble. The hub also does not appear to wobble with no tire attached even at high RPM. I would say that the holes in the rim could be elongated but it happens with new tires. I will do some testing and see what I can find. I am building up another car and I will see if it has the same issues.
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Old 07-02-2009, 10:37 AM   #326
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So if there is no wobble on the left, but is on the right... what is the difference between the mounting surfaces?. I imagine that the hub wobble would be really hard to see without the wheel mounted. I bet the slight wobble is actually with the hub itself (well... its between the hub and axle. Mounted slightly out of balance)... but you can't really see it without something large on the end, like the wheel. The larger the leverage or distance from the wobble, the more severe it looks.

That's where my money is , and it would explain why it isn't present in the 12r5.... MUCH smaller wheels. Keep me in the loop if you find anything out, or any fixes. How about this, are there any aftermarket axl/hub combos we could get for the 10r5 to try out? Is there a way to re-attach the right rear hub to the axle? It looks kind of like it's "pinned" to the axle.
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Old 07-07-2009, 04:08 PM   #327
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on all the setup sheets i've seen they all call for a 3' turn radius, how do you guys come up with that? how are you measuring the turn radius? i see the 12r5's mostly use 5' radius. inside or outside diameter? i was shown to go by the outside turning radius and i dont see any way possible to get a 3' turn radius.

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Old 07-07-2009, 04:35 PM   #328
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on all the setup sheets i've seen they all call for a 3' turn radius, how do you guys come up with that? how are you measuring the turn radius? i see the 12r5's mostly use 5' radius.
How I come up with the turning radius is by on track testing and fiddling with the end points on the radio. I would use 3' as a starting point and go from there. It will depend on your track and driving style as to what works best for you. If I want to measure it I visually mark out 3' and turn the car at low speeds in both directions to make sure that they is the same.
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Old 07-07-2009, 04:38 PM   #329
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How I come up with the turning radius is by on track testing and fiddling with the end points on the radio. I would use 3' as a starting point and go from there. It will depend on your track and driving style as to what works best for you. If I want to measure it I visually mark out 3' and turn the car at low speeds in both directions to make sure that they is the same.
that is what i was shown but there is no way possible to get the car to turn a 3' radius, maybe if i was measuring the inside diameter but not the outside.
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Old 07-07-2009, 04:51 PM   #330
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that is what i was shown but there is no way possible to get the car to turn a 3' radius, maybe if i was measuring the inside diameter but not the outside.
I would typically measure on an inside radius and as I said this is just a starting point. Drive the car and see how it feels. Sometime less radius is better. You can oversteer the car and cause the front tires to slip with too much radius. If you still think that you are not getting enough steering make sure that when you turn the wheel the steering is physically going as far as it can. If the servo is preventing this from happening then make sure the turnbuckles are mounted in the upper holes of the servo saver.
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