Mold #'s

[Pinewood Daddy]

Here's data on wheels from 44 kits. It looks like there may be more than one mold for some (all?) mold numbers. I didn't see any bad 18's (as MaxV found), but look at some of the 2's!!! I saved those!

home.att.net/~d.fengler/BSA_Wheels_11-2005.xls

Here's my setup. I flip the block to inspect side run-out without having to adjust the indicator.

[WarpSpeedINC]

The bad #18 wheels, seem to have the 18 in line with the "in" in "made in the usa". I have never seen a BSA wheel out this far!
The most consistent this season seem to be #12.
Warp Speed Inc.

[Pinewood Daddy]

warpspeedinc said:

The bad #18 wheels, seem to have the 18 in line with the "in" in "made in the usa". I have never seen a BSA wheel out this far!
The most consistent this season seem to be #12.
Warp Speed Inc.

I didn't get a bad #18. But I only got (8).

The #12's I got were fairly consistant, varying from .004 to .007, but 3, 4, 5, 8, 10, 11 & 18 had better averages.

Do you notice the (6) #2 with .034 to .041 side runout!! Also (1) #17 had .037 side runout.

Warp- What's the highest runout you'll accept before machining?? I'm thinking .006. See www.derbytalk.com/viewtopic.php?t=1291

You can true a wheel using the pro-shaver or a lathe, but the wheel will be out of balance unless you start with a very good wheel (.003 or less??). At 2000rpm (race speed) that's got to cause alot of vibration.

[RacerX]

If you true the wheel to the centerline using a lathe or Pro Wheel shaver your wheel should be free of high spots from the centerline to the tread face dimension, this will improve ballance but not totally. You still have a conciderable amount of thickness variation between the tread face and the inside cavity of the wheel, or remaining heavy spots. Machining the inside true to the outside will cure most ballance issues by removing the thick spots in the mold.

[WarpSpeedINC]

racerx said:

If you true the wheel to the centerline using a lathe or Pro Wheel shaver your wheel should be free of high spots from the centerline to the tread face dimension, this will improve ballance but not totally. You still have a conciderable amount of thickness variation between the tread face and the inside cavity of the wheel, or remaining heavy spots. Machining the inside true to the outside will cure most ballance issues by removing the thick spots in the mold.

;D ;D ;D!!!
Warp Speed Inc

[Pinewood Daddy]

racerx said:

If you true the wheel to the centerline using a lathe or Pro Wheel shaver your wheel should be free of high spots from the centerline to the tread face dimension, this will improve ballance but not totally. You still have a conciderable amount of thickness variation between the tread face and the inside cavity of the wheel, or remaining heavy spots. Machining the inside true to the outside will cure most ballance issues by removing the thick spots in the mold.

Not all of us have a lathe to true the inside of the wheel. Maybe some day.

Anyone have a way to check the dynamic balance (like high speed balancing a tire)??

[wheeler]

Wheel ballance. Place 2 double edge razor blades .75 in. apart in sheet of balsa wood. Blades must be parallel and level with each other. Install gage pin in wheel bore (slip fit) and place on blades. Wheel will find heavy side down. Remove material 30 degrees each side of heavy spot. Repeat until wheel does not stop same place. This will give you pretty good dynamic ballance.

[RacerX]

Well, I do not mean to sound like a "know it all" but automotive shop equipment is what i deal with every day so I know a bit about wheel balancing. Dynamic balancing refers to balancing or correcting 2 planes, left and right sides of the tire. This is why you usually have wheel weights on both sides of your car wheels. Static balance is when you correct for all of the inbalance by placing weight in one spot, static balance can be done by either spinning it on a computer balancer or stationary on a stand, like Wheeler spoke of earlier. For Derby racing static balancing will work fine and improve performance as well, but you should find that if you true the inside first, the amount of balance required will greatly be reduced, possiably to zero in many cases. There are other factors that need to be looked at to get zero also. Also on a side note, since we are balancing is a rotating mass, a static zero balance will remain zero at speed so a balance stand will sufice. Recripricating mass is totally different, right Warp? Buy the way, the motors looked strong yesterday, I assume things are looking up?

[wheeler]

RacerX I agree. Basically I'm saying if you remove the weight each side of the heavy point it will produce a better dynamic condition.

[RacerX]

wheeler said:

RacerX I agree. Basically I'm saying if you remove the weight each side of the heavy point it will produce a better dynamic condition.

I might not totally understand what your are doing, (but it is working for you quite well) but let me try.

Once you determine the heavy spot, straight down at 6 o'clock while viewing the wheel from the rear, you go 30 deg. on each side of 6 o'clock and remove your material? Also, are you removing it the entire depth of the cavity or in one small spot? If I am understanding you correctly, the amount that you take off of each side must be very small.

[wheeler]

RacerX, your clocking is correct. Remove the entire depth and width of removal area depends on amount of weight you need to remove. Remove small amount at a time until wheel is balanced. Fred

[wheeler]

RacerX, you should produce a tool similar to this with pin assortment to market ??

[WarpSpeedINC]

racerx said:

Well, I do not mean to sound like a "know it all" but automotive shop equipment is what i deal with every day so I know a bit about wheel balancing. Dynamic balancing refers to balancing or correcting 2 planes, left and right sides of the tire. This is why you usually have wheel weights on both sides of your car wheels. Static balance is when you correct for all of the inbalance by placing weight in one spot, static balance can be done by either spinning it on a computer balancer or stationary on a stand, like Wheeler spoke of earlier. For Derby racing static balancing will work fine and improve performance as well, but you should find that if you true the inside first, the amount of balance required will greatly be reduced, possiably to zero in many cases. There are other factors that need to be looked at to get zero also. Also on a side note, since we are balancing is a rotating mass, a static zero balance will remain zero at speed so a balance stand will sufice. Recripricating mass is totally different, right Warp? Buy the way, the motors looked strong yesterday, I assume things are looking up?

Thanks for clearing that up Racer X, well put!
I was going to try, but it has been so long since I've messed with that end, I couldn't remember it all, and new I was going to screw it up!
Yes, Things are looking up at the engine shop. it was a long summer for us, and it was nice to end on a few high notes.
Hoping to do the same with our WIRL cars.
Wheeler makes a good point by going 30* on each side of the heavy part of the wheel. This way you can attack it from each side, instead of in the middle, and chasing it aound the wheel.
Again, well put guy's!
Warp Speed