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Post by clydesdale on Feb 7, 2009 18:48:59 GMT -6
Well, we had our race today. We won our den title, but we won't win the pack. Our best speed was 2.35 seconds and the fastest was 2.30. They had us at a speed of 219 mph and the fastest was 223. I don't know how they actually come up with the mph, but that is what the program said.
Now for my question. Our wheels seemed to wobble too much. It was as if our hubs were bored too much or our axles were too thin. There seemed to be a lot of play between the hub and the axle. I used the "pro hub tool" and pushed the tool into the hub 3-4 times for each wheel. I then used and axle press and then polished the wheels. Is it possible that I did too much to the axles and hubs or is it common for there to be a wobble from the excess play? The wheel surface was wet sanded nicely and did not seem to be the problem. When I spun the wheel on the axle before mounting it to the car, it seemed to vibrate a little. I think it almost spun better before I touched them. Any thoughts?
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Post by kcbcommando on Feb 9, 2009 14:08:10 GMT -6
Are your wheels canted? What did you do for prep on your wheel bores? Graphite or oil?
Side bar-- how long is your track? We have a 32'(30' finish) Freedom and the fastest time ever on it is 2.5430. 2.30 on that length would be incredible.
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khouse
Head in the Pine
Posts: 199
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Post by khouse on Feb 23, 2009 22:53:29 GMT -6
Most stock wheels are loose. If you don't run the wheels to the head of you axle they can vibrate. Did you prep your axles? If so what did you do? Did you try to rail ride? What did your car weigh? Where is your center of mass measured from the rear axles? Could you run an extended wheel base? I'm just throwing it out there.......
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khouse
Head in the Pine
Posts: 199
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Post by khouse on Apr 1, 2009 22:28:03 GMT -6
After thinking about it maybe your wheels are not concentric around the hub bore. Meaning the wheel tread is not true to the hub? What have you done to true the tread? Maybe a Pro Wheel Shaver is in your future?
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Post by the woodbutcher on Apr 6, 2009 7:41:59 GMT -6
Khouse is right, my (limited) experience has been the wheels seem a little loose. Question is: is this really a problem ? When the car is rolling down the track the wheels behave diffrently than when spinning them with your finger. There is no load on them.
I've often thought about using the treadmill to break in the cars. Seems like a more natural way than spinning them by hand.
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derbydominator
Head in the Pine
"Zero Gravity" PWDR Pro Modified
Posts: 146
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Post by derbydominator on Apr 6, 2009 15:20:57 GMT -6
One can oversand with the lower grits. Do you have a caliper that you can use to measure the axle diameter in the polished area?
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Post by clydesdale on Apr 17, 2009 11:41:30 GMT -6
Some answers to the above questions:
The car weighed 5.0 oz on the dot.
COM was about 3/4 inch in front of the rear wheels.
I used an axle press and then poished the wheels in a drill, using a axle polishing kit from one of the vendors on the web.
I used a wheel mandrel and wet sanded the wheels.
I used graphite that home depot sells for locks.
Wheels were not canted and did not try to rail ride.
My concern was that I did too much to the hub bores and the axles. It was almost as if I polished the axles too much and cleaned the hub out too much and made them loose.
I will try to measure the axle diameters.
Thanks.
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Derbyspeed
Newbie
"Do or Do Not, There is No Try"
Posts: 8
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Post by Derbyspeed on Apr 17, 2009 12:31:26 GMT -6
I would agree with a couple of points here, maybe too much sanding, but more likely a wheel problem and the circumference is out of round and not flat. Added with some alignment factors. I would go with shaving the wheel if you are allowed, that would take a lot of vibration out. Just my $0.02 worth.
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khouse
Head in the Pine
Posts: 199
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Post by khouse on Apr 17, 2009 21:03:09 GMT -6
You just can't get your wheels true without a lathe or shaver. I took some of my sanded wheels and shaved them and they were way off. I also bought a wheel balancer. These two tools will give you smooth running wheels. Buy the Derby Worx Pro Wheel Shaver. It's worth every penny. Also buy after market axles. These will not have the crimp marks. Then you can simply get to polishing them.
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Post by clydesdale on Feb 28, 2010 10:11:07 GMT -6
ok, I have measurements of the axle thickness using a caliper. I would love it if someone could tell me if I took too much off the axle or not enough.
Original axle nails were .0881 I measured a few nails and they were all in this neighborhood.
Last year's car ( the one the wobbled) had .0850-.0875 axles.
This year's car had .0878 axles.
I believe last year's car wobbled because of a lack of a wheel shaver. The one wheel that really vibrated was also the wheel that was significantly out of round.
Can someone tell me if I am sanding too much off of my axles? Thanks
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khouse
Head in the Pine
Posts: 199
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Post by khouse on Feb 28, 2010 11:05:43 GMT -6
First thing to do is buy cnc lathed wheels. Then use at least a .091 diameter axle. You can find all sorts of axles in the .091 to .093 range that are sold. Awana stock axles are .092 and cheap. PM me for more info if you need it.
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Post by shadetreeracing on Feb 28, 2010 18:26:28 GMT -6
I like awana axles they cheep, polish up real nice,& have a good fit in scout wheels. MaxV. has them in speed axles already grooved & heads tapered
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Post by clydesdale on Feb 28, 2010 18:51:35 GMT -6
I purchased a wheel lathe this year and I believe that is now solved. But, as you see the axle measurements from above, even my virgin axles are thinner than what you are suggesting. My rules state that I must use the BSA wheels. Any suggestions?
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khouse
Head in the Pine
Posts: 199
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Post by khouse on Feb 28, 2010 21:47:10 GMT -6
Yes, use larger axles. ;D
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Post by Lucky 13 on Feb 28, 2010 21:51:30 GMT -6
Yes, use larger axles. ;D I don't think he can do that without cheating ? I sure wish BSA would have updated their axles when they updated their wheels  !! Lucky 13 |
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Post by clydesdale on Feb 28, 2010 22:07:31 GMT -6
Sorry guys, can't cheat. If I do, I will know and I will have beaten myself and it will be difficult for me to look my son in the eyes and his friends that we beat.
Did I take too much off of my axles?
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Post by Lucky 13 on Feb 28, 2010 22:10:07 GMT -6
Sorry guys, can't cheat. If I do, I will know and I will have beaten myself and it will be difficult for me to look my son in the eyes and his friends that we beat. I agree 100% !! As far as your axles go. You only removed .0003 in the de-burring/polishing process, so I think you did really good. I see you bought a wheel shaver, that should help you with making better wheels. I noticed in one of your original posts you were using graphite that Home Depot sells for locks, if you still are, get rid of it and buy you some Hob-E-Lube !! Lucky 13 |
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khouse
Head in the Pine
Posts: 199
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Post by khouse on Feb 28, 2010 22:29:30 GMT -6
All I read in one of your last posts was. "Can only use BSA wheels." I didn't see anything about using stock BSA axles. That's why I said to use larger axles. Did I miss something?
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Post by clydesdale on Feb 28, 2010 22:32:45 GMT -6
They make BSA axles in different sizes? I am supposed to use the nail type axles supplied in the usual kit.
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khouse
Head in the Pine
Posts: 199
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Post by khouse on Feb 28, 2010 23:12:22 GMT -6
They make BSA axles in different sizes? I am supposed to use the nail type axles supplied in the usual kit. Not that makes any difference. I just didn't see in your post that your supposed to use a BSA axle. My bad. |
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