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Post by Threader on Oct 22, 2004 15:52:53 GMT -6
This should apply to most PC wheels but I will be talking about BSA wheels in this post. BSA wheels are not precision racing wheels out of the box. They have different hub sizes and tend to be out of round. Your first consern should be sanding or otherwise using a tool to make them round. ( There is a pro wheel tool that does a good job. ) Check with local rules before you make any changes to the wheels. There are many methods to sand or turn the wheels and it would take a LOT of typing to cover that. Bottom line, when the wheels roll in a straight line on a flat surface they should be good. ;D After the wheels roll straight check your rules to see if you can modify the hubs. This process is called coning. You can do this by hand, but there is a good tool for this too. Bacisly this coning process tapers the hub where it contacts the body of the car so there is less friction. Less friction and round wheels mean a faster PC!
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Post by Sssnake on Nov 12, 2004 13:59:18 GMT -6
If hub coning isn't alowed, you can cone the body. The easiest way to do this is with a dremel and a concave stone.
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Post by ninjarabbi1997 on Nov 19, 2004 18:04:00 GMT -6
Is hub coning allowed in the Stock Division? I'm pretty new to this, but getting hooked pretty bad.
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Post by ninjarabbi1997 on Nov 20, 2004 5:23:18 GMT -6
How much would should you take off with the concave stone to achieve this effect? Awesome tip!
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Post by Sssnake on Dec 2, 2004 18:47:02 GMT -6
The stone I use is a dremel #937. Yuo only have to go less than 1/8" into the body to achieve the desired effect. To cone the hubs the pro hub tool works well. But wet dry paper and a wheel mandrel with a nylon (or whatever you have) spacer works just fine.
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Post by Sssnake on Dec 3, 2004 15:39:23 GMT -6
When sanding/polishing your wheels don't forget to gently, very gently, round the inner edge to lessen friction and possibilities of grabbing a rough spot on the center rail.
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Post by Sssnake on Dec 4, 2004 7:11:08 GMT -6
When polishing the tread it is possible to go to far. The friction involved with the tread is rolling friction and has to do with molecular deformation of microscopic peaks on the tread. Reducing these peaks too far results in changing rolling friction to sliding friction and increasing static friction or break away force (which is a mainly a result of molecular adhesion which increases as more molecules come in contact), which requires much more of your available PE to move the car.
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Post by RacerX on Dec 9, 2004 10:42:28 GMT -6
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Post by speedbump on Jan 3, 2006 12:05:14 GMT -6
Can someone explain the "wheel runout" to me? I am assuming that it's a diff or "out of round" from left to right on the tread surface....Is this correct? Wouldnt this just be easily corrected with the shaver XT? taking it down to the lowest point on the 4 "best wheels"
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Post by RacerX on Jan 4, 2006 8:39:32 GMT -6
You can have run-out in 2 different areas. 1st. you can have a up and down run-out from center line or the hub. This will cause a climb and drop effect in the axle as the car travels down the track causing several issues in alignment and speed. 2nd. is latteral run-out in the inside edge of the wheel. This can cause several issues as well with the most common being a kicking effect as the car touched the guide strip.
And Yes, both the tread face and inner edge can be corrected with the Pro Wheel Shaver XT.
Race Fast
Racer X
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Post by Mood Swing Productions on Jan 4, 2006 10:56:24 GMT -6
well put, i had to delete what i was typing hahahaha
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Post by speedbump on Jan 5, 2006 18:44:04 GMT -6
OK, I just got the shaver XT.. Tried it out on some "scrap"wheels I have from mold #s I didn't want to use. Is it just me or is the XT sensitive? I'm sure it's just operator error but i felt the adjustments we too sensitive to get "just right". Just appeared to inaccurate for me...dunno, any tips on using it? Seems that wheel bore played a hand in it to...wheel flexing from the bore being fractionally too small.... Maybe I'll try again later, had to put it down because it got frustrating
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Post by FAST Racing on Oct 17, 2006 9:06:24 GMT -6
I've been re-reading many of the "old" topics, so this many have already been addressed... The rolling surfaced can be polished "too much" to create sliding friction? How much is too much..... In the past I've used plastic polish to bring the contact tread to an almost mirror shine. (Too much free time in the Shop!) As a gage, should I only be going to 2000grit scratches???
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j2ce
Addicted to Speed
Posts: 92
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Post by j2ce on Oct 23, 2006 10:51:01 GMT -6
Fast,
First cool acronym, Last year my son sanded the wheels down to 2500 grit and then the plastic polish along with everything else he worked. He came in first in the District Races. Intuitively, I'm inclined to believe that he would not have been as successful on an Aluminum Track. However, I don't know the coefficent of friction of plastic to aluminum and plastic to wood but I would think that the delta is negligable. If your skidding down the track your not overcoming the frictional force to rotate your wheels and gravity is just pushing the car down the track. I would first check that your not locking up your wheels. Then check the starting gate is there something that is strong enough to hold your car up. Then check race rules and try reducing the weight of the wheels to reduce the wheels moment. And I would check the weight location it is possible that you could have to much weight at the right location that the static friction force is playing havok on your car's setup. Wheels are so important in these races that I invested in XT shaver for future WIRL and PDDR races. But to date we have not had a car slide down the track. FYI gorilla glue is not an excellent lubricant despite what others may say in this board(hahaha). Good luck
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Post by FAST Racing on Oct 23, 2006 11:57:17 GMT -6
Thanks j2ce (juice?) My 10 year old son came up with the name,kids are amazing. I wanted "Conifer Racing" had a logo & all,but when he said what the letters stood for I almost cried..... I digress, getting to the finish has not been a problem. We seem to wander down the guide rail, Alignment has been my weakest area. Changed weight placement to 28-32 grams on front axle. Helped some. Looking closely at the fast cars in WIRL/PDDR the wheels have a "satin" finish. I'm thinking maybe our wheels are "too smooth" allowing the front end to "wander" instead of "sticking" to a given line. Your thoughts
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Post by A1nogoslo on Oct 23, 2006 19:37:36 GMT -6
too smooth Your thoughts
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j2ce
Addicted to Speed
Posts: 92
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Post by j2ce on Nov 2, 2006 15:36:01 GMT -6
Fast,
Sorry i took so long. My son's and my name start with J it should read j square. My daughter starts with a C and my youngest boy starts with an E so J2CE. A play in physics E=MC2. I'm inclined to agree with A1. Two things to check were your son's tires cleaner in comparison to other cars after the event and was the wood or aluminum track polished prior to the start of the race. Some guys get a little overzealous polishing the track thinking it helps. If the tires were cleaner than you have a distinct advantage over the rest ;D. At this point focus on reducing the weight of the tire. However, that is the tricky part and so much can go wrong. Good luck and talk to you later.
j2ce
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