*Racing wheels (rims)*
Post by Tom on Aug 23, 2005, 10:41am
Doc here at ARC has been working on a racing lawnmower and he used
split rim halfs for the front wheels.
These split rims used to be very popular with karters as they allow
you to mix and match rim-half widths to come up with different total
wheel widths and offsets. This is done to stand up or strecth out the
tire sidewalls to adjust both spring rate to produce more or less
rebound and tire circumference to produce more or less stagger. It is
also done to get the wheel to clear the spindle arm on the front end
when you want to have your hub a set distance on its axle away from
the kingpin barrel of the spindle to obtain the scrub radius intended
for a given spindle.
A rubber seal is used between the two rim halves as they are bolted
together to from both sides of the tire. It is quick and easy, and
the wheels Doc put together about a month ago still have full air
pressure.
We carry both the 1 piece wheels and the split rims, but I often think
that the handling adjustment potential of the split rim is underrated.
In karting, the racers have all but forgotten how to tune with wheel
widths in favor of the use of chemicals that make the tire more
pliable and soft.
Tom
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*Re: Racing wheels (rims)*
Post by Squidd on Aug 24, 2005, 6:36pm
Thanks Tom for the insight...
I've been debating between one piece rims with hubs/bearings built in
and "seperate hub/wheel combos for next years ride...
Now I have to decide if I want one or two piece rims and then what width
for each half as well!!!
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*Re: Racing wheels (rims)*
Post by George Herrin on Aug 25, 2005, 7:09am
keep in mind that US rules call for same size tires and wheels per axle.
Would not want you dq'd. Fx can run stagger but cannot run offset. It is
measured from center of frame to outside tire wall.
George
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*Re: Racing wheels (rims)*
Post by Tom on Aug 25, 2005, 8:45am
Thanks for that clarification George, I was totally ignorant of that!
Everyone needs to understand that my knowledge comes from karting and
may not make a clean jump to lawnmower racing. But I learn different
ways of doing things in karting from you guys every day, and I hope to
reciprocate somewhat.
If anyone is interested, I made an Excel spreadsheet that calculates the
correct stagger necessary based on rear trac-width, the radius of the
turn, and the banking of the track.
I have also found that the tire prep Hotlap II can be a great aid in
shrinking or growing a tire's circumference depending on application method.
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*Re: Racing wheels (rims)*
Post by crafty on Aug 25, 2005, 4:02pm
Afternoon all. Ok, so the measurement is from center of frame to outside
tire wall. So does that mean that if you built your steering beam short
to the left or right side, either one, you can make up the difference
with rim width and still be legal? And, what if any difference would
that make to the handle of the machine? Would you be able to load more
weight to one side or the other by doing so? Not that I would try it,
but I had to ask.
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*Re: Racing wheels (rims)*
Post by George Herrin on Aug 28, 2005, 10:40pm
Nope that would be offsetting the chassis and that would be illegal.
George
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