Today's District race results

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davet
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Re: Today's District race results

Post by davet »

Stan Pope wrote:
davet wrote:...
How does a step removal make the wheel faster other than cutting weight? It seems with the step, the tapered axle head only rides on the edge of the step. Without the step it would seem to ride against more of the wheel surface. I've never seen a wheel in person though with the step removed.
With the step in place, a typically tapered axle head rides on the inner edge of the outer step. With the step removed, a typically tapered axle head rides on the inner edge of the inner step. The result is that removing the step reduces the contact radius to about 50 to 60%. Braking torque due to hub/axle head friction is proportional to the radius at which the friction acts.

The braking torque is usually quite small ... just one more "little loss" that many rules allow to be avoided.
Very good explanation Stan. Thanks. I heard that the double step is relatively new considering how long these kits have been around. I also read that adding this second step pretty much made tapering the axle heads a non-factor. So, basically, with the step removed and a tapered axle head I'm back to what they ran in the old days, prior to the second step, with the smaller contact radius and tapered head?
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Re: Today's District race results

Post by Speedster »

For a comparison of the 1999 mold wheel and the 2009 mold wheel, go to winderby.com, click on wheels and there is a side to side comparison.
ngyoung
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Re: Today's District race results

Post by ngyoung »

It is my understanding that the double step was added to address the flashing under the axle head. Instead of finding a better axle they changed the wheel. This was another misguided attempt to even the playing field between people that know how to file off the flashing and crimps and those that don't. Unfortunately it failed and the flashing even shaves off the edges of the double step.
davet wrote:
Stan Pope wrote: With the step in place, a typically tapered axle head rides on the inner edge of the outer step. With the step removed, a typically tapered axle head rides on the inner edge of the inner step. The result is that removing the step reduces the contact radius to about 50 to 60%. Braking torque due to hub/axle head friction is proportional to the radius at which the friction acts.

The braking torque is usually quite small ... just one more "little loss" that many rules allow to be avoided.
Very good explanation Stan. Thanks. I heard that the double step is relatively new considering how long these kits have been around. I also read that adding this second step pretty much made tapering the axle heads a non-factor. So, basically, with the step removed and a tapered axle head I'm back to what they ran in the old days, prior to the second step, with the smaller contact radius and tapered head?
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davet
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Re: Today's District race results

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I actually don't mind the stock axles. I wish our Northern Star Council rules would outlaw aftermarket wheels and axles. This way everyone would be able to show their sons how to build a dial indicator setup for checking wheels, how to file and polish axles, etc. I think it gives someone more opportunity to show their kids techniques. This takes more time but isn't that what the derby was about anyways. I've seen cars built from hobbystore pre-cut kits get "Best of Show" awards. One dad said his boy wanted a Hummer body so they started drawing it on paper. Dad decided it was too much work to cut so they just bought one.

I've gone off track here but I don't mind inferior stock parts as long as it keeps kit prices low.
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Stan Pope
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Re: Today's District race results

Post by Stan Pope »

davet wrote: ... So, basically, with the step removed and a tapered axle head I'm back to what they ran in the old days, prior to the second step, with the smaller contact radius and tapered head?
Right!!!
Stan
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Re: Today's District race results

Post by ngyoung »

I am all for working on the stock axles but it would make the process a lot easier not having to deal with filing the crimps and burs. I think that is where a lot of people trying to work on them from the first time mess things up.
davet wrote:I actually don't mind the stock axles. I wish our Northern Star Council rules would outlaw aftermarket wheels and axles. This way everyone would be able to show their sons how to build a dial indicator setup for checking wheels, how to file and polish axles, etc. I think it gives someone more opportunity to show their kids techniques. This takes more time but isn't that what the derby was about anyways. I've seen cars built from hobbystore pre-cut kits get "Best of Show" awards. One dad said his boy wanted a Hummer body so they started drawing it on paper. Dad decided it was too much work to cut so they just bought one.

I've gone off track here but I don't mind inferior stock parts as long as it keeps kit prices low.
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