Narrowing body for Railriding

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Speedster
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Narrowing body for Railriding

Post by Speedster » Thu Nov 01, 2018 10:36 am

Some, or one, on Derbytalk has said he never narrows the body of the car behind the dominant front wheel. I'm wondering if a specific thing is done to keep the trailing wheel off the rail.

Set more gap between body and wheel hub on trailing wheel? Set trailing wheel with toe out? What?



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Vitamin K
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Re: Narrowing body for Railriding

Post by Vitamin K » Thu Nov 01, 2018 1:08 pm

I don't believe that narrowing the body at the DFW has much to do with keeping the raised wheel off the rail. That much is accomplished by the fact that the car is rail-guided. The narrowing is more to account for the fact that the car wants to ride uneven to the rail since the DFW is hugging it. However, if you've got enough positive camber on the DFW, it extends far enough under the car to make the narrowing of the body unnecessary.



Speedster
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Re: Narrowing body for Railriding

Post by Speedster » Thu Nov 01, 2018 1:51 pm

VK, I apologize for any confusion I might have caused by writing something that caused you to write your 1st sentence. My intent was focused on the Dominant front wheel and the rear wheel that follows the Dominant front wheel. I understand the narrowing of the body of the car 1/16th of an inch is to center the rear wheels over the guide strip and it does work. Someone stated on Derbytalk that he never narrows the body of the car and I am wondering how he keeps the rear wheel that follows the Dominant front wheel off the guide strip. The suggested camber is 1 1/2 degrees on the Dominant front wheel which isn't much camber. Perhaps what you stated with lots of Positive camber is what he actually did.



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Vitamin K
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Re: Narrowing body for Railriding

Post by Vitamin K » Fri Nov 02, 2018 9:00 am

Speedster wrote:
Thu Nov 01, 2018 1:51 pm
VK, I apologize for any confusion I might have caused by writing something that caused you to write your 1st sentence. My intent was focused on the Dominant front wheel and the rear wheel that follows the Dominant front wheel. I understand the narrowing of the body of the car 1/16th of an inch is to center the rear wheels over the guide strip and it does work. Someone stated on Derbytalk that he never narrows the body of the car and I am wondering how he keeps the rear wheel that follows the Dominant front wheel off the guide strip. The suggested camber is 1 1/2 degrees on the Dominant front wheel which isn't much camber. Perhaps what you stated with lots of Positive camber is what he actually did.
I think the "suggested camber" varies depending on who is doing the suggesting! :)

The original DerbyWorx guide suggests 1.5 degrees, which corresponds with their rail rider tool. Most of the really fast guys, though, will put a lot more than that. The mantra I've seen is to put as much bend in that DFW as you can while still allowing the axle to be inserted through the bore.

I drill my DFWs with camber, and usually shoot for 7-9 degrees or so.



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