rail riding -the 1/16"

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Speedster
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rail riding -the 1/16"

Post by Speedster » Tue Mar 14, 2017 7:57 am

2 cars were brought to us this year because of wobble. We set the cars dfw with 1 1/2 degrees of Positive camber and toe-in. That corrected the wobble. The body of the car was not narrowed the common 1/16". I noticed the rear wheels were centered over the rail. The car had stock BSA wheels and axles. The dfw sits straight up and down because of the clearance between the bore and the axle. When I narrow the body a 1/16" on the cars I build I notice the rear wheel behind the dfw always is closer to the rail then the rear wheel on the other side. On Page 87 of Build a Winning Pinewood Derby Car I think the picture is not correct. I think narrowing the body of the car a 1/16" will not center the rear wheels. I think with the 1 1/2 degrees of Positive camber and toe-in on the dfw with stock parts you are better off to leave the body at its full width. My experience with the 1 1/2 degree camber the dfw will not ride on its outside edge. Using the Derbyworx tool where you lift up to make the bend it takes 2 degrees to barely get the inside edge off the ground.
I do not understand the recommended 1 1/2 degrees of Positive camber and the narrowing of the car body 1/16" behind the dfw when using stock parts. I think 2 1/2 degrees of positive camber, toe-in, and leave the car body alone would be far more beneficial.
I welcome all thoughts.



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Vitamin K
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Re: rail riding -the 1/16"

Post by Vitamin K » Tue Mar 14, 2017 9:56 am

I tend to leave the front end un-narrowed, but I usually end up with about 7-9 degrees of positive camber on my DFW.

I'm not certain that the rears have to end up /perfectly/ centered over the rail.



derbypain
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Re: rail riding -the 1/16"

Post by derbypain » Tue Mar 14, 2017 3:26 pm

According to Sporty for the four wheel rail rider... He suggested using 1.2 degree on DFW with toe in and 3/4 degree on NDFW with very slight toe out (70-80 percent work done by DFW) . He recommended to remove the 1/16" section on DFW only and I could have sworn it said the the rear wheel on the side of DFW would run close to the rail but because the 1/16" was removed from DFW the rear wheel would not touch. (That does not sound like it would be centered but makes the DFW only touch the rail and prevents the rear wheel from touching). He never did say what the back wheels should be angled but we are planning for 3 degrees. Sporty recommended the small amount of of cant due to it being a four wheel rail rider and the more cant used the more difficult to get the car to balance with toe in and out needed on the front wheels. If not using a four wheel rail rider it seems most are finding a large degree (7-9) works great. I know I am still a newbie around here but that is my understanding of why you shave 1/16" from DFW and one reason to have lower degrees for DFW.

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whodathunkit
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Re: rail riding -the 1/16"

Post by whodathunkit » Tue Mar 14, 2017 7:02 pm

Speedster wrote: On Page 87 of Build a Winning Pinewood Derby Car I think the picture is not correct. I think narrowing the body of the car a 1/16" will not center the rear wheels. I think with the 1 1/2 degrees of Positive camber and toe-in on the dfw with stock parts you are better off to leave the body at its full width. My experience with the 1 1/2 degree camber the dfw will not ride on its outside edge. Using the Derbyworx tool where you lift up to make the bend it takes 2 degrees to barely get the inside edge off the ground.
.....................................................................................................................................................................................
:scratching:
((I do not understand the recommended 1 1/2 degrees of Positive camber and the narrowing of the car body 1/16" behind the dfw when using stock parts.))
:idk:
......................................................................................................................................................................................

I think 2 1/2 degrees of positive camber, toe-in, and leave the car body alone would be far more beneficial.
I welcome all thoughts.

Speedster..
I know the Book you are talking about.. however I do not have that one to view the image on page 87 that you are talking about!

So there is probably nothing talked about in the book about using an additional wheel gap setting.. ( On the rear wheel behind the DFW only?)
(( Like what is talked about in the Derby Worx rail rider video as well ! ))
.....................................................................................................................................................................................
:scratching:
Speedster
I'm I reading the above right? ( behind the dfw) meaning the rear wheel behind the dfw .. or at the dfw side of the car front!
:idk:
.....................................................................................................................................................................................

My thoughts are:
The tighter the wheel gap setting are for the rears and set to same gap settings say 0.030
the less chance there is for the car's rear end to shift side to side with in the gap setting and / or slop from having to large of a gap setting .

And then maybe by having that additional wheel gap setting for rear wheel behind the DFW only!

That it would let the wheel behind the DFW drive out just a bit farther on the axle shaft and away from the rail..
Plus: that little dip caused by driving out just a touch farther on the axle shaft ( with canted axles)
that it would also cause a twisting affect to the rear end.
Perhaps..
With a slight lowering on the rear to the DFW side of the car as it drives out... the front DFW axle is now pushing down on the DFW bore.
While slightly causing some lift in NDRW bore.. and pehaps causing a rear wheel dive affect to keep the rear wheels off the rail.

( Anyhow just some thoughts i thought id throw out to the topic !)


What type of automobile can be spelled the same forwards & backwards?

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