Wheelbase Question

[NewDerbyDad]

Is the longer wheelbase thing one of those myths or half-truths found on some of those other sites or is there some merit to it?

I believe from everything I read in the forums here, that a longer wheelbase does provide some additional stability, but it does cost you some speed. Is the stability thing not as big a deal if you're rail riding as opposed to just trying to run straight?

I also notice that most of the pro cars are of a shorter wheelbase but initially I thought it was just to be able to fit the front fenders, but now I wonder if it's just a happy point where wheelbase and aerodynamics meet?

Finally, I've had success using the longer wheelbase (each axle hole 5/8" from the end) but noticed 2 things: 1) With the front of the wheels almost even with the front of the car I wonder how many impacts with the big foam pad at the end of the stop section affected my DFW tuning, and 2) To get the COM I was looking for I really really had to make the front end light as there really was wasn't much space behind the rear wheel for weight and as a result some of the weight was dispersed directly over the axle and some in front.

It now seems to me that going with stock wheelbase & rail riding will allow me to A) Gain more speed due to wheelbase. B) Use front fenders to gain more speed due to aerodynamics, & C) Allow for more design creativity in the front as I'll have greater control of the COM by having some additional space behind the rear axle.

I don't really know if there's a question in here lol, I guess I've just been thinking about things and trying to make sense of it all and had to get it all out and see what anyone might think!

Thanks in advance!

 

[Obsessedderbydad]

If you run the extended wheel base you lose the ability to use fenders, which John had proven fenders do increase speeds. So is the extra stability worth losing time over? IMO no when you can adjust your steer

 

[Pacfanweb]

If you run on a "less than ideal" Cub track, the extended wheel base might get your car damaged.

I found out the hard way this year. We did a Dad/Sibling race, with a 10oz limit (I ran about 7), no wheelbase or lube restrictions.

So my daughter took her Plug and Play car from Powderpuff Derby last year, re-prepped the wheels for oil, and added a couple more ounces of weight. It used the slots, stock wheelbase.

Me...I got fancy and did an extended wheelbase. First run, my car won. Next 3, hers spanked mine. Reason? Old stop section had a box and a piece of foam....when my car hit it the first time, it changed my steering. (or bent my axle, haven't pulled it to check yet) Anyway, it messed up the drift and hers stayed the same since the wheels weren't all the way to the front.

Obviously that wouldn't matter on a nice track like the NPWDRL has, but if your track is sub-standard, it might.

 

[NewDerbyDad]

Thanks guys. Ours is an old wood track with a too-short stop section leading into a brick of foam that usually throws the cars almost back to the end of the ramp section. The first couple of test runs during setup my son's car hit it and did a couple of end-overs. Took me an hour to come up with a configuration that stopped the cars consistently but I do believe every run tweaked my steering just a tad. I believe we'll be going shorter wheelbase next year for a bunch of reasons, not the least of which is that stop section!

 

[Kinser Racing]

Some of those scout stop sections are car killers. I like to recommend taking a big fluffy towel with you. Set it in the stop section and let it catch the cars. I set it so the cars will still go under it but won't be launched back or off onto the floor. /images/boards/smilies/smile.gif