Why minimum wheelbase rules?

[Vitamin K]

Hey folks,

So I'm working on drafting some rules for our District's Pinewood Derby, mostly cribbing off of the Northern Star Council's example. Anyhow, I notice they don't have a maximum wheelbase, but they do enforce a minimum (4").

Is there a particular reason you'd want to enforce a minimum wheelbase? Is there some advantage to having an itty bitty wheelbase? Or is it mostly about making sure that the car is stable down the track?

I notice that the Mid-America doesn't enforce a minimum (unless I misread). Would be funny if somebody sent a "Mini-Cooper" styled car to that, heh.

 

[Crash Enburn]

I couldn't really tell you on wheelbase minimums.

On my own ruleset, I've revised it to be pretty much that as long as it is 7" or shorter, and no wider than 3", I don't care, much. Why block a kid because the side pipes he put on his car render it to be 2-7/8" wide? I figure that this way, the kids are free to design whatever they want, and gain no advantage over anyone else (weight placement). I also allow for judgement calls regarding those limits. One of our boys had some decoration that made his car just a hair longer than 7" — there was no weight placement benefit, and no aero advantage, so I let it run.

All this to say that you want it to be as easily teched as you can, because the people checking in may not really know what they're looking for. As it is, finding lightened wheels would be about the hardest for the untrained eye to verify.

 

[Kinser Racing]

Off the top of my head, some people need to be saved from themselves.

 

[ccw13175]

I believe the reason there is minium wheel base is to help prevent cars from being so unstable they crash and damage other cars.

 

[davet]

We race in the NSC and I was told once by a tech inspector that the really short cars crash at the stop section much more frequently.

 

[LightninBoy]

I believe the reason there is minium wheel base is to help prevent cars from being so unstable they crash and damage other cars.

Sorry I'm just seeing this thread ...

Yep. This is correct.

The other factor is whether or not you want to allow staggered wheelbases as a minimum wheel base will prevent the radically staggered wheelbases you see at MA.

 

[Vitamin K]

I believe the reason there is minium wheel base is to help prevent cars from being so unstable they crash and damage other cars.

Sorry I'm just seeing this thread ...

Yep. This is correct.

The other factor is whether or not you want to allow staggered wheelbases as a minimum wheel base will prevent the radically staggered wheelbases you see at MA.

Is there a reason to disallow staggered wheelbases? They don't seem like they'd add a lot of complexity to a build. Are they more likely to crash spectacularly?

 

[LightninBoy]

I believe the reason there is minium wheel base is to help prevent cars from being so unstable they crash and damage other cars.

Sorry I'm just seeing this thread ...

Yep. This is correct.

The other factor is whether or not you want to allow staggered wheelbases as a minimum wheel base will prevent the radically staggered wheelbases you see at MA.

Is there a reason to disallow staggered wheelbases? They don't seem like they'd add a lot of complexity to a build. Are they more likely to crash spectacularly?

The main reason goes back to stability and rule simplification. With a radically staggered wheel base, we are concerned about the car coming off the rail and striking a neighboring car unless it uses a peg in front. For simplification, our clearance rule is that only wheels can contact the track, so the peg would create questions about whether it would be allowed.

IMO, the ideal rule is a minimum wheelbase, such as 4", with no other restrictions. This provides stability while allowing some design flexibility to stagger wheels a little .

 

[Crash Enburn]

Personally, I think it is a needless rule. At least at 4". That rule would have kept my Carrera from racing, as its wheelbase is just a tic over 3.5". (It is also under 7" long and less than 2.75" wide, so aside from wheelbase, legal in most races. /images/boards/smilies/cool.gif)

 

[LightninBoy]

Good point Crash - 4" may be a little high for a minimum.

And that is an awesome looking car.