Wheelbase vs. track width ratio

[Coelacanth]

Several weeks ago, I commented on a thread here about what would be the ideal theoretical ratio of wheelbase to track width. I did some research on this and there's a wealth of interesting info about this. Of course there's no magical number that's ideal for all applications; it depends on the kind of driving you're doing, the kind of track, and of course how the suspension & steering are adjusted. Very interesting reading, I thought I'd share a few links for any of you physics/logic fanatics and race gurus. I just got to thinking about all this when considering the LWB Optima Mid vs. the regular Optima Mid, and on the other hand, people talking about increasing the track width by installing longer control arms, and wanted to have a better understanding of the underlying physics principles.

http://www.f1technical.net/forum/viewtopic.php?f=5&t=9744
http://www.f1technical.net/forum/viewtopic.php?f=6&t=9567
http://www.f1technical.net/forum/viewtopic.php?f=6&t=6311

Generally speaking (kind of common-sense), a so-called "golden ratio" of 1.6 - 1.7 would be good. Of course, dragster racing is on one end of the scale, with an exaggerated ratio much higher than that, and maybe something like a go-kart would be the opposite, about 1:1 or so.

The cost/benefit would be stability (longer wheelbase) vs. agility (shorter wheelbase), all else being equal. Apparently a higher ratio (wheelbase : track width) would be better in high-speed turning while the lower ratio would handle a lot of lower-speed cornering & turn-in better. The longer, narrower car would also benefit from better airflow.

It's interesting how so many variables come into play; center of gravity, steering sensitivity, traction, track style, airflow, suspension, front track width vs. rear track width...pretty interesting stuff.

Any thoughts, as far as the various types of RC racing are concerned?

[slotcarrod]

Way to complicated for me! I can tweak a little here and there but over all I just copy fast driver setups and tweak them a bit, 70% is driver right? Not much into custom design!

Now wheres my proton pump inhibitors? GTG!

[Coelacanth]

On the other hand, I could say that I probably drive so bad that any little bit helps. Seriously though, I always like trying to understand the physics. For example - car too twitchy? One option is to narrow the track (as increasing wheelbase isn't as easy). Having problems with understeer? Perhaps shortening the wheelbase or installing longer control arms could help. I imagine the people who win races and have the best-performing cars (or their car builders, if not one and the same) have a better understanding of this stuff than most people. Copying a recipe is fine and all, but it doesn't teach us anything about our cars.

[RC10th]

Interesting but track and wheel base isn't all of it. Most of chassis tuning is just weight transfer and how it gets distributed around the car as it goes around a track. Very few cars have a track width adjustment aside from offset hexes and such. It's all about finding the magic balance and everything has a trade off. More steering here means less steering there. More grip there means less grip here.

I think racing big time comes down to mostly who can find the best set up within a limited amount of time, and who can play the mental game the best.

[kink]

Same as that thread I posted here ages ago. Back in the day you had relatively SWB cars with normal track widths. Then all the cars went LWB (as per CAT XL). Then all the cars got larger wheels. Then all the cars got wider. So we are back where we started. The only difference is all the cars are now scaled up (to 1/9th scale?), so not suprisingly they can be faster. But then again 1/8 scale cars are faster yet, so maybe that is the future for 1/10 scale. Just rebrand the inferno as a 1/10 buggy and we are all done.