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Old 12-06-2013, 06:45 PM   #1
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Default Why current TC cars are not 190mm wide?

I would like to ask why any TC companies dont design suspension systems according to the rule 190mm track width limit. It is about 187mm in front, and little less about 185 in rear. As lateral load transfer is affected only by CG height/Track width, mass and lateral acceleration,
when trying to achieve lowest CG height and mass, why dont we aim for maximum track width also? What point am I missing? Especially with very high traction carpet, I believe we have excess load transfer than we need, so we try to limit tire grip to have a "drivable" car. In my mind this is a easy but wrong solution, in theory, ideal car would be better, having about 190mm track width and increased tire additive timing, and use no glue on tire wall, yet still being easy to drive. what is different between theory&practise?

I am aware of myself that I look at the situations in a very rough and basic way, but I believe someone can enlighten me by making me see a different perspective. Thank you very much for your time.
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Old 12-06-2013, 07:17 PM   #2
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I'll take a stab at this. It's all about balance and compromise. When you narrow the track width you increase traction at that end. With todays spec tires, I will say some do not offer as much traction as others. It is also easier to widen the track width than to narrow it. Many tracks, asphalt for example, may not offer the traction of a well grooved carpet track. There-fore the car would benefit from a narrower track width than the maximum 190mm rule. If you go high traction and start to traction roll, you can go to the maximum 190mm limit (on whatever end is traction rolling) and then tune from there. Going maximum to 190mm also limits what kind of toe/suspension blocks and even wheels that you can use. You would think most wheels are 0mm offset or whatever the standard is right now. I don't remember. But some other companies offer different offset wheels.

It's also about suspension geometry and how it has evolved. Some geometries like arm length and block width play a part. Companies copy other companies or try to get close. Kinda like follow the leader so most companies end up with similar dimensions.

But going back to what I think, narrow = more traction at that end. With spec tire rule, generating traction is very important. Some of those spec tires out there suck.
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Old 12-07-2013, 03:12 AM   #3
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Wider is always better (unless you are on an exceptionally narrow circuit), but if you built the cars to 190mm and had to run a different manufacturers wheel that was 1mm greater in the offset, you would be illegal. And if you wanted to run 3 degrees camber, you'd be illegal too.

Relative track width is a tuning thing, but if you think narrower is faster, you should try running a 4wd mini tourer (I used to have a Yokomo MR4 Mini) against a 190mm tourer and see how much slower the mini tourer is.

187-ish is just a safe compromise that keeps the car legal if you make a setup change.
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Old 12-07-2013, 11:36 AM   #4
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Or if you ran any front or rear toe in any direction would make the car illegally wide as well.
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Old 12-07-2013, 11:48 AM   #5
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From a technical standpoint TC;s are in fact 190mm wide, you have to look at the whole picture, as said above as soon as you start your suspension geometry if the chassis is 190mm wide then what can you do? very very little.
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