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Old 10-25-2015, 09:35 PM   #1572
Metabrz
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Drives: MY12 NZDM Subaru BRZ "BRZ001"
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Quote:
Originally Posted by Chanpion View Post
I can't prove it on the BRZ setup but generally, a thinner tire in the front will have better turn in. Physics wise, think of it as these two examples, two wheels far apart and twowheels close together. Now imagine the distance between the two tires in these two examples as the width of a single tire. When 2 wheels are far apart, one wheel does all the turning while the other wheel creates understeer. Now for example two, place these two wheels close together in the middle. They both act together to turn instead of one creating understeer/ one wheels slower than the other. Now squish this theory into a single tire. Larger the tires, the greater the travel circumference between the inner and outer side of the tire.
That's why some people run a staggerred setup with thinner tires in the front for better turn in and entry speed. This is my best shot at a simple physics lesson.
So physics wise, a skinner tire may be faster. There's so many variables though. So whoever you quoted may actually be right.
In my experience a wider tire will improve turn-in. I think you're mistaking 'easier' for 'better' and that may be your preference but for me that's not the case.

The car has more lateral grip and thus negates under-steer better with a wider tire. Yes, the momentum of a wider tire may be higher and therefore turn-in requires more effort and accordingly turn in on a skinnier tire may be 'easier' due to lower momentum but for my money that not does not mean 'better'.

I've gone from 215/45/17 to 245/35/18 back to 215/45/17 and now on 255/35/18 in the three years I've owned my car and for me, on balance for spirited back country road driving, wider tires provide a much improved driving experience through grip and stability primarily.

The downside is tram-lining and a reluctance to return 'on center' but I got used to these and just enjoy railing corners at speeds that are far in excess of what I've experienced (and are comfortable doing) on skinny road tires.

Edit: running staggered tires will not reduce under-steer, it will increase it.
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Last edited by Metabrz; 10-26-2015 at 04:21 AM.
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