I got to experience the difference between a 225-45-15 setup (NT-01s) and a 215-40-17 setup (Z2*) both in dry ~75F weather. While not a super fair comparison compound wise, the difference in acceleration is pretty marked. I actually thought something had broken or my hood scoop was blocked. The acceleration out the uphill turns at the end of the track makes it pretty obvious. I had never felt lacking in power till my first time on track with 17s :arf: The difference in braking Gs is mostly compound driven, but I am power limited not grip limited acceleration wise
That's good to hear. I always suggest 15 for track wheels/tires because of cost: a set of 15" R compounds are considerably less. I also am into the look of small wheels/big rubber for MINIs.
No car wants 4 big flywheels bolted to it. As you have shown it takes energy to turn them & they also make the brakes work harder to slow them down.
Yea....the 15's are about 5% smaller in diameter and this translates into faster acceleration. Math doesn't lie........
I'm thinking is not the size as much as the weight. The i5 inch wheel & tire package will have an overall diameter close to that of a 17 inch wheel & tire package. The difference is the weight. Yes a smaller overall diameter will be like having a shorter gear.
225/45/15's have a significant decrease (about 1 inch) in diameter, and that changes the gearing, like you said. It's at least if not more significant than the weight, as it also lowers the car and the center of gravity. If you have coilovers, raise your car an inch on all four corners--it's a huge difference. I run 9 inch wide up front, 8 in the rear, and this combination is phenomenal, but I do miss having 8's on all corners and being able to rotate the tires front to back.
Yeah the smaller OD has a big impact on effective final drive and cg height, my speedo is hilariously optimistic with the 15s. The weight wasn't much different. I was using 15lb 15" and 17lb 17" I don't remember the tire weight but it was within a couple lbs iirc. That said I did have the change up my shock settings to tweak the car's behavior so it was different enough to notice. Also, like Eric mentioned a set of 4 nt-01s in 225 are like $600 17" r-comp are more.
15x8 Jongbloeds with NT-01's (36lbs ea.). Heading to VIR this coming weekend. Will be interesting to see how they compare to my AD048's on 16" wheels (32.6lbs ea with 50%tread)