3.7%

 

8 gigawatts

 

P = (f2my/c◊ÇØ∏Œ‰ˇÁ¨ˆØÒÎÔÓ˝ÏÍŸ˛Ç◊ı˜Â¯˘¿Æ’»’”⁄€‹›fifl‡°·‚—±)

 

Are you keeping the stock diameter? I assume you must be going to 17s for that much weight savings.

 

If and when it happens, I'll go 17's too, need more rubber between wheel and the road. Daily driver, not a shown car.

 

Not keeping stock. Will even go to a narrower tire if need be. Also, I have found several answers elsewhere, so this thread can be locked as far as I'm concerned.

 

Well your welcome to go narrower but considering traction is your limiting factor in the first two gears, you'll likely end up slower.

 

Performance reduction will result if contact patch is reduced.

decreased lateral grip, decreased traction, decreased fun.

 

Effects of Upsized Wheels and Tires Tested - Tech Dept. - Car and Driver

What’s immediately apparent from the results is that as the wheel-and-tire packages get larger and heavier, acceleration and fuel economy suffer. Neither is a huge surprise, but we measured a 10-percent drop in fuel economy and a four-percent degradation in 0-to-60-mph acceleration from the 15s to the 19s, which is worth considering should you be thinking about “going big.” Increasing wheel diameter and width, in turn, requires wider tires with shorter and stiffer sidewalls, which we found will increase skidpad grip, but as our test shows, there is a limit to this assertion. The 19-inch package came with the widest tires (235/35R-19) mounted to the widest wheels (8.5 inches), but this setup had less grip around the skidpad than the narrower 225/40R-18s on 8.0-inch-wide wheels. We asked the folks at Goodyear why that might be, and they postulated that the added width may have given the outside tire more grip, which would increase body roll and could therefore decrease the load on the inside tire enough to lose 0.01 g on the skidpad.

Surprisingly, the 225/40R-18s showed a big skidpad advantage compared with the 225/45R-17s (0.89 g versus 0.85 g). We *suspect the difference is due to the grippier compound (lower wear rating) of the W-rated 18s. Goodyear does offer a W-rated GT in the 225/45R-17 size, which is what we intended to use, but Goodyear sent us the V-rated version for our test.

 

The test car was a Gulf...

Of corse it didn't benefit from more grip. It wasn't testing the grip it already had.

I'm not even sure what this test was even conducted for. To put 8.5 inch tires on a Gulf, you'd have to have had a desired result before the test began.

It reads to me like the author wanted to make a statement about absurdities, not really discuss tires on performance oriented vehicles.

 

Just remove your "FOCUS" badge and it saves you 0.00057 grams which in turn should cut your lap time down by 0.000005 seconds per lap. :haha: On a more serious note, by reducing wheel size you will do two things.

1.Smaller wheel means quicker acceleration due to the size of rotating mass. 1" less of wheel to spin

2.More tire allows for more tire flex thus improving traction. if you look at most street/drag vehicles they run 15" wheels this way they can have more tire.

 

throw some throw some Ds on it

 

Just thought I'd throw this out here, but if you're looking to cut 13 pounds per wheel you must have a ton of money to spend and I think you should send some my way. The reason I say this is because I weighed my rims when I had the tire off to have it re-balanced and it only weighed 25 pounds (give or take half a pound). 13 pounds off that puts you in supercar light weight wheels. The lightest I've seen for our cars without going to a 16" wheel is about 18 pounds per wheel. That said will your performance increase? Not really.

 

The op was looking to cut 13 lbs per corner, not 13 lbs per aluminum wheel. If you shave 6 lbs off the wheel and 7 off of the tire you've hit the 13 lb weight reduction or any combination there of without going to stupid expensive forged magnesium wheels or carbon fiber.

It might require going for light weight 16 or 17" wheels however depending on how much weight could be shaved from the tires.

 

Wildwood sounds like the better deal to me.