20" Wheel weight = Slower Car?

[Pnasty]

does anyone know how much the CS wheels weigh

Sponsored

 

[Cloak]

my 20x10.5 with 315/35r20 definitively felt slower. an inch taller in overall diameter, and possibly heavier than my performance pack wheel/tires

those wheels/tires are now sold. going back to 19s.

 

[WKT]

my 20x10.5 with 315/35r20 definitively felt slower. an inch taller in overall diameter, and possibly heavier than my performance pack wheel/tires

those wheels/tires are now sold. going back to 19s.

Thats why I changed to 19's, my car was slower with the 20's. The 20's were 28.6 inches tall, my stock tires were 27.3 tall. My 325/30ZR19's are 26.77 tall and the MRR350 wheels are light, between the weight and tire height the car is way the hell faster.

 

[Cloak]

Thats why I changed to 19's, my car was slower with the 20's. The 20's were 28.6 inches tall, my stock tires were 27.3 tall. My 325/30ZR19's are 26.77 tall and the MRR350 wheels are light, between the weight and tire height the car is way the hell faster.

yep, my tires were 28.6" tall, back down to the stockn PP 27.7" wheels now. Got a set of 19x10 squared forgestarrs, which weigh about the same as the M350s, and popping 285/35r19 tires all around, which is 26.9" . I expect to feel the difference from weight dropping, as well as feel the 3.73 gears more.

 

[Flat Stanely]

Also needs to be noted that with a larger wheel diameter the overall reduction in weight is minimized because the outer portion is further from center. Example from a 19 to 20 inch wheel.

 

[SubZombie]

rotating weight and unsprung weight has 4 times the effect of sprung weight. losing 10 lbs per wheel is 40 lbs of unsprung weight which is like losing 160 lbs of vehicle weight/sprung weight.

This is kind of silly, because it isn't that simple (though I know its a popular thing people say).

You can easily have a 20lbs wheel that requires more force to accelerate than a 30 pound wheel. It depends if the weight is in the hub, spokes or rim. There are many after market wheels that have much less weight in the spokes and hub (which makes the wheel lighter overall, which is great for advertising) but they have to compensate for that with more weight in the rim of the wheel to make it structurally sound - especially wheels that have smaller/fewer spokes - they really beef up the rim to support that.

More weight in the rim of the wheel has (literally) an exponentially greater effect on acceleration that weight in the hub or spokes, and the further the weight from the hub the larger the effect.

Some people get these "lighter" wheels and get a slight increase in mpg on the highway and the reason is they added more weight to the rim of the wheel which slows acceleration but it increases the wheels rotational inertia making it easier for the car to maintain a speed. It's the same thing people factor in when buying bicycle wheels.

Basically, those PP wheels that are "heavy as thor's hammer" could easily give better acceleration than much lighter aftermarket wheels, depending on the design and weight distribution.

 

[dgc333]

I think 19s look fine, 20s fill the gap a little better, but if you can save 3-5lbs per wheel it'll be worth a decent amount of acceleration. I know or have been told way more tire options with 20s, but lowered on 19s look just fine to me.

Don't know how the factory 20's fill the gap any more. Whether the wheels are 17, 18, 19(except the GT PP rears) or 20" they all have the same overall diameter.

Also, not sure why people think there are more choices in 20s. Tire Rack lists 23 20"s, 58 255/19 and 67 275/19.



Dave

 

[Higgs Boson]

This is kind of silly, because it isn't that simple (though I know its a popular thing people say).

You can easily have a 20lbs wheel that requires more force to accelerate than a 30 pound wheel. It depends if the weight is in the hub, spokes or rim. There are many after market wheels that have much less weight in the spokes and hub (which makes the wheel lighter overall, which is great for advertising) but they have to compensate for that with more weight in the rim of the wheel to make it structurally sound - especially wheels that have smaller/fewer spokes - they really beef up the rim to support that.

More weight in the rim of the wheel has (literally) an exponentially greater effect on acceleration that weight in the hub or spokes, and the further the weight from the hub the larger the effect.

Some people get these "lighter" wheels and get a slight increase in mpg on the highway and the reason is they added more weight to the rim of the wheel which slows acceleration but it increases the wheels rotational inertia making it easier for the car to maintain a speed. It's the same thing people factor in when buying bicycle wheels.

Basically, those PP wheels that are "heavy as thor's hammer" could easily give better acceleration than much lighter aftermarket wheels, depending on the design and weight distribution.

This doesn't negate anything I said, it's all born out of measuring changes in elapsed times on the strip as well as measurements taken around corners and road course effects, removing weight from the car vs from unsprung/rotating mass.

The only real time more weight is added on the rim of a wheel is with width increases and especially when you get a heavier set of tires (especially problematic with the truck crowd).

BTW, "thor's hammer" reference has been used at least 80 times this week, let's get another comparison, it was funny the first time, now unoriginal.

 

[Sasuketr]

This isn't really a wheel and tire question, but overall, do the people installing 20" wheels on their car feel like their car is slower?

I've noticed that there are not too many affordable and lightweight forged 20" wheels available, and most of the pictures I see people posting are of cast 20" wheels, and the great majority of these wheel/tire packages weigh more than the factory wheel.

I'm on the fence about spending a bunch of money for 20" wheels that might hurt overall performance, and sure some others are too, so please give your feedback and experience on wheel/tire weight vs overall vehicle performance.

If you have a PP car i would definitely suggest going with a lighter 19 9.5 square setup or 19 9 and 19 9.5 staggered setup! The PP wheels are extremely heavy 34 lb rear and 33 lb fronts. There are some really nice looking 19" lighter wheels out there such as TSW Baghurst's. You could loose close to 50 lbs rotational weight which is not a brainer. You can still run 275 square or 285 back and 275 front with those wheels if i m not mistaken!( Double check that with the vendor)

Advantages will be better steering feel, quicker acceleration, less harsh ride, mpg improvement and list goes on! 20" wheels will look good with the current suspension setup with the gaps and all, but the ride will be harsher cause you will end up with a skinny rubber, and you won't loose too much rotational weight! I am not sure if it will change the accuracy of the speedometer, cause the height of the wheel is changing!

On paper it looks good too, imagine if Ford had put lighter wheels on the GTPP's! A base GTPP would be around 3690lbs and a loaded one would be 3770lbs! The cars wouldn't even reach the pig weight of 3800lbs! There is a reason why the GT350 R is coming from the factory with lighter carbon fiber wheels! Why not improve things while you can?

 

[racer24crm]

Wheels don't fill in the gap. Taller tires do. A 20" wheel with a 35 side profile is relatively the same diameter as a 19" wheel with a side profile of 40. You can increase the sidewall height to fill the gap but it can mess up the dynamics of the car. Probably rise more comfortably but it will be slower, get worse mpg and feel sloppy when turning.

Like was mentioned before, try to stick as close to a 27" wheel and tire height. The cars were designed around this and will perform best from the factory this way. Use a tire calculator to compare tire sizes and you will see what you can get away with.

 

[kn7671]

I think we the responder said "fill the gap", the interpretation may have been on visual preferences, as most 20" wheels, or aftermarket wheels in general, have a more positive offset, providing a more flush and full appearance.

 

[Higgs Boson]

On paper it looks good too, imagine if Ford had put lighter wheels on the GTPP's! A base GTPP would be around 3690lbs and a loaded one would be 3770lbs! The cars wouldn't even reach the pig weight of 3800lbs! There is a reason why the GT350 R is coming from the factory with lighter carbon fiber wheels! Why not improve things while you can?

3800 is russian boar hog weight. pig weight is 3300. fighting weight is 2800. truly lightweight is under 2500.

mustang is way too far gone to worry about 5 or 10 lbs in the wheels in relation to overall vehicle weight, although dropping unsprung weight is still fun to do.

 

[dcasandman]

There is a small exert in car and driver on the gt350 on the regular wheels vs the r wheel. There was a huge difference in acceleration time saving the weight.

 

[Higgs Boson]

There is a small exert in car and driver on the gt350 on the regular wheels vs the r wheel. There was a huge difference in acceleration time saving the weight.

yes, wheel weight still has an effect when just comparing wheels but can you imagine if the mustang lost 1000 lbs?

 

[dcasandman]

yes, wheel weight still has an effect when just comparing wheels but can you imagine if the mustang lost 1000 lbs?

1000lbs then we'd be driving around 400hp lotuses. It'd be a dream world.

Sponsored