tires and wheels Unsprung weight, tires, rear discs my rims etc etc

[Guest Anonymous]

Well The center roundels are new, still available, concaved adhesive metal ones from BLUNT

Are you sure they are "concaved" and not convex?

[nbristow01]

Well The center roundels are new, still available, concaved adhesive metal ones from BLUNT

Are you sure they are "concaved" and not convex?

LOL you are correct Convexed.

[nbristow01]

Thanks Les!

[RayC911]

Curious, how much does your steel wheels weigh? A 15x7 RS weigh 15-16lbs

[nbristow01]

Not sure, I would imagine at least 20+ lbs each. There is a secondary reason for liking the BBS RS wheels. My wife has been after me to turbo flare my car. The BBS RS would look perfect, I think I would have to add a spacer to get them out intot he flare if I go ET 25 rims

[RayC911]

If you go flares and RS, then keep the rear disc. It'll push the wheel out a bit more too. 20lbs is heavy especially with 205s.

[nbristow01]

With lighter wheels ou will most likely notice the lower rotational mass then the unsparing weight.

Steve k.

Steve that seems to make sense. I guess kind of the same way a lightened flywheel will allow the engine to rev quicker.

[steve k.]

With lighter wheels ou will most likely notice the lower rotational mass then the unsparing weight.

Steve k.

Steve that seems to make sense. I guess kind of the same way a lightened flywheel will allow the engine to rev quicker.

sorry about the typos, was doing all that on my phone

Most of the people will not notice changes in unsprung weight since all that does is change he dynamics of the shocks and springs.

Rotational mass on the other hand plays a huge effect for almost anyone. You also should not forget the weight of the tires that you will be using. Most of the time they are heavier then the wheel itself.

My 15" wheels set up consist of a 15lb wheel and a 20lb tire. My 13" set up has a 11lb wheel and 17lb tire. I used to run a 10lb wheel and 16lb tired.

The width of these three are 275mm, 255mm, and 225mm. You can easily notice the acceleration changes between these three set ups. But the first 2 tires make the car dramatically faster through the course then the lighter combo Sometimes you have to sacrifice weight to go faster

A while back i tried a wide steel 13" wheel that was about 15lb. with the same tire as was on my 10lb wheel. That allowed the tire to have a bigger patch, but the weight difference was too dramatic and the car became a lot slower.

steve k.

[nbristow01]

That is pretty interestng Steve. So you lost noticeable performance with the 15lb wheel 16 lb tire as compared to the 10lb wheel and 16 lb tire. That first combo is 5lbs heavier. So even at 5lbs per corner, 20 lbs total you had a big difference. I bet bigger than if you just stuck a 20lb weight in the car. So that wheel tire weight calculates out to a lot of weight in reality

[steve k.]

That is pretty interestng Steve. So you lost noticeable performance with the 15lb wheel 16 lb tire as compared to the 10lb wheel and 16 lb tire. That first combo is 5lbs heavier. So even at 5lbs per corner, 20 lbs total you had a big difference. I bet bigger than if you just stuck a 20lb weight in the car. So that wheel tire weight calculates out to a lot of weight in reality

rotational mass counts for a lot more then just car weight. That s why people mention that 1lb of unsprung weight is like 10lb of spring weight. People spend a lot of money lightening parts of the drivetrain and all rotating parts.

installing one of these will really help you understand

DSCN7578 by misfit76, on Flickr

[nbristow01]

That is pretty interestng Steve. So you lost noticeable performance with the 15lb wheel 16 lb tire as compared to the 10lb wheel and 16 lb tire. That first combo is 5lbs heavier. So even at 5lbs per corner, 20 lbs total you had a big difference. I bet bigger than if you just stuck a 20lb weight in the car. So that wheel tire weight calculates out to a lot of weight in reality

rotational mass counts for a lot more then just car weight. That s why people mention that 1lb of unsprung weight is like 10lb of spring weight. People spend a lot of money lightening parts of the drivetrain and all rotating parts.

installing one of these will really help you understand

DSCN7578 by misfit76, on Flickr

Wow I actually understand!!! Man thanks for that lesson