[Josephkao]

I just install a set of BBS forge RG-R 18" on the my E90 with OEM RFT.
Each one only weight about 19 lbs. A total weight saving of 46 lbs over the OEM 162.
The ride is much smoother, suspension is very well control especially over brick road and railway track, with the 162 it felt like they are hammering the road. The brakes just grab hard and stop the car sooner with the same force. And the steering felt lighter.
Please note my car is stock, with no suspension mod.
Before this I alway use to up-grade all my ride with plus 1 wheel/tires or even plus 2, and never once been able to experience the benefit of light wheels.
My next up-grade would be look for better and light tires.
I have found some tires are 4-5 lbs lighter than the OEM run flat.
I would strongly recommend anyone who is looking for performance over look should go for 18" light wheels instead of 19".
The car now handles better with comfort.

[Vudoo4u2]

Or....you can get light 19's...with lighter tires as well (my 19s are only ~20lbs) and my tires are slightly lighter than stock

I agree, the stock RFT/162 combo or 189 combo ride like bricks

[Josephkao]

Your set up will be even lighter if they are 18"?

[Vudoo4u2]

not necessarily

the added tire that I would be running is likely to be heavier than the wheel I am replacing that 1" with (assuming identical diameters)

the tire is the heavier item in the combo in this case, and its weight is on the outside edge...thus making it a more detrimental factor to this combo...

[Vudoo4u2]

For comparison:

BBS RG-R 18" (beautiful wheels ps): ~19.4 LBS F ; 20 LBS R
OEM RFT (garbage tires..sorta): ~24 LBS F ; 26 LBS R
total weight: 43.4 F/46 R

MORR Monoforged VS8: ~20 LBS F ; ~20.4 LBS R
Vredestein Ultrac Sessanta: ~23 LBS F ; 24 LBS R
total weight: 43 F/44.4 R

Roughly similar weights between these two combos...but consider that theres less weight around the edge of my combination vs an 18" setup which has more weight around the edge

They should perform similar, with the 18's having the edge in comfort, 19's having a bit more grip because they are wider

Both good combos

[Josephkao]

I am not comparing wheel saying mine is better/lighter than your, I am saying if your VS8/tires is available in 18", your whole package will be lighter.

[Vudoo4u2]

Originally Posted by Josephkao

I am not comparing wheel saying mine is better/lighter than your, I am saying if your VS8/tires is available in 18", your whole package will be lighter.

I wasnt saying one was better worse either ...I love the RG-R's, actually wanted them haha, but wasnt willing to wait and fell for the VS8s (dont regret the choice)

But the combination wouldnt necessarily be lighter is what I was getting at. I was making a point that you have a light 18" wheel, and I have a light 19" wheel, but our combination with tires come to about the same weight because of the tire weight. Having a thicker tire negates the weight change between the sizes....so my point was, whether you get light 18's with good tires, or light 19's with good tires, your combo will be roughly the same

[kuvesh]

i dont have the exact numbers on hand but my 19" advan rs are less than 19lb so something to consider if you are looking for light rims...

[S4to335]

My track and street wheels are both light..19-20 lbs each...18 and 19s.

[Josephkao]

Originally Posted by Vudoo4u2

For comparison:

BBS RG-R 18" (beautiful wheels ps): ~19.4 LBS F ; 20 LBS R
OEM RFT (garbage tires..sorta): ~24 LBS F ; 26 LBS R
total weight: 43.4 F/46 R

MORR Monoforged VS8: ~20 LBS F ; ~20.4 LBS R
Vredestein Ultrac Sessanta: ~23 LBS F ; 24 LBS R
total weight: 43 F/44.4 R

Roughly similar weights between these two combos...but consider that theres less weight around the edge of my combination vs an 18" setup which has more weight around the edge

They should perform similar, with the 18's having the edge in comfort, 19's having a bit more grip because they are wider

Both good combos

Sorry, I can not agreed with you. I am not comparing rims or tire, just 18" and 19".
Giving the same brand and style of the wheel/tires in 18 & 19, first 18" is always lighter and 19" tires would put more weight around the outer dimension of the combo.

[Vudoo4u2]

18" tires of the same brand, are not necessarily lighter than 19" of the same brand...check the specs

[r.c.y.k.]

Originally Posted by Vudoo4u2

For comparison:

BBS RG-R 18" (beautiful wheels ps): ~19.4 LBS F ; 20 LBS R
OEM RFT (garbage tires..sorta): ~24 LBS F ; 26 LBS R
total weight: 43.4 F/46 R

MORR Monoforged VS8: ~20 LBS F ; ~20.4 LBS R
Vredestein Ultrac Sessanta: ~23 LBS F ; 24 LBS R
total weight: 43 F/44.4 R

Roughly similar weights between these two combos...but consider that theres less weight around the edge of my combination vs an 18" setup which has more weight around the edge

They should perform similar, with the 18's having the edge in comfort, 19's having a bit more grip because they are wider

Both good combos

same here, can't agree... have u weighted ur Vredestein Ultrac Sessanta? i found online that even the 19" is heavier than ur 20"... those weight just seem to be too good..

[Vudoo4u2]

Originally Posted by r.c.y.k.

same here, can't agree... have u weighted ur Vredestein Ultrac Sessanta? i found online that even the 19" is heavier than ur 20"... those weight just seem to be too good..

I dont have 20s...I have 19", and even if the tires were an extra 2 lbs each, it would still be a comparable overall weight to the 18" set that josephkao has...

[Pyrat 2]

Not to confuse things further but the weight in and of itself is only one factor in the equation. The distribution of the weight within the wheel/tire combination also makes a difference. The more of the weight that is distributed to the center the easier the wheel is to accelerate or deaccelerate.

[SoQuick]

Originally Posted by mdemange

Not to confuse things further but the weight in and of itself is only one factor in the equation. The distribution of the weight within the wheel/tire combination also makes a difference. The more of the weight that is distributed to the center the easier the wheel is to accelerate or deaccelerate.

With this being said. A 19"x9.5 with a lip, however many inches. Would accelerate and deaccelerate easier. As opposed to a rim with no lip Since the majority of its weight, i.e. spokes, lugs, etc, etc, is closer to the center of the wheel?

Am I correct? Does this make sense?

[Josephkao]

Originally Posted by mdemange

Not to confuse things further but the weight in and of itself is only one factor in the equation. The distribution of the weight within the wheel/tire combination also makes a difference. The more of the weight that is distributed to the center the easier the wheel is to accelerate or deaccelerate.

Well said!!

[Pyrat 2]

Originally Posted by SoQuick

With this being said. A 19"x9.5 with a lip, however many inches. Would accelerate and deaccelerate easier. As opposed to a rim with no lip Since the majority of its weight, i.e. spokes, lugs, etc, etc, is closer to the center of the wheel?

Am I correct? Does this make sense?

I understand what you are suggesting but wouldn't jump to this conclusion as a blanket statement. The distribution of the weight within any given wheel is a function of the design and materials.

Also keep in mind that beyond the wheel itself is the tire which typically weighs 24 to 28 pounds. For a given size and diameter, a 1 pound change in the weight of the tire will have more impact than a 1 one pound change in the weight of the wheel.

All of this discussion, of course, assumes that we are talking about the rotational dynamic characteristics of the wheel. It's basically a flywheel when spinning and the more weight on the outside of the flywheel the harder it is to turn or slow down or speed up.

[stressdoc]

Nice test of the effects of lighter rims by the OP. Keeping everything else constant, he just changed rims and noted the consequences.

It is amazing how much weight can be saved by light rims, tires, and, going further, ceramic rotors.

[MisterBMW]

All things equal. What then would be the ideal shape and design of the wheel for best acceleration/decceleration ?

[TSM330i]

http://www.tirerack.com/wheels/tech/...jsp?techid=108

I've read quite a bit of physics articles on the web and there are a ton of calculations and factors coming into play with rotational mass and unsprung weight. Bottom line is that lighter is better when it comes to wheels.
Most of the articles I read said that the rotational mass reduction of the driveline played a larger roll in performance enhancement than wheels and tires (i.e. lightweight flywheel).
Food for thought.

[Lane]

Originally Posted by Vudoo4u2

For comparison:

BBS RG-R 18" (beautiful wheels ps): ~19.4 LBS F ; 20 LBS R
OEM RFT (garbage tires..sorta): ~24 LBS F ; 26 LBS R
total weight: 43.4 F/46 R

MORR Monoforged VS8: ~20 LBS F ; ~20.4 LBS R
Vredestein Ultrac Sessanta: ~23 LBS F ; 24 LBS R
total weight: 43 F/44.4 R

Roughly similar weights between these two combos...but consider that theres less weight around the edge of my combination vs an 18" setup which has more weight around the edge

They should perform similar, with the 18's having the edge in comfort, 19's having a bit more grip because they are wider

Both good combos

Generally though when comparing 18" and 19" of the same wheel&tire combo, the 18 are lighter. In case of very light wheels, the weights of 18" and 19" can be close, but even in that case the tire having more weight per inch than the wheel, means that the 19" the low profile tire is more at the outer edge, meaning more moment is needed for turning it.

When it comes to wheels, as fas as the strength is enough, the less weight the better, but in tires you don't want too low weight to compromise other good qualities such as stiff tire wall.