Will The Weight Of Wheels Make A Difference On 375 Rwkw?

[Turbz RB-25]

Hi Guys,

I am planning on getting some starcorp impul wheels 18x8.5 front and 18x9.5 rear.

I have around 370 rwkw on my r33 GTST (RB25/30 with GT3540)

Anyway, my question is, are these wheels that significantly heavier than my R34 GTT wheels that I will feel a significant decrease in acceleration?

Or do you think at that sort of power level the weight difference in wheels wouldn't mean jack shit?

I've read a few posts, people saying they are "sooo heavy" and makes your car sluggish, but seriously, can 5kg extra per wheel make the car that much slower??

Can people with personal experience please get back to me as I wanna buy these wheels really soon.

Cheerio.

Edited March 11, 2009 by Turbz RB-25

[SS#eater]

370 kw i doubt you would notice any loss in power....

[djr81]

Hi Guys,

I am planning on getting some starcorp impul wheels 18x8.5 front and 18x9.5 rear.

I have around 370 rwkw on my r33 GTST (RB25/30 with GT3540)

Anyway, my question is, are these wheels that significantly heavier than my R34 GTT wheels that I will feel a significant decrease in acceleration?

Or do you think at that sort of power level the weight difference in wheels wouldn't mean jack shit?

I've read a few posts, people saying they are "sooo heavy" and makes your car sluggish, but seriously, can 5kg extra per wheel make the car that much slower??

Can people with personal experience please get back to me as I wanna buy these wheels really soon.

Cheerio.

I doubt very much you will feel any great difference in acceleration. But obviously an extra 20kg wont help. Try going for a drive then chucking a bag of cement in the boot & see if you can feel any difference.

What you will almost certainly notice is that the car rides worse than previously & it struggles for traction whenever there are bumps in the road.

Bottom line:

Please don't put cheap heavy wheels on a Skyline.

[dezz]

20kg of unsprung weight is a lot worse than 20kg in the boot...

[vidospace]

Speaking from experience (going from 15s to 17s on a Civic) yes, quite definately it makes a massive difference.

[djr81]

20kg of unsprung weight is a lot worse than 20kg in the boot...

Yeah I was trying to give him an indication of how it would feel for acceleration.

[Basti]

Speaking from experience (going from 15s to 17s on a Civic) yes, quite definately it makes a massive difference.

[N-DAWG]

I recall reading about weight at the wheels in comparison to say weight in the boot of the car.

Basically the point was that it takes more rotational power at the wheels to turn a heavier wheel to get the vehicle in motion than if that weight was on the car.

When I upgraded my 16" GT wheels to 18x8 Mesh Wheels, I was very suprised by the weight comparison when I changed them over (I knew they'd be heavier, but not THAT much heavier), and definitely noticed the difference the first week or so driving. But after that I got used to it. Now I wouldn't know what difference it would make with stock wheels compared to what I have now being that my performance has changed significantly.

[Turbz RB-25]

I just emailed tempe, they said the fronts weigh 14KG (18x8.5) each, and the rear (18x9.5) weigh 16kg each.

Now, in comparison to other wheels around a simular price range (please don't come on this thread comparing $4,000 wheels to $1,500 wheels), how does this weight compare to them?

Has anyone measured the weight of there wheels without tyres? or are their any websites that show the weight of their wheels?

Cheers fellas.

[djr81]

Well relative to a good quality rim - say a Rays - Tempe's rubbish will weigh in at approx 75% to near on 100% heavier.

http://www.nismo.co.jp/en/products/competi.../aluminum01.pdf

Obviously if you get cast rather than forged rims the difference will be less substantial.

None the less Tempes rims weigh 60kg. Rays a little under 34kg.

I am sure you can do better than what is offered.

[Turbz RB-25]

Also thinking about the DTM Z7 wheels, I read somewhere on here that they are 9KG in weight, only 2kg more than the Nismo wheels?

DTM z7 or Starcorp Impul?

(I must admit the starcorp look much better)...

[br3ndan]

just buy some lightweight rims!

for example p1s.

problem solved.

[Turbz RB-25]

just buy some lightweight rims!

for example p1s.

problem solved.

and how much are they?

[Damo_R34]

lol your car is 375rwkw and you have a budget for wheels?

for around the 1500 you'd be looking at used rims with tyres, or new rims with no tyres, nothing decent that is new with tyres will come close to $1500.

[HEKT1K]

get some 34 gtr wheels. can be had for 2.5k with tyres and they're light(ish)

[SLEEPR85]

lol your car is 375rwkw and you have a budget for wheels?

Lol, have to say i'm with damo on this one. Why go all out on engine mods, then to skimp on wheels which possibly won't compliment your driving style, i'm sure you've spent a lot of time and effort to get to that figure.... doesn't make sense man.... If money's the issue, save up for a bit longer and get some decent rims and rubber to get your 375kw down to the ground.

[Turbz RB-25]

Lol, have to say i'm with damo on this one. Why go all out on engine mods, then to skimp on wheels which possibly won't compliment your driving style, i'm sure you've spent a lot of time and effort to get to that figure.... doesn't make sense man.... If money's the issue, save up for a bit longer and get some decent rims and rubber to get your 375kw down to the ground.

Buddy, I've spent around $40,000 on my car, If I spend $4,000 on wheels, my girlfriend will get my .308 rifle, stick it up my ass, and shoot.....

It just doesn't make sense to me how an extra 5 kg per wheel can make such a difference?

Go find something in your garage that weighs 5kg, or better yet, go to the gym and pick up a 5kg weight, you'll see it's light as....

and considering my car is not a civic with 40 fwkw (if even), it puzzles me how it would make THAT much of a difference.

Drag cars have MASSIVE tyres on the rear (and rubber weighs a fair bit), and it doesn't seem to impeed on performance.

I can understand if the difference was like 30kg per wheel, then yes, I would probably say it would make a pretty big difference, but 5 kg per wheel???

[SLEEPR85]

Buddy, I've spent around $40,000 on my car, If I spend $4,000 on wheels, my girlfriend will get my .308 rifle, stick it up my ass, and shoot.....

.... I have no come back to that! Maybe your making the right decision after all....

[Pattygtst]

I got the same rims your chasing star corp impuls 19 x 8.5 & 19 x 9.5, i tried on some 18x9.5 all round workmeisters the other day and couldnt tell the difference between the two when i picked them up. I didnt put it on a scale so i couldnt give you a figure. I was very suprised though i expected the jap rims to be alot lighter.

You'll be fine.

I got a mate with a 2jz in his 180 puting over 600hp he has chinese rims too.

[Phatboy]

I was looking into this myself recently, and I believe the following person from the bimmer forums describes it nicely. Hopefully it helps explain it:

"Rotational Un-Sprung Mass: Some of the un-sprung and semi-sprung weight is rotational and some is fixed. The wheels, brake rotors, and hubs are rotational. It takes a lot more energy to accelerate the wheels in a forward direction AND in a spinning motion than would if you were just carrying them in your trunk. Also when you get up to speed, the mass of the wheels creates a gyroscopic force, which has to be overpowered when you change direction and speed. These spinning forces are largely why lighter wheels can make such a noticeable performance impact. Mass towards the center has a lessor impact where mass towards the edge of the rim and tire has a greater impact. This can be VERY important when determining how much energy it takes to accelerate a certain wheel, but because of the complexity, I have never seen a wheel retailer market such specifications. It is possible that if a 30lbs wheels mass was centered near the hub and a 20lbs wheel center of mass was near the rim… the 30lbs wheel may require less energy to accelerate.

Non-Rotating Un-sprung Mass: The non-rotating unsprung and semi-sprung parts are the brake calipers, control arm, and other suspension parts. These parts are not rotating, but they are moving as you drive over bumps in the road. When you hit a bump that pushes tire up it moves the wheel and suspension parts. Ideally the wheel would move up so quickly as to match the contour of the bump, but since the un-sprung wheel and suspension parts has mass, the bump needs to exert energy to accelerate these parts up. If these parts were to have less mass, then your suspension would ride up the bump better and most importantly down the other side quicker. This would give you a better tire contact patch, better road holding, and a smoother ride over the bump, but lightening up the non-rotational mass probably will not give you a noticeable improvement in acceleration.

If you significantly change your unsprung weight, it will also be a very good idea to change your spring rates and dampening (bump and rebound) rates of your shocks."