The effect of wheel weight

[wadragracing]

Was wonderinf if anyone has any experience or can link me up with some articles regarding wheel weight. I know any weight reduction is good, but how dramatic would wheel weight be on quarter mile times?
I've got some drag tyres but the rims they are on, thought they look damn nice, are rather heavy (at least they seem it) Starcorp items.

Any opinions would be neat...

[Muppet_Guy]

The heavier the wheels, the more torque required to make them spin. Not sure of the physics behind it all, but it only seems like common sense the lighter wheels the better...

[wadragracing]

Yeah I gather as much, I'm just trying to find out what the difference is. If it is negligible I won't worry about changing them.

[TJ]

At your power levels and with the auto.... most like no big deal Luke.

[ER33CTION]

unless your running huge torque/power it really shouldnt make any difference

[YOUR MATE]

VY Senator, ~300rwhp, 19" HSV rims = 13.7, 20" chrome XHP rims = 14.2
Thats a fair difference imo, half a sec added just running on bigger rims. I need some 17's to race on, and more power lol.

[wadragracing]

Cheers guys.

[Skitzo]

VY Senator, ~300rwhp, 19" HSV rims = 13.7, 20" chrome XHP rims = 14.2
Thats a fair difference imo, half a sec added just running on bigger rims. I need some 17's to race on, and more power lol.

id say that may be more to do with less traction then extra weight... barely any side wall.. but yeah the weight probably countered into it aswell..

[YOUR MATE]

When it spun off the line it ran 14.4, every other time it gripped and got 14.2's. Cars with same power and same mods will hit 13 flat with stockies or 17's etc. I know each car is different and all the rest, but the bigger rims sure seem to make a difference and coz of my brakes I cant run smaller than 17's :(

[wadragracing]

When it spun off the line it ran 14.4, every other time it gripped and got 14.2's. Cars with same power and same mods will hit 13 flat with stockies or 17's etc. I know each car is different and all the rest, but the bigger rims sure seem to make a difference and coz of my brakes I cant run smaller than 17's :(
You don't always feel the spin that can make a tenth or two tenths of a second difference to your 60 foot times.
Plus, depending on tyre size, it may have given your car slightly taller gearing, but that is a long shot.
Do you have the 60 foot times for your 20s versus your 19s? that would tell the story.

[Riggs]

Mate of mine has a s14a, few mods. Had the 16 inch stockies on it and then threw some 18 inch Lenso chrome boat anchors on. Was a noticable difference even driving around the street.

[zeroyon]

Its an interesting subject.

Everything I have read / heard it makes a huge differnce even in lower powered cars.

I've never done a back to back but I can say I didn't really notice all that much difference.

I've never gone the extremes though, gone from light weight volks to steelies to convo pro's(basically a slice of ally).

I have picked up some VERY heavy rims there usually in the larger dia though 18" ++ I'd say they would mess with your times but the simple fact they have little sidewall is going to screw your times more !!

[locote]

I tested my 14s stockies to 17s and half a second difference in times with 2mph drop....
N/A 4cyl with fu#$ all torque but...

[CyberNetiC]

i went from 17" CV Pro Volks, lightweight as all fuck, to Koya Drift Teks.

the drift teks arent boat anchors, but they are heavier, and it is noticable.

[Sciflyer]

There can be a huge difference in weights between wheels of the same size too

eg on Wheelweights.net, the lightest 17x8s are around 6kg each, heaviest are ~15kg ea

So worse-case scenario you could be carrying an extra 36kg on your car

[bodybodyrock]

i think were talking about 2 difernt things here, i can see 2 difernt arguments, size and wight, larger rims will have a larger rolling diameter needing more tourqe to turn them at the same speed as a smaller wheel, smaller wheels turn faster with same amount of torque faster turning wheels give better skids :) or better times with traction... now weight, heavier rims will be harder to turn, but in saying that things like wheels and brakes are unsprung mass

and now ive confused myself im goin to get my books out and ill get back to u

[wadragracing]

Yeah its a complex deal hey. I'm talking about weights more as opposed to size. Like let's say you put on set of wheels that weighed 5kg more in total than previous, would you just get the 5kg weight penalty as if you put it anywhere on your car or would it have a x2 or x3 effect? *head explodes*
Phil, that link was great. Interesting that even the Supra rims are quite heavy.

[bodybodyrock]

yea basiacaly wheels are unsprung mass so that means yes if u put the car on a weigh bridge it would physicaly weigh more, however unsprung mass (wheels and brakes) dont have a direct afect on weight of the veicle in the scence that the more weight in the car the slower it goes, the suspension hold the sprung mass of the car, more sprung mass slows cars down

fuk this is getting deep hahaha

[S133LTR]

John at wheels world is a good one to talk to about this subject. Has experience with alot of a/m rims for exotics that use flash light weight materials, also i think he did a talk for prth wrx on this topic??

carbon crt ozzy prk, old speedworks

[Lonewolf]

big difference for me.
I've about 5mph and 1/2 a second down on 1/4 mile times with heavy wheels. Will be changing soon....

[cactus]

when i went from my 15's to 17's you could feel the acceleration loss instantly, and it was a huge difference....

[wadragracing]

http://www.mustangevolution.com/forum/t16705/

Ok from what I have gathered in reading around a bit more tonight...rotational mass increases the faster you get based on centrifugal force. Figures range anywhere from 5x to 10x. So for each kg extra on your wheel, it is the equivalent of carrying 5kg to 10kg in the car. This could be a pretty big deal! It also depend where the mass is, the further out from the centre of the wheel the mass is, the more of an impact it has.

[RICEY]

when i went from my 15's to 17's you could feel the acceleration loss instantly, and it was a huge difference....

Same here going from 17s to 19s

[bodybodyrock]

thats from roling diameter, the cars not actualy slower it just feels it coz it takes more power to turn the diameter of the larger wheel, u can counteract this by getting a higher diff ratio

[RICEY]

The car would be slower if it takes more power to turn the wheel, you been on the crackpipe?

[YOUR MATE]

It's not slower, it just FEELS slower coz it's GOING slower. Get it?

[RICEY]

Yeah that makes heaps of sense


Not.

[Brett_J]

It's not slower, it just FEELS slower coz it's GOING slower. Get it?


Crackpipes

Contributing to awesome logic since "02"


Brett

[YOUR MATE]

Erm, twas being sarcastic in regards to the post 2 prior to mine. Kinda lame when you have to explain it to people, no?

[Brett_J]

Erm, twas being sarcastic in regards to the post 2 prior to mine. Kinda lame when you have to explain it to people, no?

In my defence you can't see the previous post on this page.:D


Brett

[bodybodyrock]

The car would be slower if it takes more power to turn the wheel, you been on the crackpipe?

no but im sure u are

if the car is slower from using more power i might put 13"s on my car n gain 50 hp :shake:

[RICEY]

no but im sure u are

if the car is slower from using more power i might put 13"s on my car n gain 50 hp :shake:

You didnt do high school did you...

[cactus]

also went from 3.7s to 4.11s and still feels a lot slower.

[bodybodyrock]

bigger rims reduces tourqe at the wheels so off the line car will feel slower as car has a tourqe loss at the rims from turning the larger diameter, so in a drag point of veiw depending on how the car is geared depends on wat size rims would best suit the gearing, street car ull just be slower off the line

u go to school either?, looks like were in the same boat:lol:

[Joe]

My 18's are heavier than my stock 17's, but not massively heavier....I don't really notice too much difference when going back to the 17's.

My car has a fair amount of torque though, which I think would assist in compensating for the extra wheel weight.

[bodybodyrock]

and ull probly notice the profile of the tyre on the 18s is lower, so the rolling diamelter of the 18's is probly almost identical to the 17's with a larger profile tyre, but yea the tourqe of the car would make it almost un noticalbe

[Lonewolf]

exactly, cars with minimal torque (such as mine) notice a greater difference than cars that push out 300nm+

[RICEY]

bigger rims reduces tourqe at the wheels so off the line car will feel slower as car has a tourqe loss at the rims from turning the larger diameter, so in a drag point of veiw depending on how the car is geared depends on wat size rims would best suit the gearing, street car ull just be slower off the line

u go to school either?, looks like were in the same boat:lol:

Hardly, Im saying larger rims will slow a car down unless they are lighter than the rims originally on the car. You said it wouldnt slow the car down.

[cplagz]

front runners + steelies ftw.

[Don]

Yes, agreed, the wheel weights can make a huge difference to the car.

Last week I used (for a few days) my old Chromies that I used to run on my R33, while I was in the process of changing rims and tyres. It made a BIG difference to the way the car drove and it felt like I lost 30-40hp. I don't know the actual physics on IF it was slower or not, but I know it felt BAD!!!

Estimated weight on the Chromies is probably 10+kg's each, the 17" Forged BBS Rims weigh 8.1kg's each and the 18" Advan Cast Rims weigh 7.9kg's each.

I didn't notice any difference when the Chromies were on my R33 and later on my 350Z compared to the Stock rims, but noticed it majorly on the Evo. You can even tell the difference between the BBS Rims and the Advan's.

[Mister Two]

I went from BBS 17x7 Forged rims weighing 7.4Kg each to another set of 17x7 with the same profile tyre. The new 17s weigh 9.6Kg.

Made a substantial difference. Acceleration off the line was a little slower. But I felt even more difference in the corners. Steering felt a little sluggish, had less feedback.

[Drift_R32]

20s will cause your diff gears to be taller and accelerate slower-spoke to mitch about this one when i went down he suggested 16s or 18s would be a lot better

i ran 15s and i could feel the difference once i put the 20s back on the rears.

run 15s or 16s with slicks on the rears the drags..on the street how much of a difference is having 20kg less of rims when you have a 50 to 80kg person in the car.

[radddavey]

its not so much the extra mass that slows you down but the moment of inertia. A larger rim weighing the same as a smaller one will have a moment of inertia further from the centre of the wheel so will require more energy to get it spinning, it will also therefor have more momentum and be more difficult to slow down.

[gazza750]

wheels equate to 1kg static weight =4 kg rolling weight
in other words a wheel weighing 8 kg equals 32 kg rolling weight 10 kg rim = 40 kg
so 4 wheels on road equates to an extra 32 kg in weight to get down the 1/4 etc so effectively making the car slower

[Smoked]

VN calais, v6 with the usual mods nothing special..= 15.7 with pursuities 16.1 with 18's

[Halle Terry]

would the traction i gain via 18x10's at the rear be more adventageous over stock 16x8's, or is the added rolling diamater and weight going to slow me down on a 1/4 mile

[SimonR32]

wheels equate to 1kg static weight =4 kg rolling weight
in other words a wheel weighing 8 kg equals 32 kg rolling weight 10 kg rim = 40 kg
so 4 wheels on road equates to an extra 32 kg in weight to get down the 1/4 etc so effectively making the car slower


care to tell how u worked that out?!?

[DCIEVE]

lol im interested also

wheel weight will affect acceleration, the greater the inertia the more 'work' requried to accelerate it. Ignoring the effect on final drive ratio's, the inertia of a wheel is the square of its radius, so a larger wheel needs to be lighter to maintain the MOI of the smaller wheel and hence not affect acceleration.

End of the day smaller lighter wheels will require less power (torque) to get up to speed, and also less to slow down.

[gazza750]

care to tell how u worked that out?!?
i found it on a site a couple years ago but cant remember what site

[SimonR32]

i found it on a site a couple years ago but cant remember what site


oooo teh internet, must be true haha :hahano:

[DCIEVE]

might add, every % increase in wheel mass for a given diameter will require an equal % increase in the torque required to turn that individual wheel....on the other hand for each % increase in diameter for a given weight, the torque required to drive that wheel increases by that %^2