the effects of big wheels

[Dinan3]

Since the diameter of my 18" rim w/ tire is obviously bigger than my stock one, how will it effect my car overall? (speedometer, acceleration, etc)

my stock steelies w/ tire - 35lbs

my 18" acs type 3 w/ tire - 44lbs

Thanks,
-Tim

[Beamin']

More outside inertial/ mass to over come,BUT beter gas MPG( whelll on highway, but worse on city), but a slower car.

[NeverLeaned]

better turn in grip do to the small sidewall flex, but generally harsher ride.

[Beamin']

better turn in grip do to the small sidewall flex, but generally harsher ride.

17" are best. I have 18" they slow my car down.

And if you are worried about side wall flex get Michelin Pilots. Run you close to a grand ($1000)for a set, but they are the most kick ass tires. Problem is they only last 10-20k Whelll if you drive like I.)

[STEVE36]

I'm getting 18s - against what I always thought I'd do but I can't resist these wheels. I'll have to perk up my engine a little (intake instead of my debaffle and software) to compensate .

Steve

[NeverLeaned]

I had the same problem with mine, I got the replica M-Parrarells. I wish they made em in 17s but, I just love em to much to let an extra inch disuede me

[dz223]

While it is true that heavier wheels slow your car down, bigger and heavier does not always mean slower. It depends on where the weight was added. If you had 18s with light ass tires vs 15s with heavier tires but the 15s were lighter overall, Id say the 18s might actually make your car faster, might. The point of the story is the weight differences only really matter on the outside of the rim and mainly in the tire.

[MJFX328]

So whats a good lightweight tire?

I dont usually see tire weights listed.

[STEVE36]

What is the average weight of an 18 inch wheel. Non-ltw.

[dz223]

So whats a good lightweight tire?

I dont usually see tire weights listed.

yea most tire companys dont list the weight of the tire but the information is avaiable. Try the companies websites.

[LinearX]

Your wheel bearings will wear out a little more quickly. On certain vehicles this is a much bigger problem, such as on trucks/suvs. 22" spinnaz just DESTROY the bearings on them.

[Dinan3]

I'm running on steelies right now for winter, and i feel my car accelerates faster.


So with my 18s, i would assume that my actual speed is faster than what my speedometer indicates, can someone correct me if im wrong.

[themadhatter]

less weight at the end of each axle will always be quicker then more weight. think of it as free horsepower for your car.

running heavier weight wheel/tire combos will:

kill your fuel economy
kill your acceleration
kill your handling - your suspension has to work harder
kill your suspension - it'll wear out faster
kill your braking distance
kill your brake hardware - wears it out quicker
kill your wallet - more expensive


the average weight of an 18" wheel is around 26lbs for a descent wheel. many replica or cheapo wheels weigh in at 28-35lbs per wheel.

I've switched from 18's back to 17's and noticed a dramatic improvement in my car's dynamics.

the same thoughts above apply to big brake kits (BBK). Getting a massive brake rotor for a bbk (some weigh as much as 35lbs per rotor!) is going to kill your car's dynamics.

-Ron

[WildStorm]

less weight at the end of each axle will always be quicker then more weight. think of it as free horsepower for your car.

running heavier weight wheel/tire combos will:

kill your fuel economy
kill your acceleration
kill your handling - your suspension has to work harder
kill your suspension - it'll wear out faster
kill your braking distance
kill your brake hardware - wears it out quicker
kill your wallet - more expensive


the average weight of an 18" wheel is around 26lbs for a descent wheel. many replica or cheapo wheels weigh in at 28-35lbs per wheel.

I've switched from 18's back to 17's and noticed a dramatic improvement in my car's dynamics.

the same thoughts above apply to big brake kits (BBK). Getting a massive brake rotor for a bbk (some weigh as much as 35lbs per rotor!) is going to kill your car's dynamics.

-Ron

Better listen to Ron he knows his stuff

[dmurray14]

Shit, guys, don't tell me this! I supposed to be getting some nice 18's soon. They weigh in at 26lbs each. How much is that going to slow me down over the stock 16 inchers? All these "kill your..." effect that you are talking about, how pronounced are they?

Thanks,
Dan

[themadhatter]

Shit, guys, don't tell me this! I supposed to be getting some nice 18's soon.

18's for bling. 17's for sting.

They weigh in at 26lbs each. How much is that going to slow me down over the stock 16 inchers?

allot. you'll lose to a comparably equipped car with similiar mods but with the factory size wheels.

All these "kill your..." effect that you are talking about, how pronounced are they?

night and day.

Thanks,
Dan

[beatniks325]

While it is true that heavier wheels slow your car down, bigger and heavier does not always mean slower. It depends on where the weight was added. If you had 18s with light ass tires vs 15s with heavier tires but the 15s were lighter overall, Id say the 18s might actually make your car faster, might. The point of the story is the weight differences only really matter on the outside of the rim and mainly in the tire.

hmmmmm, this quote just doesn't seem to jive with physics. It isn't just the weight of the larger 18 inch wheel that slows a car down but also the increased effort that is needed to start the larger wheel turning......

heck my 17 contours feel slower than the stock 15s, but i'd never trade back the added grip on the road.

[dapper83]

My 18s are only 19lb if not a little less. but yeah honestly 17s are the best option if you are looking for some good handling. Although you do gain a stiffer sidewall costs still out weigh the benefits when it comes to the handling of the car.

[dmurray14]

18's for bling. 17's for sting.



allot. you'll lose to a comparably equipped car with similiar mods but with the factory size wheels.



night and day.

Thanks for the reply, but I find this a tad bit hard to believe. You're telling me that a 1" difference in wheels is going to completely wreck havoc on my suspension? That doesn't seem to make sense. Similarly, I don't see how lightweight 18" that are the same if not lighter than stock wheels could make that big a difference in wear. Maybe I'm misinformed, but this just doesn't seem to make sense to me...

Dan

[Kos-motate139]

If you check the diameter difference between the old tires and new tires, you'll be able to see the % difference, and make a guess at how much your speedo will be off. My 16x8 race wheels with 245/45x16s at 24.4" tall are actually smaller in diameter yet still pretty close to the stock 15x7 205/60x15s (24.8" tall) so I don't worry about the speedo much in the unlikely case I'm driving race tires on the road.

The weight on the other hand is harder to measure, easiest thing might be to do some 0-60 runs, get the new wheels, then repeat to see how much slower you are.

[themadhatter]

Dan,

the heavier 18" wheel (not an SSR Comp or other lightweight wheel) is going to wear out your suspension earlier then a lighter 17" wheel will. also consider that an 18" tire will be heavier then a comparable 17" tire, this is a fact.

of course I can run out and buy 50# 17s but that's not the debate here.

how catastrophic are these changes? well for one, you're going to lose a race in terms of mechanics (not driver skill, that's a whole other idea). second, you're going to lose say 10,000 miles (or more) from the life of your bushings and other suspension components, your brakes will also suffer the same fate.

are you going to see the accelerated wear in 30,000 miles? probably not but it's something to keep in mind.

Are you going to see the performance effects as soon as you swap your wheels? YES.

-Ron

[1995red318i]

i think he was generalizing.

there are always exceptions, but those exceptions are always expensive too

[1995red318i]

apparently people replied before i posted

my post was addressed to dmurray, but it looks like madhatter gave a much more in depth explanation.

just use my post for cliff notes

[NegativeCambre]

17 is probably the right size for these cars... BMW sure thought so with the M3... but I'm a bigger fan of 16" wheels for the non-M's for a performance application. You can get short-sidewall tires in 16" no problem (I have two tires that I use on my car that I love recommending... the quintecential falken Azenis... and my favorite "budget performance" tire, the Falken ziex....). Not only are 16" wheels generally a tad cheaper and overall lighter, they can also have the nice side effect of lowering your cars gearing. 16" doesn't look very small when you have a low profile tire on it... some of you may disagree... but I'll still argue that it has performance benefits over larger diamater tires.

(Obviously this doesn't apply if you've gotten a bigger diameter brake setup... but for people who autocross especially, and this is generally not a really important point... this setup can be killer)

Steve

[TrunkImpaired]

changing the wheel size has no effect on your speedo and can have varying effects on gas mileage. If you keep the same OD of the tire then your speedo will not be off and your mileage change should be negligable.