Any Benefits To A Larger Size Rim & Low Profile Tire

[Nd4SpdSe]

I know its been said that for AutoX (and im guessing handling in general) to have 15" rims, or 16" max if you want better looks, cause you seems to need the sidewall flex, but is there a performance increase, in any aspect, going with a bigger rim/smaller tire? Or is it just for looks?

<small>[ April 21, 2004, 09:32 PM: Message edited by: Nd4SpdSe ]</small>

[thebox]

i was under the impression the only reason people say to use a 15" or 16" is because they are typically lighter, not because of sidewall. am i wrong?

[DavidOS]

larger rims do not improve ur performance infact they hurt it

15/16 inchs is the best for performance
above that you start feeling the road more, reason being it takes more energy to move the wheels one revolution, also once at certain speeds the larger wheels displaces the actual spped of the car, so your actually going faster then ur speedo says... bad for radar guns/cops.

17s look great though.

this is of course for our sport/performance cars.

cars like f1s, ferarris etc..etc... are made specifically for their tire sizes.

[monty73741]

well light depends on what type of wheel you but, i have lifted a set of enki's & a set of wheel maxs es & the enki's were lighter

[Nd4SpdSe]

Originally posted by DavidOS:
reason being it takes more energy to move the wheels one revolution, also once at certain speeds the larger wheels displaces the actual spped of the car, so your actually going faster then ur speedo says... bad for radar guns/cops.

but you can get 17"+ and keep the same wheel diameter, you just need a smaller tire, IE: Low Profile

I was just wondering if going with a lower profile tire/larger rim, is actually better for performance..

[Flashpoint2]

Having a bigger tire/wheel combo is a little bit of both, actually. It's better to have less sidewall flex, and, hence, less sidewall. Also, because you typically have a larger contact patch (195/15s are stock, 205 or 215/17s have a larger footprint), your stoppong distances, acceleration times, and cornering prowess are all improved.
Now, the downside is that many rims are cast, so they are heavier than stock. More unsprung weight slows you down. If you have lightweight rims (you can get rim/tires that weigh 15lbs per) that's a bonus. Your speedo is generally going to be off a little bit. The speedos are calibrated for stock, so even a small change in rolling diameter will throw it off. And you do feel the road more. It really depends on the driver if it's bad or good, because some people like to feel the road, and some dont. I do, personally, because I feel like I have a bit more control.
Anyway, I think that's the skinny.

[thebox]

Originally posted by DavidOS:
larger rims do not improve ur performance infact they hurt it

15/16 inchs is the best for performance
above that you start feeling the road more, reason being it takes more energy to move the wheels one revolution

this is entirely false unless you're talking only about heavy @$$ 17" or 18"... a lightweight wheel of larger size matched with a low-profile performance tire would sure as hell perform better than a typical 15" or 16"...
how many exotic cars (or race cars for that matter) do you see running around with small wheels?

<small>[ April 11, 2004, 03:42 AM: Message edited by: thebox ]</small>

[mazdubber]

this is entirely false unless you're talking only about heavy @$$ 17" or 18"... a lightweight wheel of larger size matched with a low-profile performance tire would sure as hell perform better than a typical 15" or 16"...
how many exotic cars (or race cars for that matter) do you see running around with small wheels?

It's true that there are some very nice lightweight 17's out there. But you have to factor in that the tires are going to weigh a lot for those. The less weight that's thrown around at the corners the better. Show me a 10 pound 17 and I'll eat my hat.

[curtklze]

oh good lord

tires and wheels need to be set up for a particular style of driving.

F1 cars dont use 19 inch low profile tires, they have very stiff suspension, they use a large sidewall tire to absorb bumps and to keep unsprung weight down.

Most spec racing series or grass roots racing uses a 14-16 inch rim with a tall sidwall tire (55-65 series).

Now on the street, MOST Ultra high performance tires only come in 17,18,19 inch sizes, so if you want the performance offered by the tires then you will have to buy larger rims.

but there are many high performance tires that you can get that are 15-16 inch, like the falcon azines, and kumho 712, ect.


it is VERY hard to "only add 1 inch" and maintain the weight of a rim. This is where that little C=PIr2 comes into play. there is ALOT more material in a 17 inch rim than a 16 inch rim.

Low profile tires (30,35,40,45 series) are heaver then regular tires, they have alot more stuff insid them to make them maintain there flat shape, the tires are basicly squares, it takes alot of stuff to make someithg that wants to be round into a square.

Un sprung weight (tires, rims, reake assemblies, wheel nuts, steering knuckles) will affect your handling, if you have alot of unspring weight, then there will be more inertia on each corner, the wheel assmbliy will be slow to react to changes in the road, it will just want to stay where it is, or if you hit a bump, it will want to keep moving up and the shocks will have to work extra hard to control the movement.

if you use a small light rim and a light tires, the wheel will fallow the road better and you wont loose contact as much in the corners, this will result in better cornering and shorter stoping distances, as well as better overall drivability.

on a street car with stock suspension, a set of 17's with good tires will increase your cornering grip. it will also make you feel every pebble in the road and you WILL dent your rims on pot-holes,

will 18's whith 30 series tires increase grip and cornering perfromance on a stock car? yes.

But just like carbon fiber, spoilers, air splitters, and every thing else that has been takin from racing, its all Mostly used for Bling Bling, and the street cars that use them wont use them corectly or gain the full performce that they can offer.

<small>[ April 13, 2004, 07:23 PM: Message edited by: curtklze ]</small>

[DavidOS]

the larger the wheel the slower the acceleration off the line is for our cars.

gs, has stock 15s i think and the rs(i have no idea)

but adding 2 inches etc..etc.. still decreases accel. You can only decrease your profile so far to reduce the overall increase. if Still haveing the car streetable and comfortable is more important go with what kurt said, 16s are a good balance.
17s you can feel alot of bumps and cost a fortune when you hit ur potholes

[Gro Harlem]

increasing the circumference 2" will decrease accel since it makes the gears taller. Buy just upsizing to a 17" rim and some 205/40 tires isn't going to mess with the gearing much. But most 17's are 10 lbs heavier than the stock 15's so you'll lose some accel b/c of that.

[jplar]

Originally posted by Flashpoint2:
The speedos are calibrated for stock, so even a small change in rolling diameter will throw it off.

Don't mean to ask an uninformed question, but can the speed be recalibrated for different rim/tire sizes?

[mazdubber]

tires and wheels need to be set up for a particular style of driving.

F1 cars dont use 19 inch low profile tires, they have very stiff suspension, they use a large sidewall tire to absorb bumps.

Most spec racing series or grass roots racing uses a 14-16 inch rim with a tall sidwall tire (55-65 series).

Now on the street, MOST Ultra high performance tires only come in 17,18,19 inch sizes, so if you want the performance offered by the tires then you will have to buy larger rims.

but there are many high performance tires that you can get that are 15-16 inch, like the falcon azines, and kumho 712, ect.


it is VERY hard to "only add 1 inch" and maintain the weight of a rim. This is where that little C=PIr2 comes into play. there is ALOT more material in a 17 inch rim than a 16 inch rim.

Low profile tires (30,35,40,45 series) are heaver then regular tires, they have alot more stuff insid them to make them maintain there flat shape, the tires are basicly squares, it takes alot of stuff to make someithg that wants to be round into a square.

Un sprung weight (tires, rims, reake assemblies, wheel nuts, steering knuckles) will affect your handling, if you have alot of unspring weight, then there will be more inertia on each corner, the wheel assmbliy will be slow to react to changes in the road, it will just want to stay where it is, or if you hit a bump, it will want to keep moving up and the shocks will have to work extra hard to control the movement.

if you use a small light rim and a light tires, the wheel will fallow the road better and you wont loose contact as much in the corners, this will result in better cornering and shorter stoping distances, as well as better overall drivability.

on a street car with stock suspension, a set of 17's with good tires will increase your cornering grip. it will also make you feel every pebble in the road and you WILL dent your rims on pot-holes,

If you have a REAL ($2000.00 +) performance suspension, a set of High perfromance 16 ich tires will be perfect, great handleing and low weight, absorbes bumps and rumble strips.


will 18's whith 30 series tires increase perfromance? yes.

But just like carbon fiber, spoilers, air splitters, and every thing else that has been takin from racing, its all Mostly used for Bling Bling, and the street cars that use them wont use them corectly or gain the full performce that they can offer.

[Steeb]

Originally posted by MX3-Freak:
So your saying you can make a 10lb 16, but not 17? Your only talking about an inch here... The most that a light alloy would add is 3-5lbs. And also, the larger the tire, the higher the top speed. The extra circumfrence of the wheel per revolution can add quite a bit of high end speed... like box said, have you ever seen a modern exoctic car come with 15" rims?

Oh yea, one last thing. You said the less weight you throw into a corner the better? Correct to an extent. However, take a 10 foot high car that wieghs 100 lbs, and put 70lbs of that weight in the top 5ft. Then take the same car, but switch the wieght. Which would you rather take a fast corner in? By adding wieght to the tires, you lower the center of gravity, thus improving conering, not degrading it.

oh yea??? exotics have larger wheels because they wouldnt be able to fit 15 inch wheels over 13-14 inch brakes. not to mention they also carry a great deal more weight than small cars with small wheels and small brakes, of course low hp. nobody is talking about weight distribution through out the car. the benefits of a lightweight rim is listed above. please dont listen to anything this guy posted.

whoever mentioned race cars, they choose wheels according to the size of brakes they are running. sure touring cars ran gigantic wheels but their brakes were probably the size of our wheels.

[MX3-Freak]

My post was deleted (by me) to anyone that cares...

<small>[ April 17, 2004, 07:49 PM: Message edited by: MX3-Freak ]</small>