X-Lite wheels = More Horsepower ?

[kshapiro]

Reading a current ad from Centerline Wheels. It says that in a Honda Accord, shaving off 11 pounds per wheel "you can physically feel a 6HP increase in power." And by shaving off 8 pounds per wheel, it amounts to 4HP.

So, if you keep those 16" X-Lites on your "S" instead of going to the 17" S-Spokes, it's like getting more ponies? With theoretically equal drivers an X-Lite equipped car will beat an S-Spoke equipped car?

Watcha think?

[groovy_jr]

no idea! Possible...need to test it...but even then two drivers drive differently!

[ELISEBOY]

may be quicker in a straight line but many variables will be taken into affect

cornering for one would be different with the 2 sizes of tyre

[noahe]

Anytime you reduce wheel weight, the car can accelerate faster, there is less inertia to bring up to speed. So there is definately an effect. Further, any reduction in unsprung weight makes the suspension more responsive, so it will handle better. On rough roads, a lighter wheel will track better so you can accelerate or brake better on undulating surfaces.

But, this is just the theory. The effect a minute difference in wheel weight will have is best measured by computers, not drivers. Do you really notice your car is faster empty, than with the groceries in it? Is it that much of a difference?

Secondly, a lower aspect ratio (the tires that look like they're painted on the 17" wheels) will provide better cornering response, and a much better slalom feel. The sidewall dosen't flex as much on a low profile tire. But this also means the wheel must be stronger (usually heavier too) to cope with the added stresses.

Racing cars are always trying to strike a balance between the two, so should you:

A runflat is heavier than a regular tire, but with the MINI, factor in the fact that the spare is eliminated.

A runflat has very stiff, resilient side walls, so they corner crisply. They also have a more harsh ride.

The lower aspect ratio the tire, the harsher the ride.

I'm getting the 17" wheels, but that's as much a part of them being in the sport package as anything else. Plus, I like the way they look.

On our previous cars, I never noticed much of a difference in FEEL between the heavy steel rims with winter tires, and the summer rubber on alloys. But if you need pure performance numbers, I can't give you any.

[Garfield]

Another thought is that each pound of unsprung weight is equal to 6 lbs of sprung weight (essentially everything above the suspension). So, drop 7 lbs./wheel and it's like loosing 42lbs.X 4 = 168lbs of sprung weight.

Another consideration is also where the weight exists on the wheel. A high end light weight wheel (3 piece) has the the majority of it's weight on the hub pad (inside center of the wheel.
On the other hand, a cast wheel, such as the 17's on the MINI has heavy weight AND it's spread to the outside.
The point being that a 26lb 3 piece will actually outperform a 26lb cast wheel because of where the rotational mass exists.

I've raced a Miata for several years and can tell you that unsprung weight is significant in every realm of performance: braking, acceleration, and handling.

Now, to what point would "I" change the weight? I think if I had to spend a significant amount of money on new wheels for the purpose of weight savings, I'd like to loose at least 5lbs/corner.

This said, what am "I" getting? You can bet I'm starting with the lightest Cooper S wheel, the V-Spoke/X-lite. At 17lbs, they're also lighter than the "Daytona" five spoke. I'll even tell you that I think the V-Spoke IS the ugliest, but I'm still getting that. I may be replacing them with a better looking, but at least the same weight or lighter, aftermarket.

One more thing, tire weights vary greatly as well. The Toyo T1-S is a lightweight tire, the Falkens, Kumhos, and especially Run-Flats are NOT.
In DOT R Compounds (race tires) 205/50R15, the Kumho Victoracer weighs 22lbs, the Hoosier A3S03 weighs 16lbs!

Do the math I mentioned at the top of this post and you can see how far this goes. It sounds unbeleivable, but a 17" MINI with run-flats will be gestimated at 50lbs or more. A lightweight (albeit expensive) aftermarket 16" wheel with a Hoosier race tire will weigh approximately 36lbs. 14lbs/corner...14x6=84...84 x 4 corners = 336lbs of sprung weight!?!

Exact science, probably not, but it's close enough for me.

[noahe]

But if you don't race your MINI against the clock or other people, and you aren't a race car driver yourself, would there be a noticeable difference to the untrained driver, if they say took both cars out for a test drive, one after another?

Not that I care a whole lot... I like the look of the 17" wheels I'm getting, and they come with the sport pack, so I'm happy. The car wil still be more peppy than the Integra was, and it was pretty fun.

[Garfield]

If you have to keep it to test driving MINIs here's what I think:
In the handling department, I feel that a Cooper with the 7 hole 15" wheels will definitely feel more tossible and responsive than a Cooper with 17" run-flats (non-US).

Also, if the driver drives the Cooper/Cooper S with 17's and then drives the competition that, for the sake of arguments, has smaller lightweight wheels and tires, the same will apply.

Now, if the driver test drives a Cooper S with 16's and then 17's, it probably won't be much different to the average driver.

I guess what I'm implying is that, giving the assumption of people going to buy aftermarket wheels, buy something lighter in weight than the standard 17's, they're very heavy.
There are other factors that apply in the long run to overweight wheels that we won't get into such as wear and tear on brakes, suspension, and tires.

You've made a good point though, the average driver who doesn't flog their car everyday through every turn will not care, most don't. But, the performance enthusiast should seriously consider these factors.

[noahe]

I am concerned for the safety of my 17" rims. I have never owned a car with such a low aspect. I think the lowest aspect I have ever owned was a 195/65R 14" on an Integra.

Since the stock 17" rims on the MINI are clearly inferior for racing or enthusiast type, is there ANY benefit to the added weight for someone like me: I drive the car mostly in the city, to the cottage every weekend in the summer (2 hours each way) and I'll never race it. I WILL hit the occasional pot hole. I do not PLAN on hitting a curb, but these things could happen.

Is the 17" heavy because it is strong? Since there is only a tiny bit of rubber and air between the rim and the road, will these stock rims resist on-road damage a little better than an ultra light weight rim?

In the winter, I plan to have 15" alloys or steel fitted, with winter rubber. I'd rather slide a cheapo rim into something than the nice one. I also believe a narrower tire will help with traction, and the taller aspect ratio is desireable when the tire is traveling through snow laced with abrasives such as road salt and sand.

Hey, with DSC, maybe I'll never lose it in winter!

At any rate, my current factory wheels are perfect. No scuffs, dings, cracks, etc... So I'm not purposely hard on them. I want to know if I can rely on a 17" factory rim holding up as well.

[Garfield]

Without necessarily talking you out of the 17's, NO the 17's are NOT strong. Any "Cast" wheel is the weakest in make of aluminum wheels.

For the purpose you are using the car, no, I would not get 17's, except for the looks.