I Just bought a 2003 mini cooper s. It came with the factory 17" s lites and riken raptor tires size 205/45/17.

My wife didn't like the way it drove, so I found a good deal on a set of new Spoolers and mounted some 185/65/15 kuhmo tires on them.

I was hoping the 15's would bring a smoother ride, better acceleration, and much better mpg.

Are there any technical people that can let me know the differences these wheels will bring to my Mini?

Side note, I am frugal, gas mileage is more important than performance.

I need help deciding which wheel an tire combo to keep.

Thanks!

 

A narrower tire should lower fuel consumption due to less surface area (wind resistance), although on a car this low I doubt it would be noticeable. The two are almost exactly the same diameter, so that won't affect mileage or acceleration. But a lighter overall weight will improve acceleration and handling. In summation, I don't think the new setup will be any more economical in terms of fuel consumption, but it WILL be cheaper to replace the tires.

 

The lightee rims will make it feel like a different car....
going from 16's to 15's, was a huge change.(snow tires)..bet 17 to 15 will be amazing.
car will feel more playful....removing the heavy slites will make it turn better, acclerate faster, etc.
Not sure about the size...compare it to the stock cooper 15's....they are pretty narrow to maximize the coopers mpg, and accleration..
Imo the 17 is just to heavy and wide for a non s car. Then again, i feel anything bigger than the stock 195/55r16 on an s is for looks unless you buy lightweight 2 or 3 piece $$ rims...
On an s, 15'should work if the brakes are not the red jcw ones....test fit them.
Many debates, but don't be frugal on octane requirements....valves/heads+pistons are $$ on a s, and it NEEDS the octane with the sc.
there are various web calculators where you can calculate the spedo error...
just make sure the load range on the tires a correct...most 15's are not made for a heavy car like a mini.....

 

Ps...on a 10 year old car, it may be due for struts/shocks....oems usually get less comfortable gradually.....as opposed to leaking or suddenly failing.

 

I run premium gas, I am not cheap on that end. But gas mileage is important. Or I should say getting the maximum mileage out of whatever car I own. The 15's fit perfectly. And I do think the car feels more playful.
But I love the way the 17's look.

I will post pictures of both setups when I get home.

 

picture are loaded and can be viewed in my gallery. not sure how to upload to this thread.

if you can let me know what wheels you like better and the reasons why.

thanks!

 

I did some quick calculations.

s-lites with tires weigh in at 46.1 pounds

spoolers with tires weigh in at 31.7 pounds, but are .25 inches taller of a tire. than the 205/45/17 and .5 inches taller than the stock 15" tire size of 175/65/15.

will saving 14.4 pounds per corner be extremely noticeable in normal driving conditions?

will it net and fuel savings?

 

spoolers plus tires = 31.7 pounds

s-lites plus tires = 46.1 pounds

difference of 14.4 pounds per corner

what does this mean?

 

I'd be interested to hear more re: gas mileage or any other details of your driving experience.

I'm about to go in the other direction; changing my stock 15" R81 Holies ti 17" R85 S-Lites. Mostly becasue I prefer the look of the S-lites.

If it makes the car considerably less playful, then i guess I can get rid of the little wicker basket that holds my wallet, phone and such to keep them flying off the passengers seat!

 

S-Lites are so heavy, you couldn't pay me to put them on my car. The loss of 14lbs per corner explains why it feels more responsive and playful. I imagine it will help with mileage a little if you do a lot of city driving: less energy required to get rolling from every stop, etc.

 

bebates: 14# per corner less means about 56# less total weight. That's a big weight savings; and it's also in the unsprung rotating mass category, so you should easily feel the difference in performance. Some say it would be like losing as much as 4 times 56# in sprung non-rotating mass. Whatever the exact equivalency is, I thought I could feel the difference when I saved only 6# per corner, so I assume that a 14# per corner savings could easily be felt in performance.

Mynewt: Your plan to go the opposite way would probably result in a similar weight gain instead of a loss. The extra unsprung rotating mass should be particularly burdensome for your MC, so I'm pretty sure you'd notice a loss in performance under acceleration and braking. For a compromise, you might consider lightweight aftermarket 16" wheels.

 

Not sure which kumho tires you got, but in general, most performance tires are only ok in rolling resistance...GENERAL TIRE (now owned by contintial) has a few lower rolling resistance pergormance tire....the narrower, lower rolling resistance tire should save you quite a bit...but it is possible to get lower rolling resstance performance tires....but since widrg is a factor...and weight...narrower, and better rolling is a win win...loss in handling, but compermise.

On my 15 winters, i kept the width....so it is possible to do both...matain traction with width, and get a lighter tire rim combo...and then look for lower rolling resistance....

 

I am nearing the end of the first full tank with the 15's. I was at 26.1 earlier today, but then I let a friend of mine take it for a joyride. Now it reads 25.8. I don't know how accurate the computer is. I will hand calculate it when I fill it up. I have 220 miles on it and it says I have 130 left.

My first tank with the 17's for the first half and 15's for the second have the computer read 24. I didn't hand calculate it because I had reset the trip 3 times and couldn't remember the odometer reading on the last fill up.

I do a lot of city driving, so there are lots of variables here.

 

Also the computer/ecu adapts a bit...so it may take a few tanks of fuel to adjust..not saying, much, but slightly different weight/size/rolling resistance may change fuel/tq requirements. A 30 average is about what you need...the trip computer is usually optimistic by a few %.

 

bebates: Since you're just comparing the mpg of different setups on your car, you can just go by what the optimistic car computer reads, re-setting at the start and end of each run.

The tougher part is to try to insure that your mpg test runs are over the same route, at the same average speed (measurable by computer) and throttle load (not measurable, so you'll have to try to keep it steady).

 

So, even though i ended up buying a set of S-Lites off this forum, I decided not to use them. (They do have the centercaps I need and the whole wheelset cost little more than a set of caps off ebay).

Instead, i stuck with my 15" R81 Imola Holies and went with a wider tread. I went all the way up to a 205/55/15 Toyo Proxes4 which added 4.3 pounds per wheel over the stock Conti 175/65's. Between the added weight and the increased contact patch, the handling of the car has definitely been dumbed down. It's nice and stable at speed and in corners, just a bit more numb. (They are V rated)

I'm thinking of taking advantage of Town Fair Tire's 30-day satisfaction guarnetee and replacing them with a set of stock 175's.

I can only imagine what it would have been like to add 14 pounds per corner with the S-Lites, plus the bigger contact patch. I would have been miserable.


FWIW, my OBC under reports my mileage by about 1.5mpg. I always get better milage than the car tell me when I calculate it at the pump.