I'm looking to swap out the 15" stock rims on my 09 MC but I'm concerned about the weights of the aftermarket rims.. I have to say that I haven't had this much fun driving a car in a very long time and have had 3 series, p-cars, GTI's, nothing compares to the dynamic of the MC and i'm in stock form (non-turbo)..
Most of the rims I'm liking so far in 16 and 17" fashion seem to weigh over 20Lbs.. I'm sure the stock 15" rims are a lot lighter. What difference will I feel if I use a rim that is that much heavier? I also like the ride of the 15" in terms of comfort so I'm little concerned going to the 17" in a 45 sidewall. I think the 16" with a 50 sidewall will be my best compromise.. what do you guys think about the weight issue?

 

Longer braking distances, slightly slower acceleration.

Alex

 

Alex's post says it best, heavy wheels are a non starter.

I read somewhere that going from a 12 lb. wheel to a 20 lb. wheel would be like hauling around an extra 200 plus pounds.

I have no idea if it's correct but the phrase "less is more" defiantly applies here.

Go here: http://www.mini2.com/forum/faq.php?f...heel_tire_tech to see the weight of stock wheels and tires.

Hope this helps...

 

awesome. thanks for the posts

 

Also, the steering will feel heavier, since they are larger 'gyroscopes' you are trying to counter.

 

There are 16" wheels that only weigh 14 lbs. such as the Rota Slipstream 16x7 wheels. The 7" width allows 205 or 215 tread widths.

 

I've got 16x6.5" wheels for use on the track, they weigh 11.5lbs vs the standard 21.5lbs. I can't say I notice any difference that the weight makes.

 

That is what I have always assumed. People get caught up in super light weight wheels. I imagine a light weight setup may stop the car several feet sooner but who is going to be able to notice that... If you were competing at the very top level of autocross then is probably a good thing to have but other than that I am sure its all hype.

 

In theory, a lighter wheel will also give a smoother ride. When the wheel is forced upward by a bump, the lighter wheel will have less inertia and transfer less force to the suspension. The suspension would be more successful keeping the wheel on the ground -- improving handling on rough corners.

I can't say to what extent this is noticeable because I switched both tires and wheels at the same time. The ride improved considerably, but some of that was due to switching from runflat to non-runflat.

 

Go to Miata.net and seach wheel weight effects. These cars are excelent examples, because they wern't blessed with tons of power.

Alex

 

I'll agree on the wheel question. While I don't own a MINI some years ago I purchased some nice 18s for my (former) F150. Man, they looked great! I took the truck and race car to one race in CO and when I came home immediately took them off and sold them for a loss. The change in gearing, braking and acceleration were soooo obvious it was stupid. Oddly I had saved the stock 16s and weighed them before the second switch. Don't recall the number but the 18s were foolishly heavier. Lesson learned.

That being said this is part of the argument made on big brakes also. The same principal of rotational mass applies including the gyro effect. A MINI has about as much use for a 17lb 13 x 1.25" rotor as my F150 did a cool set of wheels....

 

You will notice the difference on the Cooper. The 15's combined with the tires weigh around 28lbs each which make the MINI much more tossable. The heavier wheels with wider tires feels more attached to the pavement IMO. My current wheels for example weigh 26lbs and combined with the tires run 56lbs a corner.

 

Something's not right. 30 lb tires? What type and size?

 

Hopefully not 30 lbs.

Most 205/45-17 (even runflats) are about 21-22 lbs each.

If you do street driving and drive sanely at the speed limit most of the time, brake and accelerate smoothly, then you can run a range of wheel weights and do fine. You'll be a little slower with wheels that are 25 lbs each or more.

Generally you will do fine in anything about 16 to 20 lbs each which are the bulk of wheel weights for the MINI. You usually will pay more for wheels that weigh less especially in any sizes larger than 16".

16" is a good size for looks and reasonable weight and gives good sizes of tires for the MINI.

Consider tire weight in addition to wheel weight when calculating the effect on performance. 18" wheels usually require short and stiff sidewall which results in more weight to the outer diameter of the rotating wheel/tire combo. You can get better handling but a stiffer ride and more risk to damage to the larger rim.

Lighter wheels as mentioned help with-
Faster acceleration
Quicker braking
Better handling

Brake upgrades can limit fitment of some wheels. Plan ahead.

 

The tires are Primewell PZ900 225/40/18 and I just weighed them again and the scale says 53 lbs so give or take a few but nothings wrong considering they were 90 bucks each with a 420 wear rating and directional tread.

 

225/40-18 are taller than stock tire diameter at about 25.1"
Do you rub under load (rear passengers)?
215/35-18 a more common size.

Stock tire diameter is about 24.3".

Michelin Pilot sport PS2 in the same size weigh about 21 lbs each.
Bridgestone RE960AS all season tires about 24 lbs each.

 

there are several lightweight 17s out there, they range from an arm to arm a leg and a kidney. (ie: Kosei, OZ, Enkei) But keep your 15s for winter.

BTW I was out there in Newburg for a while (totaled my MCS near Middletown) and ran into a MINI club check them out:http://www.hudsonvalleymini.com/blog/

 

On my Charger SRT8 I run 17" rims instead of the stock 20" rims when drag racing due to better gearing and lighter weight. It is worth about .25 seconds in the quarter mile (12.20 vs. 11.95).

I've read all sorts of things about reduction of wheel and tire weight (unsprung weight) being worth 4, 8, 10 or even 20x the weight reduction of the vehicle itself. I'm not sure about braking or handling but when it comes to actual acceleration if you remove the gearing difference it is really more of a 1:1 relationship. If you remove 20 lbs. you remove 20 lbs., period. Your car doesn't suddenly become 200 or 400 lbs. lighter and accelerate accordingly.

Again the difference in acceleration is the gearing (from a smaller diameter tire) not the weight.

 

Umm, I don't think so. When you're spinning something, it's about the rotational moment of inertia. It depends on the distance away from the center of rotation AND the mass. Reducing the overall diameter is one way of reducing the moment of inertia but you can also keep the diameter the same and just reduce the weight.

 

O.T.
You need one of my rear drag kits...then you could run 15" slicks on it.

 

I've seen these thanks. I hook fine so don't need the extra sidewall height.

 

Reducing the overall diameter of the tire changes your effective gear ratio. When I run a 25.5" tall tire (17" rims) vs. 28" tall tires (stock 20" rims) with a 3.08 gear it is like running a 3.23 gear ratio. This improves acceleration regardless of the weight of the wheel/tire combo.

With a smaller diameter tire you get more revolutions of the wheel/tire combo per the same number of engine revolutions (rpms). More tire revs per the same number of engine revs improves acceleration as long as you have traction.

I'm sure inertia plays a role too with lighter weight wheels but I don't think the tire diameter as related to gearing should be ignored (I think it is more significant to acceleration than wheel/tire weight in general).

I read a good article on this in a magazine not too long ago where they dropped 100 lbs in wheel/tire weight and only gained a 1/10th of a second in the quarter mile. It is a general drag racing rule of thumb that 100 lbs of weight reduction (in general) yields 1/10th of a second gain in the quarter mile. Based on the results of their test it appeared that removing weight specifically from the wheels/tire vs. anywhere else on the car made no difference (if you keep the overall tire diameter the same).

 

I currently have the 17" Flame spoke wheels..

which are about 25lbs for the rims

how would I be going to an 18" OZ ultraleggerra?

the rims weighs ~18lbs but obviously the rotational inertia is further out

would it negate the performance benefit? or would it still be worth while?

if i could have the same performance level i'd be content as well...

 

I think the position from the center point being further would take a bit more energy than lighter wheels, at the same diameter. I think the feeling of loosing 7lbs a corner would still be noticeable, in braking and accelerating.

Alex

 

I went to the 1/4 mile track with my 19's and my best run from the night was a 16.6. I got my new rims which are a 16x7 and my first run was a 15.7, my best run which I only ran twice was a 15.6. My 19's weighed 45 pounds and my new ones weighed 35, so i could feel a huge difference. just a personal experience.,