I heard that you compromise the ride and handling w/ bigger tires? but you gain less miles on your odometer because the factory has it set at 16 inches and if you move to 18's then you have 16/18 ratio. So like 7/8 of every mile is recorded?? Is there any truth to this at all?
Do you lose gas mileage or speed w/ bigger tires?
What is the best compromise..as far as size goes? I really want 18's but if it's only going to look great but hurt every other aspect I may not.
thanks in advance....

 

You are confusing wheels and tires. 15", 16", 17", 18" refer to the diameter of the steel or alloy wheels. The diameter of the rubber tire is a separate matter and it is what the odometer and speedometer are calibrated to. Typically a certain model of car would specify a standard tire diameter, then as an option you can choose the size of the wheel to go with it.

Changing to larger wheels while keeping the same tire diameter means reducing the tire's sidewalls. This means stiffer sidewalls, which improves handling but provides less cushioning, thus a rougher ride and less ability to absorb severe impacts that may damage the tire.

 

upsilon23,

What are you planning to use the wheels for primarily? Street use, track, autocross, driving events, or auto shows?

If mostly street use and not really much else then you'd want rims and tires that fit your MINI and it's suspension without the tires rubbing against the fender wells and a somewhat comfortable and not too noisy ride that gives decent cornering and performance.

Your MINI is designed with a certain limit to the outer tire diameter which fits. It's roughly 24.4" to 25" depending on your suspension. Once you lower your MINI with aftermarket parts like springs then you have to be more careful how large the tires are.

Rims that are smaller about 15" or 16" allow you to run tires that have a higher side wall, usually 50 or 55 series tires that are less stiff and more comfortable yet allow for decent street performance.

Rims that are larger such as 17" will usually fit tires that have lower profile side walls, usually 40 or 45 series which are rougher riding on the street but better for handling. They also tend to wear out faster and be slightly heavier.

Rims that are 18" often allow for 35 series tires, not as comfortable for street use, looks good with low profile, tends to cost more and there is less selection of tires to choose from.

From a comfort standpoint the 16" wheels are good. 17" wheels with 45 series tires such as the stock sized 205/45-17 or wider 215/45-17 usually work fine.

Go to a MINI club event in your area and check out the MINIs with aftermarket wheels. Ask what suspension they have and go for a ride and see what you think.

Also talk to alex@tirerack to get some idea on the cost of aftermarket rims and tires. Go check out tirerack.com or edgeracing.com

 

just street, no racing but I do want to push it a bit. I really like 18's, w/ 35mm tires do I need anything changed to accomadate these rims/tires? so no loss of handling or speed right w/ larger overall wheels?

 

I'm running 205/40-18 on my Centerlines. Just a little more sidewall than the 215/35's. Overall diameter is 24.3". Stock 17's are 24.5". My car is lowered with H-sport springs and I have no rubbing.

Sent you a PM.

 

upsilon23,
If you like 18" rims then look for 18x7 or 18x7.5" rims
35 isn't mm but is the side profile or series- very low and stiff.

Tire size can be 215/35-18 or as mentioned 205/40-18 (more narrow and comfortable).

The selection of tires is larger in the commonly used 215/35-18 size.
Yokohama Parada Spec 2 (see Alex@tirerack)
Toyo Proxes 4
Hankook Ventus Rs2 Z212 (performance tire for the street- affordable and lightweight) http://www.edgeracing.com/tires/2153518/

 

There is some loss in preformance and handling due to the heavier tires and wheels in the 18" size. To minimize buy the lightest wheel that you can afford, if preformance is not a concern then buy what looks good to you.

This has been discussed many times here or in MINI2.com. A quick summary.
Larger diameter rims push the weight further towards the outer circumference, increasing the "flywheel" effect, regardless of overall weight. Larger rims generally weight more. 18" tires generally weight more. Heavier rims & tires; 1. accelerate slower, 2. lenghten your stopping distances, 3. are less compliant over rough roads(tire is not in contact with road as much), 4. ride rougher becasue of the shorter sidewalls inability to adsorb impacts, 5. slow down the "turn-in" and transition thru a series of corners. 17" & 18" rims are more suseptable to damage from potholes, see reason #4 above.

 

The ideal size is 17, it will not sacrifise from comfort and give you optimum handling. 18s look great however you will have to spend extra attention on the road watching every single holes and trust me it will get you at the most unexpected.

i spend a lot of time thinking of upgrading to 18s, but at the end made a wise desicion with satying on 17" shoes.

you are on 16s, so believe me it is going to make a huge diffence when you go upto 17s.

good luck.

 

35 series tires, as someone else pointed out-- you'll want to be very careful about hitting pot holes or other obstacles. You need to run pretty high pressures in a 35, or even a 40, to gain some protection for the wheels themselves. And then the ride is much harder. 17 inch with 45's are a great compromise, I run 17's and 40s and they work fine also but ride harder than 45s. I am more paranoid about hitting holes...

Also, don't go more than 3-6% larger or smaller than the stock tire diameter so you stay within the ABS design specs.

This is a handy tool: http://www.miata.net/garage/tirecalcold.html