I have a 2006 R50 with factory aluminum 15 x 5.5 7 spoke wheels with offset 45mm. I have gone through many tires over the years such as General, Continental, Bridgestone, etc. in the factory size of 175 65 15. Not too long ago I purchased a Miata with "the wrong look' aftermarket wheels. I sold them to purchase some very nice looking 16" OEM Miata wheels. I also sold the aftemarket wheels and tires to pay for the replacements. Before selling the wheel/tire set I tried them out on my R50 and was amazed at the improved cornering ability. It was transformed from an economy car to a slot car. I need opinions on what made the difference, was it tire brand or the tire size and proportions, or something else? The wheel/tire combo that performed very well was 195 50 15 Hankook Ventus V2 Concept 2 tires and what I deduced were probably Verde 15 x 7 V36 Protocol wheels with 40mm offset. I would like for my R50 to perform as well as t did with the temporary wheels/tires, and need to know if purchasing "the right" tire would accomplish this, or is it necessary to purchase a different size tire, and will that necessitate buying new wheels, too. Thank you in advance for any input.

 

Your experience sounds like a combination of multiple factors, wheel size, tire, size, and tire compound.

First, you went from a 5.5 inch wide wheel all the way up to a 7 inch wide wheel. That’s quite a bit more tire support. Then you went from a 175/65 tire up to a 195/50. Mount that tire on a 7 inch wide wheel and you get much more handling response. Your older tire was likely an economical compound based on the size, and the new one is a more performance oriented tire.

If you want to get that special handling experience again, you’re going to need a whole new set wheels and tires.

 

OK, lots of things going to to improve your handling and performance on your R50. Bottom line is that with MINIs you can rely on getting better handling and make the most out of available power by using the:

Right tire for your driving needs- I assume you daily drive, how much urban vs highway, how many miles do you drive per year, how cold is your weather/any snow?

The right wheel to fit the right tire of choice in the size that fits your OEM suspension with tire diameter of about 24.2". A perfect fit wheel for your tire size is key to best handling and performance.

When I am shopping for wheel tire combos or just better handling and performance the first thing I consider is what am I needing this tire for? Only you can answer that.

As for your OEM MINI wheels- there is nothing wrong with them but you are limited on tire sizes due to the 5.5" width. I run the same size wheel with 195/60-15 Bridgestone Ecopia EP422 plus Grand Touring All Season tires for daily mixed street driving in dry or wet weather less than 6000 miles/year. Works well even though I have a Cooper S with mods galore and have it setup for racing in Autocross Street Modified class. I just adjust the Bilstein PSS9 suspension to softer for street use and put on the basic wheel and all season tires. Handling and performance are not as good as with Max Summer tires on 17x7" rims which I also use for autocross or performance events but the basic tires work OK as long as you know their limits.

This all means that you can use your old wheels but need to find if the tire of your choice comes in sizes that are workable for 15" rims. The answer is maybe, but many of the better street tires these days do not come in sizes that will work. So pick the optimal tire and consider the sizes that fit your MINI then look at the range of wheel sizes that will work whether 16" or 17". No problems using widths of 7" just keep tire diameter near 24.2".

I have owned my MINI since 2003 and used 8+ different sets of wheels with it and they can all work OK, widest was 15x8" with tires in the 225 widths. A 15x5.5" wheel can take a 175mm wide tire but will also accept a 195mm wide tire if it is within fitment range.

For example
175/65-15 fits rims 5-6" wide, perfect for 5" wide rim, tire diam. 24" Load 84, H speed rated
195/60-15 fits rims 5.5"-7" wide, perfect for 6" wide rim, tire diam. 24.2" Load 88

When looking at tire sizes if you go wider than OEM with keeping tire diam. similar the load rating will go up which is fine. H speed rated is meant for basic family cars, higher speed ratings are for sporty or sports cars like V or W which is fine for a Cooper S but overkill for a base Cooper unless you are racing it.

So here is an example of a tire search based on size-
195/60-15 because it fits your current wheel OK
Performance Summer tire classes- not much to choose from, probably better to look at Grand Touring All Season tires first.
In Grand Touring All Season
Vredestein Hitrac All Season $116.20 each, 700 treadwear Gets good tirerack test results, slightly better handling and performance, good in wet
Yokohama Avid Ascend GT $114.03 each, 740 treadwear. Also good tirerack test results, slightly less good in snow. more comfortable for daily driving
Test results-
https://www.tirerack.com/tires/tests...y.jsp?ttid=274
Tirerack owner survey results for Grand Touring All Season tires in 195/60-15
https://www.tirerack.com/tires/surve...=true&filter=y

If you did go with 195/60-15 tires you can still move to 15x7" rims at any point that they will work giving you more usable tire tread contact patch. Note that a wide tire size on a narrow rim will give less tire tread patch grip since the tire is being pinched into a smaller width rim, still works but less grip. However a narrow rim gives less tire rolling resistance and slightly better mpg especially with higher tire pressures on the freeway.

You can also look at other tire sizes that fit and work, sometimes you will find other tires available.
Example from Vredestein Hitrac All Season-
185/65-16 fits rims 5-6.5" wide, perfect for 5.5" wide rim, tire diam. 24.4" Load 88 but it is on backorder and out of stock.

You mentioned a tire that you tried on the Miata 16" wheel- Hankook Ventus V2 Concept 2 (High Peformance All Season tire)
TIrerack owner survey ratings in 205/50-15 (doesn't really fit 15x5.5" wheel for a MINI on OEM suspension.
https://www.tirerack.com/tires/surve...=true&filter=y

For sake of argument an extreme example of going with more tire performance would be to use 205/50-15 tires in Extreme or Max Performance Summer tire class.
205/50-15 fits rims 5.5-7.5" wide, perfect for 6.5" wide rim, tire diam. 23.1" is a full inch smaller which increases wheel gap by 0.5" and drops ride clearance by 0.5" so center of gravity is lower and risk of scraping things is increased. I have used this tire size for racing and my MINI is lowered 1" so it fits and is good for handling and performance.
Now there are many tires that come in 205/50-15 but again this is a wide tire size for a 5.5" wide rim. Any Summer tire is going to wear faster and Max Summer tires are going to cost more, be less comfortable for daily driving and be more noisy. Some are firmer riding but steering and handling is usually more responsive. Everything is a trade off, no tire is perfect. Again, moving to a 15x7" rim will make this tire size work better.

A word about diameters and widths of rims. Larger wheels and wider wheels means more weight and more cost or weight will be much higher than a narrow 15" wheel. This is why I use OEM Cooper wheels for my daily driving, they are cheap, they are light weight, they fit the tire I can get cheap for daily driving and though not as good, they offer much better comfort for street use. 16 x7" is a good wheel size for an R50 , 17x7" is OK for modern tire sizes but wheels tend to be heavy. To reduce weight on a 17x7" wheel you can look for forged construction rather than cast wheels but cost is higher.
see
https://www.tirerack.com/wheels/tech...n&gclsrc=aw.ds

OK, so how do you use your MINI? What type of driving do you do?