Hey everyone!

I'm contemplating making the switch to 15" wheels. Right now I have two sets of 16" wheels/tires: 16x7 Konig Feathers with 205/50 S.Drives for the summer, 16x7 Konig Rush with Falken Espia EPZ winters in 205/55. I'll probably keep the winters because they have a ton of tread left, but the fronts on the summers are near the wear bars (time to rotate I guess, then they're done.)

99% of my driving is city, and back roads. Some highway sprints, but no long commutes. There's always the possibility of a few road trips, but they're not common.

I'd like to hear from anyone who's downsized on the real world pros and cons. Is the acceleration boost appreciable? Any difference in highway driving?What's an ideal wheel width and tire size for a good mix between (primarily) handling and tolerable ride?

Thanks in advance! Here's my car as she sits now.

 

I have not made the switch from 16s to 15s, but I looked into it. What I found is a very limited choice of tires that I'd want to consider. That would be the case whether I stuck with the 15X5.5" size with the OE tire size, or bought aftermarket 15X6.5 or 15X7 wheels with 195/60/15 or 205/55/15 tires. There are a few decent all-season tires, but very few (none in 195/60/15) higher performance summer tires. Of course, there's no problem with a limited selection as long as one of the tires offered happens to be the one you want. There are no tires shown at Tire Rack in the 215/50/15 or 215/55/15 sizes.

 

Interesting... I guess it's not a popular size? It looks like the S.Drives (which have been great, although they wore fast.) come in a few flavours of 15:

195/45R15
195/50R15
195/55R15
205/50R15
205/55R15

I imagine I'd go with 205/50 if I went that direction.

 

1. yes the acceleration boost is appreciable
2. speedometer error is a linear 4 mph (go figger)
3. the 15x7 +38 Kosei with 205/50-15 was a very good street solution

And the 15" solution is lighter of course.

Here's the current setup (15x8 front, 15x7 rear, with 225 RS3 on the wider front rims).

Cheers,

Charlie

 

Thanks, that's just the kind of information I'm looking for! I'm not too worried about speedo error. I'm driving either with/slightly above flow of traffic, or if there's no one around, as fast as I feel I can safely get away with.

Is it the Kosei K1's you're referring to? I'm looking for a wheel that isn't multi-fit, if possible. No extra holes.

 

I run 15's for my winter rims..
Suggestions...do not us the mini oem size for the cooper...too narrow for an s...stick with about the same width you have now...and about the same rev per mile, and you speedo will be reasonablely accurate, as your gearing will stay about right...there are 2 that are very close common sizes....a few posts, but not near my car, i went uwith a slightly smaller 15....gain tourqe, minus, higher cruising rpm....good for back roads, minus on the highway, but still only a 4 mph diff from oem.the lighter rims actually feel more sporty, faster, easier turning....the reason why folks like them for auto x.
As fo handling...will mostly vary on the tire imo...snowtires have pretty soft sidewall, so it rides kinda soft, butif i had a stiff sidewall, i bet i could match a car on 17's 90% of the time, and beat it 5% due to faster acceleration....imo the mini has more/better handling than 90% of folks know how to use, so the loss should not be noticable.the look is subjective, but imo it looks fine, heck kinda more classic with the wider rubber. Biggest plus is lower cost tires....you can spend the same $$ for a much better 15, as opposed to a 16 or 17.....guess youcould go cheap, but imo atleast go comparable, or you are likely to get very soft sidewall...like the typical grand-touring/all season tire.
Only issue is trying to find a tire with the correct load rating in the 15...so shop by that AND the size/speed ratings, or a blowout is more likely.

 

I had a couple of Kosei's and none of them were multi-fit.

 

Awesome, thanks for all the insight! I''ll definitely be looking for a quality summer tire. I emailed Alex @ TireRack to ask for suggestions based on my driving needs. Just browsing it does seem way cheaper to go with 15's.

 

It is cheaper provided you break even on selling your 16's. If not then you have to look at how many cheaper tires do you need to buy to offset the cost of new rims. Just my .02 as far as factoring cost into the equation. I am curious to see the results, and read about this as I have actually thought about going to 17"'s but the idea of going to 15's for quicker handling is intriguing.

 

Yeah, that is true. It's going to depend on which wheels I go with, how long I keep the car, and so forth. It seems like I should be able to get rid of the 16" Feathers without losing too much. I bought them used, and I know a lot of people want them for the light weight.

 

Advantages of 15" wheels and tires; generally lighter weight and lower cost.

Disadvantages of 15" tires; limited selection.

Every pound of unsprung weight saved is the equivalent of saving six pounds of sprung weight. This effects acceleration, braking, ride, and handling in very positive ways.

By switching to 15" wheels you can choose tires that have taller sidewalls, with the associated improved ride, without increasing the rolling diameter of the tire. In fact you can have the same height sidewall as a 16" or 17" tire and reduce the overall diameter of the tire which will effectively lower the gearing offering improved acceleration, similar ride and handling, but lower fuel mileage.

There are many choices and compromises that you have to sort through and decide which are important to you.

I have three sets of wheels and tires; winter wheels in 15"x5.5" with 185/65R15 Nokian Hakka2 tires with studs, three season wheels in 16"x6.5" with 205/50R16 all season, high mileage tires, and summer play wheels in 16"x6.5" with Falken Azenis RT-615K super sticky, very soft, performance tires used on the weekend auto-x and HPDE track days.

My choice of the narrow winter tires is because they just plain work better in snow and slush, and on ice and hardpack. The high mileage three season tires save money by not wearing out every other year. The weekend tires is self explanatory.

The diameters and weight of each of the wheel/tire combination are as follows:
185/65R15 = 24.5" closest indicated speed compared to GPS - 30.5lbs
205/50R16 = 24.1" close to stock tire diameter - 37.6lbs
215/45R16 = 23.6" about 3.5% slower than stock tire - 39.6lbs

I can definitely feel the difference when I switch to the winter wheels as they are by far the lightest. Even though the 215s are the heaviest, the smaller diameter, shorter and stiffer sidewalls, and stickier compound make them the most responsive and quickest.

If I didn't want to stay in D stock class for auto-x I would probably switch to some 15"x7" wheels with 225/50R15 tires and drop an additional 8lbs, per corner, of unsprung weight. That would be similar to removing 192lbs from the car.

Just my $0.02

 

If you ever do decide to run STX, I'd respectfully recommend based on several years of frustration that the minimum rim width that will adequately support 225 mm tires is 7.5.

I ran RS3 on the Kosei 15x7, and the R1R - neither worked well. I now run both on 15x8 front rims depending on weather, and the tires are transformed!

Since I used to run the Hoosier 205/50-15 with it's monster 9" wide tread cantilevered onto relatively narrow rims it took me a long time to admit that the TW140 tires have different sidewalls and just won't do the same trick!

Better late than never I guess,

Charlie

 

Bumping my old thread in a bid for more information!

The winters are going on soon, so I'll be shopping for my new summer rubber (and possibly wheels...) shortly. It looks like all the good tires are available in 205/50/15. This will give me 1" shorter OD than my current 205/50/16. One thing I'm worried about is it looking too small and weird in the wheel well. Any of you guys running 15"s have some side view photos I can check out?

 

dannyhavok,

I'm not sure that 15" wheels is the best solution for what you are looking for compared to your current setup.

There isn't anything lacking with your Konig Feathers for summer use, if anything I would suggest looking for better tires in 205/50-16 perhaps with less weight but good for street use, comfort over grip.

Moving to 15" for street use is fine and there are some wheels that are lighter it is true. However choice of tire size can be somewhat limited because many of the best performance tires don't come in 15" or even 16".

Also you get more weight savings if the 15" wheels are more narrow such as the stock 15x5.5" holeys vs the 15x7 or wider option. Still, 15x7 is pretty low in weight.

Using 205/50-15 seems OK but in my opinion is not a good choice for street use using stock suspension since the wheel gap would be increased by about 0.6 or 0.7". Tire diameter is 23.1" vs 24.3" OEM.

A better choice would be 205/55-15 but tire selection is limited.
However Kumho Ecsta 4x (Ultra High Performance All Season tire) comes in:
205/55-15 $88 each, 19 lbs, 420 treadwear, 23.9" tire diam.
195/55-16 $86 each, 19 lbs, fits rims to 7" wide, 24.4" tire diam.
205/50-16 $92 each, 20 lbs, 24.1" tire diam.
Tire rack test-
http://www.tirerack.com/tires/tests/...y.jsp?ttid=151

If you were to stay with 16x7 wheels then look at 205/50-16 tires like-
Continental ExtremeContact DW (Max Summer tire)
$99 each, 19 lbs, tire diam. 24.1", 340 treadwear
Tirerack test result-
http://www.tirerack.com/tires/tests/...y.jsp?ttid=148

Are you currently using 205/55-16 or 205/50-16? If you are using 205/55-16 you might consider the lower sidewall option.

 

Some pics of 15" wheels and lower 205/50-15 or similar tires but with suspension drop of 1.7"

https://www.northamericanmotoring.co...5x15-6uls.html

 

Hey, thanks for the replies! As I suspected, the 15s do look a little odd, even lowered a bit. The vertical gap can be reduced but the horizontal gap is still pronounced. Maybe it is more suitable for autocross rather than street driving, aesthetics wise, anyway.

Currently I'm running S.Drives in 205/50/16. Some other tires in that size Alex suggested (when I asked about 15" options.) are Z1 Star Specs, and Toyo Proxes R1Rs. Available in 205/55/16 but otherwise appealing are Potenza RE-11's. However I run that size for my winter set, and it does rub and squeak a bit when I hit dips in the road... I'm going to raise the ride height up a bit this winter and see if it alleviates the problem. If so I might go ahead and stick with the 16x7 Feathers and get the Potenzas. They're supposed to be a good balance of comfort, grip, and wet performance, which is important here.

My whole motivation for going to 15" was to get a little better acceleration, but the funny look and the added cost is starting to look like a bad trade off.

 

Subscribed. Good info here.

 

15" can be lighter but you have to look for that in a wheel you can find a design that you like better than the Konig Feathers.

I run stock 15" Holey wheels and Bridgestone RE960AS in 190/60-15 for daily driving in dry or wet. No problems and works well. While not as grippy as summer tires it's much more comfortable yet there is good handling for street use.

The stock Holey rims are narrrow at 5.5" wide but also great on weight, only 12 lbs each. Your MINI is a base cooper so you don't have the power of a Cooper S. I'm not sure that you can find the right combination of lighter 15" wheel with a tire size you will find OK for street use that will give enough grip and traction and look OK with not a huge wheel gap.

In that respect the 190/60-15 tire size fits the bill, wide enough but also near stock tire diameter with reasonable cost and weight. Tire selection is limited but there is the RE960AS.

Your Konig Feathers in 16x7 are about 15lbs each, which is not bad. You can find very light 15" wheels but some are very expensive and not practical on a budget.

When trying to get better acceleration on the street you want- less weight, the more the better and more grip/traction to minimize slip and spin.

If you were to stay with 16" wheels then consider these Extreme Summer tires-
Yokohama Advan Neova AD08
205/55-16 $160 each, 21 lbs, 180 treadwear, 24.8" tire diameter.
Bridgestone Potenza RE-11
205/55-16 $163 each, 23 lbs, 180 treadwear
Hankook Ventus R-S3
205/55-16 $130 each, 22 lbs, 140 treadwear
Dunlop Dizezza Sport Z1 Star Spec
205/50-16 $152 each, 22 lbs, 200 treadwear, 24.1" tire diameter.

In Max Summer tires
Bridgestone Potenza S-04 Pole Position
205/55-16 $136 each, 24 lbs, 280 treadwear, 24.9" tire diameter.
Other than weight a good value for a very good handling moderate wearing tire.
Tirerack test results-
http://www.tirerack.com/tires/tests/...y.jsp?ttid=162

If lower weight is of interest then-
General GMax AS-03 (Ultra High Performance All Season tire)
195/55-16 $95 each, fits rims 5.5-7" wide, 18 lbs, tire diameter 24", 480 treadwear
Tirerack test result-
http://www.tirerack.com/tires/tests/...y.jsp?ttid=151