I need help making a decision.

I have some new 18" x 7 +42 wheels and I can not decide if I should get 35 or 40 series tires.

I currently run 17" x 7 +40 wheels with Kumho MX in 215 x 45 x 17. I had to make room for them to fit but I love the ride and the look. Pics in gallery

Overall Dia for 215 x 45 x 17 is 24.6
Overall Dia for 215 x 40 x 18 is 24.8

Not much difference at all.

What would you do?

Longboard

The recommended size from Tirerack (and what many here have) is 215/35/18

I know but I don't want the ride that comes with the 35.

I want the look of an 18" with the ride of the 17". I know I can't have both but I think going with the 40 series will help. Hell, the 18"/40 series combo would only be a 1/4" taller then my current 17"/45 series set up. I think?

Longboard

for 18's i would do 40's. 215/40/18.

I take it that you are going for looks and not performance. The larger diameter will slow acceleration. The added unsprung weight will effect the ride, and not in a good way.

JOHO

Yes, I am going for looks but I don't think the .200 Dia difference will change anything. The new wheels are 2pc forged and are about 2lb's lighter then my 17" wheels. My 215 x 45 x 17 tires weigh 23.2lb's while the 215 x 40 x 18 weigh 22.5.

It looks like a plus.

As for acceleration, I'm pulling over 230whp. No problem there

Longboard

215/35/18 here. looks good. surprisingly the car rides smoother on these than with s-lites and 215/45/17. cant quantify it but it could be attributed to the 10lb difference between the SSRs and s-lites (27 vs 17)

You and I are in the same boat as I have been trying to figure out what to go with as well. We all know what's recommended. Hell, Discount Tire doesn't even give 215/45/17 as an option for a tire setup for the MINI. I can't see much difference between the 35 and the 40 though. The 35 will increase wheel gap and the 40 will minimize it. Maybe a bit more rubbing on a 40 though? I'm currently running 215/45/17 with rubbing on big dips. It may be worth it to check out the Miata tire size calculator to check the differences.

Out of curiosity, what type of suspension do you have? I'm going to keep an eye on this thread.

OK, here is what I found based on the Miata thingy:

215/45/17
Sidewall: 3.8"
Radius: 12.3"
Diameter: 24.6"
Circumference: 77.3"

215/40/18
Sidewall: 3.4"
Radius: 12.4"
Diameter: 24.8"
Circumference: 77.8"

215/35/18
Sidewall: 3.0"
Radius: 12.0"
Diameter: 23.9"
Circumference: 75.2"

To me the choice is obvious...go with the 40 if it's for looks because it's going to fill the gaps better. Anyone please correct me if I'm missing something.

Thanks Duck,

I think I will go with the 40 series. I have already made room for the 215 x 45 x 17 so the 215 x 40 x 18 should fit fine. I hate wheel gaps. It drives me crazy. Here is how it looks now.



Now I have to pick the tires. Not allot of choices at 215 x 40 x 18. I'm thinking the new Falken FK-452.

Longboard

35's add a bit of insurance if you're contemplating a drop and will provide a bit more grip because of the shorter and stiffer sidewalls, 40's are just a touch more comfortable and have a diameter closer to stock so your speedo will be off by less.

BFG makes T/A KDW's in that size and Toyo's T1R is a solid choice as well.

Thanks, I tried the the BFG KDW's and hated them.

I think it's between the Toyo T1R and the Falken FK-452

Longboard

My car is lowered and I love to really push it. I drive everything really hard (keep it clean). The lower side wall does not give enough warning to when it will break lose. With my 17" and 45 series tires I have the suspension set so when pushed hard in a turn the car will break lose in a controlled 4 wheel drift. With the power my car has I can control the drift with the throttle and power through the turn. It makes me smile every time.

The rear never comes around without warning like it did with the 40 series 17".

In my head, the 40 series 18" should handle about the same.

Longboard

WHat are you lowered on? Coilovers?

**EDIT** Dang, just checked the tire choices available. Not much at all!!!! Let me know what you get longboard!

thats a hard choice but if you have already made clearance I would go for the 40's if that is better for you.

I had to make a similar decision since I am running an 8" wheel the 215 wasn't wide enough and looked stretched, it was already REALLY close but I wanted to run something that actually fit the rim so I went for 225/35/18 and surprisingly enough THEY FIT and I didn't trim anything to do it. I was soooo surprised! And because the sidewall is slightly wider and the tire is no longer stretched the ride is MUCH MUCH better.

Just H-Sport springs. My car is a street car so I never felt the need for coilovers on the street. Even though I don't have coilovers, with a good adjustable sway bar and drop adjustable drop links you can still play with the handling and really make the car fun to drive.

Longboard

see

https://www.northamericanmotoring.co...3&postcount=28


very happy with 215/40X18 Kumho Ecsta SPT, especially if you've already fixed the tire rub problem.