Is anyone running 225/45/16s or 225/50/16s with the JCW suspension? Are there any clearance issues?

I'm currently on 215/40/17 BFG Rivals on 17x7s with a +42 offset. And I'm looking to switch to 16x7 also with a +42 offset. I am on the JCW suspension conversion. So the car is about 1/3" lower than the Sport+ suspension.

First option is 225/45/16 Dunlop ZII. This is esentially the same diamter I have now. Tires will be a tad wider, but I think I should have enough clearance on the front shock. Right now I can fit a full finger width (about 10mm) in between the sidewall and the Koni.

Then there is a 225/50/16 BFG Rival. It is 1" bigger in diameter than 225/45/16. Will there be clearance issues due to tire height?

I would prefer the larger diameter of the 225/50/16 for a slightly taller 2nd gear for nearly an extra 3mph in 2nd. My 2nd gear tops out at only 57 mph on the rev limiter currently (GPS-measured, not speedometer). I am more concerned about top speed in 2nd gear than I am acceleration gearing. I hit top of 2nd gear on nearly every course, and the car is not hurting for power to accelerate.

 

you may be going too wide in tire for a street tire. i went with 205/50s-16 z2s, worked decently. i'll actually be going shorter tire next but i'm in a base cooper, also on the jcw suspension. i don't think you'll have clearance issues

 

For another point of reference, I've been running 235/40-17 (yoko AD08) on 17x7 (42mm offset, Kosei K1-TS wheels) and I'm posting the best PAX times I ever have. Car is an R53 JCW on sport suspension and there is slight rubbing on the plastic wheel arches in back, but I've been daily driving this for months with no real issues. On JCW suspension it might be a problem, but I'm talking about a much wider tire here @ 235.

I'm also looking into options for next year, the AD08s will no longer be legal being under 200 treadwear. Looking at ZIIs since they're available in the same 235/40, but the treadwidth is advertised at just 8.7" compared to 9.1" for the same size AD08s.

I didn't really think there was such a thing as going too wide in tire for autocross, even sacrificing sidewall stiffness, but I'm just running locally for what it's worth .

Is there an advantage going down to 16x7? I'm not sure the R53 JCW front brakes would clear anyways.

 

advantage from 17x7 would be weight & cheaper tires. probably better ride as well

 

I'm also curious why he step down in wheel size? Just because of price?

 

This got me curious so I looked into 16x7 options. I could save 2.7lbs per wheel/tire combo (16x7 Enkei RPF1 vs 17x7 Kosei K1TS, both about as light as you can get for their size). Not too significant but maybe worth a tenth being unsprung, rotational mass? With tires cheaper maybe this is a good way to go for the long term, currently only $112ea for Hankook RS3 version 2's.

I'd probably go the 225/50-16 route for higher gearing as well, I'm in the same boat with the car seemingly not hurting to accelerate, would go for the shorter gearing in a non-S. If I decide to go this route I'll report on fitment, but just sport suspension here.

 

Don't just look at the overall wheel/tire combo weight. Look at WHERE that weight is in the wheel/tire combo. Where the center of mass is affects the moment of inertia of the wheel/tire combo.

Take for example two theoretical wheel/tire combos that both weigh exactly 50lbs and have the exact same total diameter. But one of those wheel/tire combos uses a 16" wheel, and the other uses a 17" wheel. Even if the overall weight AND diameter of the wheel/tire combo is exactly the same, the smaller diameter wheel will have a center of mass that is closer to the center of the wheel/tire combo. Because the center of mass will be closer to the axis of rotation on the 16" wheel/tire combo, it will have a lower moment of inertia than the 17" wheel/tire combo. Moment of interia is how resistant the wheel/tire combo is to rotate. And therefore, if you apply the same amount of torque to our theoretical 16” wheel/tire combo as you do to your 17” wheel/tire combo, the 16” one will always accelerate faster – even though the two wheel/tire combos are the exact same weight and diameter.

 

So anyway...

Same tire dilema this year, but with new tire options. The new Bridgestone RE-71Rs are looking very fast. They come in a 205/55/16, which would be my 1st choice and 215/45/17, which would be my second choice. (The 17" size is actually cheaper than the 16")

Or I can wait for the 215/45/16 BFG Rival S, when they are available. But we still don't know if they will be good. And I don't like that size because the last thing I need is shorter gearing due to the smaller diameter.

 

Regarding the RE-71Rs, I am wondering how the 225/50-16s would fit an R53... wide AND tall. Have seen mixed feedback, some say just minor rubbing with 42 offset wheels on stock or JCW springs. "Minor" rubbing is fine with me.

 

I'm leaning towards trying the 205s this season. I ran the 215/45/17 Rivals last year, and I have come around to belive that 215 is about the width limit you want on a 7" wide wheel. The competitive street tires are all oversized in width to begin with.

I'm probably looking at a 205/55/16 this season on 16x7 wheels. And I think with the extra tire sidewall, the nominal 205 width could be a better option for both feel and control.

 

that's pretty tall - i'm running 205/45-16 rs3v2s on my mini and rarely hit the limiter in local events

 

^^^ That's because your Mini is a non-S, I presume. The Cooper S has shorter gearing than you do. Even with taller than stock 215/45/17s, I still top out at only 57MPH in 2nd gear. This is problematic on most local autoX courses, and any nationals style course, especially given how much faster the Cooper S can accelerate from say 30mph to top of 2nd gear compared to a non-S.

 

ohh did not realize (read carefully enough) the gearing was that short. 205/55-16 is probably a decent option for you.

 

I am running 205/55-16 RS3's. The size seems to work nicely but is slightly taller than stock. What year is your R53? I don't hit the limit @ 57.

 

Chili, any pictures of the 205/55's? Do they raise the ride height substantially? Also any noticeably change (decrease) in responsiveness?

 

205/55/16 raises ride height 0.4" compared to 205/50/16, and in general,
slightly more give to the sidewall and slightly heavier, but none of these
are more than minor differences. I think 205/50/16 is the better size, but
there's a better selection of tires in 205/55/16.

 

Follow up: I ended up getting the 215/45/17 RE-71Rs. They are noticably less girthy than the 215/45/17 BFG Rivals they replaced. The Rivals run at least 10mm wider than the RE-71R in that size.

In retrospect, I should have gotten either the 225/45/17 or the 225/50/16 RE-71Rs. I do not reget the tire model choice though. I ran my first event on the new Bridgestones on Sunday, and the RE-71R is an incredible tire.

 

keep us posted on the wear - how many runs, how many miles, before they go please

 

Also of note - I was speaking with a competitive CS Subaru BRZ driver on Sunday who was running the 245/40/17 RE-71Rs on his car. The BRZ has the same size 17x7 wheel as we do. He said he loved them in 245 and that they felt very responsive and not sloppy even in that extreme width.

I'm not recommending 245/40/17 for a MINI because I doubt it would fit without rubbing. But the anecdote should give you some idea about the stiffness of the RE-71R tire carcass.