Fysisist

I expect to get a barrage of "search the forum" replies, but if you are running the 20x11, 20x10 staggered setup, can you share your tire size and offsets please? I've gone through a search and not really finding any simple answers to this, I think, simple question.

My plan is Rohana RC10 matte black in the size mentioned above, with Michelin PS4S.

Many thanks in advance.

05RollaXRS

I have not put aftermarket wheels on my RCF, but with the 10 inch front and 11 inch rear width, you would want to be safe with the offsets. The most aggressive I think would be around +45 mm rear and +35 front. Stock offsets are 45 mm rear and 55 mm front. Plus, the 1/2 inch width gain in the wheels also adds another 17.5 mm in offsets. So, effectively that would be +25 mm rear and 20 mm front offsets. I think it would avoid the wheels stick out like a 4x4.

Fysisist

Thanks yeah those are my thoughts as well. I've had the car for over 5 yrs now, still enjoying it and no plans to sell it. But it is time to sort-of reinvent it, and new wheels at 20" is a good start. I think any reputable wheel/tire vendor can help me get this right. I currently have spacers on my OEM wheels, +15 rear and +20 front, which brings the wheels out so it doesn't have that tucked in look. So I'll try and keep esssentially that same appearance while adding the 1/2" overall due to the bigger wheels.

05RollaXRS

Yeah that is good. You might want to keep an eye on the weight of the wheels while making sure they are strong/forged.

Keep in mind that you want to keep your circumference as close to stock as possible so that you don't end up with longer gearing (we already have such long gearing). You might have to go with thinner aspect ratio Pilot Sport 4S tires. Make sure you get "extra load" rated ones like I did. I have spoken about it extensively that stiff sidewalls are a must on RCF. I got the PS4S XL and they are a dream to drive the car on. They have reinforced sidewalls to handle deformation under high corner loads. They are so much better than the OEM Pilot Super Sports with standard load rated sidewalls the car came with, it is not even funny. They are not that much harsher than stock tires either.

Fysisist

Thanks for the good info bro. If this looks like it's gonna be too close on rubbing or it's just not really practical I'll drop back to the 20x10, 20x9 staggered setup. I did see a lot of posts from owners who did 11's though, but never gave all the numbers.

05RollaXRS

You are welcome. I would recommend you at least get 9.5 inch front and 10.5 inch rear, which is the stock width. If you go narrower, the car especially with a bigger circumference wheel/tire combo will feel "tippy" and the roll center would be raised. You want to at least preserve the driving dynamics.

Mingofish

FY,
The fronts will be your issue.
Rears at 11 +45 is no prob. You’ll be able to run 305 with plenty clearance.

Pretty sure 20”x10” at even +35 you will scrub some at full lock.
It will depend on the tire and it’s shoulder profile too.
A possibility is 25 series profile? Not my choice for sure. Tire choices very limited.
If your car isn’t lowered, may help some.
Or run a 255/30 stretched if you like that look.
Me, I like a meatier tire and less rim.

My street wheels which are 20x9.5 +32 scrubs a lil bit with 265/30 and my car isn’t super low, but it is lowered.

Personally I would stick with 19”.
19x10 +35 square set up front and rear and you can run 295/30 with very very minimal scrubbing.
That’s my track set up.
Actually wanting to go to 18x10.5 square so I can run 305/30 on fronts.

Call Mike at Figs if you’re interested in BC wheels? He can def help you get the offset right.
Good luck.

Fysisist

I think what I'll do is run the same tire widths at the new wheel size. So 295/30/20 and 275/30/20 which will be + 0.4 inch in height compared to OEM. I don't think that would really be noticeable and the speedo will run be a little slow, which is not really ideal. I'd need to get a good feel for that. I think it's just a fraction of a percent.

And then to retain the current look with the offset, I'd be looking at about +43 rear and +57 front, taking into account that I have +20 spacer in the front and +15 in the rear. Unless I miscalculated, which yeah it's entirely possible ;-{

Mingofish

Think you’re adding the wrong direction...
or you planning on using the spacers plus new rims?
+57 would be cray on the front. With spacers would be 37 so ok.
But why use spacers if you’re buy new rims. Just get the right offset.

if it’s a custom rim, stay between +30 to 40 in the front and you’ll be fine.

Fysisist

That's why I'm putting it out there, somebody to reign me in if I'm going out into left field. And no I'm definitely not planning on using the spacers. My reasoning was as follows: OEM wheel offsets are, unless I got bad info, +50 front and +41 rear. I currently have the spacers to get rid of that tucked in look, to wit -20 front and -15 rear. But yeah I just realized I'm looking at it bass ackwards. So right now I have front: +50 then -20 spacer which leaves me at +30, and rear: +41 and -15 spacer giving +26 overall. Is that right? Now with 11" and 10" inch wheels, that is another 0.5 inches or about 13mm, right? That is like negative offset since it moves the wheel face outwards vs the narrower OEM wheels. Therefore, to keep about the same look with the wider wheels, I'll need about 43 front and 39 rear? Or did I compensate the wrong way? That seems right.

05RollaXRS

If you are getting 0.5 inch wider wheels then don't do spacers at all. Just get the right offsets ton the wheels o keep it looking flush. 0.5 inch is already 13 mm gain outwards so you want to get close to stock offsets of +45 and +55 on the wheel (or maybe +35 mm and +45 mm like I said above, at the most) since the 13 mm gain in offset will eliminate any chance of the "tucked in" look.

Fysisist

Yes that's what I just said - I absolutely would not use spacers, you just buy the offsets you want with the new wheels. I'm just looking for a double check on the figures I used to come to the conclusion I have now: about +43 front and +39 rear in the wider wheels.

JT2MA71

iTrader: (7)

I am running 19x11 +35 and 19x10 +41. 305 wide rear tires and 255 fronts. To keep the overall diameter in spec., you'll have to run lower than 30 and 35 aspect ratios tires, which I personally would not like. As Ming said, stay with 19's.

Mingofish

Here’s settings using your oem wheel plus spacer compare to +57

See how it’s in more

Here’s +35

You see with 35 the tire is much closer to your current position

Fysisist

I think it will work well, although not perfectly because I'll be running a slightly larger outside diameter both front and rear, which I've already been doing for the past 2 yrs. The speedo is off a small amount and the cg of the car is slightly higher. I'm not runnning it on a track with this setup, it's daily driving. I don't see an issue.