So I've done some research and I cant seem to find an actual answer on the best tire size, width, or sidewall that will fit with STOCK wheels and swift springs.. some say 295/35/19 , 305/30/19, then I see 305/35/19 will fit but will effect car negatively? Can we see some real answers here from people who have done it? I want to go 305 width but am going to be in stock wheels for a bit and idk if 305/30 or 305/35 better , or would 295/35 be better for traction?

 

I am running Michelin PS4s 275/30R19 in the front and 295/30R19 in the rear. It looks very nice and have great traction on straight line acceleration. One drawback I notice is cornering as the sidewall seem to flex more. On my next tire change I think I will go with 265 front and 285 rear instead. I don't like the sidewall flexing on hard cornering. Steering feel does not feel as sharp as when it was on stock PSS 255 and 275. Check out one of my thread I posted last year.

https://www.clublexus.com/forums/rc-...tock-rims.html

 

That is typically a symptom of too wide tires on wheels that don't have enough width to let the tire fully "expand" over the width of the wheel. It results in a "bulge" on the sidewalls. Since stock fronts are 9 inches wide, the maximum tire width without compromising on handling/steering feel,would be 265. Since the side wall does not properly sit over the outer lip of the wheel, it causes it to flex under high lateral forces. I personally find 255 on the front to be plenty adequate. With a stiffer sidewall like on the MPS4S or the XL version of MPSS, the turn-in most probably will become even more crisp.

 

Are we talking stock wheels? The correct way to get more rubber on the back is to widen the wheel and get appropriate sized tires. I am running 10.5" wheel with 305/30/19 PS4 tires. No bulge on this setup and traction is not an issue

 

From another thread:

Lou

 

While 275 mm might be the widest allowable for 9 inch wheels, it is not optimal at all. That is what I was saying. The tire will bulge out on 9 inch wheels on the sides. There is nothing wrong with it and will work fine. Just that it will roll on the sidewalls more and turn-in will become "spongy" rather than "crisp" which is achieved by having the wheel a bit wider than the size of tire you are using.

 

^^^^Many many folks in the ISF forum have been running 275s on the rears with 9" wheels for many years without problems.

Lou

 

ISF rears are 9.5 inches.

 

^^^^Nope - Early ones thru 2011 were 9". 2012 to 2014 were 9.5". My statement stands. The 9½" can run 285s.

Lou

 

So many options, choices, decisions to make. Have you changed your rubber since this?

https://www.clublexus.com/forums/rc-f-2015-present/871000-rcf-1-4-mile-issues.html

*Not you Rolla, OP.

 

 

Guys, I Don't think it's going to make THAT MUCH Difference either way, even IF you put a SC on it! SMDH!

 

I SOOO agree with this statement. I listened to the CL folks and the FB F group about them swearing how awesome 275 width tires are on stock wheels. WRONG. The turn in is not crispy like it was with the stock tires. In a straight line, yes, I do get better traction. But I like to carry more speed in corners rather than do 1 or 2nd gear pulls.

 

Are you talking about a RCF or your ISF?

Happen to be in Northern VA by chance?

 

no I have not, I believe part of my issue with bad times was my tires.. I was drag racing in 50 degree weather with worn rears.. not ideal for traction. I don't do burnouts but still 13.1 was a slow time for stock rcf without burn out.