~ (( Need Your Help!! )) - - Widest Rear Tire on OEM 20"X9" SL Rear Wheel Please.....

Here's the 295/30/20 I used before going big

But there are times you have to say bigger is better and go to a 345/20/20. But it does need an 11 1/2" wheel thougj

Here's a link to Michelin's recommended wheel widths for their Pilot Super Sport tires - https://www.michelinman.com/up…ecs-pilot-super-sport.pdf. Looks like they recommend a 10" wheel minimum for their 295 tires. 305 & 315 should be OK with a 10.5" width. Most tire manufacturers seem to recommend a minimum 9.5" for a 285 tire. FWIW, I bought a Sumitomo HTR Z III 295/30 from NTB and they mounted it on a 9.5" rim, but Sumitomo recommends a 10" rim. I'd assume mounting a tire on a non-manufacturer-approved rim width may void any warranty from the manufacturer, since you'd be operating outside their design boundaries. I'd also assume it might also expose you to insurance problems if you had an accident..

Quote from Funinthesun

Here's the 295/30/20 I used before going big

But there are times you have to say bigger is better and go to a 345/20/20. But it does need an 11 1/2" wheel thougj

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Curious did you see a big difference with traction and handling once you went jumbo? Do you have any pics to show how much space you have between tire and arm etc with the superwide tire?

Use http://www.willtheyfit.com and enter the stock SL wheel info (255/35R20 tire size, 9" wide rim with 45 mm offset) for the first set of inpouts and then add the 345/20R20 along with 11.5" rim and since we don't know the offset on @Funinthesun's wheels, just assume it's also 45 mm and WillTheyFit will provide a visualization of the differences between the 2 wheel/tire sets and you can then compare the positioning of the wider wheel/tire to get an idea about swingarm clearance. This link will show you the differences between the 2 sets of heels/tires - https://www.willtheyfit.com/in…eel_width=11-5&offset2=45. According to WillTheyFit, the 345 tire on an 11.5" 45 mm offset rim will need at least an additional 1.25" or more clearance compared to the stock SL wheel/tire position. For better clearance, even more clearance would be desirable.

Quote from neostar

Curious did you see a big difference with traction and handling once you went jumbo? Do you have any pics to show how much space you have between tire and arm etc with the superwide tire?

I changed from stock Kenda 305/30 R20 to a Cooper Zeon RS3-S 305/35 R20. Changing to a better, slightly taller tire made an enormous difference in grip, launch, and handling.

The Cooper is a "summer" tire, does less well in snow, but I'm not driving in snow! Those big grooves should make it a better rain tire as well, but I try my best to avoid wet conditions, too.

The Cooper is taller, more sidewall makes a better ride over rough pavement, and better launch grip before you break traction. 2% bigger circumference also means that the speedometer and odometer are both 2% low. The speed means you have to be careful of the legal limit, the odometer affects milage calculations a bit too.

Don't worry about these little technical bits, research a bit here & on line for a good tire. Tread design and rubber compound technology will outdo simple width every time. If you can make it to a meet up, ask around, you're going to be amazed how much you will learn!

Basically nothing helps getting better traction. You go wider to have a larger footprint on the ground, and you end up having LESS weight (pounds per square inch of rubber) on the rear tire. But it does seem to let you use more of the turbo power sooner once you're rolling. It does look impressive having that much meat on the ground (I can say that with confidence now that Tripod isn't here)

Quote from Doc&Ruby

I changed from stock Kenda 305/30 R20 to a Cooper Zeon RS3-S 305/35 R20. Changing to a better, slightly taller tire made an enormous difference in grip, launch, and handling.

The Cooper is a "summer" tire, does less well in snow, but I'm not driving in snow! Those big grooves should make it a better rain tire as well, but I try my best to avoid wet conditions, too.

The Cooper is taller, more sidewall makes a better ride over rough pavement, and better launch grip before you break traction. 2% bigger circumference also means that the speedometer and odometer are both 2% low. The speed means you have to be careful of the legal limit, the odometer affects milage calculations a bit too.

Don't worry about these little technical bits, research a bit here & on line for a good tire. Tread design and rubber compound technology will outdo simple width every time. If you can make it to a meet up, ask around, you're going to be amazed how much you will learn!

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Good info, I will be considering the tire you have. I am not a fan of low profile wheels/tires so more sidewall is always better in my book. I have already been at a meetup (15 slingers). Saw some interesting mods but mostly bling vs performance. One thing I already know I will be getting down the road is relocating the exhaust to the back. I could tell it really does make a difference from the demo I got. I also want to get the SLR seats vs my SL down the road as well.

I have already got most of my mods done and I am very satisfied so far. Going to get the new exhaust and wheels/tires next year and I will be all set. I will mull over replacing the seats later on.

Quote from neostar

Good info, I will be considering the tire you have. I am not a fan of low profile wheels/tires so more sidewall is always better in my book. I have already been at a meetup (15 slingers). Saw some interesting mods but mostly bling vs performance. One thing I already know I will be getting down the road is relocating the exhaust to the back. I could tell it really does make a difference from the demo I got. I also want to get the SLR seats vs my SL down the road as well.

I have already got most of my mods done and I am very satisfied so far. Going to get the new exhaust and wheels/tires next year and I will be all set. I will mull over replacing the seats later on.

Be careful with what exhaust you choose if you have a top and a tall wind screen

Quote from Doc&Ruby

I changed from stock Kenda 305/30 R20 to a Cooper Zeon RS3-S 305/35 R20. Changing to a better, slightly taller tire made an enormous difference in grip, launch, and handling.

The Cooper is a "summer" tire, does less well in snow, but I'm not driving in snow! Those big grooves should make it a better rain tire as well, but I try my best to avoid wet conditions, too.

The Cooper is taller, more sidewall makes a better ride over rough pavement, and better launch grip before you break traction. 2% bigger circumference also means that the speedometer and odometer are both 2% low. The speed means you have to be careful of the legal limit, the odometer affects milage calculations a bit too.

Don't worry about these little technical bits, research a bit here & on line for a good tire. Tread design and rubber compound technology will outdo simple width every time. If you can make it to a meet up, ask around, you're going to be amazed how much you will learn!

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IIRC, someone ( TravAZ, maybe?) posted that he felt a taller tire, in addition to a slightly smoother ride, provided more sidewall flex and allowed the tire to generate better traction compared to a lower profile tire.

Quote from Funinthesun

Basically nothing helps getting better traction. You go wider to have a larger footprint on the ground, and you end up having LESS weight (pounds per square inch of rubber) on the rear tire. But it does seem to let you use more of the turbo power sooner once you're rolling. It does look impressive having that much meat on the ground (I can say that with confidence now that Tripod isn't here)

I agree about the width vs weight/sq in of contact patch, but the wider tires do look much better! I generally try to apply as much throttle as possible w/o causing the rear tire to slip and then really getting on the gas once moving. Unfortunately, this method sometimes means neighboring vehicles might pull ahead and the added gas with better traction may or may not allow you to catch up or regain the front position. I do like to get to the speed limit as fast as possible, but also try to avoid spinning the rear tire or having my vehicle slide sideways since some LEOs view that losing control of your vehicle as reckless driving. Back in 1977, my Wife and I were visiting her parents in McAllen, TX in the Rio Grande Valley after returning to the US from 3+ years in Berlin (I was in the Army and she was in the Air Force). I was out driving by myself in my 1976 Trans Am and got pulled over and given a warning for spinning my rear tires. I never slid or anything, but the cop was not impressed, saying I was close to losing control of my car. Of course, with the Slingshot's relatively low rear wheel weighting, it's all too easy to slide that rear tire, especially under acceleration. With wider tires on the Slingshot, it sometimes feels to me like torque steer with the rear tire seeming to shift traction from one edge of the tire to the other and back and fourth until firm traction is reestablished.

Quote from FunCycle

Be careful with what exhaust you choose if you have a top and a tall wind screen

The only exhaust I am eyeing is the carbon twin exhaust that exits behind and very low by the rear rear. "Thermal R&D Ceramic Coated Dual Rear Exit Touring Exhaust System". It has rave reviews so far.  I don't plan on getting a roof, the wing is just too damn pretty for me to spoil it with a roof (pun intended). So far I am content with the stock wind screen.