How overkill is 245/35 vs 225/40 tires?

[Skyehigh55]

Pretty set on getting 18x8.5 +38 Konig Hypergrams and found that using the wheelitfit calculator, 245/35 fits pretty darn square and flush with little to no difference in speedometer readings whereas 225/40 has a slight stretch and higher speedometer difference.

235/35 tires are almost impossible to find and 235/40 has too big of a speedometer difference for my comfort, so I feel regulated to choose either 225/40 or 245/35. I will most likely be running Michelin PS4S too.

Just how overkill are 245/35's on stock power? Changing out the stock Performance Package wheels/tires with the new setup will still be saving about 2-3lbs per corner after estimate calculations with information provided online of both sets of wheels/tire combinations.

I've scoured the forums but had a hard time finding a dedicated post towards the feel difference when moving up in tire sizing. I'm sure going from Primacy HP's to PS4S in any wider width is going to be a big difference but just wanted your guys input as I'll be making a decision on tires soon.

Thanks in advance!

[Danny318]

For the street its very overkill. For the road courses its proven to be slightly faster than the skinnier sizes.

[TommyW]

They’re all overkill until you learn to
drive the car with stock tires

[NoHaveMSG]

Originally Posted by Danny318

For the street its very overkill. For the road courses its proven to be slightly faster than the skinnier sizes.

Depends entirely on the track but for the most part 245 is a bit much.


Tire compound matters more than width.

[StraightOuttaCanadaEh]

Haven’t noticed any difference apart from about 5% decline in fuel efficiency but mine is heavier than stock. You shouldn’t notice any apart from increased grip

[NLSP]

Originally Posted by Skyehigh55

...I've scoured the forums but had a hard time finding a dedicated post towards the feel difference when moving up in tire sizing...

Don't mean to be a downer, but going bigger/wider isn't necessarily better in terms of feel in my opinion. My experience with 17x9 with 245/40 is:

Pros:
- heavier/more steering feel
- more confidence with high-speed turns/sweepers
- looks really nice when wheels & tires are more flush with the body

Cons:
- acceleration feels a bit more sluggish
- less agile with quick/tight transitions
- more body roll if you're not making any suspension changes

I missed the more agile feel, so I ditched the 9" + 245 combo and went to a 8" + 225 as a compromise between stock. But even now, I'm contemplating on downsizing again to 7.5" or 7" + 215...

So I think it really comes down to whether you prioritize looks over driving feel. Putting the PS4S in stock size on your stock wheels would probably be the best balance of maintaining stock feel and increasing grip, but of course, giving up the aesthetics.

[Vracer111]

Originally Posted by NLSP

Don't mean to be a downer, but going bigger/wider isn't necessarily better in terms of feel in my opinion. My experience with 17x9 with 245/40 is:

Pros:
- heavier/more steering feel
- more confidence with high-speed turns/sweepers
- looks really nice when wheels & tires are more flush with the body

Cons:
- acceleration feels a bit more sluggish
- less agile with quick/tight transitions
- more body roll if you're not making any suspension changes

I missed the more agile feel, so I ditched the 9" + 245 combo and went to a 8" + 225 as a compromise between stock. But even now, I'm contemplating on downsizing again to 7.5" or 7" + 215...

So I think it really comes down to whether you prioritize looks over driving feel. Putting the PS4S in stock size on your stock wheels would probably be the best balance of maintaining stock feel and increasing grip, but of course, giving up the aesthetics.

Agree 100%... around stock or slightly smaller and noticeably lighter/less mass is where it's at if you want to maximize the car's reflexes and responsiveness.

I run 205/45-17 Firestone Firehawk Indy 500s (19lbs) on 17x7.5 +40mm offset Enkei Fujin's (17lb)... absurdly comical how quick it responds along with how much grip it has both wet and dry... huge increase over stock plus more planted feel due to the nearly 0.2" CG drop from slightly shorter tire diameter not to mention better off/on throttle acceleration. Would never give up the 4+ lbm reduction a corner currently and to go back to the heavier stock wheel/tire mass. Would love to get wheel mass even lower with 17X7.5 wheels like the BBS RF...and the Essex Sprint AP Racing front brakes (10lbm each front corner reduction in unsprung weight) - just too expensive for me right now.

I would say my setup is overkill for stock power... no issues with braking or acceleration (on WinMax W3 pads) like there is on stock setup with stock brakes. Tire compound is what really matters... 'width matters not'... weight and diameter of tire is MUCH more important than it's width.

[Dzmitry]

Originally Posted by Skyehigh55

Pretty set on getting 18x8.5 +38 Konig Hypergrams and found that using the wheelitfit calculator, 245/35 fits pretty darn square and flush with little to no difference in speedometer readings whereas 225/40 has a slight stretch and higher speedometer difference.

235/35 tires are almost impossible to find and 235/40 has too big of a speedometer difference for my comfort, so I feel regulated to choose either 225/40 or 245/35. I will most likely be running Michelin PS4S too.

Just how overkill are 245/35's on stock power? Changing out the stock Performance Package wheels/tires with the new setup will still be saving about 2-3lbs per corner after estimate calculations with information provided online of both sets of wheels/tire combinations.

I've scoured the forums but had a hard time finding a dedicated post towards the feel difference when moving up in tire sizing. I'm sure going from Primacy HP's to PS4S in any wider width is going to be a big difference but just wanted your guys input as I'll be making a decision on tires soon.

Thanks in advance!

I own the Konig Hypergrams in your exact size. Love these wheels. Combo'd them with 235/40 after doing a lot of searching and reading for months on feel and reviews of a variety of tire/wheel sizes and weights. The Konigs are light weight wheels and help to keep the overall wheel/tire weight reduced or on par with the stock setup depending on the tires you go with. As many on here say, 245 can start to stretch it towards overkill. But to be honest, this very much depends on what your goals are. If you are street driving mostly, it is really up to you what setup you'd like to get. In my case, my car has had a noticeable performance improvement in terms of traction and cornering grip, even on the street. I have noticed no difference in the smoothness or acceleration feel for my day to day driving. In fact, in some ways, the car feels more agile and quicker to accelerate, but this is more likely a placebo effect. I can only say positive things about my experience with my setup so far. The extra tire thickness will also keep your car feeling a little smoother on bumps and rough roads, unlike going to 245/35. I also like that the wheelwell gets filled in a little more for stock suspension, making the setup look a lot cleaner (you can check in my garage to see how the fitment looks).

The point I am basically getting at, is your two tire size options should be perfectly fine for street or track. Each has their benefits and negatives. Choose what suits you best based on how you feel. If you are using it for street only, then go with what you think will look/feel better in your daily driving (this would probably be 225/40). If the speedometer thing bugs you too much, then go with your other option. Besides, they're just tires, you'll need to replace them some day anyway. Worst comes to worst, you got a set and they weren't your absolute favorite, so you could switch up to something new when the time comes.

The best thing I would recommend is to simply stay away from anything that strays too far off stock setup. And from everything I've read, in my personal opinion, 235/40 is about as large as you'd want to go without sacrificing performance much. But again, this is subjective and up to you in this case. Enjoy whatever setup you choose to go with!

Also here's a an old link to give you some general information.
https://www.roadandtrack.com/car-cul...ransformation/

[DarkPira7e]

I run a 215/40 Falken Azenis RT-615K and the level of grip even with that tire is incredible on the street. The responsiveness of the small sidewall and the lightweight wheel/tire combination is very much noticeable over my previous 235/40 tires and heavy 18s.

As has been said by the others, don't go overkill with your grip; it'll prevent you from learning a lot of fundamental basics and can end up confusing you more than anything else. Some of the grippier tires also don't give you fair warning before they break away, or communicate with you when they're getting hot and become greasy.

[Grady]

If all you want is looks, ok then. If it is performance larger tires do not make a stock car faster, better tires do. Every back to back test I have seen the car is slower when 245 were installed. It may feel more planted in the corner but you acceleration goes to shit and cancels out any improvement in the turns.

[Tristor]

I prefer driving on 225s for feel and I get faster lap times (stock power), however I will say that 245s are much more controllable when you're on the edge, as they can recover much quicker. There's definitely a mechanical grip advantage from the 245s, but in a way having it be a bit less refined is more enjoyable for me. I wouldn't recommend going skinny sidewall though, you can do 245/40R17s and that works very well on 17x9 wheels. A common choice for performance on this platform.

[Leonardo]

I have run both 245/40/17 and 245/35/18 in MPSS. The 245 18 has 1/2 wider tread. Even in the same tire and brand, the width can be different for widths that are supposed to be "the same".

I run 245/35/18 on 18x9 wheels. The are a bit heavier feeling than the 225/40 on 18x8 I had. But they feel more confidence inspiring, and look amazing.

I have been looking at the Falkin rt615+ in a 225/40/18. Their 225/40 is basically the same size as a narrow 245/35/18. Anyway, when looking at tires, it is important to look at the actual size of the tire in some extreme cases.

[daninplymouth]

How about once going turbo? Would it be a benefit to the 245s then?

[steverife]

I think 245's are perfect for stock power or for I/H/E/tune power levels.

Going F/I? I'd go as wide as I could.