Affect of wheel width and offset on stock suspension feel

[Capt Spaulding]

To echo some of what Churchx said: If you want the feel of the car to stay the same, leave the OEM tires and wheels alone. If aesthetics are what you're after and you don't mind the "stretched" tire look you could go to 8" wheels with the OEM tires. I suspect it will change the dynamics a bit. Will you notice it? I can't say. Probably not.

As soon as you change the tire, however, it will change how the car feels. That may be for the better (it was in my case) or it may not. It's highly subjective. I went to 17x8 Konig Ultraforms with 225 Conti EC Sports. It made a significant change in the feel of the car. Before I did that, though I installed some camber bolts and had the front camber set to -1.5. That made a substantial change in the feel of the car. It was more surefooted on turn in and a little more tail happy.

The wheel/tire change increased the sureness of the turn-in and calmed down the tail happiness.

OE - I re-read your original post. If you with either of the tires you mentioned it WILL change the feel of the car. A few tenths of an inch in width won't matter much. Going to a high(ish) performance tire will. Which takes me back to the first sentence.

[Ohio Enthusiast]

Originally Posted by Capt Spaulding

As soon as you change the tire, however, it will change how the car feels. That may be for the better (it was in my case) or it may not. It's highly subjective. I went to 17x8 Konig Ultraforms with 225 Conti EC Sports. It made a significant change in the feel of the car. Before I did that, though I installed some camber bolts and had the front camber set to -1.5. That made a substantial change in the feel of the car. It was more surefooted on turn in and a little more tail happy.

The wheel/tire change increased the sureness of the turn-in and calmed down the tail happiness.

Thanks for sharing your experience!

Originally Posted by Capt Spaulding

OE - I re-read your original post. If you with either of the tires you mentioned it WILL change the feel of the car. A few tenths of an inch in width won't matter much. Going to a high(ish) performance tire will. Which takes me back to the first sentence.

Yeah, I'm starting to lean toward the school of thought that tire compound is much more significant than tire/wheel size. I'll probably go with the RPF1 in 17x7.5 (being the lightest option, and almost the only lightweight wheel at that width) and consider the tire choices when the Primacys wear out (and I have more experience under my belt with the BRZ).

[scotto79]

I love the stock Primacy tires on my 720Form 17x8. There is a bit of stretch, and not all tire places will mount them, but they are fun for daily driving. The 17x8 +35 offset fills the fenders pretty close to flush too. I'm not bothering with lowering as then I have to rebuild the whole suspension, and it won't be any better than stock.

[Busybee]

Originally Posted by scotto79

I love the stock Primacy tires on my 720Form 17x8. There is a bit of stretch, and not all tire places will mount them, but they are fun for daily driving. The 17x8 +35 offset fills the fenders pretty close to flush too. I'm not bothering with lowering as then I have to rebuild the whole suspension, and it won't be any better than stock.

Any pics?

Thanks


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[NoHaveMSG]

Originally Posted by 86TOYO2k17

225 is still far from over “tireing” the car and will still feel amazing. As good or better than 215, and will out perform 215s in every way. 3lbs if it is that much is still minimal and the lighter wheels more than make up for it. 215 is a great size for stock power. If you end up going full bolt ons you’ll really wish you had at least 225. Many just go straight to 17x9 with 245s as 245s are faster around a track even at stock power vs 215/225s and you will future proof yourself for bigger power. I got 17x8 w/ 225s and it was perfect for NA full bolt ons, but i had to replace the rears with 17x9 w/ 255s once i went FI, in hindsight i wish i would have planned more in advance to save money not rebuying. 2 Wheels and 4 tires.

That is really track dependent. NW tracks like The Ridge, PIR, or Pacific Raceways are quicker with a narrower tire for me. Guys racing twins in SCCA TT4 seem to have come to the same conclusion judging by their build threads. But that is just my experience and I suck

[churchx]

Narrower tires may also have another less obvious pros .. eg. what happens if during trackday it rains? They should also have less rolling resistance/better economy for ones that daily on them aswell. And often they are cheaper, and they fit well even on OE wheels. So even if on some tracks in some circumstances they do slightly better, if one is not hunting for every second competitively but is out there for fun and if one pays himself all track wearables, imho narrow tires look a bit more desirable overall choice.

[TommyW]

Stickier tires cause more body roll so it’s advisable to lower the car

[Ohio Enthusiast]

Originally Posted by TommyW

Stickier tires cause more body roll so it’s advisable to lower the car

Yeah, no necessarily lower, but stiffer springs for sure. That's in the long term plan as well (the stickier tires will be mounted once the stock Premecys wear out, so I still have time for that).

[86TOYO2k17]

Originally Posted by NoHaveMSG

That is really track dependent. NW tracks like The Ridge, PIR, or Pacific Raceways are quicker with a narrower tire for me. Guys racing twins in SCCA TT4 seem to have come to the same conclusion judging by their build threads. But that is just my experience and I suck

Individual results and experiences may vary. But I’ve seen about a dozen different tests all with a professional driver across several different platforms all stock (albeit no 86s) comparing stock size tire vs 10mm wider 30mm wider and staggered stock front 30mm wider rear. And every single time the 30mm wider squared performed the best, 10mm wider 2nd best, staggered 3rd, and stock 4th. Same results every time.

Possibly the tracks used for testing where all more advantageous to wider wheels,
Possibly the professional driver can bring out the true limits of each size tire and a casual can’t or at least needs more time with each size or whatever size he has most seat time with is fastest for him.
Possibly this car is vastly different than the other cars tested.
Possibly the other cars stock tire was way undersized to begin with and our 86 is perfect size from factory or closer to perfect size with stock setup.
But it was repeated so many times on so many cars with 100% identical results across the board.

[NoHaveMSG]

Originally Posted by 86TOYO2k17

Individual results and experiences may vary. But I’ve seen about a dozen different tests all with a professional driver across several different platforms all stock (albeit no 86s) comparing stock size tire vs 10mm wider 30mm wider and staggered stock front 30mm wider rear. And every single time the 30mm wider squared performed the best, 10mm wider 2nd best, staggered 3rd, and stock 4th. Same results every time.

Possibly the tracks used for testing where all more advantageous to wider wheels,
Possibly the professional driver can bring out the true limits of each size tire and a casual can’t or at least needs more time with each size or whatever size he has most seat time with is fastest for him.
Possibly this car is vastly different than the other cars tested.
Possibly the other cars stock tire was way undersized to begin with and our 86 is perfect size from factory or closer to perfect size with stock setup.
But it was repeated so many times on so many cars with 100% identical results across the board.

Confirmed. I suck.

[Goingnowherefast]

Generally a slight stretch will give you better initial turn-in and steering response at the small expense of a marginally harsher ride.

In reality, the tire you select will have magnitudes larger effect on vehicle dynamics (turn-in, steering response, general NVH) than splitting hairs on 10mm of section width. Just choose a quality tire (the Michelin P4S and mentioned Conti's are the best street centered tire that money can buy) and be done with it.

Originally Posted by NoHaveMSG

That is really track dependent. NW tracks like The Ridge, PIR, or Pacific Raceways are quicker with a narrower tire for me. Guys racing twins in SCCA TT4 seem to have come to the same conclusion judging by their build threads. But that is just my experience and I suck

Not really though. We have beaten this topic to absolute death in the Miata world. In 99.9% of circumstances a 245/255 tire on a 9 inch wheel will be MUCH faster than a 225 on an 8 inch wheel.

On the note of T4, let's talk about it. Looking at the 2019 TTN Results, guess what the class winner was running? 255 on a 9.5. Guess what the 2nd place was running, guess what the third place was running? All 245's/255's. We need to put this myth that a 225 on an 8 inch is even in the realm of competitive compared to 245/255 on a 9+ wheel to bed.

[NoHaveMSG]

Originally Posted by Goingnowherefast

Generally a slight stretch will give you better initial turn-in and steering response at the small expense of a marginally harsher ride.

In reality, the tire you select will have magnitudes larger effect on vehicle dynamics (turn-in, steering response, general NVH) than splitting hairs on 10mm of section width. Just choose a quality tire (the Michelin P4S and mentioned Conti's are the best street centered tire that money can buy) and be done with it.



Not really though. We have beaten this topic to absolute death in the Miata world. In 99.9% of circumstances a 245/255 tire on a 9 inch wheel will be MUCH faster than a 225 on an 8 inch wheel.

On the note of T4, let's talk about it. Looking at the 2019 TTN Results, guess what the class winner was running? 255 on a 9.5. Guess what the 2nd place was running, guess what the third place was running? All 245's/255's. We need to put this myth that a 225 on an 8 inch is even in the realm of competitive compared to 245/255 on a 9+ wheel to bed.

Like I said, I must just suck and can't utilize the 245 well enough.

A twin in T4 is limited to 17X7 wheel size. I believe the reason the T4 guys went narrow is the wider tire wasn't working on that narrow of a wheel for them.

[Goingnowherefast]

Originally Posted by NoHaveMSG

Like I said, I must just suck and can't utilize the 245 well enough.

A twin in T4 is limited to 17X7 wheel size. I believe the reason the T4 guys went narrow is the wider tire wasn't working on that narrow of a wheel for them.

My guy, what are you talking about? I cited TTN, I think you are confusing Touring-4 with Tuner 4 rules.

There is no wheel size limitations in SCCA TT T4. Here's a link to the rules: https://timetrials.growsites.net/pages/tuner-category

"1. Any width or diameter wheel and wheel spacers may be used provided it complies with the following:

A. Non-metallic wheels must be certified/approved from an appropriate, recognized standards organization. (e.g., FIA, SFI, SAE, TUV, etc.)
B. Wheel spacers are permitted.
C. Wheel studs, lug nuts, valve stems (including pressure-relief types) and/or bolt length may be changed. Wheel bolts may be replaced with studs and nuts, but the number of fasteners may not be changed.
D. Tire pressure monitoring sensors may be removed.
E. Centerlock/spline drive/knock-off type hubs may be converted to lug-type hubs."

For the tire size, 2WD cars are limited to a 265 tire.

[Tokay444]

Wheel offset has a huge impact on scrub radius, which has a huge impact on steering feel.