Tires question

[talha514]

Quick question

The factory OEM rims 19inch 437 and tires can come with the car are

255/35/19
275/35/19

When I got the car the previous owner has these on, on the same rims

265/35/19
275/35/19

No issues I been 200km+

-

My question is can I go

275/35/19?
285/35/19? Or 295

Can I run wide tires? Or what’s the widest tire I can run on the same OEM rims?
I hear you can stretch the rubber running 285?295 not safe? It can pop

Your thoughts?

[M3SQRD]

275 is too wide for a 9” wide wheel and a 295 is too wide for a 10” wide wheel. Will they fit? Yes. Will you fully extract the grip and performance of the tire? No. Look at all of the articles/videos of tests of tire width vs rim width and you’ll find that a narrower tire performs better on a wide rim than the grip/performance of a wide tire on a narrower rim.

[gunsmoker]

I run 265/35/19 and 285/35/19 on the 437 rims and it is in spec. These are my summer wheels and I currently have Yoko advan ad09. Before that I had Goodyear Supercar 3. The goodyears were less noisy but the pattern is such that people think they are worned out before they actually are and I did not pass track inspection once. The yokos are good but the tread pattern is very noisy.

[greysea]

I just recently had to get new tires for my 437s.

I had the stock MPSS 255/275 but read in the forums that you can fit 265/285 on the stock 437s so I opted for that in the MPS 4S and so far super happy.

Still on stock suspension and no spacers as well. But she hooks up better. Still kind of waiting to push and really warm up the tires but loving it so far. No issues. Also got an alignment just to ensure even wear and its been about 2 yrs since last.

[N1rve]

Originally Posted by talha514

Quick question

The factory OEM rims 19inch 437 and tires can come with the car are

255/35/19
275/35/19

When I got the car the previous owner has these on, on the same rims

265/35/19
275/35/19

No issues I been 200km+

-

My question is can I go

275/35/19?
285/35/19? Or 295

Can I run wide tires? Or what’s the widest tire I can run on the same OEM rims?
I hear you can stretch the rubber running 285?295 not safe? It can pop

Your thoughts?

You should technically be experiencing more oversteer because of that setup.

I run 265/285 to keep the balance of the car and this is no problem with stock suspension or wheels.

The widest I would run is 265/285 because you run into other issues once you go wider, which is hydroplaning and uneven shoulder wear on stock wheels.

Since the stock setup is 255/275, you want to go up and the same as the front and rear, 10mm so 265/285 or 275/295. I am not sure if you can run 275 in the front without rubbing though. I think you can fit up to 305s in the rear but by increasing grip that drastically, you will have an increased in understeer.

[M3SQRD]

Hers one article discussing tire width vs. wheel width linked below. There are plenty more articles/videos from reputable sources that show the same trends.
https://grassrootsmotorsports.com/ar...always-better/

265/285, especially if BMW * spec tires, on a 9”/10” wide wheels is the widest you should go. Rule of thumb is for each 0.5” reduction in wheel width, tire section width decreases by 0.2”. Also, it affects the shape of the contact patch. Additionally, it changes the way a tire performs at high slip angles and loss of grip. A wide tire on a narrow rim results in a tire that abruptly snaps at the limit vs. a progressive loss of grip from a tire mounted on a proper width wheel which supports the tire.

I used to believe wider tire is always better until I started heavily tracking in the mid 90s with an e36 M3. Always thought the 195 I was running on my CRX Si and Civic Si, instead of the stock 185, was reducing my lap times (no in-car data acquisition systems weren’t readily available in late 80s to 00s and the ones that were had to be buckled into the passenger seat! so you needed a friend with a stopwatch to time your laps). Oh was I wrong. The ‘94 e36 M3 came with 235 square tires so I figured going to at least a 245 would improve grip. So once the 235s were worn out from tracking, I switched to 245s Michelin MXX3. Averaged clean ap times at Summit Point Main increased by 0.75 sec over the 235 times. Averaged time were from multiple days, not just one day each. I thought it had to a problem with the 245s so I doubled down with a set of 255s. Well, this only made it worse and resulted in another 0.5 sec of lap time. Combined 1.25 sec slower averaged lap times. Handling characteristics at the limit weren’t predictable and went from grip to no grip frequently. Switched back to the 235s and the lower averaged lap times were back. Wide tire on narrow rim, even if it fits or is in spec, does not increase grip/performance. Remember the actual width of a rim measured from outside to outside, not the spec’d rim width which is measured from inside lip to inside lip such as 11et44, is actually 1.0” wider so the 11et44 is actually 12” wide. Sticking with the 11et 44 rim, you want a tire that is roughly equal to the 12” outer width measurement which is 304.8 mm or a 305 tire. This is one of the most common size wheel and tire widths - 11et40-44 with a 305 mm tire.