Bigger tires on m parallels

[bymep]

I need to replace rear tires on M Parallels. I am looking at 275/45 as I want a little more side wall. I know this will cause a height mismatch between front and rear. What I am curious about is what systems will this cause to go haywire? Will the dash light up like a Christmas tree? Will the traction control kick in when it's not suppose to kick in?

If this will cause issues can I compensate by putting 245/50s in the front to match front and rear height or will the car know that the overall height is different than stock?

[kouks]

I know the traction control will sense the difference, and so will the transmission, since it uses the speed sensors. Best bet is 275/40. The speed sensors measure speed related to each wheel, so going bigger all around will be OK if you keep the rolling diameters within 3% of each other. Once you get outside of that its game on. You should do some more research on this, maybe Q has the real technical answer for you.

[armiller1]

I think I was running 245/45 and 275/45 and had no problems. I will have to check the rears. The 275/45s are about 1.4% bigger than stock whereas the 275/40s are 2.6% less. Whatever sizes I have, I was happiest with this setup. The new one has 255/45s all around on a staggered setup. it looks terrible but I get my replacement wheel today so I can get my set on it!


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[CPHES]

Consider 255/45/18 front - the rear size, and 285/40/18 rear. I have not yet, but that is the combo I am looking into

[RUFREDBIRD]

That combo will work, I have been running that combo for over 8 years without issue.

Consider 255/45/18 front - the rear size, and 285/40/18 rear. I have not yet, but that is the combo I am looking into

[billh]

I am running 255/45-18 F and 285/40-18 R. Rear circumference difference is 2.36mm smaller in the rear (0.13754% difference).

[clarkitect]

I am also running 285/40's in the rear on stock mpars for the summer set up. They work perfectly.

[haynes740]

I’m with 245/45/ front
285/40 rear 3 yrs so far no issues


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[Jamos]

When I took the 95's off to put the MPars on. Here's the difference.
355.jpg

283.jpg

I know it's not the MPARs but at least it shows the sidewall differences. Our car does a good job of eating up the noticeable sidewall size differences.

[bymep]

When I took the 95's off to put the MPars on. Here's the difference.
355.jpg

283.jpg

I know it's not the MPARs but at least it shows the sidewall differences. Our car does a good job of eating up the noticeable sidewall size differences.

I am assuming tire on the left was in the front and tire on the right was in the rear?

[Jamos]

Yes. Just showing that "ah it's only 1" makes a massive difference is all.

[bymep]

Yes. Just showing that "ah it's only 1" makes a massive difference is all.

Were you actually driving the car like that and if so were there any adverse effects?

[Ruskii]

I've got 245/45 front and 275/40 rear on mpars. Wider rear tire looks correct on the 9.5" wheels, no more stretch compared to 255s.

[Jamos]

Yeah I drove it for about 20,000km. It didn't like inclines as much and I kept getting "transmission failsafe" or whatever that message is. Never had ISSUES with braking or TC though but.. 27" is the way to go regardless.

[clarkitect]

I've got 245/45 front and 275/40 rear on mpars. Wider rear tire looks correct on the 9.5" wheels, no more stretch compared to 255s.

275/40 is not the best size. 285/40 is better. Gives the same tire width to wheel width relationship on the 9.5” wheels as the 235/50’s on the 8” fronts. Also overall cicumference is closer to stock.

[shanecarmaster1]

Does anyone have pics of 255/45 on front M Parallels? I already run 275/40 in the rear (thinking about 285/40 next), but the front needs more grip. I'm not sure if 255 would look too fat since 235 already does.

[740iSport303]

Does anyone have pics of 255/45 on front M Parallels? I already run 275/40 in the rear (thinking about 285/40 next), but the front needs more grip. I'm not sure if 255 would look too fat since 235 already does.

Don't have any pics but used to run 255/45 18 on front with 285/40 18 on rear. Looked and handled perfectly in my opinion. Only reason I went back to the 235/50 front and 255/45 rear was tire price at the time. But next set, definitely going back to the 255 and 285 respectfully.

Here are some of the 18" M-par options:
Stock:
Front. 235/50ZR18
Rear. 255/45ZR18


Option1:
Front 245/45/18
Rear 275/40/18


Option 2:
Front 255/45/18
Rear 285/40/18

With these you'll never be out of the +/- 3% for the ABS/Trans/etc...

[nmlss2006]

I will ask a possibly stupid question: why?

[Ruskii]

275/40 is not the best size. 285/40 is better. Gives the same tire width to wheel width relationship on the 9.5” wheels as the 235/50’s on the 8” fronts. Also overall cicumference is closer to stock.

I went with 275 because I wanted all-season tires, and it was hard to find a reasonably priced matching set of 245/275 tires.

[purplecty]

I have 245 45 18 and 285 40 on my mpars... I'd like to have the 235 50 18s back on the front because the 245 45 sidewall looks a bit small for the front and leaves more fender gap on the stock sport suspension...

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[clarkitect]

I will ask a possibly stupid question: why?

Because the stock 255/45s on the rear look stretched on the 9.5” wheel. The 285/40s look just right with sidewall bulge that perfectly matches the 235/50s on the front.

[armiller1]

I’m definitely running 245/45 and 275/40. The rears could easily handle 285s. I just couldn’t find any at a reasonable price when I was looking.


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[clarkitect]

I’m definitely running 245/45 and 275/40. The rears could easily handle 285s. I just couldn’t find any at a reasonable price when I was looking.
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I scored last year and bought a full set of Continental ExtremeContact summer tires on closeout from Tirerack for less than $600 shipped. I got a call from them questioning the rear tire size lol.

[armiller1]

I scored last year and bought a full set of Continental ExtremeContact summer tires on closeout from Tirerack for less than $600 shipped. I got a call from them questioning the rear tire size lol.

I buy almost all my tires used. That way I can always keep them matching. Except I got a great deal on a pair of nittos with almost no wear for the rears so I have potenzas in the front and nittos on the rear for now


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[haynes740]

I buy almost all my tires used. That way I can always keep them matching. Except I got a great deal on a pair of nittos with almost no wear for the rears so I have potenzas in the front and nittos on the rear for now


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I run nittos all around, definitely not a cheap tire to purchase but they perform great.


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