HELP with tire sizes for the rear

[dak911]

I need front tires, so I was thinking to put the good 225's from the rear on the front of my 01 2.5/5 and go to 245/50 or 255/50 ( for no other reason than to make it look wider) for the rear BUT will they fit, and that will change the revolutions per mile from about 835 to 798 (for the 255's) so, what will that do to speedo reading and to the rear ratio..??
And, no I don't rotate because I like to buy 2 rather than 4 tires at a time...
tnx, Daniel

[amancuso]

I've seen you post this many times. There is info out there on the net if you care to find it. For example, On Continental Tire's website. They offer PDFs of every range of tire they sell with specs on it. For the Continental DWS tire this is the range for a 16X7 wheel.

55 series This # is approved rim width (ie: 5.5"-7.5" etc.)
205/55ZR16 91W SL BSW 15461960000 No 24.9 18.7 51 8.4 (6.5) 5.5 - 7.5 1356 10 834
215/55ZR16 93W SL BSW 15462960000 No 25.3 19.1 51 8.9 (7.0) 6.0 - 7.5 1433 10 821
225/55ZR16 95W SL BSW 15462990000 No 25.7 20.6 51 9.2 (7.0) 6.0 - 8.0 1521 10 784
50 series
195/50ZR16 84W SL BSW 15459990000 No 23.7 16.3 51 8.5 (6.0) 5.5 - 7.0 1102 10 877
205/50ZR16 87W SL BSW 15460990000 No 24.1 18.2 51 8.4 (6.5) 5.5 - 7.5 1202 10 862
225/50ZR16 92W SL BSW 15462980000 No 24.9 19.9 51 9.2 (7.0) 6.0 - 8.0 1389 10 834
205/45ZR16 83W SL BSW 15460960000


I would imagine the same would hold true for most manufacturers, if you would like to research further, check out each one's spec.
You can then use this online calculator to check the speedo error due to a different tire size
http://www.miata.net/garage/tirecalc.html

Keep in mind the Z3's speedo calibration is about 3-5MPH optimistic stock.

[dak911]

What I want to know is HAS ANYONE PUT 245 OR 255's on the rear of a non M simple question, no need to get narky

[rf900rkw]

I don't see anything in Al's post that was snarky. All the information you seek is readily available on the internet. Indeed, the tire size placard in the door of your own car should list the rear 245s as the optional tire size from the factory. Now, will 245s fit on your rim width? That will require checking the tire manufacturer's recommendations.

[dak911]

I have been asking if....ANYONE HAS PUT 245 OR 255 on 16" WHEELS ON THE REAR OF THEIR 01 Z 3
YES....I've looked at at the specs...
There is NO mention of larger than 225 on the DOOR JAMB ON 16's ONLY on 17....
OK? ....Please NO WISE answers....IF YOU HAVE DONE THIS OR HAVE KNOWLEDGE THAT IT WILL/WON'T WORK....then me know

[jajou318]

You must not have had your snickers today. lol.

Just chill out, you don't have to attack someone or even those replying saying search... Just chill out I'm sure someone will post with the answer you are looking for.

[dkindig]

The biggest factor here is if the wider tires will work well with the width of your stock rims. It will take some digging on tirerack.com. Use tirerack's recommended width ranges for each size tire and make sure that they will fit the rims properly, and then adjust the profile using the miata tire size calculator so that the circumference is the same as your old tire, and then go back to tirerack and make sure the new width and profile is available in that brand of tire and will work with your stock rim width.

[dak911]

I have verified that they will fit the rims, and there will be about a 5% variation...doesn't seem too bad...BUT WILL THEY FIT UNDER THE FENDER?????

[E.Hands]

Yes

[Scarceas]

Someone is grumpy today.

The factory 16" wheel specs: 16x7 et 46. The factory tire size is 225/50.

If you don't want to mess up your speedo, keep the diameter close. So if you want 255s in the back, decrease the series profile accordingly, e.g. 225/50 is 24.9", and a 255/45 is 25" in diameter. That's less than 1% difference; I'd call it close enough. If you do 255/50 the diameter is 26.1" and that would put your speedo nearly 5% off.

With the diameter essentially the same, you don't have to worry about it fitting under the fender, but it will be 15mm closer to the suspension: 30 mm wider total, 1/2 on the outside, 1/2 on the inside. It will probably fit, but be prepared to use some spacers if not.

I suspect it will work, but I don't think you'll get the optimum grip from a 255 on a 7" wide wheel. I would want an 8" or wider wheel.

[dak911]

Someone is grumpy today.

The factory 16" wheel specs: 16x7 et 46. The factory tire size is 225/50.

If you don't want to mess up your speedo, keep the diameter close. So if you want 255s in the back, decrease the series profile accordingly, e.g. 225/50 is 24.9", and a 255/45 is 25" in diameter. That's less than 1% difference; I'd call it close enough. If you do 255/50 the diameter is 26.1" and that would put your speedo nearly 5% off.

With the diameter essentially the same, you don't have to worry about it fitting under the fender, but it will be 15mm closer to the suspension: 30 mm wider total, 1/2 on the outside, 1/2 on the inside. It will probably fit, but be prepared to use some spacers if not.

I suspect it will work, but I don't think you'll get the optimum grip from a 255 on a 7" wide wheel. I would want an 8" or wider wheel.

THANK YOU THANK YOU
That is what I wanted to know.....I think I'll go with the 245....

[dak911]

The word from TIRE RACK is, it is not recommended to use staggered tires on 16" wheels....OK, so has anyone put 245 or 255's on the 16's...on the rear of an 01 2.5 ??
Could be that TIRE RACK has a liability problem (thanks Lawyers), Oh, and it seems to be OK for 17" wheels...??????

[amancuso]

The reason why is because the width on 17" Z3 wheels is staggered. 7.5 in front and 8.5 in back on my OEM 17" wheel set. I don't know anyone who has done as you ask. personally I wouldn't unless you get staggered alloys.