Should I go with a 225/235 front & 265/275 rear tire?

[Alext]

Looking at some Goodyear Eagle F1 A2's . Not sure if I should go with the wider 235 on the front. This is for the 35is 19 inch rims.

And a wider 275 tire on the rear because I am worried it might set the speedo off too much and also affect the electronics for DTC etc. as the RPM's are a lot different to stock tires.

[ManiacGT]

My car (35i) has 225 front and 255 rear. I'm considering taking this up to 235 and 265 to give more rim protection. It has a difference of 61.5mph real speed when speedo shows 60. Hardly anything really. I'll just keep a smidge under the speed limit and I should be spot on.

[CedarZ4]

BMW is known to have a 3% error in their speedometer readings (not official, of course, but many speculations with "scientific" data. Do a search). So, upgrading to 245/275 will actually correct your actual speed since BMW speed is faster than actual speed. (this contrary to what Maniac's case - from what I've read, never done the test myself so take this with a grain of salt). From my understanding though, BMW overestimates speed so if you get a speeding ticket, you can't argue the speedometer says you are going slower (due to regulation in Germany). I worried about this before switching to 245/275 as well.

Also, if you do 275 rears, make sure to do 245 fronts. You want the different (in staggered set-ups) to be 3 size (30mm) apart for increased performance (look at most OEM staggered tired sizes - almost all are 3 sizes apart). Another popular option is 235/265, but depending on width of your wheels, you may want to run 245/275 if you don't like the stretched looks.

Oh and also, if you do decide to do 245/275, here is from when I got my wheels. Hope it gives you an idea of the wheel space because I had a lot of trouble finding 245/275 on a Z4 with stock suspension (M)

http://e89.zpost.com/forums/showthread.php?t=852609

[Innovative AutoConcepts]

I have 235/265rear

[Gizmo-R]

Are the alloys on the Z4 staggered?

[CedarZ4]

Originally Posted by Gizmo-R

Are the alloys on the Z4 staggered?

Stock OEM (18s and 19s) are staggered. The 17s are squared (which is also used in the Winter Package)

[nicknaz]

I believe there are some 35i with staggered 17 (earlier cars with no sport package).

OP, my understanding is that 245 front may rub and you will have to do some digging/measuring to verify.

225 and 235 front are the "set it and forget it" sizes.

[CedarZ4]

Originally Posted by nicknaz

I believe there are some 35i with staggered 17 (earlier cars with no sport package).

OP, my understanding is that 245 front may rub and you will have to do some digging/measuring to verify.

225 and 235 front are the "set it and forget it" sizes.

Nick is correct, I stand corrected.

In regards to the rub, I was really concerned about rub especially on uneven roads but I really did not like the stretched looks of 235 on 9' wheels. However, after many measurements, I decided it would fit. Have had it for a few months now and over 3,000 miles. With M-Sport suspension, there is no rub and I did not have to roll fenders.

[army_men]

235 and 265 on mine with VMR rims. Fronts are fine and a lot of grip. rear has rubbing on the track. no rubbing during daily drive.

[Alext]

Cool thanks for the replies. Looks like I will go for 235/265.

Anyone got the alignment specs?

[Alext]

I like the look of the 275 rears. What would happen if I go for 235 fronts and 275 rears? IS the difference between front and rear that critical?

[army_men]

Originally Posted by Alext

I like the look of the 275 rears. What would happen if I go for 235 fronts and 275 rears? IS the difference between front and rear that critical?

i dont think you'll feel too much during daily drive, if you push the car in corners you may experience more understeer as the front wheel will lose grip before the rear. But this car was engineered with understeer so you aren't changing much.

May get rubbing though.

[nicknaz]

traction control uses difference in rotational speed of tires as one input so I would say yes, difference in front and rear diameter matters. The key question is "how much is too much" and I haven't ever found a good answer to that. My rule of thumb has been to check the diameter difference front and rear of the OEM staggered setups and not exceed that difference with an aftermarket combo

Another thing to keep in mind is that rub marks is a sure sign a car is/has been modified and some shops look harder for more mods when doing work. Not sure what your plans for the car are or how important warranty is to you, but it is something to keep in mind

[Hujan]

A lot depends on the (1) tire type and (2) the rim width. A 235 tire in one brand/style may be wider or more "square" shouldered than another. Also, a 235 tire of whatever brand/style will "sit up" more on an 8" rim than an 8.5" rim, since the latter will stretch the tire out a little more.

Having said all that, I am on 235/265 Michelin Pilot Super Sports with 8.5" fronts and 9.5" rears and have no issues. Everything sits fairly flush, too. I've had no problems with traction control, either.

Highly recommend the 235/265.

[Frank Costanza]

I went with 225 fronts 265 rears when I went through this.

I could have done 235 / 275 but I thought it might tram line more. I doubt there's any difference considering most people seem to be running that setup.

[Alext]

So what do people think of the Goodyear F1 Asymmetric 2s? Can they compare to the Michelin PSS considering the price difference?

[nuebbes]

rim ---- tire min ---- tire best width ---- tire max

8,0J ---- 215 mm ---- 225 or 235 mm ---- 245 mm
8,5J ---- 225 mm ---- 235 or 245 mm ---- 255 mm
9,0J ---- 235 mm ---- 245 or 255 mm ---- 265 mm
9,5J ---- 245 mm ---- 255 or 265 mm ---- 275 mm
10,0J ---- 255 mm ---- 265 or 275 mm ---- 285 mm

reference: http://www.reifen-pneus-online.de/zustandstabelle-ratschlaege.html


In my opinion, 235/265 on the oem rims already look borderline (I had these on my previous winter rims (style 296) - too angular.

For 8J and 9J 225/35 and 255/30 are the best choice.
For 8,5J and 9,5J 235/35 and 265/30 are the best choice.

Here in Germany it is forbidden to have too big differences in the diameter because of the tachometer-deviation.

[jts1981]

I have 245 in the front, 275 in the rear with absolute no rubbing.

[jts1981]

But my 275 is on a 10 inch rear