ma'z'y Posted February 23, 2011 Share Posted February 23, 2011 Getting some new tyres and want to go with 225/35/18 up front and 255/35/18 on the rear, i think the rolling radius difference comes out at 3.4 % which is only 1% (ish) over stock so shouldnt cause any problems with TC. If anyone can see a problem with this set up or has ran it themselves please chime in as it could be a very expensive mistake. ( wheels are 8.5 wide and 9.5 respectfully ) Quote Link to comment Share on other sites More sharing options...
Ekona Posted February 23, 2011 Share Posted February 23, 2011 225/45/18 on the front would be much better, no need to drop the sidewall width as you'll kill the ride. 255/40/18 on the rear would be better if they do them on the rear, or a 275/35/18. You'll get a standard 245/45/18 tyre on a 9.5" rim anyway. Quote Link to comment Share on other sites More sharing options...
ma'z'y Posted February 23, 2011 Author Share Posted February 23, 2011 225/45/18 front and 255/40/18 gives a -0.2 % reading so i think id be seeing the TC light a little more than i want. Difference between front and rear stock is around 2.7% i think. Quote Link to comment Share on other sites More sharing options...
Ekona Posted February 24, 2011 Share Posted February 24, 2011 Eh? Don't go on the difference between front and rear, go on the difference between each tyre compared to stock. For example: The difference between a 245/45/18 and a 255/35/18 is 6.2%, or way over spec. The difference between a 245/45/18 and a 255/40/18 is 2.4%, or just slightly over spec. I'm assuming you've gone for wider tyres so you can run wider rubber, in which case the 275/35/18 is 4.1% over spec which should be fine. A 245/40/18 would be a better companion too on the front, as you've only increased the stagger by 10mm which shouldn't lead to too much understeer. Quote Link to comment Share on other sites More sharing options...
ma'z'y Posted February 25, 2011 Author Share Posted February 25, 2011 I thought by keeping the tyres (front and rear) within a small percentage would be what affected the Tc- surley it works by making sure the wheels are all turning at the speed. So as long as that difference between front and rear rolling radius stays the same it should work. Have i got this completely wrong or does my thinking make sence? Heres a good way to test what im saying- according to my theory we should be able to run any size wheels (as long as they fit of course) by keeping the rolling radius between the front and rear within stock percentage parameters? What you think ? Quote Link to comment Share on other sites More sharing options...
ma'z'y Posted February 25, 2011 Author Share Posted February 25, 2011 Right iv got it......... 350Z-TECH STOCK BASE - FRONT 7.5 225/50/17 SIDEWALL=112.5MM RADIUS =328.4MM REAR -8 235/50/17 SIDEWALL=117.5MM RADIUS =333.4MM TOURING - FRONT 8 - 225/45/18 SIDEWALL=101.2 RADIUS= 329.8 REAR 8 - 245/45/18 (35/ 18 WILL FIT) SIDEWALL=110.2MM(85.8MM) RADIUS= 338.8(314.4) So iv got good tread left on my front tyres which are Vredestein 225/45/18 on 8.5 wide alloys giving me stock dimensions'ish (slightly stretched because of the wider wheel). Ill go for 255/40/18 on the 9.5 wide rears (again slightly stretched but will keep stagger only 10mm over). 225/45/18 fronts - sidewall 101.2mm radius 329.8 255/40/18 rears - sidewall 102mm radius 330.6mm must be right this time Quote Link to comment Share on other sites More sharing options...
Ekona Posted February 25, 2011 Share Posted February 25, 2011 Try it and see. If you're gentle on the throttle you'll probably not notice any difference anyway. Quote Link to comment Share on other sites More sharing options...
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