jumping350 Posted October 5, 2014 Share Posted October 5, 2014 Need help off the tyre size gurus if possible. I currently have a set of Rota GTRs 18s Im getting a set of rear 19 inch Rota GTRs which will be 19x10j et20 The 18 inch rears are currently 9.5j and running 245/45/18 (I also have a rear set of tyres at 255/40/18 if it will help the situation) My question is can I move the rears to the front with the tyre size I have (or the set off the car 255/40/18) and if so what size would I need for the rears to keep TCS happy? If not what sizes would I need for the front and rears to keep everything normal? Im doing this basically because I can then have concave effect on all 4 wheels as opposed to just the rears and also with the adding of a supercharger would aid in some more grip back there. Any help much appreciated Quote Link to comment Share on other sites More sharing options...
GMballistic Posted October 5, 2014 Share Posted October 5, 2014 Your post is a little confusing when referring to the sizes 18" and 19" but I'm guessing you're asking if you can run a 255/40/18's on the front before you get the 19" alloys are you? If so then yes. You would need a 285/40/18 then on the rear I believe. If you meant 19" then you can run 255/35 front and would again need a 285/35 on the rear. FYI ~ I currently run 245/35/19 on a 9.5J ET20 on the front and 275/35/19 on a 10.5J ET20 on the rear of my Zed. Works fine with no TC issues. You could also run 255/35/19 & 285/35/19 but depending on your ride height you may start to find issues with rubbing but if you're standard ride height it should be ok. If you're still struggling with what sizes to get try a PM to Mitz at The Cougar Store as he was a godsend when getting mine. Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 5, 2014 Author Share Posted October 5, 2014 (edited) maybe it wasnt explained well then I wanted to put the current rear 18 inch on the front (which runs 245/45/18 at the moment, 9..5j) and 19 inch on the rear 10j so what tyres would i need for 18 front and 19 rear and could I use any of the 18s tyres I currently have for the front? if that makes sense Edited October 5, 2014 by jumping350 Quote Link to comment Share on other sites More sharing options...
GMballistic Posted October 5, 2014 Share Posted October 5, 2014 So run 18"s on the front and 19"s on the rear? Hhhmm. It's doable I'm sure but I wouldn't want to advise you as I have no experience with that tbh. Honestly I'd send a PM to Mitz to see if he can help you as he's a good guy or maybe zmanalex to see if he knows "maybe". Link: http://www.350z-uk.com/user/8724-cs/ Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 5, 2014 Author Share Posted October 5, 2014 yeah thats right 18s front 19s rear, cheers GM will do, Ive been searching but cant seem to find an answer, im sure its doable loads of other cars have larger rears than fronts Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted October 5, 2014 Share Posted October 5, 2014 Will you be changing the front to 19's eventually ? Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 5, 2014 Author Share Posted October 5, 2014 wasnt planning to, is not ideal to run that setup then? Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted October 5, 2014 Share Posted October 5, 2014 Please check but I think you would need too small a tyre wall on the 19 to retain the rolling radius of the 18 Standard 19's run 245/40/ 19 and 275/35/19 Quote Link to comment Share on other sites More sharing options...
GMballistic Posted October 5, 2014 Share Posted October 5, 2014 Only for your info but found some info in this thread. Link: http://www.350z-uk.com/topic/36491-handling-differrences-18-vs-19/ NISMO 350Z (2007–2008)This edition of the 350Z Coupé debuted in New York International Auto Show on 2007-04-04. This version featured the same engine as the regular 350Z (VQ35HR) with 6-speed manual transmission only. The car featured NISMO aerodynamics package based on the Super GT championship car, which included an aggressive front fascia with chin spoiler, side skirts, an extended rear fascia with under body diffuser and a rear wing. The car also had NISMO-tuned independent multi-link suspension, Brembo brakes with four-piston front and two-piston rear calipers (with 12.8-inch (330 mm) front and 12.7-inch (320 mm) rear rotors) and NISMO-branded gunmetal grey RAYS alloy wheels (18x9-inch front and 19x10-inch rear with 245/40WR18 front, 265/35WR19 rear Bridgestone Potenza RE050A tires), and NISMO-branded tuned exhaust. All Nismo versions are "Ready For Track" with the safety equipment in it. I'd still ask Mitz though to see what he thinks just to be safe. 1 Quote Link to comment Share on other sites More sharing options...
Ekona Posted October 5, 2014 Share Posted October 5, 2014 No reason you can't run different sized wheels at all. It might look a bit odd at first, but as long as you keep the tyres vaguely balanced front to rear then you won't have too many issues. Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted October 5, 2014 Share Posted October 5, 2014 Only for your info but found some info in this thread. Link: http://www.350z-uk.c...ences-18-vs-19/ NISMO 350Z (2007–2008)This edition of the 350Z Coupé debuted in New York International Auto Show on 2007-04-04. This version featured the same engine as the regular 350Z (VQ35HR) with 6-speed manual transmission only. The car featured NISMO aerodynamics package based on the Super GT championship car, which included an aggressive front fascia with chin spoiler, side skirts, an extended rear fascia with under body diffuser and a rear wing. The car also had NISMO-tuned independent multi-link suspension, Brembo brakes with four-piston front and two-piston rear calipers (with 12.8-inch (330 mm) front and 12.7-inch (320 mm) rear rotors) and NISMO-branded gunmetal grey RAYS alloy wheels (18x9-inch front and 19x10-inch rear with 245/40WR18 front, 265/35WR19 rear Bridgestone Potenza RE050A tires), and NISMO-branded tuned exhaust. All Nismo versions are "Ready For Track" with the safety equipment in it. I'd still ask Mitz though to see what he thinks just to be safe. http://www.willtheyfit.com/ Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 5, 2014 Author Share Posted October 5, 2014 cheers everyone and for links il do some reading and report back Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 5, 2014 Author Share Posted October 5, 2014 (edited) hmmm mitz didnt really know as never supplied in those sizes before. so still trying to figure out from above information: Fronts Nismo: 18x9 245/40/18 Mine: 18x9.5 245/45/18 Rears Nismo: 19x10 265/35/19 Mine: 19x10 ???/??/?? or shall I just get fronts and rears the same as the Nismo setup and will the fact the front wheel is .5 wider matter? and as mentioned the standard size for the 19s is 275/35/19 would i be ok going down to 265? Not much info about so im hoping it wont have to be trial and error Edited October 5, 2014 by jumping350 Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 5, 2014 Author Share Posted October 5, 2014 (edited) I used the tyre fitment calculator Gixxer linked to and got these results Rear: Old 245/45/18 New: 275/35/19 Diameter 677.7mm 675.1mm Circumference 2129.1mm 2120.9mm Poke 90.7mm 107mm Inset 150.7mm 147mm Speedo error 0% 0.39% Reading at 30mph 30mph 30.12mph Reading at 60mph 60mph 60.23mph Ride height gain 0mm -1.3mm Arch gap loss 0mm -1.3mm Front: Old: 235/45/18 New: 245/45/18 Diameter 668.7mm 677.7mm Circumference 2100.8mm 2129.1mm Poke 78mm 90.7mm Inset 138mm 150.7mm Speedo error 0% -1.33% Reading at 30mph 30mph 29.6mph Reading at 60mph 60mph 59.2mph Ride height gain 0mm 4.5mm Arch gap loss 0mm 4.5mm Not sure what any of that means but if any one has a clue let me know Edited October 5, 2014 by jumping350 Quote Link to comment Share on other sites More sharing options...
GMballistic Posted October 5, 2014 Share Posted October 5, 2014 The .5" wider front rim won't matter providing you are using the correct tyre dimensions. I would say you need to reduce the profile down to the 40 to match the Nismo setup. If the sizes are good enough for Nismo then I'd imagine it was correct. If I was doing this though I would be looking at 245/40/18 front and 275/35/19 rear. This is not a recommendation though jumping350 as I said previously I have no experience of this setup so if this is what you are going to do is it at your own risk. Quote Link to comment Share on other sites More sharing options...
Ekona Posted October 6, 2014 Share Posted October 6, 2014 If I was doing this though I would be looking at 245/40/18 front and 275/35/19 rear. This. If you don't reduce the front profile having increased the width, you'll end up with a balloon of a tyre. Quote Link to comment Share on other sites More sharing options...
Lexx Posted October 6, 2014 Share Posted October 6, 2014 Just as a side note. ...what offset are the 9.5 18s you want to put on the front? At 9.5 wide they'll need the right offset otherwise they could end up sticking out beyond the cars profile. Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 6, 2014 Author Share Posted October 6, 2014 Thanks guys I'm going to go with those sizes (at my risk of course GM lol) I was expecting it would probably be trial and error but those sizes make sense really, well at least il find out soon enough, thanks again il get some tyres and report back Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 6, 2014 Author Share Posted October 6, 2014 They are et30 Quote Link to comment Share on other sites More sharing options...
jumping350 Posted October 6, 2014 Author Share Posted October 6, 2014 (edited) is et30 and that tyre size ok? just checking as im about to order some tyres, would that stick out beyond the cars profile at the front? I would of thought so as they looked liked they needed spacers on the rear Edited October 6, 2014 by jumping350 Quote Link to comment Share on other sites More sharing options...
jumping350 Posted February 24, 2015 Author Share Posted February 24, 2015 Just reviving this. The 19s are covered now with 275/35/19 so no problem there. With the fronts as mentioned above I would have to reduce profile to 40 though am i able to keep the 45 profile on short term whilst other stuff gets done to the car? So driving wise would it be ok? Surely the rolling radius is the same as its going from the rear tot he front? Not fussed if it looks ballooned as it will be changed to a 40 later on here is that tyre on the 18 (rear) and how it looks any help appreciated Quote Link to comment Share on other sites More sharing options...
brillomaster Posted February 24, 2015 Share Posted February 24, 2015 (edited) you'd likely get TCS issues running the 245/45/18 on the front with a 275/35/19 on the rear, but you can turn the TCS off for a while I guess. A Zed needs rear tyres with a slightly larger diameter (approx. 2.5% larger) than the fronts, for the TCS to be happy. did you mention you had some 255/40/18s kicking around? if you fit them to the front it would drop the profile enough to then match up with the rears nicely. but you are correct, the right size front to go with a 275/35/19 rear would be a 245/40/18 on the front. Edited February 24, 2015 by brillomaster Quote Link to comment Share on other sites More sharing options...
KyleR Posted February 24, 2015 Share Posted February 24, 2015 If you are running 245/45/18 front and 275/35/19 rears you are in effect running a square set up, so this will likely cause you TCS issues. Quote Link to comment Share on other sites More sharing options...
jumping350 Posted February 24, 2015 Author Share Posted February 24, 2015 Thanks Brillo and Kyle R, thought as much and to top it all off, like a douche I sold the 255/40 as I thought I wouldn't need them will keep the old fronts on then till I get the right tyres for the rear to go on front. Quote Link to comment Share on other sites More sharing options...
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