Stock wheels an tire question
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As dkmura says, yes, you can and it won't affect the VDC if your car is so equipped. But, a better size for exact matching diameters (to both avoid the "front end raised look" - the 245/45 is 0.71" taller and maintain exact steering response) is to run a 245/40-18 which is almost the exact same height as the stock 225/45-18.
Mic:
Are you saying to go to 40 series on all four wheels, or just the fronts?
I had assumed that the OP was looking for wider fronts as well as the ability to do a four wheel rotation.
My 2005 GT roadster was OEM Bridgestone 225/45/18 front and 245/45/18 rear. Single directional no less. No ability to rotate, short of cross rotation which would requre remounts. This voids all tire manufacturer warranties I found out the hard way on replacement set of Michelins, which were non single directional.
It ate the OEM tires in about 20,000 miles. Not equally of course. Just ate down to bare threads on the inner front.
The second set of Michelins it ate in about 30,000 miles. Which is when I found out about the warranty issue.
Multiple alignments and shop opinions didn't seem to help. I ended up playing games with used, same manf, model, size tires off eBay for a while to run a set to where all four were equally worn and simultaneously replaced.
I considered going to cheaper tires and accepting that at 20,000 miles at least one would be dangerously unusable and just replace all four then. But I hate waste and, my life experience with tires has been that cheap tires always gave me headaches. So, I finally opted for another set of Michelins because COSTCO has such good deals on them. I drive the car much less now and have only put about 6,000 miles on them. I haven't measured tread depth in a while but plan to rotate them side-to-side when we get some nice weather.
Along the way to 90,000 miles I found this wierd thing with tire wear - this car & the Michelins - setting the fronts to 31 PSI cold and the rears to 36 PSI cold - gave me the longest tread life before some wierd wear pattern made at least on of them unusable. Go figure.
Don't even get me started on TPMS sensors and the $160 I wasted on a set of those because tire tech "swears" I didn't get the right ones, that mine are for a 370Z, even though part number is exact match to OEM replacement number. To be fair, my "OEM Nissan replacements" bought off eBay, might be some cheap Chinese knock offs. Although they look identicle to the originals and are stamped with the same part number, they do lack a couple of other markings that the OEMs have.
So, I'm stuck with the aftermarket sensors that COSTCO installed, which for some strange reason, only work when the outside air temperature is above 65 degrees or, if the car hasn't been started/driven in a coupld of days. Most of the time, I get only two or three readings.
The whole TPMS thing, especially the 4 wheel kind like our Zs have, turned out to be more headache than value. This was true across all makes and models which is why it was shortlived.
Are you saying to go to 40 series on all four wheels, or just the fronts?
I had assumed that the OP was looking for wider fronts as well as the ability to do a four wheel rotation.
My 2005 GT roadster was OEM Bridgestone 225/45/18 front and 245/45/18 rear. Single directional no less. No ability to rotate, short of cross rotation which would requre remounts. This voids all tire manufacturer warranties I found out the hard way on replacement set of Michelins, which were non single directional.
It ate the OEM tires in about 20,000 miles. Not equally of course. Just ate down to bare threads on the inner front.
The second set of Michelins it ate in about 30,000 miles. Which is when I found out about the warranty issue.
Multiple alignments and shop opinions didn't seem to help. I ended up playing games with used, same manf, model, size tires off eBay for a while to run a set to where all four were equally worn and simultaneously replaced.
I considered going to cheaper tires and accepting that at 20,000 miles at least one would be dangerously unusable and just replace all four then. But I hate waste and, my life experience with tires has been that cheap tires always gave me headaches. So, I finally opted for another set of Michelins because COSTCO has such good deals on them. I drive the car much less now and have only put about 6,000 miles on them. I haven't measured tread depth in a while but plan to rotate them side-to-side when we get some nice weather.
Along the way to 90,000 miles I found this wierd thing with tire wear - this car & the Michelins - setting the fronts to 31 PSI cold and the rears to 36 PSI cold - gave me the longest tread life before some wierd wear pattern made at least on of them unusable. Go figure.
Don't even get me started on TPMS sensors and the $160 I wasted on a set of those because tire tech "swears" I didn't get the right ones, that mine are for a 370Z, even though part number is exact match to OEM replacement number. To be fair, my "OEM Nissan replacements" bought off eBay, might be some cheap Chinese knock offs. Although they look identicle to the originals and are stamped with the same part number, they do lack a couple of other markings that the OEMs have.
So, I'm stuck with the aftermarket sensors that COSTCO installed, which for some strange reason, only work when the outside air temperature is above 65 degrees or, if the car hasn't been started/driven in a coupld of days. Most of the time, I get only two or three readings.
The whole TPMS thing, especially the 4 wheel kind like our Zs have, turned out to be more headache than value. This was true across all makes and models which is why it was shortlived.
Joined
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79 Posts
Tire choice is all about intent-of-use. If you drive the car the way it was to be driven, sooner or later, you probably want to upsize the tires. To answer the question about 40 series all around. IF one is upsizing wheels or just wants a slightly wider set on OE wheels then going to a 40 series tire is required to keep the rolling diameter (tire height) the same or as close to stock as possible.
Meaning: if you go to a 245 section width in front (up from 225), you need to go to a 40 aspect ratio tire to keep the diameter the same as stock. Same for rear, going up to a 275 width means you need to move to 40 aspect as well. Same applies to going Plus-1 wheels (say, from 18s to 19s), the aspect ratio needs to go even further down to, say 245/35 and 275/35 rear.
It's a pretty simple concept actually, just do the math to figure out which size you have as OE and that will tell you what height to maintain.
(Section width/25.4) x aspect ratio (as a percentage) x 2 (two sidewalls) + wheel diameter = Tire diameter in inches
(Or, if you prefer it all in metric, skip the first division by 25.4 to keep it metric but since the wheel diameter is almost always expressed in inches - except for those odd TRX tires back in the day - a conversion will have to take place somewhere along the way. :laugh
Oh, and your mileage comments.... you're lucky to get 20-30k on performance tires for the Z.
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18 Posts
So I have a set of ssr gt3 2 piece wheels, fronts are 10” wide, rears are 12”, and they’re 19s, I want to run a 255/35R19 front and a 305/30R19 rear, they’re on a 2004 350Z, procharged, 414 hp to the wheels, I just picked this one up, it’s running 285s in the rear and I just think it can hook up better. General g-max RS will be the tire, I just installed a ISC N1 coil over suspension and have it about 1/2 inch lowered, I don’t think they will rub but I wanted to see if anyone is running a similar set up. Any information would be great!
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79 Posts
Fenders rolled? I would tend to think so if you're running 285s with no rub. BUT, no mention of the most important factor in sizing.... offset. What are the offsets of your SSRs?
Your 255/305 combination might also be a bit too widely staggered and lead to more understeer. If you're going to a 305/30 (which is a bit short but could work), would strongly suggest a slightly wider front tire. 255 will work but again, paired with the 305, may not give you the type of handling you want.
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18 Posts
Thanks for the reply, all I can say at this point is they have spacers and are flush, after doing some size calculations l feel that I can do 265/35zr19 front and 285/35zr19 rear without affecting the vdc or trac, the spacers are probably about 10 mm, and are literally just taking up wheel stud space, so I will need to replace the studs with longer studs or replace the spacers,as I just purchased this Z I am just coming across things I need to make right. It has potential but needs some finessing, I am trying to dial it in, and am starting from the tires up, though I have replaced the eibach springs with ISC N1 coil overs and have spc rear toe elongation eccentric bolts to install as well, which will happen prior to the tire installation. This will be my 3rd 350Z, and the most modified, the first 2 were mildly modified, exhaust, intake, plenum and tires, I feel like this one can be a restoration of sorts with a strong supercharged and built motor. I am going off on a tangent now but this Z is so fun to drive that I just want to make it right. Thanks for the info!
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