Hey guyz when you go up in tire size do you have to mess with you speedo to get the mph correct since your tires will be larger, i want to go to 18s rather than my 16s but i wasnt sure if i would have to do this or if my LT1 computer would just "kno" please help me out, thanks~!

 

Well you have to plus size the tires correctly. Stock size for 16s was 235/55/R16 I believe, so you'd be going up to 18" rims which would be plus 2 giving you 255/35/R18. Which would fit on an 8.5" to 9" rim just fine.

I'm only plus one so I run 245/45/R17s on my car.

 

You should go find some wheel calculators. I used google to find some when I did my research. The basic idea is what Frik92RS said, when the rim gets bigger, the sidewall gets smaller. The goal is to end up with the same overall measurement as the OEM wheel (or as close as possible). Your width of the tire will also play a role in this. Here's a pic of my 91Z on 18's:



My tire sizes are 245/40/18 front and 275/35/18 rear. Both of those tire sizes were as close as possible to the overall measurements of the OEM wheels. The reason the front is 40 series and the rear is 35 series is because the front is a 245 and the rear is a 275 (these were what fit my wheels which were 18x8 front, 18x9.5 rear). If I had 18x9.5 all around I would be running 275/35/18 all around but I would probably have fitment issues in the front with the ammount my car is lowered. There is a .03% difference in the reading of my speedo. So if my speedo reads 50mph, I'm actually going 51mph (very small difference). 18's kick ***!

 

Thanks alot guyS!!! tell me what you think of these kick *** rimz i found for my black formula... I'm not sure yet on what brand of tires i wanna run yet tho... any suggestions?

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2443329614

 

other than the fact that they aren't going to fit on your black formula, they look good

 

why dont you tell me y they wont fit rather than just lettin me hang...

 

what did i miss

 

the bolt pattern is incorrect.

your car is on a 5x4.75" bolt patter (or 5x120.65mm)

those wheels are on a 5x4.5" (5x114.3mm)

basicly, if you had a mustang or an import that uses that bolt pattern, they might work work.

i didn't even take the time to look at the offset, which is probably not correct either.

 

the offset was +35, and damn it i thought i had that bolt pattern...

 

not like i have the money for em, or i woulda checked that but soon enough i will, thanks for the info guys

 

you must go off your particular cars stock tire size....for instance mine was 245/50/16 so i went with the same idea as crazy. my fronts are identical to his in size but my rears are 285/35 because they are on a 10" wheel.

i love my 18's but because of the dish i almost wish i went with 19's. they look like a 17 on the car but i still love them.

2-3 piece billet is the way to go.

 

I think those rims would require spacers which makes the bolt pattern ok. You can just get the spacers that convert your pattern to 4.5".

 

thats not a recommended thing to do though right? isn't that a little unsafe or something like that? or am i just nutz? Because i'd love to get those rims if i could!

 

wheel adapators are plenty safe IMHO, spacers on the other hand...

 

bolt on spacers = good.

slip on spacers = bad.


simple



anyhoo to give you a idea how to compare two tires, this is the best "visual" wheel calc ive seen so far:

http://www.miata.net/garage/tirecalc.html

 

thanx dude, that is a tight *** calc! so adapters or spacers?? which is more expensive, where can they be acquired? Which will not break and is stronger?

 

just for the heck of it, and because ive posted that link a few other times, i put a copy of that calc in my webspace:

http://josh.swoca.net/board/mrdude/T...c/Tirecalc.htm


anyhoo...

http://www.skulte.com/adapterfaq.html

good FAQ.....and he sells great adapters too.



edit: whoops, hit the send button too soon by accident.

 

thanks man thats alot of help!