Profile Tyres And Act Rego

[CeJay]

Since ACT rego seem to want to stuff me around, anyone on here able to confirm how much bigger profile tyres I can run vs standard? Ie is my cars came with 205/35 front tyres can I run 235/45 or whatever?

Also what about diameter of tyres?

[W1ngnut]

CeJay, I cannot confirm with the R32, but my rim/tyre combo are engineered and passed through dickson. 235/40 front and 265/35 rear. (Std for R33 I was pretty sure are 205/55 or something like that)

The diameter of the tyre doesn't matter as long as you don't modify the rolling diameter (much). Which is tested with the GPS by the engineer against your speedo.

[CeJay]

well ended up giving canberra connect a call and they ended up saying the following.:

Rolling diameter can't go up more than 15mm.

Track can't go up more than 25 mm etc.

Just need to check if my "235/45" profile tyres will be withing 15mm of the standard r32 profiles.

[nerm]

Ie is my cars came with 205/35 front tyres can I run 235/45 or whatever?

Also what about diameter of tyres?

i assume you meant 205/55??

diameter of the tyre depends on the size of the wheel (ie 16 or 17 inch + the side wall of the tyre) the standard r32 wheel is a 16inch.. so are you running your 235/45 on a 16 or a 17 inch wheel?

235/45R16 is 7mm smaller (rolling diameter) than a 205/55R16

however a 235/45R17 is 18.4mm bigger (rolling diameter) than a 205/55R16

This is all assuming that the tyres arent stretched too much over the rims

Track is all to do with the offset of the wheel as compared to stock so i got NFI on that front.. i think stock r32 (non GTR) offset is around +40

why dont you just borrow someones stock wheels to get your car over the pits?

Edited September 14, 2009 by nerm

[CeJay]

I'm running it on 17 inch rims at this stage I'll probably just be swapping my 235/45 profile tyres onto my 7.5 inch wide 17' ROH rims. Will confirm the tyre placard tonight as i think they were slightly different front to rear. Otherwise I'll get other rims.

[nerm]

japs tend to have different sizes front and rear. my car comes stock with 205/55R16 Front and 225/50R16 on the rear.

im currently running 235/45R18 front and 265/30R18 rear. Strangly enough 265/30R18 is only 17mm bigger than 225/50R16 on paper but it actually comes at about 14mm because the tyre is streched

[Victory]

Chris this is all about the overall diamater of the rim and tyre combination and is best explained by the attached Toyo tyre chart.

The standard Skyline tyre size is 205/55R16 and has a diamater of 634mm and this means that any tyres that are between 619mm and 649mm are legal on your car.

Some common tyre sizes that guys run are:

235/45ZR17 644

255/40ZR17 636

235/40ZR18 644

265/35ZR18 644

The other interesting point is to try and find common sizes that are sold in larger numbers as the unit cost will be lower (eg on my R33GTS-T I run 245/40ZR18 on the front and 265/35ZR18 on the rear and the 265 are about $40 cheaper per tyre).

Toyo_Proxes_4.pdf

[nerm]

Chris this is all about the overall diamater of the rim and tyre combination and is best explained by the attached Toyo tyre chart.

The standard Skyline tyre size is 205/55R16 and has a diamater of 634mm and this means that any tyres that are between 619mm and 649mm are legal on your car.

the 634mm will change depending on the width of the rim and the stretch of the tyre. what is the width of the rim that that measurement was taken from?

[Sinista32]

Im prolly way off here but doesn't the plackard on the inner of the drivers door provide the info on Rims/Tyres ???

[CeJay]

well looks like my tyres might just scrape in

r32 runs 205/55 R16s on the front

225/50 R16's on the back

or 631.90 and 631.40

235/45 R17 rims are 643.30 mm rolling diameter

http://www.sr20tuning.com/tyresize.html

and yeah I've finally got my tyre placard, thanks for the help though

[Sinista32]

Thanks Chris. I used the table in your thread for tyres on my shitter...

[MIVEC]

Thanks Chris. I used the table in your thread for tyres on my shitter...

Your toilet has wheels? Bet it helps when you really need to go!

[W1ngnut]

Don't even want to picture the skidmarks that get left from it....

[Sinista32]

I knew I shouldn't have had the vindaloo curry!

Edited October 5, 2009 by Sinista32