Staggered Tyre Size Recommendations

Re: Staggered Tyre Size Recommendations (Admin)

Mon, 14 Jan 2019 10:13:00 GMT

FYI I have a pair of 255x40x17 Kumho street legal semi slicks for sale. These will fit nicely on the rear assuming that you have lipped guards. They have lots of tread left. $100 for a pair.
I'm in Sydney.

Re: Staggered Tyre Size Recommendations (Sivocci)

Sat, 12 Jan 2019 12:42:03 GMT

I went through the tyre size exercise two years ago, upgrading from the standard 14" wheels. 17s are the first size that now really has performance tyres, and the Kumho I got were one of the few that that you could get in both the front and rear sizes.
The 215/40/17 work quite well. The rear 235/40/17 is needed for the load rating. With either 225/45/17 or 245/35/17 there isn't enough air inside the tyre to get the load rating without going to XL tyres (stiffer sidewalls and heavier).
From memory the diameter rule was something like no more than 15 mm and then 3%. With 235/40/17 compared to 205/60/14 you need the 3% bit to stay within the legal maximum diameter. The speedo will run low.
A wheel offset of +38 mm has been recommended. My new MCA coilovers have allowed a bit more clearance under the guards with my +38 front and +36 mm rear wheels.

Re: Staggered Tyre Size Recommendations (Wolfspire)

Wed, 02 Jan 2019 22:41:56 GMT

Will do Reddtarga cheers for the guidance

Re: Staggered Tyre Size Recommendations (Reddtarga)

Wed, 02 Jan 2019 18:24:31 GMT

Wolfspire
So ReddTarga if the speed rating which is H is higher that should be ok? if im wrong please do correct me!

Yes, and it is probably the sort of thing that would be checked if you were getting a roadworthy.
But if you want to learn more about tire speed ratings, Google is your friend.

Re: Staggered Tyre Size Recommendations (Wolfspire)

Wed, 02 Jan 2019 11:34:51 GMT

So ReddTarga if the speed rating which is H is higher that should be ok? if im wrong please do correct me!

Re: Staggered Tyre Size Recommendations (Reddtarga)

Wed, 02 Jan 2019 11:06:23 GMT

Wolfspire
im located in QLD,
The sticker you were talking about Reddtarga that's this sticker here that ive linked right? still a newb when it comes to rims and tires i do apologize.

Correct, although your car appears to be a JDM with several tire options listed.
The 'H' figure relates to the tire speed rating.

FWIW the sticker on my ADM SW20 lists only one set of sizes:
Front 195/60 R14 load 85V
Rear 205/60 R14 load 88V
The 'V' speed rating is apparently higher than a 'H' rating

Re: Staggered Tyre Size Recommendations (Wolfspire)

Wed, 02 Jan 2019 10:45:21 GMT

Carmikey

Depends what state you are in. Normally they work on a total rolling diameter up to / no more than 5-8% increase. So 17" 40 profile should be ok, but best check with local road transport compliance dept.

Sent from my SM-J320ZN using Tapatalk

Will do Carmikey my plan for the build for the car is to keep it all legal and by the book

Re: Staggered Tyre Size Recommendations (Wolfspire)

Wed, 02 Jan 2019 10:42:45 GMT

im located in QLD,
The sticker you were talking about Reddtarga that's this sticker here that ive linked right? still a newb when it comes to rims and tires i do apologize.

Re: Staggered Tyre Size Recommendations (Reddtarga)

Wed, 02 Jan 2019 09:05:07 GMT

Apart from rim/tire width and rolling diameter, another thing to check is the load carrying numbers of the replacement tyres, and compare that to the numbers on your doorpost sticker.
The numbers should not be less.

Re: Staggered Tyre Size Recommendations (Carmikey)

Tue, 01 Jan 2019 23:35:22 GMT

Wolfspire
Hi,
Does anyone know what the legal tire / rim width for a 1990 mr2 sw20 is? Im running the stock 14"s (195 front and 205 rear) and I'm hoping to upgrade into some 17s going 205/40/17 front and 235/40/17 rear and Ive been struggling to figure out if the rears are legal, i know its a trivial question. i want to keep the tires/rims legal for the build I'm doing on the car.
Cheers

Re: Staggered Tyre Size Recommendations (Wolfspire)

Tue, 01 Jan 2019 22:15:28 GMT

Hi,
Does anyone know what the legal tire / rim width for a 1990 mr2 sw20 is? Im running the stock 14"s (195 front and 205 rear) and I'm hoping to upgrade into some 17s going 205/40/17 front and 235/40/17 rear and Ive been struggling to figure out if the rears are legal, i know its a trivial question. i want to keep the tires/rims legal for the build I'm doing on the car.
Cheers

Re: Staggered Tyre Size Recommendations (midmadness)

Thu, 09 Jan 2014 21:55:15 GMT

Looks like I'm fine here in Canberra. ACT works according to the National Code of Practice (NCOP11). Within that VSB14 covers modifications. For wheels and tyres it allows overall diameter no more than 15mm larger than standard, maximum tyre width no more than 30% wider than the widest standard tyre and rim width to match that 30% wider tyre. Track must not be increased by more than 25mm and it is stated that this means offsets can't change by more than 12.5mm. This makes offsets the real limiting factor.

Based on the stock 195 front/225 rear tyres mentioned above that would allow maximum front rim width 9.5 inches and rear width 11.0 inches, so I'm well within the limits. For track, my offsets are also OK.

Hope this helps others.

Re: Staggered Tyre Size Recommendations (midmadness)

Thu, 09 Jan 2014 20:47:16 GMT

Thanks for the info guys. I think I'll play it safe and go with the 235 rears.

The width question is interesting, as these rims are still a bit on the narrow side (but OK) for these tyres. Looks like there may be a set of deliberately (or accidentally) conflicting requirements here.

I also wonder whether wider TRD rims that could be bought from Toyota at the time would count as being manufacturer options for setting the width baseline.

Re: Staggered Tyre Size Recommendations (Mr2gtracer)

Thu, 09 Jan 2014 12:51:25 GMT

Possibly. That's a good point. I guess this is where offset comes into play - maybe.

Re: Staggered Tyre Size Recommendations (wiso)

Thu, 09 Jan 2014 12:40:39 GMT

yeah you're right, there are new rules. 7% larger overall diameter than what is shown on your tyre placard.

BUT it also says "Replacement of wheels where the rim width exceeds the largest wheel combination specified by the manufacturer by greater than 25 mm."

rim width 1" wider than the tyre placard. does a 90 have 6.5" rears?

http://www.rms.nsw.gov.au/registration/downloads/vsi/vsi6.pdf

Does that mean they no longer care about rim diameter, but now they only really care about rim width?