RA28 Aus Spec Factory tyre fitment

[Jimmy]

All those specs I'm a bit confused as to which ones apply to my car because I dont see LT 2000 liftback on there I'm keen to know which one I should be using because, given the NCOP rule of 30% increase in section width over standard, that means my 225s are only legal if the standard tread was 175 or more Is there any way i could say that my car is one of the ones that came with 175 or 185 tyres standard and get away with it? If claiming one thing and compliance plate saying another thing could be a problem, then don't worry cos my 28 doesnt have one im in the process of getting it done now hence the need to know details

I did find this link whilst searching for more info on the RA28 on the Drive website

1977 Celica LT Aus Delivery specs here

If this info is correct, you can see it says that our cars were delivered with 4.5J x 14 wheels... unfortunately nothing about tyres there.

[airfireman1]

Tyre placards were non existent when these were licensed so they must have gone from the manufacturers specs. I think that in WA you are allowed to go a certain size larger than the placard states. When I had a commodore I put a placard from the HSV model on and that allowed me to go a fair bit wider and bigger,.
I really think you need to speak to a licencing centre person. I really think you wont have too much trouble with getting wide tyres passed.

[Jimmy]

plus rep 4 u! That is one handy tip.

[TA-022]

Rod post up what your clculations give as the largest possible... ie profile / wheel combo.

Since were using the same engineer that will help me.

[timbosaurus]

Sorry Rod, I tried to get the scanner working to scan the whole manual, but failed.

Who woulda thought an electrical engineer would give up on a scanner

I took a photo of the relevant page anyways, leave the whole manual for next time.



as it says, we should have got 13 inch wheels.

I have what I think is an unused original tyre as a spare in the back of my 28, so i'll go and take a photo of it and post it up.

[timbosaurus]

This is the tyre that I believe is original toyota.

'tis a 165SR14.



This is the wheel. It reads 5 1/2 * 14 32



And I just found another page in the user manual. This must have been where airfireman1 was looking.



Seems as if we got ST 2000 spec tyres over here on the 28's!

Cheers,
Timbo

[Jimmy]

how come in that last pic, under tyre size, all the vehicles have two different fitments displayed? ie. the GT liftback says:
165 HR14
185/70 HR14
and what does HR, SR etc mean?

[CLG]

HR, SR, ..., were indicators of tyre build and rating when radial tyres were first introduced. Regardless of the size of the tyre and the design - all tyres marked as SR, HR, ..., have an 82% aspect ratio, unless an aspect ratio is given - which is the norm these days. The aspect ratio is the size of the tyre's sidewall in relation to it's designated width. The "H" part is a load and speed rating, the "R" means radial tyre.

To determine your choices in choosing differnt wheel and tyre combinations, you generally have to consider the overall diamter of the original tyres - regulatory guidelines dictate any wheel tyre combination change must be within a specific percentage of the original.

To calculate the diameter, it's simple. Take the width (165mm) and multiply it by the aspect ratio as a percentage of 1(165 x 0.82). Remember when doing the calculation for diameter, there are two sidewalls in that figure so, you also multiply that derived figure by two (165 x 0.82 = 135.2mm x 2 = 270.6mm). you then need to include your wheel diameter too, in mm also (14" x 25.4 = 355.6mm). Add those two figure together to get the total rolling diameter of your wheel tyre combo (270.6 + 355.6 = 626.2mm)

So the rolling diameter for the 165SR14 and 185/70/14 (614.6mm) are 11.6mm different.

[TheToyman75]

Clint,

The SR is an 82 profile, The HR was 80 Profile. For calculating your tyre size options I use an only calculator to make it easier.

http://www.tyresave.co.uk/tyresize.html

I have the A4 reference page I have worked out on my PC at work so wil post it up on Monday.

[GRUMPIRA28]

Just confirming the original Toyota tyre fitment to Australian RA28's. They were 165 SR14 on a 5.5J x 14" rim. Toyota did fit tyre placards on the drivers door and I just checked my spare, which is the original tyre that came with the car when I bought the car (new) in 1977. Hope this helps.

[timbosaurus]

Grumpi... yours is a one owner huh?

Do you have thread on it?

[airfireman1]

That tyre looks so much like a dunlop aquajet radial?. The techno tyre of the 70's
Cheers

[timbosaurus]

looks like a bloody snow tyre when you see the tread on it!!!

[GRUMPIRA28]

Timbo,

Yes I'm the original owner and yes the original tyre was indeed a Dunlop Aquajet.
Don't have a thread yet but will in time.

[twentyEight]

Don't have a thread yet but will in time.

4 mins have passed... It's been time...