How to decipher the numbers on the tyre tread

[richardharris51]

Hello folks,

Not wanting to sound like a complete idiot, I was hoping for some clarification on the numbers on the tyres I have fitted to newly bought GQ td42 diesel.

This is my 1st post after introducing myself last week so please bear with me, I am sure In a few months iwill sound a million times more technical :biggrin:

Right so on the tyre it says:

31x10.5 r15
This is what I think it means;
31 inch tyre
R is for the rim size being 15 inches
BUT what is themiddle number 10.5 all about??


If I am right about the 31 and r15 part my next question is, if I was to buy 33inch tyres would they fit on the same rims I have now or would I have to upgrade them too??


Thanks for your help and patience


Richard

[threedogs]

10.5 is how wide 31 is diameter in inches and 15 denotes rim size all in inches these are USA speak, yeah then it would be 12x33x15 R is radial. you'll need 15x8 rims for the 33s. 15x7 are fine for the 31s

[richardharris51]

Thanks for the response threedogs,

I'll get out there and have a look to see if they are 15x7 or 15x8

How much do a set of 15x8 steelies cost these days????

Cheers

[threedogs]

Sent you a PM, but retail 15x8 are about $80 plus a pop, not cheap, It'll say 7JJ or something like that. the wider rim will make the side walls straighter and not bulge out and collect tree roots etc easier to spike

[nissannewby]

Dont know where your getting your rims from but 15x8 can be as little as $55 each these days

[threedogs]

Chinese or ROH ? Rims need to have the 6-8mm centres not 4mm

[nissannewby]

Gecko wheels- 50-55 ee
Dynamic- 65
King- around the 65 as well

[threedogs]

do they have the thick centres?? good price

[nissannewby]

As far as im aware they do. I have a set of 16x8 -13 i bought for my GU picked them up for 52.50 ea (in the industry) and they got the thick centres.

[threedogs]

15x7 dime a dozen then you go to 8" in either 15 or 16 and they usually want heaps more

[Woof]

Hey Richard, just ask any question you like mate, nothing to be ashamed of here...........we are all here to learn and pass on our knowledge.
Me, I know absolutely nothing about anything but I am learning slowly...haha

[richardharris51]

Thanks to all who got involved this was really helpful

Hopefully see you out there soon driving or fishing

[Robo]

[QUOTE=richardharris51;241711]Hello folks,

I was hoping for some clarification on the numbers on the tyres I have fitted to newly bought GQ td42 diesel.
Right so on the tyre it says:
31x10.5 r15
This is what I think it means;
31 inch tyre
R is for the rim size being 15 inches
BUT what is themiddle number 10.5 all about??
If I am right about the 31 and r15 part my next question is, if I was to buy 33inch tyres would they fit on the same rims I have now or would I have to upgrade them too??

If you have a squizz around at tyre manufactures web sites you can pick up a whole lot of useful info.
EG- list of sizes, rolling diameters, load ratings, amount of ply's use. see attached pic's.
hope this helps.
these are examples of a particular brand for given tyres they have in their range
cheers

[growler2058]

10.5 is width in inches
31 is the overall tyre height in inches
35 will fit on a 15 inch rim
Mine are 33"x12.5"x15


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[roon]

ur rim size is 15 and u can install low profile tyres and huge profile tyres of 15 size which u like

[roon]

u can also install up to 22 size rims with lowprofile tyres