How to decipher the numbers on the tyre tread

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

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

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

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

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

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

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

do they have the thick centres?? good price

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.

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

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

Thanks to all who got involved this was really helpful

Hopefully see you out there soon driving or fishing

[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

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

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