Sidewall sizes on tyres

[6310T]

I'm thinking of increasing the width of rubber on my jd 6800. There are 420x85x24 on the front and 460x85x38 on the rear currently. If I change the rears to 600x65x38 will the fronts have to be the same sidewall - 65? Or can the sidewall sizes front and back be different?

 

[Thomas5060]

@Terry Elsey Tyres will be the man to sort you out

 

[Nearly]

Sidewall figure is just a % of the width.
Standard tyres are 85. You just need the heights of the tyre overall to be right. Google tractor tyre rolling radius chart for comparison tables of matching sizes.

 

[kill]

I'm thinking of increasing the width of rubber on my jd 6800. There are 420x85x24 on the front and 460x85x38 on the rear currently. If I change the rears to 600x65x38 will the fronts have to be the same sidewall - 65? Or can the sidewall sizes front and back be different?

There's no problem with keeping the same size front tyres as you already have and keeping a tighter turning circle but replacing the rears with wider but I'd put all 4 tyres on at the same time as like any tractor 4wd wind up will be horrendous else every time brakes are touched.

 

[6310T]

There's no problem with keeping the same size front tyres as you already have and keeping a tighter turning circle but replacing the rears with wider but I'd put all 4 tyres on at the same time as like any tractor 4wd wind up will be horrendous else every time brakes are touched.

I'm thinking of changing the fronts to 540s for extra width too. Do you know if 540s on the front and 600s on the back would work?

 

[kill]

I'm thinking of changing the fronts to 540s for extra width too. Do you know if 540s on the front and 600s on the back would work?

That's the combination my 6430 came on from new so that's fine but steering lock is well compromised as the QE2 would turn almost quicker. Steerable fenders would help alot tho.

 

[C.J]

I'm thinking of changing the fronts to 540s for extra width too. Do you know if 540s on the front and 600s on the back would work?

That will be fine but you'll need 15" rims on front and 18" on the back.

Some 68/69 will have 650/65R38 and 540/65R28 tyres fitted but need to check if they will work with your gear pairing.

 

[Nearly]

The holy grail, but you will need wider rims as C.J says
save the picture above to your phone for taking to farm sales etc.

 

[6310T]

That will be fine but you'll need 15" rims on front and 18" on the back.

Some 68/69 will have 650/65R38 and 540/65R28 tyres fitted but need to check if they will work with your gear pairing.

Thanks for the reply. I'd rather keep R24s on the front because it should save me bother to do with the gear pairing as you said. Looks like i'll have to be on the look out for some 15" and 18" rims.

 

[6310T]

View attachment 474158

The holy grail, but you will need wider rims as C.J says
save the picture above to your phone for taking to farm sales etc.

Thanks a million this will definitely come In handy

 

[C.J]

Thanks for the reply. I'd rather keep R24s on the front because it should save me bother to do with the gear pairing as you said. Looks like i'll have to be on the look out for some 15" and 18" rims.

What width are your front rims currently ? 420 should be on 14" or 15"

 

[Simon Chiles]

I'm thinking of increasing the width of rubber on my jd 6800. There are 420x85x24 on the front and 460x85x38 on the rear currently. If I change the rears to 600x65x38 will the fronts have to be the same sidewall - 65? Or can the sidewall sizes front and back be different?

Acceptable rims for the 540/65 R24's are 14, 15 and 16 inches the ideal being 16. For the 600/65 R38 are 15, 16 and ideally 18 inches. If you have anything other than the ideal rim width you'll loose a bit in load carrying capacity.