Front wheels change

[lucweg]

Hello,

The dimensions of the front wheels of my Kubota L1-24 (4WD) are 7R16.
Can I replace those wheels by 8R16 or by 9,5R16 whithout any risk ?

Thanks
LUCWEG

 

[85Hokie]

Find the rolling circumference of the old...... and match accordingly, otherwise bad things will happen!

 

[lucweg]

Find the rolling circumference of the old...... and match accordingly, otherwise bad things will happen!

If on all wheels it is R16 I think that the rolling circumference is the same for those wheels ?

 

[RCW]

If on all wheels it is R16 I think that the rolling circumference is the same for those wheels ?

It’s possible, but I would not assume it to be. I wouldn’t be surprised if a wider tire had a taller sidewall.

As such, would make the tire taller and a much different rolling circumference.

Given the mathematical definition of circumference, a small variation of height causes a large variation in RC.

If tires are not properly matched on a 4WD, binding can occur and cause drivetrain damage.

 

[lucweg]

It’s possible, but I would not be surprised if a wider tire had a taller sidewall.

As such, would make the tire taller and a much different rolling circumference.

If tires are not properly matched on a 4WD, binding can occur and cause drivetrain damage.

Thanks, I will try to find out if there is any difference in the height of the sidewall.

 

[RCW]

Thanks, I will try to find out if there is any difference in the height of the sidewall.

More importantly, check the actual rolling circumference, not sidewall.

In modern auto and light truck tires, sidewalls are measured in relation to width. My truck takes 265/65-R18. The 65 is the aspect of the sidewall, or 65% of the 265mm width.

If I put a 275/65-R18 on it, the sidewall is of comparable aspect, but net effect is a taller tire.

Tractor tires are sized differently, but I used auto as example.

Hope that makes sense....always go with the actual RC.

 

[lucweg]

More importantly, check the actual rolling circumference, not sidewall.

In modern auto and light truck tires, sidewalls are measured in relation to width. My truck takes 265/65-R18. The 65 is the aspect of the sidewall, or 65% of the 265mm width.

If I put a 275/65-R18 on it, the sidewall is of comparable aspect, but net effect is a taller tire.

Tractor tires are sized differently, but I used auto as example.

Hope that makes sense....always go with the actual RC.

Thanks.
There only the indication 7R16 or 8R16 or 9,5R16 but no number for the aspect.

 

[RCW]

Thanks.
There only the indication 7R16 or 8R16 or 9,5R16 but no number for the aspect.

Correct - some tractor tires are sized much differently than auto/light truck. I simply used that as an example and hopefully didn’t confuse things by doing so.

R1, or agricultural-type tires simply have a width and wheel/rim spec, as you have. The rear tires on my old farm tractor are 12.4-38. Simply width and wheel(rim) diameter.

It still boils down to RC. That can vary by size as well as manufacturer and tire model.

As you are in Belgium, there should be some technical specifications on-line for certain tire models available in the European market.
Measure the RC of the tire you’re looking to replace, then see what is available in other wheel widths.

If you use the search function here on OTT for “rolling circumference “ you will likely find many references to this issue. There may also be some reference tables for various tires, etc.

 

[North Idaho Wolfman]

Simple answer is no, you can not change from a 7R-16 to a 8R-16 or 9.5R-16

Both of those tires will have a larger rolling circumference.

 

[lucweg]

Correct - some tractor tires are sized much differently than auto/light truck. I simply used that as an example and hopefully didn’t confuse things by doing so.

R1, or agricultural-type tires simply have a width and wheel/rim spec, as you have. The rear tires on my old farm tractor are 12.4-38. Simply width and wheel(rim) diameter.

It still boils down to RC. That can vary by size as well as manufacturer and tire model.

As you are in Belgium, there should be some technical specifications on-line for certain tire models available in the European market.
Measure the RC of the tire you’re looking to replace, then see what is available in other wheel widths.

If you use the search function here on OTT for “rolling circumference “ you will likely find many references to this issue. There may also be some reference tables for various tires, etc.

Thanks a lot for the information !

 

[Treckerzeug]

Hello,

The dimensions of the front wheels of my Kubota L1-24 (4WD) are 7R16.
Can I replace those wheels by 8R16 or by 9,5R16 whithout any risk ?

Thanks
LUCWEG

Hello,
16" is the diameter of the rim,
A tyre with a one or two digit no as e.g. 7,8 or 9,5 is the approx wdth in inches, but also the height of the side walls,
So to replace a 7" wide tyre by a8" wide gives a larger circumference,
The ratio, the no of revs done per a given distance rear wheel versus front wheel won' t be correct any more leading to excessive wear in the drive line, but only if you use your front wheel drive system...

 

[lucweg]

Hello,
16" is the diameter of the rim,
A tyre with a one or two digit no as e.g. 7,8 or 9,5 is the approx wdth in inches, but also the height of the side walls,
So to replace a 7" wide tyre by a8" wide gives a larger circumference,
The ratio, the no of revs done per a given distance rear wheel versus front wheel won' t be correct any more leading to excessive wear in the drive line, but only if you use your front wheel drive system...

Hello,
Thanks for the clear explanation.
I have found on the internet a numeric illustation of your theory.
For BKT tires 7-16, 8-16 and 9,5-16 the rolling circumferences are (in mm) : 22

 

[lucweg]

Hello,
Thanks for the clear explanation.
I found on the internet a numeric illustration of your theory.
For BKT tires 7-16, 8-16 and 9,5-16 the rolling circumferences are (sorry : in mm) 2217, 2360 and 2542.
So the difference between 9,5-16 and my present tires 7-16 is 325 mm or about 12,8 inch which is a lot.
Between the 8-16 and the 7-16 the difference is 143 mm or about 5,6 inch.
So would such a difference of 5,6 inch on field soil conditions cause problems ?
Thanks

 

[i7win7]

Between the 8-16 and the 7-16 the difference is 143 mm or about 5,6 inch.
So would such a difference of 5,6 inch on field soil conditions cause problems ?
Thanks

I think it would unless this is your field

 

[North Idaho Wolfman]

Hello,
Thanks for the clear explanation.
I found on the internet a numeric illustration of your theory.
For BKT tires 7-16, 8-16 and 9,5-16 the rolling circumferences are (sorry : in mm) 2217, 2360 and 2542.
So the difference between 9,5-16 and my present tires 7-16 is 325 mm or about 12,8 inch which is a lot.
Between the 8-16 and the 7-16 the difference is 143 mm or about 5,6 inch.
So would such a difference of 5,6 inch on field soil conditions cause problems ?
Thanks

Yes you will break parts!

 

[lucweg]

Thanks everybody !
I am sure I will keep the 7-16 in the future ...
Kind regards
Luc