4wd tire size (again)

[Lil Foot]

Forgive me if this has been covered, but my searches have not revealed the answer to my one question: I realize the ideal ratio is 3%, but what tolerance is acceptable? Is 2% or 4% usable? Is there a standard range such as 1% to 5%?
Thanks in advance.

 

[85Hokie]

Forgive me if this has been covered, but my searches have not revealed the answer to my one question: I realize the ideal ratio is 3%, but what tolerance is acceptable? Is 2% or 4% usable? Is there a standard range such as 1% to 5%?
Thanks in advance.

Lil Foot,

what cha placing tires on ? Whats on it now, and what are you planning to place on it?

 

[Lil Foot]

B7100. It had ancient (maybe original) tires, fronts were 2ply, badly busted up, probably 60-70% of cords loose inside the tires. While it was down for front axle repair, I bought a pair of
6ply, 6.00x12 & mounted them. Just checked the rolling circumference on them & the old rears- 10%, because the old rears are obviously undersize. The new rears that would match the fronts that I would like to buy would yield a ratio of 2.07%. Close enough, or do I have to search further, or shave the fronts, or just give up on 4wd?

 

[ShaunBlake]

From what I recall on the threads I've read, you want to be within about 2 or 2.5 percent of 5% (I think that's what NIW is saying in this thread)

 

[85Hokie]

B7100. It had ancient (maybe original) tires, fronts were 2ply, badly busted up, probably 60-70% of cords loose inside the tires. While it was down for front axle repair, I bought a pair of
6ply, 6.00x12 & mounted them. Just checked the rolling circumference on them & the old rears- 10%, because the old rears are obviously undersize. The new rears that would match the fronts that I would like to buy would yield a ratio of 2.07%. Close enough, or do I have to search further, or shave the fronts, or just give up on 4wd?

LF,

at that % I would run with 'em.

You are not going to engage the 4wd on something that will not give a little anyway, so I would not worry about it one bit.....

mud,grass,gravel, and snow and ice all give a bit when pushed on, so run it in 4wd there and leave the hard stuff in 2wd!

I run my two Kubotas in 4wd almost all the time.....except when I get near the street........lift the handle back.....

then again i make DAMN sure it is in 4WD when going down that grass hill in the back yard.........damn near shyt myself one time.......once was enough skiing down the hill

 

[tiredguy]

Forgive me if this has been covered, but my searches have not revealed the answer to my one question: I realize the ideal ratio is 3%, but what tolerance is acceptable? Is 2% or 4% usable? Is there a standard range such as 1% to 5%?
Thanks in advance.

The difference in tire size allowed is 2% period.
( do not confuse this to mean inches the answer you need is a percentage only not the actual tire size) Then you search for tires that will fit and provide the correct ratio staying within the 2% parameter allowance.

To get the ratio:
The measurement's you use is the rolling circumference published by the
individual manufacturer of the tires. Takes some digging sometimes to get
those numbers but once you do the rest is a simple formula to answer what
the ratio is front to rear then stick within those parameters and you're good to go.
Divide the rolling circumference of the front tire by the rolling circumference
of the rear tire and the answer to that is the % ratio front to rear.
Al

 

[HThomure]

Please forgive me for hijacking this thread, but it touches on what I was just getting ready to ask in a new thread.

I have a B2910 and just got new front tires/wheels for it. The new tire/wheel is 2 inches bigger than the old (the old was 23x8.5-12 and the new is 23x8.5-14) The rear tire is 12.4-16 R-4. If I'm doing my math correctly, though admittedly I don't really understand all the ratio stuff, the old rolling circumference ratio was .61 and the new is .63. Does this sound right? And am I good to go with this?

The new tires were bought in a different size by accident, but I'm pretty much stuck with them.

Sorry again for the hijack, and thanks.

 

[85Hokie]

Please forgive me for hijacking this thread, but it touches on what I was just getting ready to ask in a new thread.

I have a B2910 and just got new front tires/wheels for it. The new tire/wheel is 2 inches bigger than the old (the old was 23x8.5-12 and the new is 23x8.5-14) The rear tire is 12.4-16 R-4. If I'm doing my math correctly, though admittedly I don't really understand all the ratio stuff, the old rolling circumference ratio was .61 and the new is .63. Does this sound right? And am I good to go with this?

The new tires were bought in a different size by accident, but I'm pretty much stuck with them.

Sorry again for the hijack, and thanks.

If you are screwed in a situation that you cannot work out - then make sure when you place the tractor in 4WD - that it will be in a situation that WILL allow some slippage. I would imagine that you would never place it in 4WD on concrete or asphalt, even IF the ratio was perfect. SO if on snow, ice, wet grass or mud - somewhere the front to rear ratio will be allowed to slip. IF you forget while on concrete - you will notice it - the chirping or moaning the tractor will make, will remind you quickly.

Understanding the ratio is difficult if you don't know the internal ratios....even IF you bought new tires of the right size.......they would still be slightly off!!! As tires wear - they get smaller - in theory the fronts will wear a little quicker.....why you ask? they TURN as a higher rate across the surface(assuming that the owner is not spinning the rears!).....and if you replaced them with the correct size - the ratio would still be off OF A BRAND new machine....the rears are worn slightly and the new fronts will be a little off the ratio. There is a huge amount of room in ratios, simply because in a perfect world - it would only be perfect for a while, as the sets of tires wear - the ratio is constantly changing, slight - but still changing! They say 2% is tha largest that you should go.....

 

[Rodnok]

I have a similar situation. . I have a b7100 hst 4x4 with very badly worn turf tires. I want to change over to ag tires. The sizes are 29x12x15 and 20.5x8x10 on the turf tires per Tractordata.com The ag sizes are 6x12 and 8x16 per Tractordata.com. why are the rim sizes different on the ag tires.I have been to several tire stores and amazon and fleabay and cannot find 20.5x8x10 ag tires. The closest I can get are 20x8x10. Will I be ok with those along with 29x12x15 on the rears.

 

[Rodnok]

In place of 20.5x8.0-10, you need to use 205/65-10, see link;

http://www.millertire.com/products/implement-tires/20-5x8-0-10/205-65-10-kenda-loadstar-c-6-ply-20-5x8-0-10/

I am looking for ag tires not turf.