Farmall Cub

My B7100 has the original 20.5-8.00-10 front tires that need to be replaced. This size is no longer available and the closest I can find are 20-8.00-10. The Kubota dealer says that since it is four wheel drive I will need to match the front tire ratio with the rear tires and wants to sell me a new set of rears. I don't plan to go that route just yet.

How critical is it for the tires to match? I have been around four wheel drive all my life and know that the tires need to match if 4wd is locked in, but just how much difference would there be between a 20.5 and a 20 tire?

I would check with Messick's, to see what they recommend doing. JMO.

Bruce T.

Barnyard wrote:My B7100 has the original 20.5-8.00-10 front tires that need to be replaced. This size is no longer available and the closest I can find are 20-8.00-10. The Kubota dealer says that since it is four wheel drive I will need to match the front tire ratio with the rear tires and wants to sell me a new set of rears. I don't plan to go that route just yet.

How critical is it for the tires to match? I have been around four wheel drive all my life and know that the tires need to match if 4wd is locked in, but just how much difference would there be between a 20.5 and a 20 tire?

That really stinks Bill but I'm afraid he's right about that. We've been running into a year Massey that has 20" on the front that are no longer available. I'm guessing those folks now will need to find something close and just have a 2 wheel drive tractor...

The first number will be the circumference so that means your new tire will be 1/2 inch larger. You might kick in 4x4 if your stuck in the mud/ snow just to get out but that's about it.
Some trucks are really touchy about different brands of tires even in the same size. I've seen several where you couln't get the 4x4 to lock in at all.
I'm not sure just how sensitive Kubota's are but I'm betting your dealer knows best....

You've run Jeeps for many years so I'm glad you understand how this all works.

I'll do some digging today and see if there might be any strays out there somewhere.
Do you run turf tread or tracks ?

Bill, I ran into the same problem on my B8200, although my fronts are 12". My original size was 24 8.50 X 12, which appears to be NLA. I put 23 8.50 X 12 garden tractor rears on it. I've had no problem, but I'm usually on soft ground, it might bind a bit on pavement but then I'd be in 2wd anyway. I'd go with the 20's, for what your tractor is used for, I doubt you'd notice the difference.

The only time 4x4 will be used is if I till the garden or plow snow. Of course I have a Cub or two around to do those jobs, but the Kubota comes in handy for that now and then.

I'd go with them Bill. On blacktop there may be a difference but on dirt I don't see any problem. How many times have we put new tires on just the front or rear which would throw off the ratio. Trucks and cars...yep, but on a tractor, no. Just my .02 Grump

Bill, did a little fast checking this morning and the 20.5 tire is avaliable in the trailer type tread only in 6, 8 or 10 ply.
USA Trail 6 ply
Power King 8 ply
power King 10 ply

I could get any of these costing between $60 to $80 each.

Yogie wrote:Bill, did a little fast checking this morning and the 20.5 tire is avaliable in the trailer type tread only in 6, 8 or 10 ply.
USA Trail 6 ply
Power King 8 ply
power King 10 ply

I could get any of these costing between $60 to $80 each.

Thanks Yogie, I made a few calls this morning and found them as a trailer tire also at Gateway Tire about twenty miles away. the guy said he had 180 of them in stock. I'm going to get a look at them, probably next week. They are ten ply for $66.00 plus tax and $6.00 installation. I think the trailer tires would work for what I need, but at least I can get a look at them first.

Wouldn't you know it, I have checked TSC for this tire every now and then when I went there for other things. Today I stopped in and thought what the heck, I'll check the tires while I'm here. Yep, they now have them. They are six ply trailer tires though at $89.95 each.

Looks like it time for a little drive this weekend Bill.
Just let me know if I can lend a hand.

Yogie wrote:Looks like it time for a little drive this weekend Bill.
Just let me know if I can lend a hand.

Thanks, I think I'll go with the 10 ply for $66.00. I'm busy tomorrow and traffic is a killer during rush hour near where Gateway is, so I figure next weeend or the following weekend will work for me.

Bill, does your Kubota have bolt together wheels? If it does, the tires are super easy to change. Another thing, they're generally tubeless, I've had better luck with tubes in mine. The 2 piece wheels have a rubber seal in the center and are prone to slow leaks.

Gary Dotson wrote:Bill, does your Kubota have bolt together wheels? If it does, the tires are super easy to change. Another thing, they're generally tubeless, I've had better luck with tubes in mine. The 2 piece wheels have a rubber seal in the center and are prone to slow leaks.

Gary, it has one piece wheels and one has had a tube added over the years. I bought this in 1992 and replaced one tire after about five years. After all this time they have developed some pretty serious cracks in them and leak down over night.

Barnyard.. try looking around in "orangetractortalk". Kubota site..I remember there was alot of info for matching up tire sizes. I do know the front turn faster than the rear when they are properly matched..So if you are a tick bigger in tire size, especially where there will be some slippage anyway, I can't see a major problem...Good Luck..Greg