front tire size

[dvan1966]

I asked this in another forum, but I'll ask it here again since it is about a Kubota. I have a B6200DT 4WD with Bridgestone 20.5-8-10 4ply front turf tires that need replaced. The dealer or tire shops cannot find 20.5's in anything but trailer tires. My manual calls for 20.5-8-10's in turfs. The dealer and tire shops have
20-8-10's, but I'm worried about putting a smaller tire on it when in 4wd. My only option is to get the 8ply 20.5 trailer tires.
Anyone with 20.5's on the fronts have this problem finding new tires?

 

[art]

Measure the outside diameter to see if they are the same. You don't want to make them smaller or larger or it will change the lead/lag ratio which might hurt the drive train.

 

[RobJ]

I don't think that small difference willl matter much. At least I wouldn't worry about it.

 

[SPYDERLK]

I asked this in another forum, but I'll ask it here again since it is about a Kubota. I have a B6200DT 4WD with Bridgestone 20.5-8-10 4ply front turf tires that need replaced. The dealer or tire shops cannot find 20.5's in anything but trailer tires. My manual calls for 20.5-8-10's in turfs. The dealer and tire shops have
20-8-10's, but I'm worried about putting a smaller tire on it when in 4wd. My only option is to get the 8ply 20.5 trailer tires.
Anyone with 20.5's on the fronts have this problem finding new tires?

When going straight the front/back ratios are always set up so that the fronts are trying to drag the backs a little. This aids steering response in 4wd. Im guessing the new slightly smaller front tire will do this since the rears are worn a little smaller and arent being renewed. I am surprised that Kubota has not kept the correct replacement available. Is it a real old tractor?
larry

 

[dvan1966]

I am surprised that Kubota has not kept the correct replacement available. Is it a real old tractor?
larry

It's from the early 90's.
I contacted Bridgestone and their reply was to go to their 21x8-10.

 

[RobJ]

When going straight the front/back ratios are always set up so that the fronts are trying to drag the backs a little. This aids steering response in 4wd.

Where did you get this? This says that the fronts are trying to pull all of the weight first, or I break it down as the fronts are trying to spin faster than the rears. And it wouldn't matter going straight or turning...the diff will allow for different speeds, but one is still going to spin at the same rate.

IMO there is plenty of slop in the systems to not matter with small corrections.

 

[dvan1966]

I emailed Kubota and here is their response:


"What you need to do is give your tire shop the 4 wheel drive ratio (drive
train ratio) for your tractor. That number would be 1.467. They will be
able to take the tire in question an figure out if it will or will not
work. With the 4 wheel drive ratio they will even be able to see if there
is another tire that might work also."