u-joint vs turf/r4 tire mix

RobertN · Apr 30, 2004

I needed new tires a while back on the rear of my Kubota B8200. I replaced the rear turfs with new R4/Rims. The front turfs were pretty new, and I didn't have the extra change for front tires too.

I checked the books for rolling diameter and all; they were a pretty close match between the R4 and Turf sizes(same as used on B20, B21, B2150, B2710, B2910). So... I ran them for about 8 months now, till I got R4's up front a couple weeks ago. Matched R4's made engaging 4x4 easier, and steer better on the non-PS tractor.

So, yestaerday, my front driveline came loose at the tranny. A cross pin lit go, and the ujoiny yoke slipped off. I thought that was wierd. So, I looked under there and found the u-joint VERY sloppy.

Pulled it all apart, and found no bearing in the u-joint!

So, even though the R4/turf mix worked, and did not exhibit any issues,, I think it did a job on the u-joint. I thought I got along fine till I got new front tires to match, but, alas, I did not.

FYI for those thinking of replacing one set of tires, and waiting on the others. I couldn't afford it at the time, and did not want to continue with Turfs. Fortunately it appears it only ate a u-joint.

slowrev · Apr 30, 2004

Consider it lucky if you only ate a U joint. Running mismatched tires on 4WD can break many expensive things.

Ronbo · May 1, 2004

If the size is close, it should not affect the u-joints. When you turn a corner, we do that a lot when we operate our tractors, the front tires travel a shorter distance than the rear. The tractor tires slip to accomodate this. Also the tires all wear at different rates and so they travel different distance.

Sounds like the u=joint was out of grease.

Ron

RobertN · May 2, 2004

The U-joint had no grease for sure, but also had no zerk for which to add grease /forums/images/graemlins/frown.gif

It is an '87 built tractor by the serial number, but only has 889 hours on it. coulda gone dry over time, or coulda been drying out and the insult of slightly mismatched tires pushed it over the edge maybe.

JimR · May 2, 2004

More than likely the reason for failure was a dry joint. I have mixed tires on my 7275 and have no problem shifting in and out of 4wd. All 4 of mine are new. You said you changed two new rears. Were the fronts new of well worn? If used the front will not equal the rear in travel. The other problem associated with 4wd failures is using it when not needed. This will cause parts to wear by putting stress on the driveline. Especially if you are driving on any type of hard surface. Try driving a 4wd pickup on dry roads for a short distance and take a sharp corner. Watch your front end wind up like a pretzel as the tires try to jump off the ground. That is why the front tires rip up grass in 4wd on turns.

Currmudgeon · May 3, 2004

( The U-joint had no grease for sure, but also had no zerk for which to add grease /forums/images/graemlins/frown.gif )

BTDT on my truck. I use the spiders on my desk for paperweights. I swear, it's a conspiracy between the automakers and the repair shops.

LBrown59 · Dec 20, 2004

( Consider it lucky if you only ate a U joint. Running mismatched tires on 4WD can break many expensive things.

)
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Would bar turfs on the rear and regular turfs on the front be considered a miss match?

RickB · Dec 21, 2004

Mismatched for porposes of this discussion means a loaded radius or circumference that falls outside the spec of the OEM tire size. I'll bet the u-joint would have failed regardless. Any grease left in it was 17 years old. The cup seals could have failed 10 years ago or more.