Mixing bias ply tires and radial tires on a tractor

   / Mixing bias ply tires and radial tires on a tractor #1  
T

tmc_31

Gold Member
Joined
Nov 21, 2005
Messages
394
Location
Texas
Tractor
NH TN70D, NH L190
Hey all,

I have ruined a tire on my TN70D and need to replace it to finish a job. I don't want to buy a new one yet as as I would like to replace all of the tires at the same time in a few years. I have found a used tire, a 420/90 R30 that a guy says is a good tire and he wants $100.00 for it. It will fit on my rim. The rear tires on my tractor are 16.9-30. I called a tire guy, he said that the tire would fit on my tractor. But, he said that mixing bias ply and radial tires could cause transmission problems down the road. I called my tractor dealer, he said that people mix radials and bias ply tires all the time and that the transmission problems can occur when there is a major difference in the rolling circumference.

Opinions?

Thanks,

Tim
 
   / Mixing bias ply tires and radial tires on a tractor #2  
I am not a tire expert but I would never mix on the same axle, even if the same size and or circumference.
If it was radials forward, bias aft or the opposite on a slow speed tractor might consider it but I would not do so on the same axle.
We will see what others say.
 
   / Mixing bias ply tires and radial tires on a tractor #3  
If they are the same circumference when fully inflated, I would use it. You may have to increase the air pressure a bit on the radial side to reduce the side wall flexing (this would reduce the circumference a bit if excessive)which is how the radials provide a bit more traction and ease of rolling. Just air it up till the side walls look the same as your bias ply tire. The only time your tires are really locked together is if you use the differential lock so a bit more or less of circumference isn't going to hurt your differential or transmission.
Where you would be likely to hurt the transmission is if you had bias on the rear and radial on the front (or vice versa) that were not the same circumference ratio as this would cause excessive pressure on the drive train when in 4 WD as some of the tires would always be either sliding or spinning.
Just do a thorough check of the tires outside circumference to verify the distance. An inch or two wont make a lot of difference but the closer the better. Most of the time, when pulling in loose ground, one tire usually has more traction that the other so a little slip is going on most of the time which doesn't affect your tractor at all.
 
   / Mixing bias ply tires and radial tires on a tractor
  • Thread Starter
#4  
Thanks guys,

one vote no, one vote yes:) aren't forums wonderful. I checked the rolling circumference of the tires on my tractor (174") and the radial tire that the fellow is offering me (also 174") I think, given what information I have and the fact that this is only a temporary solution, I will go ahead and take him up on his offer. He sent me a picture of the tire and it looks almost new. I think he said it came off of the front of a JD combine or something like that.

please keep the opinions coming as I have not pulled the trigger yet!

Thanks,

Tim
 
   / Mixing bias ply tires and radial tires on a tractor #5  
If you were running 70MPH down the highway, I'd say no...but a low speed tractor...just don't see a problem.
Most folks don't use the differential lock for more then a minute or so...can't see that being a problem.
 
   / Mixing bias ply tires and radial tires on a tractor #6  
RoyJackson said:
If you were running 70MPH down the highway, I'd say no...but a low speed tractor...just don't see a problem.
Most folks don't use the differential lock for more then a minute or so...can't see that being a problem.
Click to expand...

Exactly. If slightly different sized tires would cause problems with the rear differential, turning your tractor & or just not going straight a lot would cause similar problems. I could see transmission (or more precisely transfer case) problems if you front to rear sizes were way off. Even then you'd be fine if you just left it in 2wd instead of 4wd.

When was the last time anybody bothered balancing a tractor tire like you do a car tire? As opposed to filling them 75% full of sloshing liquid.
 
   / Mixing bias ply tires and radial tires on a tractor
  • Thread Starter
#7  
Thanks all,

The majority here seem to support what my tractor dealer says, that it's not harmful to mix bias and radial tires on the same axle as long as the outside diameter or rolling circumference is close to the same. I called the guy who offered the tire and told him I will take it:)

Tim
 
   / Mixing bias ply tires and radial tires on a tractor #8  
If that $100 tire really looked almost new, BUY IT NOW!!!
Next ask if he has any more. Maybe he changed both to a different size?
If not, go buy a 2nd new one, then sell your good rear tire for $100 and you will have radial rears for 1/2 price.
 
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