B7100HST Front/Rear drive train ratio

[pfloyd]

Does anyone know the Front/Rear drive train ratio of a B7100HST-D. I do not have this information in any of my manuals (aftermarket). I just switched from turf tires to ag tires and I would like to see how closely matched the front and back tires are.

Thanks,
Phil

 

[daTeacha]

I can't give you any specifics, but the front wheels on a 4x4 tractor usually move just a bit faster than the rears. I'm told this is for better steering behavior and it's easier on the tires if they slip a bit. This is also why a tractor will tend to lurch when turning tightly on a solid surface in 4wd. I don't think you will be doing yourself any good trying to compensate for it by tinkering with tire sizes. Just stick with stock or manufacturers sizes.

 

[pfloyd]

I'm not going to try to adjust the ratio with the tires, I just wanted to find out if the ones I have are within the 5% of slippage they say you are supposed to be. The front tires originally had 10" rims and I had to put 12" rims on for the ag tires. The rolling circumference is more now than it was and I wanted to check if I was still close.

Phil

 

[WVBill]

Here's a recommendation I got from TBN several years ago when I replaced the wheels/tires on my B6100.

On a hard surface, put the tractor in 4WD and drive for a couple hundred feet in a straight line. Stop. Shift out of 4wd. If you can shift easily your ratio is OK. If its' hard to shift, there's binding between the front & rear and your ratio is off.

I have a B6100 DT Gear drive - don't know for sure if this test will work the same for a HST but I suspect so.

 

[btolle]

I would be concered about the long term effect of improperly sized tires. Seems to me it might cause a lot of strain and wear on the drive train.

A the least I would recommend that you seriously limit use of 4WD. If you seldom use 4WD it shouldn't be too serious.

You should look into finding some front tires the same circumference as the originals, the wheel size would not matter, just the circumference.

Bill Tolle

 

[Egon]

Have you considered marking the tires, driving forward one revolution of the back tire,count the revolutions of front tire, measuring the distance and then compare to the outer circumferance times revolutions of the front tire to the distance traveled by the back tire.

Egon

 

[Wall]

Firestone has a procedure to test Lead/Lag
Go here web page

 

[pfloyd]

Thanks everyone for the replies. I'm not sure I'm smart enough to do all of these calculations but I do have the family coming over for Thanksgiving dinner so at least I can recruit some help.

Phil

 

[pfloyd]

Well, for what it's worth...After using the method of Lead/Lag testing on the firestone page, I come up with 12.4% lead. My front tires are the correct size ag tire I am supposed to have. The rear tire is an ag tire but it is the same size as the turf tire that came off and is slightly smaller than the ag size should be. This shouldn't cause too much of a problem as I will not be using the 4wd very often.

Phil