Henro
Elite Member
- Joined
- Jul 4, 2003
- Messages
- 4,982
- Location
- Few miles north of Pgh, PA
- Tractor
- Kubota B2910, BX2200, KX41-2V mini EX
K_Daulby,
As indicated by others above, the concern is having the wrong ratio of tire size, front to back.
The reason this is a concern, is that the tractor gearing is designed so that when in 4X4 mode, the front tires will turn slightly faster than the rears in surface speed. Being smaller, the fronts without question have to turn more RPMs.
You could look at a tire site like Goodyear's for a detailed explanation. The reading I have done on the subject indicates that front tires turning (at the tire surface) slower than the rears causes stress on driveline components. Front tires should lead, not lag the rears.
There is a simple check you could do to get an idea of where you stand with your new tires. Find a flat space where you can run the tractor about ten turns of the rear tires. I think a dirt surface may be better, but pavement would probably work too.
First, you need to mark the one front and rear tire with something, chalk, paint, whatever. Position the marks either top or bottom at the ground contact point.
Run the tractor straight in 2WD for ten turns of the rear tire, while having someone else count the revolutions of the front tire (unless you are really good and can keep an eye on both double up on your counting). Write both numbers down.
Return to the starting point, put the tractor in 4WD and do the same thing again. Write the numbers down.
Compare the number of revolutions of the front tires. If you have more revolutions in 4WD, that is good. Less in 4WD is not good.
Either Goodyear or Firestone (or both, or somewhere else?) has a detailed procedure one can follow to calculate actual percentages, but the above is what I would do to simply find out if I was in the good ballpark or the bad ballpark.
Relative speeds can change for various reasons. For example, tire pressure variation can change effective tire diameter a bit. I think it may be for this reason that a little lead is built into the drive system, so that when things change in the operating environment, you still end up with a bit of lead speed on the front.
Just a thought in case you want to make a quick check to find out where you likely are with your new tire setup.
Once you find out where you are, you can decide if you want to do something or nothing about it... /forums/images/graemlins/smile.gif
As indicated by others above, the concern is having the wrong ratio of tire size, front to back.
The reason this is a concern, is that the tractor gearing is designed so that when in 4X4 mode, the front tires will turn slightly faster than the rears in surface speed. Being smaller, the fronts without question have to turn more RPMs.
You could look at a tire site like Goodyear's for a detailed explanation. The reading I have done on the subject indicates that front tires turning (at the tire surface) slower than the rears causes stress on driveline components. Front tires should lead, not lag the rears.
There is a simple check you could do to get an idea of where you stand with your new tires. Find a flat space where you can run the tractor about ten turns of the rear tires. I think a dirt surface may be better, but pavement would probably work too.
First, you need to mark the one front and rear tire with something, chalk, paint, whatever. Position the marks either top or bottom at the ground contact point.
Run the tractor straight in 2WD for ten turns of the rear tire, while having someone else count the revolutions of the front tire (unless you are really good and can keep an eye on both double up on your counting). Write both numbers down.
Return to the starting point, put the tractor in 4WD and do the same thing again. Write the numbers down.
Compare the number of revolutions of the front tires. If you have more revolutions in 4WD, that is good. Less in 4WD is not good.
Either Goodyear or Firestone (or both, or somewhere else?) has a detailed procedure one can follow to calculate actual percentages, but the above is what I would do to simply find out if I was in the good ballpark or the bad ballpark.
Relative speeds can change for various reasons. For example, tire pressure variation can change effective tire diameter a bit. I think it may be for this reason that a little lead is built into the drive system, so that when things change in the operating environment, you still end up with a bit of lead speed on the front.
Just a thought in case you want to make a quick check to find out where you likely are with your new tire setup.
Once you find out where you are, you can decide if you want to do something or nothing about it... /forums/images/graemlins/smile.gif
