Tire Selection Tire size options

[missesalot]

I have a TC45d that is 4wd, and am in the market for a set of turf tires with rims. I have found a set locally that came off a TC35. There is overlap in the specs between the two machines, which are different between recommendations for tire size in 2wd and 4wd. Is there any reason to think that these tires and rims could or could not work on my machine? Thanks guys

 

[missesalot]

The tires a that are available are 13.6x16, and 24x8.5x14.

 

[rScotty]

Sounds like you might have found a good way to go to turfs for less money. But there is one important thing to check:

The original ratio between front and rear tires "rolling circumference" has to be maintained - give or take about 5%.
When the tractor is designed, the ratio between the OEM tires is known and is matched to the internal 4wd transmission ratio to keep the drive shaft from winding up and binding the transmission shafts & U joints.

There is some wiggle room, and it isn't impossible that by changing all 4 tires to turfs you will end up with a good match. Manufacturers tend to stay with their favorite front to rear transmission ratios, and of course tires are built with that in mind. So it may be a bolt-up. It's worth checking.

One way you will know if you got it wrong is if you put on the turfs and find it very hard to get the lever out of 4wd or you hear popping from the U joints - both because the driveshaft is being elastically wound up in torsion.

There are several fairly difficult ways to check for sure if this swap will work before buying the turfs. The easy way is to go to the tire manufacturer's chart & look up the "Rolling Circumference" of your OEM tires and of the prospective tires and compare the front to back ratios. You have to look up that particular specification. Sometimes it involves calling the tech dept. Rolling circumference is very, very difficult to calculate from any other tire measurement or spec..
rScotty

 

[missesalot]

Sounds like you might have found a good way to go to turfs for less money. But there is one important thing to check:

The original ratio between front and rear tires "rolling circumference" has to be maintained - give or take about 5%.
When the tractor is designed, the ratio between the OEM tires is known and is matched to the internal 4wd transmission ratio to keep the drive shaft from winding up and binding the transmission shafts & U joints.

There is some wiggle room, and it isn't impossible that by changing all 4 tires to turfs you will end up with a good match. Manufacturers tend to stay with their favorite front to rear transmission ratios, and of course tires are built with that in mind. So it may be a bolt-up. It's worth checking.

One way you will know if you got it wrong is if you put on the turfs and find it very hard to get the lever out of 4wd or you hear popping from the U joints - both because the driveshaft is being elastically wound up in tension.

There are several fairly difficult ways to check for sure if this swap will work before buying the turfs. The easy way is to go to the tire manufacturer's chart & look up the "Rolling Circumference" of your OEM tires and of the prospective tires and compare the front to back ratios. You have to look up that particular specification. Sometimes it involves calling the tech dept. Rolling circumference is very, very difficult to calculate from any other tire measurement or spec..
rScotty

Thank you very much for taking the time to explain that, very helpful

 

[rScotty]

Thank you very much for taking the time to explain that, very helpful

You are welcome. I well remember how I wrestled with that very problem the first time that I wanted to change the type of tires on my tractor.
It turned into quite a learning experience.

And just like you, I had found a great deal on some used fat turf tires with their special hubs. I ended up keeping the expensive rear turfs on their special hubs and replacing the front hubs and tires both in order to get the tire ratio to match the internal front/rear transmission ratio.
It worked great.

Sometimes the workshop manuals will list the front/rear transmission overall ratio. They never seem to point to it, but it may be buried rather deeply in the specs. I suppose the writers of the manuals figure if you know what you are looking for you will know when you find it...
rScotty