keeping 4wheel drive wheels same ratio...

[alexuk]

I understand that using 4wd wheels in a different ratio to the originals will errr ruin the tractor but my math isn't so hot. I've seen some wheels which aren't huge but are quite a bit wider . They look a good fit and "look" the same ratio but I can't work it out. Its to go a ts1610 4wd
the originals are
6.3 8/22
6-14

I thought it might be easier to work it out from the max diameter of each but of course they have probably worn off a couple of inches...

the wider ones i'm considering are :
12 and 10 wide
back measure 40" and the front 28" diameter... mmm
Do I just work out what % 28 is of 40 and see if it matches mine? which are at present 36" and 25"..Of course I guess it wouldn't matter on soft ground or 2wd if you went on the road???
Anyone good at maths
Alex

ps the seller describes the new ones as front 29x12-15 and rear 355/80D 20

 

[Ilikeurtractor]

You're on the right path. Keep the ratio of the tire diameters the same and you'll be fine. So, using the numbers in your post your current front/back ratio is 25/36 = 0.69. The ones you're looking at are 28/40 = 0.7 so they will be fine. In reality you can get away with minor differences in tire diameters (compared to factory ratios) with no ill effects. The main thing is a person should disengage the front axle when it's not needed to minimize synchronous wear issues.

 

[alexuk]

You're on the right path. Keep the ratio of the tire diameters the same and you'll be fine. So, using the numbers in your post your current front/back ratio is 25/36 = 0.69. The ones you're looking at are 28/40 = 0.7 so they will be fine. In reality you can get away with minor differences in tire diameters (compared to factory ratios) with no ill effects. The main thing is a person should disengage the front axle when it's not needed to minimize synchronous wear issues.

thanks, sounds good. As you can tell math isn't my strongest point. Just chewing the cud here but it can't be "that" vital because I guess front wheels could wear differently to fronts or lower pressure. All would give you a slightly different ratio.
One thing I did look at though was the price of the bigger tyres when they wear out!!! yikes
alex
Theres not much tread on them so that could be expensive!

 

[Ilikeurtractor]

One shining example of even the factory using different tire diameters is between an Iseki 2160 and 2140 with ag tires. The 2140s came with 16 inch rear rims and the 2160s came with 18 inch rear rims and both used a 12 inch front rim for the 4wd versions. Overall tire diameters were similarily different and, as far as I can tell, the transmissions (and gearing ratios) for each tractor are identical. The Satoh Buck and Beaver are another example of this from the factory.

A lot of times you can tell there is stress in the drive train when you disengage the front axle and the tractor "creeps" a bit when relieved and you can feel some stress in the lever. I've read claims where a front axle should "lead" the rear by about 6-9%. I'm guessing this is to account for greater front tire wear over time due to turning and the front tires just doing more revolutions than rears and subsequently wearing "shorter" faster.

Compared to auto tires I think tractor tires are reasonably priced. I'm assuming this is mainly due to tractor tires not being steel-belted but I'm certainly no tire expert.

 

[NHmitch]

Thats tough, Ilikeurtractor has a better explanation than I can offer. One thing to think about is that when Iseki sold these tractors in Japan, they were outfitted with huge lug rice paddy tires classified as R2. They had very tall lugs, changing the diameter off the the tire quite a bit. If seen where they use R2's on the rear, and slick type tires on the front. I have also seen quite a few that have huge lug r2's on the rear, and the front tires are completely worn down. Are you having trouble finding the correct size tires?

 

[284 International]

Off-topic, but that dozer blade on the TX1510 looks like it would get really old to use! At least they saw fit to put a threaded link to get SOME adjustability into it!

I agree with what others have said already. If your ratios of diameter (or circumference) are very close, there shouldn't be any trouble. These machines should generally be run in 2 wheel drive unless significant slipping is occurring anyway. You can go onto several tractor tire manufacturer's websites and get exact dimensions of almost any tire, too, for specific measurements.

 

[/pine]

When I was researching this issue (because OEM sized tires are not available)...the most important factor came down to "rolling circumference"...there are a few different threads mostly in the K ubota forums on the problems and they contain links to tire charts that have rolling circumferences...and how to measure...there were cases where everything with available tires seemd to be OK but the rolling circumference was way off from the OEM tire size...

 

[Ilikeurtractor]

Off-topic, but that dozer blade on the TX1510 looks like it would get really old to use! At least they saw fit to put a threaded link to get SOME adjustability into it!

Not only does that blade appear to be difficult to adjust I really wouldn't feel comfortable with the way it is attached. Seems like a lot of leverage can be applied to the tractors front frame. Being basically a 1/4" piece of strap I don't think it was designed to handle a plow configured that way. Might be ok for light snow but I'd be afraid of catching some concrete with it and twisting the strap.

I really like those three-cylinder Iseki machines though and don't recall seeing many for sale in the U.S. (other than the Bolens versions). Maybe more will show up here in the coming years...

 

[284 International]

I agree with everything you said above.

I've only looked at one Iseki machine (A Bolens version, in point of fact) and I actually liked what I saw. The tractor wasn't for sale, but I bough the owner's backhoe, and was looking over his machine to see how it mounted. Oddly, he didn't have a loader, but I liked how the tractor was equipped with cutout under the grille to make mounting a front PTO or auxiliary hydraulic pump very straightforward. I would be excited at the prospect of people importing many more of them. They seemed top notch in all respects; just as the Mitsubishis, Yanmars, Kubotas, and Shibauras do.