XM108 Multibib front tires on L5740?

[hayden]

Hi, I've read through the various threads on this topic, but couldn't get a clear answer on these tires in place of stock 9.5-16 R1 tires. The particular Michelin XM108 is the 320/65R16. The rolling diameter is the same, but width is 12.2" vs 9.5" on the Goodyear DuraTorq 9.5-16 that are on the tractor now. Rim size is the same, and the only question is clearance between the tire and loader frame. I know on some of the smaller models people had to grind down the frame, and I'd rather not do that. I am running R1s now, and want to continue with them, hence the XM108 vs the XM27 which is more of an R4 tire.
I measured, and it's darn close. The difference between fitting and not will be how domed the tread profile is side to side. If it's curved like the stock R1, it looks like it will fit fine, but if it's really flat, I think I will have contact between tread and frame.

The biggest reason for the change is that the stock tires are under-rated for loader operation. They are 6 ply with a capacity of 1350lbs each, so 2700 lbs total. The loader can lift 2000 lbs, and more if lifting in closer to the pins. That only leaves 700 lbs for the front end of the tractor, and the loader alone weights 1700 lbs with a bucket. The front axle weight is more likely around 2500 lbs, so with a full bucket the front tires are running at about double their rated load. With a heavy load teh tires are nearly flat. I'm actually quite surprised Kubota sold it that way, but they did.

The XM108 tires are rated at 2300 lbs each at up to 20 mph, so 5600 lbs for the axle. That's reasonable sizing for a tire in this application.

Goodyear used to make an 8-ply version of the Duratorq and I tried to buy them, but they have been discontinued.

Can anyone tell me if they clear the loader frame? The tires are over $500 each, so an expensive failure if they don't work.

Thanks

Peter

 

[Fallon]

No clue, but it sounds like you researched everything properly.

 

[ovrszd]

They are 2 3/4" wider. That puts inside corner of tire 1 3/8" farther in.

When you are turned to full lock and oscillated in the position that puts the tire closest to your frame, how much gap do you have?

Got a pic?

 

[hayden]

They are 2 3/4" wider. That puts inside corner of tire 1 3/8" farther in.

When you are turned to full lock and oscillated in the position that puts the tire closest to your frame, how much gap do you have?

Got a pic?

What I did was put a 12" ruler across the face of the existing tire, and turned it to locate the closed point of contact. If the tread face is flat like the ruler all the way out to the edge, and if the tread face is the full 12.2", then I think I will have contact.

But I don't think either of the above assumptions are true, and the real question is how "untrue" are they. The widest part of a tire is typically around the middle of the sidewall, with less width at the tread face. That would buy me clearance. But some tires are "squarer" than others.

Also, the face of the tread is typically domed a bit, or at least tapers off at the edges. That would buy additional clearance as well. If the tread face is shaped anything like the R1 that's on it now, the MX108 I'm pretty sure will fit fine.

So what it's down to is the actual shape of the tire around the tread, and that's not in any of the specs. Or, if I can find someone who has already done this, I can get an empirical answer.

 

[ovrszd]

Heres a pic of a 320/85Rx24. The total width across the lugs is approximately 1/2" narrower than the carcass.

I gained 1 1/2" width going from a 12.4x24. I could have went one more size wider. Wish I had. Noticeably better handling loads.

Worst case for you. If it hits during full lock turn, adjust the stops until it doesn't.

 

[hayden]

Just a quick update. The Michelin XM108 is unavailable, at least in the 320/65R16 size. Nobody could get them. I've been looking at a few other alternatives, but it seems to be an uncommon size, with much larger sizes readily available.