Grand L vs. MX

crazyal · Apr 17, 2011

My front Ag's are 8.3x16. I'm wondering if they went with a slightly smaller tire to allow for a little more room for a center pto attachment?

Dargo · Apr 18, 2011

Those mentioning the R4's sidewall (weight carrying advantage) over the R1's are correct. I have a 100 hp JD tractor, similar to the Kubota M9540 tractor. I only went with JD because of the larger cab and 2nd seat in the cab. Anyway, in the dead of winter I was finishing filling an area behind a newer barn I'd build and I had my R1 tires on the tractor because I was running through 18" or more of muck in the fall with each bucket load of fill from a several thousand cubic yard dirt pile I have from when I dug my pond. No way the R4's would have made it through that muck and allow me to get the fill in place. It eventually got so sloppy that I was running out of a hard bottom and running the risk of getting stuck, so I had to stop.

After temps below zero for several days, I used my 7' tiller to grind out 8" of then easily scooped dirt from my dirt stash for fill. All was fine until I unwittingly crossed a frozen rut and ridge with a yard of fill in my front bucket. Even with my R1's aired up to the max (rears loaded but fronts are not), I absolutely crushed my right front rim. I was able to remove it where it sat and straighten my rim enough to be surprisingly round and hold air in my machine shop and get the tractor into the barn to switch to my R4's for that tractor. I didn't need the R1 traction on the hard frozen soil and the R4's sagged a bit going over that rut, but never came close to getting to my rim. So, guys talking about that potential issue have a valid point. Now that I think about it, I think I've had the R4's on ever since. They generally pull fine, but will never equal an R1 in muck. Also, as mentioned previously, the smaller diameter the front tires are, the more they are going to sink and less they will pull in poor conditions.

I just thought I'd point out my experience because I didn't particularly enjoy working outside in below zero temps with a nice breeze trying to fix a crushed rim. Depending on your soil conditions, it's possible you can go through more muck with R4's on a larger tractor than with R1's on a smaller tractor. You just need to figure which is going to be best for you.

slowzuki · Apr 18, 2011

No the R1's were 9.5 x 16, you could go to the smaller fronts and rears from the L31/34/38/4330 if you asked for them but they are puny.

The R4's are 10x16.5 on the same models.

The rear R1's were 14.9 x 26 or 13.6 x 28 optional size.

The rear R4's were 17.5 x 24.

Grandad4 said:
I think the R1 fronts were 8.3x16's and the R4 fronts were 9.5x16's on the L4610's and L5030's. Likewise, the rear R1's were 14.9x24 vs 17.5x24. Don't see the tire specs on the Kub website for the L40's, but I think they've stayed the same, and match the MX series. You are correct that the MX resembles an updated L4610, minus the rubber floormat. Original MX5000 even had the same LA852 FEL.

Grandad4 · Apr 18, 2011

slowzuki said:
No the R1's were 9.5 x 16, you could go to the smaller fronts and rears from the L31/34/38/4330 if you asked for them but they are puny.

The R4's are 10x16.5 on the same models.

The rear R1's were 14.9 x 26 or 13.6 x 28 optional size.

The rear R4's were 17.5 x 24.

I'll defer to your knowledge of the L30's, but the original sales brochure printed in 2000 for the L10's (don't say it, I'm a nut because I still have it :laughing

- says the standard front was 8.3x16 for the L3710 through L4610.

My L4610 still has the original R4's... definitely better for serious FEL work. Geez, we sound like a couple of antique car fanatics... they can spend hours debating whether all the visible slotted screw heads should be aligned perpendicular or horizontal!

Dargo · Apr 18, 2011

Grandad4 said:
Geez, we sound like a couple of antique car fanatics... they can spend hours debating whether all the visible slotted screw heads should be aligned perpendicular or horizontal!

Definitely vertical.

slowzuki · Apr 18, 2011

I'm not up to snuff of the 10 series for sure, I know the 4610 was a much different animal than the rest of the 10's with heavier front axle, orbital valve and ram, etc, some of the early TBN posters fitted much larger Michelin R1W tires, even cutting back the loader mounting brackets to get them on there! One had 19.5 x 24's on the rear with the correct fronts.

I cheated, I really wanted R1W's on my L5030, but couldn't spend the cash at the time. When my front r4's wore out, I had no time to wait so popped 12x16.5's on. They are a tiny bit big but better than the 10's which were way too small (I'm talking in terms of lead/lag)

To make up for it I've got monster radials on my MF, the rears are 600 mm wide (about 2 ft wide), even though it weighs 2x the Kubota, I can drive though soft ground with only light ruts, that the Kubota's little fronts just sink into.

Grandad4 said:
I'll defer to your knowledge of the L30's, but the original sales brochure printed in 2000 for the L10's (don't say it, I'm a nut because I still have it :laughing - says the standard front was 8.3x16 for the L3710 through L4610.

My L4610 still has the original R4's... definitely better for serious FEL work. Geez, we sound like a couple of antique car fanatics... they can spend hours debating whether all the visible slotted screw heads should be aligned perpendicular or horizontal!

TripleR · Apr 18, 2011

slowzuki said:
I'm not up to snuff of the 10 series for sure, I know the 4610 was a much different animal than the rest of the 10's with heavier front axle, orbital valve and ram, etc, some of the early TBN posters fitted much larger Michelin R1W tires, even cutting back the loader mounting brackets to get them on there! One had 19.5 x 24's on the rear with the correct fronts.

I cheated, I really wanted R1W's on my L5030, but couldn't spend the cash at the time. When my front r4's wore out, I had no time to wait so popped 12x16.5's on. They are a tiny bit big but better than the 10's which were way too small (I'm talking in terms of lead/lag)

To make up for it I've got monster radials on my MF, the rears are 600 mm wide (about 2 ft wide), even though it weighs 2x the Kubota, I can drive though soft ground with only light ruts, that the Kubota's little fronts just sink into.

Do you have any pictures or advice as I am going to have to replace the front R4's on my L5030 soon.

crazyal · Apr 18, 2011

I figure when the time comes to replace my front tires I would switch to the Firestone 4000 TL R1W in 280/70-16. They seam to be a close match to the 8.3x16. They are wider though I I think I need to buy new wheels. But they are rated very well for weight.

slowzuki · Apr 19, 2011

My advice on the 12x16.5's is try to find 11x16.5's. They are the perfect diameter for the 17.5x24 rears. The 12's are more common but lead at about 6% which is high. I leave them at low pressure and use 4wd sparingly. The old 10's lag by about 5% which is bad too.

If going to an R1W, there are a few good matches in Goodyear and Firestone, but you need the 16" ag rims. Nothing available in 16.5. I've got a few old threads on here about going R1W all around and what sizes are needed.

TripleR · Apr 19, 2011

slowzuki said:
My advice on the 12x16.5's is try to find 11x16.5's. They are the perfect diameter for the 17.5x24 rears. The 12's are more common but lead at about 6% which is high. I leave them at low pressure and use 4wd sparingly. The old 10's lag by about 5% which is bad too.

If going to an R1W, there are a few good matches in Goodyear and Firestone, but you need the 16" ag rims. Nothing available in 16.5. I've got a few old threads on here about going R1W all around and what sizes are needed.

Thanks for the information, I will look into them. I bought the tractor used and the rears are in really good condition and are Firestone, so I hate to spring for a full set of R1W's. We have Ag tires on our M8540 if I really need to do anything requiring really great traction. For what I use my L5030 for, the R4's work quite well.