Lead/lag ??? on Grand L series

[ttowne66]

Hey Guys

Reading thru some of the old Glenmack's tire swap threads and found out that the 3830 and up may not have the correct lead. Possibly needing a larger front tire to make up for the issue. Anyone know any specific details to this. Thanks.

Tom

 

[CT_Tree_Guy]

Hiya Tom -

In my opinion, this is an excellent point that you just raised, and one that doesn't get nearly enough attention.

I'm short on time right now, but - short version: the stock R4's on most if not all of the Grand L's are WAY off on lead/lag. 0-6% lead is acceptable, and ANY amount of lag is unacceptable. The 5030 with stock R4's has over 5% lag, which is off-the-charts bad. If I recall, the other GL's were as bad, or almost. (The ags were fine). For that reason and others, I went with turfs that gave me about a 3% lead (if memory serves), and a set of XM27's with about a 1% lead.

Here are two threads on the subject:

New wheels for L3130?

L series tire question and problem.

John

 

[ttowne66]

Tree Guy

Thanks, somehow I knew you would be the first to post on this issue! For my peice of mind, I really need a source that has the actual gear ratio information so the calculation can be performed. There is nothing in my owners manual on gear ratio. The overall diameter of the stock R4's is 30.3in. I imagine you could go up to the next size R4 12-16.5 NHS which is 32.7 in overall diameter and 12in wide(maybe too wide for the stock rim). Without knowing the ratio though, this may or may not be big enough. I checked my clearance to the loader frame and there is enough for the 32.7 diameter tires. This may not be the case on the 3830, 3430 or 3130 though!

Here are the Titan Tire specs

http://www.titanstore.com/store/agricultural.html

click on backhoe/skidsteer, then on HD2000 II

Tom











2

 

[SnoFalls]

I also would like to hear the gear ratio(s) (both at the diffs and in the trans). Also, do the portals at the front have a reduction ratio?

 

[CT_Tree_Guy]

Hiya Tom -

The mechanical ratio for all the Grand L's is 1.5640; (snofalls), this should be the only tractor-related info you need to calculate the lead-lag ratios. Make sure you use the "rolling circumference" of the tire(s) in question to do the calculations; you won't get accurate results if you work from the "overall diameter". Rolling circumference is a much more accurate measurement of how much ground the tire will cover in one revolution when it's inflated, loaded, etc. Most every tire manufacturer will list the rolling circumference of all their tires on their website. I also have two different lead/lag worksheets that I can post if y'all need them.

And here's another good link: Picking up Glenn's Work - R1W Tires Grand L's

Thanks slowzuki for putting together this "master thread" (sort of a "Glennmac's Greatest Hits" on tire info).

John

 

[AB4D]

Tom,

Check out Tractorsmart.com they have a section on this subject.

Jim

 

[RFB]

John,

I read all of the tire threads, and still did not achieve a solid understanding. I have yet to take delivery of my 5030; it currently has r4's, and the dealer said (at my request) that he would switch them to r1's at no change in cost.

I am going to use this tractor in a strictly ag, dirt/gravel road, and snow-moving environment. No turf or lawns to worry about, and no paved roads.

My question is: Should I stick with the Kubota r1's, or should I tell the dealer to get the Michelins(and what model?), and if I do, will it be a straight size for size swap with no mods necessary for size of tire or rim?

Thanks again,

RFB

 

[ttowne66]

CT and AB4D Thanks a bunch...Time to do some quick math now!

 

[CT_Tree_Guy]

RFB -

I don't have as much info at my fingertips as I "should" about wheel sizes and tire sizes for the 5030. It got pretty complicated as I went through all the choices - stock R1 ags, R3 turfs, R4 industrials and Michelin radials.

The Titan turfs that are on my tractor now are 29 x 12.50 -15 (29" diameter, 12.5" wide on a 15" wheel) on the front, and the rears are 44 x 18 - 20. My Michelin XM27 radials are 11LR16 on the front (11" wide, 16" wheel) and 19.5R24 on the rear. There is a slightly narrower XM27 for the rear (16.5? 17.5?) that also gives an excellent lead ratio.

Bottom line: the Michelins are insanely expensive (almost $2K including tax just for the tires), and when Kubota says they have "too much traction"; for all I know, they might be right. If your dealer will swap the R4's with the terrible lag ratio for the stock ags (9.5-16 fronts and 14.9 -26 rears) with an excellent lead ratio of around 1-3%, that might just be the way to go. The main reason I went with the Michelins was to keep ground pressure to an absolute minimum, but since you don't have those constraints you might just be wasting your money. The radials might last longer than bias ply, but maybe not by enough to make it worthwhile.

Also, your dealer would probably not be able to get them for you - you'd probably have to go directly through a tire distributor, as I did. Here in the Northeast, last time I checked there was only one distributor, Pete's Tire Barn. I ordered the extra wheels from a Kubota dealer, had them shipped to Pete's, then picked up the mounted tires from one of their distribution outlets in Torrington CT. All in all, quite a pain in the you-know-what.

Hope this helps more than hurts, but to me, those stock ags are starting to look pretty good.

Good luck, and feel free to ask any more questions you might have,

John

 

[RFB]

John,

Thanks a lot. You are always prompt and informative, and I do not want to wear you down.

But...

You mentioned 9.5-16 fronts and 14.9 -26 rears, and I see those numbers as the spec for the 5030. The dealer said he is looking at 13.6 x 28 for the rears. All of these numbers are greek to me. What practical (positive/negative/neutral) effect will there be in changing from 14.9 x 26 to 13.6 x 28 rear tires?
(And just what do those numbers mean?)

John, thank you for all your help.

RFB