L1500DT Final Drive Ratio

billrigsby · Feb 17, 2018

I wonder if any knows the final drive ratio for the L1500 DT?
or
How to figure out the final drive ratio?

I am looking for tires and it seems I need this to determine if
the sizes I am looking at will work based on the rolling circumference.

Rear RC=109.4
Front RC=77.9

Since there are no operators manuals available for this model
and Tractor Data does not list it, I am not sure where to look, also
not sure if any US model is the EXACT same when it comes to this?

As a side note when I purchased it the fronts were 6-14,
Tractor Data list the fronts as 4-12, wondering if the front wheels
were changed or if Tractor data is incorrect?

SRG · Feb 17, 2018

Could the 4-12 be the 2WD front tires size? Tractordata.com seems like a Wiki page where its only updated by user supplied info. If the info isn't supplied by an owner of a specific model, then only partial or no info is shown on the website. Seeing as there are 2WD and 4WD versions of your machine, and only one pair of tire sizes listed, i'd venture to guess that the info is incomplete. My guess is based off of other random models having multiple tire sizes listed and that data differentiating between 2WD sizes and 4WD sizes.

Solely based off of the tire size rolling circumferences you provided, the drive ratio is: 1.35. However, knowing what the OEM tire brand and model is and getting those specific tires rolling circumferences, may show a different number. Not all makes and models of tires measure the same, or are listed the same.
What tire info, brand, model and size do you currently have?

North Idaho Wolfman · Feb 17, 2018

If you wrap a string, rope or tape around the tires you have now, that will give you a very close measurement on what the RC is now.

billrigsby · Feb 17, 2018

SRG said:
Could the 4-12 be the 2WD front tires size?

Solely based off of the tire size rolling circumferences you provided, the drive ratio is: 1.35. However, knowing what the OEM tire brand and model is and getting those specific tires rolling circumferences, may show a different number. Not all makes and models of tires measure the same, or are listed the same.
What tire info, brand, model and size do you currently have?

That is correct, I missed that the L1500 model shown is the 2WD,
and Tractor Data is not known for accuracy from what I have heard.

Parts manual does show the 6-14 and 8/22 but no other information

Currently on the front is Ng Shin Tire 6-14 AG
and on the rear is Bridgestone Farm Service Lug 8.3/8.22

I doubt either are original

billrigsby · Feb 17, 2018

North Idaho Wolfman said:
If you wrap a string, rope or tape around the tires you have now, that will give you a very close measurement on what the RC is now.

Measured the circumference of the front and rears,

OLD
79.375
115.625

NEW
77.9
109.4

Found this in an older post from "tiredguy"
"Now here's the simplified and correct formula to determine what you need to know
in order to keep the proper ratio: Divide the front RC by the rear RC 61 divided by 86=
.7093 which we'll round up to .71 which is the magic number you need to keep the
difference at no matter what sizes you end up using it must be within 2% of that
number and you won't have any problems with the lead/lag front to rear."

OLD; 77.9 / 109.4 = .71
NEW; 79.375 / 115.625 = .69

.71-.69 = .02 / .71 = .03 * 100 = 3%

So it seems based on this I do not need to know the final drive ratio,
but I wonder just how accurate that 2% is when using on dirt/gravel/turf
which "gives" when turning?

Wonder how even the front to rear tire wear was?

100 td · Feb 17, 2018

billrigsby said:
I wonder if anyone knows ...
How to figure out the final drive ratio?

Engage 4wd, make sure the rear diff is not locked, drive tractor onto level concrete, chock wheels both directions one side of tractor, apply park brake to wheel on concrete if your split brake pedal allows it, pull decompression lever, pull fuel stop lever, jack up other side of tractor, mark top of rim front and back, select low gear, crank engine for 2 full revolutions of rear wheel whilst counting revolutions of front wheel, stop at top of second revolution of rear wheel, add remaining revolution of front wheel to it's tally, you now have you ratio to use to match RC of your particular tires. Depending on your tractor, you may be able to select neutral and physically roll the rea tire and drive the front through the drive train to do the same thing.
My belief, fronts should be correct ratio, or slightly larger to pull, instead of being pushed if they are slightly smaller.

billrigsby · Feb 17, 2018

100 td said:
Engage 4wd, drive tractor onto level concrete, chock wheels both directions one side of tractor, pull decompression lever, pull fuel stop lever, jack up other side of tractor, mark top of rim front and back, crank engine for 2 full revolutions of rear wheel whilst counting revolutions of front wheel, stop at top of second revolution of rear wheel, add remaining revolution of front wheel to it's tally, you now have you ratio to use to match RC of your particular tires.
My belief, fronts should be correct ratio, or slightly larger to pull, instead of being pushed if they are slightly smaller.

Thanks, I will have to try that, even if I do not need the info for tire purchase, it will be good to know.

100 td · Feb 17, 2018

Forgot to mention, make sure the rear diff is not locked and apply park brake to chocked wheel if the split pedal allows it, also shut off fuel at fuel tap

SRG · Feb 17, 2018

The problem with all that is, Manufacturers don't wrap a string around tires to get rolling circumference. They use a mathematical equation to get rolling circumference. There are too many variables with tractor options that will put different amounts of weight on a tire(s) and air pressures that people use, for them to be able to account for.

Tire manufacturers use tire advertised diameter, multiplied by pi (3.14) which gives advertised rolling circumference. Which is why i was asking for info on the tires you have on it now. Some basic reverse math and you can figure out the final drive ratio, if you have OEM spec tires. Which, from everything i have read, staying within 5% of the final drive ratio is ideal.

I personally don't think you'll run into an issue in 4wd, provided you use 4wd where it is meant to be used, ie; dirt/mud/snow/ice etc. Places where tire slippage will be allowed. Use 2wd any other time you don't need the pulling power/traction advantage.

Front tires in a 4wd staggered size setup (pretty much all 4wd CUT's), you'll experience faster front tire wear than the rears. There's a few reasons for this. One is because a steer tire always wears faster than a non steer tire (unless your doing burnouts). Two, the tread is not as deep as a rear tire, so of course it's going to need replaced first (being a steer tire exacerbates this). Third, they turn faster (more revolutions per mile than a larger rear tire).

xmikew · Feb 17, 2018

Bill. I had this same question but never posted since I’m waiting on my tires to die. I’m pretty sure mine are still original. I know the rears are Bridgestone and still have Japanese writing on them. Don’t remember what was on the front. Id like to move to r1s where the lug is not as aggressive once I actually start having grass.

Also I never checked 4wd drive on my tractor. Is the lever pushed down (forward) engage and up (back) 2wd?

I’m interested in you tire choice. I could only find the expensive bridge stone rice paddy tire or the Hoye turf tire set due to the odd rim diameter. Let us know what you end up with! Very curious!

Thanks.

- Mike

Sent from my iPhone using Tapatalk

xmikew · Feb 17, 2018

Just went out with flashlight to check fronts. They are Bridgestone with Japanese writing. 6-14. They say 4 pr ht nylon on them as well. Guessing they are 4 ply. I have no idea how they hold air they are so cracked. Probably not helpful but pretty sure they are original if you want me to look for some other number on there.

- Mike

Sent from my iPhone using Tapatalk

billrigsby · Feb 17, 2018

xmikew said:
Bill. I had this same question but never posted since I’m waiting on my tires to die. I’m pretty sure mine are still original. I know the rears are Bridgestone and still have Japanese writing on them. Don’t remember what was on the front. Id like to move to r1s where the lug is not as aggressive once I actually start having grass.

Also I never checked 4wd drive on my tractor. Is the lever pushed down (forward) engage and up (back) 2wd?

I’m interested in you tire choice. I could only find the expensive bridge stone rice paddy tire or the Hoye turf tire set due to the odd rim diameter. Let us know what you end up with! Very curious!

Thanks.

- Mike

Sent from my iPhone using Tapatalk

Pull the front wheel drive lever back to engage 4WD

I'll keep you posted on tires.

billrigsby · Mar 11, 2018

billrigsby said:
I'll keep you posted on tires.

Finally pulled the pin on new tires, should be here in 2-3 days,
loaded up the rears in the work truck, I'll dismount them
tomorrow at work and see what we have for rust to clean up.

billrigsby · Mar 14, 2018

billrigsby;273038 I'll keep you posted on tires.[/QUOTE said:
New Shoes - Just waiting on the fronts, scheduled for tomorrow.
Need to get the old ones off now and see what those rims look like.

EDIT: Still need tubes, better get them ordered.

North Idaho Wolfman · Mar 14, 2018

Bill,
You planning on going into rice farming?

Why didn't you go with something like a normal R1's that won't make chiropractor and dentist rich!

xmikew · Mar 14, 2018

585 not bad for tires all round! Interested in the 4wd operation when you get them on. I like they are r1 and although have tall lugs seem shorter and flatter than the originals.

Sent from my iPhone using Tapatalk

billrigsby · Mar 14, 2018

North Idaho Wolfman said:
Bill,
You planning on going into rice farming?
Why didn't you go with something like a normal R1's that won't make chiropractor and dentist rich!

For 22" rims?, thats all I found, I asked here and got no guidance?
The ride was not that bad on the old ones, and they were hard as a rock,
these at least have some give.

billrigsby · Mar 14, 2018

xmikew said:
585 not bad for tires all round! Interested in the 4wd operation when you get them on. I like they are r1 and although have tall lugs seem shorter and flatter than the originals.

Sent from my iPhone using Tapatalk

Actually there was a 10% discount that I thought was automatic,
they had to credit my card, so even better.

billrigsby · Mar 14, 2018

North Idaho Wolfman said:
Bill,
You planning on going into rice farming?
Why didn't you go with something like a normal R1's that won't make chiropractor and dentist rich!

I saw these and they claim to be R1's?
Did not see much difference?

For less $$ I got all 4 ?

North Idaho Wolfman · Mar 14, 2018

billrigsby said:
I saw these and they claim to be R1's?
Did not see much difference?

For less $$ I got all 4 ?

Yes the ones in the picture are R1's, look at the height of the tread, huge difference from what you have which are R2's.

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