Looking for tire advice for Deere 770

[NickTaylor]

Hello all,

I have a 1998 Deere 770 with MFWD. I purchased it used 15 years ago with original R1 rears (Firestone field & road 12.4-16) and replaced the fronts when I bought it with Carlisle 6-12 farm specialist R1s. The fronts are starting to fail, and the rears are finally dry rotting, time to replace all four. Thinking about switching to something other than the R1s. I do mostly bush hogging 12 hilly acres, trail mowing in the woods, some loader work (moving mulch, firewood), and occasionally wood chipping with a pretty heavy Woodland Mills 3 point wood chipper. The reading I've done on R4s doesn't sound very encouraging (lots of stories of them loading up and losing traction?), but the new R14s seem to be getting good reviews. Has anyone put R14s on a 770 or 790? Any recommendations on tire vendor / size in order to maintain my MFWD specs?

My current rims are stamped 12x4JA (front) and W11x16 (rear).

I couild just go back with R1s, but want to think about other options before just going back to these really aggressive bar tires.

Thanks in advance!

 

[LouNY]

I switched one tractor over to BKT IT 696's.
I think they are a better choice then the R14's, I do have r14's on the little Kioti and they do good.

The BKT sitting side by side with the R1 it's replacing.

 

[Spindifferent]

It really sounds like all of your tractor uses would be best suited with traditional R4 tires. If you are not doing any serious ground-engaging work that requires the most traction, then R1 tires may not be the best choice. Seems like you already know this...

That said, I just replaced the R4s on my 20-year-old JD 3520 (tires starting to dry-rot) with the following on the front: Carlstar Trac Chief 6 ply, and Carlstar Ground Force 400 R4 14 ply G rating on the rear. All have great reviews, and I've been happy with them so far for the same uses as you. I've also used them for tilling with my reverse-rotation tiller and they have better traction than the original Galaxy R4s. Most of my tractor use is bush hogging and loader work.

No experience with the R14s, and they look interesting, but wonder why you think you need them based on what you use the tractor to do. If the majority of time on your tractor was tilling, discing, plowing, chiseling (working the ground), with a little bit of the bush hogging and loader work, then traditional R1s would likely be best.

My opinion is to look for the highest-quality R4s you can afford. Titan, Galaxy, Goodyear, Calstar all have lots of models and sizes. BUT, this may well require different rim sizes for the R4s.

My biggest issues with the new tires were actually finding a reseller that had my sizes in stock, and then finding someone to install the new tires. And, there was the cost of it all...

Good luck with whatever you decide!

 

[Peter 315]

I had a JD 770 with turf tires swapped over to R4's had to change the rear rims.

 

[LouNY]

It really sounds like all of your tractor uses would be best suited with traditional R4 tires. If you are not doing any serious ground-engaging work that requires the most traction, then R1 tires may not be the best choice. Seems like you already know this...

That said, I just replaced the R4s on my 20-year-old JD 3520 (tires starting to dry-rot) with the following on the front: Carlstar Trac Chief 6 ply, and Carlstar Ground Force 400 R4 14 ply G rating on the rear. All have great reviews, and I've been happy with them so far for the same uses as you. I've also used them for tilling with my reverse-rotation tiller and they have better traction than the original Galaxy R4s. Most of my tractor use is bush hogging and loader work.

No experience with the R14s, and they look interesting, but wonder why you think you need them based on what you use the tractor to do. If the majority of time on your tractor was tilling, discing, plowing, chiseling (working the ground), with a little bit of the bush hogging and loader work, then traditional R1s would likely be best.

My opinion is to look for the highest-quality R4s you can afford. Titan, Galaxy, Goodyear, Calstar all have lots of models and sizes. BUT, this may well require different rim sizes for the R4s.

My biggest issues with the new tires were actually finding a reseller that had my sizes in stock, and then finding someone to install the new tires. And, there was the cost of it all...

Good luck with whatever you decide!

I detest R4's wet pastures and hills they are ridiculous. Hard packed gravel or pavement they are fine.

 

[beenthere]

I prefer the R4's for woods work, brush mowing, loader work, and only find them coming up short in the woods when spring thaw leaves the trails a bit muddy. Good for going on the lawn without leaving a mark. All in all, I'd suggest the R4's but have not run the R14's. Hope you find the best tire for you.

 

[Jaygyver]

Be aware 6-12 is NOT the same size as the 6.00-12's that came OEM on the tractor, there's almost 2 inch's difference in the diameter. You have to make sure you get the right size because of the MFWD. I bought my '97 JD-770 in '98 and had an issue finding front tires a few years ago. I looked around for months and finally found BKT's (I think ?) that were the right size.
Whatever way you go just make sure you find someone that knows the formula for the MFWD when updating your wheels and tires. My JD dealer was zero help in that.
You also have to remember that our 770 isn't the heaviest tractor so the traction will be different with the R-4's so I would probably go with the R-14's for the middle ground. They do make different tread patterns also.

I live in the PNW and for the most part left mine in 4x4 almost all the time except when on asphalt. When I replaced the fronts a couple of years ago the rears were still probably 60%. It's been stored in my unheated shop 98% of its life so there isn't any age cracking. The next time I need tires I will probably go with R-14's but for now I'm staying with the R-1's.

I bought a 35hp LS a few years ago and it came with r-4's but I wanted the R-1's but they were back ordered for months. I've had to pull the LS out of the mud twice with my 770 because of the r-4's. Didn't want to tear up the yard any more "bucketing out". (Using the bucket to get out.)
I am leaning towards the R-14's on the LS as a best of both worlds but I will probably have to change wheels also, at least I would have to if I went with the R-1's.

 

[BHW961]

In the for what it's worth category of replies, I have a JD 2320 equipped with R4's. Although they work fine for me for most of my needs around the house and in the woods, I soon learned they were helpless on ice or hard packed snow. After some research, I bought a tire groover and grooved the center of the lugs on the R4's. What a difference! Traction on ice and hard packed snow was vastly improved.

 

[NickTaylor]

Be aware 6-12 is NOT the same size as the 6.00-12's that came OEM on the tractor, there's almost 2 inch's difference in the diameter. You have to make sure you get the right size because of the MFWD. I bought my '97 JD-770 in '98 and had an issue finding front tires a few years ago. I looked around for months and finally found BKT's (I think ?) that were the right size.
Whatever way you go just make sure you find someone that knows the formula for the MFWD when updating your wheels and tires. My JD dealer was zero help in that.
You also have to remember that our 770 isn't the heaviest tractor so the traction will be different with the R-4's so I would probably go with the R-14's for the middle ground. They do make different tread patterns also.

I live in the PNW and for the most part left mine in 4x4 almost all the time except when on asphalt. When I replaced the fronts a couple of years ago the rears were still probably 60%. It's been stored in my unheated shop 98% of its life so there isn't any age cracking. The next time I need tires I will probably go with R-14's but for now I'm staying with the R-1's.

I bought a 35hp LS a few years ago and it came with r-4's but I wanted the R-1's but they were back ordered for months. I've had to pull the LS out of the mud twice with my 770 because of the r-4's. Didn't want to tear up the yard any more "bucketing out". (Using the bucket to get out.)
I am leaning towards the R-14's on the LS as a best of both worlds but I will probably have to change wheels also, at least I would have to if I went with the R-1's.

Good comment about the MFWD limit. I think the spec I have seen in the forums is 1.571 lead, but I’ll be darned if I can find that number listed anywhere in the owners manual or service manual. Do you know what the true 770 spec is and where it can be found?

 

[Jaygyver]

From what I read the formula doesn't have to be exact just near enough. There has to a be a little "lee way" built in for tire wear anyway.

As far as getting close, my original fronts at the end were smooth as a baby's bottom. I could almost see my self where the tread was they were that smooth and the rears had probably 60% tread left. I did make sure the wife and kids knew not to use the 4x when on the asphalt. But in general we usually just left it in 4x. I had maybe 700 hrs on the tractor at the time of the tire change so I was probably a decade behind changing the tires out. I don't have 40 acres so there is no travel time for me on the tractor, just stuff around the place.

It's been a few years now but I did look A LOT online at the time and it is out there but you have to look for it. There are a few other tractor forums out there I looked at and sometimes the major tire manufacturers white pages had some information and sometimes an obscure article came up. You can probably call around to JD or other brands as most compact tractors have the two different wheel/tire sizes. The tires I ended up with were listed as for a Kubota and a few others when I was looking but didn't have my JD listed which was funny.

My local dealer sold out then was bought out by Pape' then they pulled out because there were too many dealers too close to each other. One was a commercial heavy duty and the other was for the small tractors, mowers etc, guess which one they shut down? Figure that one out.

As far as finding replacement OEM tires,
What I did was finally found out what the diameter size of the Firestone tires I had when they were new and looked around to the different online stores and found one that was pretty close. I did run them for around a year or so until I found the right size.
I finally found a few tire sellers online that did make it known there was a difference in tires sizes. And in my case still sent me the 6x12 instead of the 6.00x12 I ordered, lol. They did apologize and sent me the right ones.
27 years owning the 770 with R-1 tires I never once had a flat tire, which astounds me with all the crap I drove over, but on the other hand got my first flat (picked up a nail at the neighbors place) on the 1-1/2 year old r-4's on my LS.

 

[Jaygyver]

In the for what it's worth category of replies, I have a JD 2320 equipped with R4's. Although they work fine for me for most of my needs around the house and in the woods, I soon learned they were helpless on ice or hard packed snow. After some research, I bought a tire groover and grooved the center of the lugs on the R4's. What a difference! Traction on ice and hard packed snow was vastly improved.

You know, if the lugs on the R-4's were a bit deeper I think that would help, at least until they got worn. Maybe I'll try the tire groover, $1500 a couple years ago to switch wheels/tires can wait a bit more.

 

[LouNY]

All of the major and even many of the smaller tire manufactures will have specification sheets for their tires. Those will list the O.D. of the tire and much more info on the tires. Even within the same manufacturer all of the different models of there tire will have different dimensions with the same listed size. One of the important measurement will be loaded rolling circumference, or loaded radius which are the important numbers. I have seen more then 8 inches difference in rolling circumference for the same nominal size in the different series of R1 tires they offer.

 

[evan waa]

You should get the mechanical ratio between the front and rear axles. Then even though the tire number sizes may be the same. The rolling circumference of tires varies with number of lugs and number of plies and manufacture of the tire at the factory rated pressure. You would probably want about a 2 to 3 % pull 5 % is high

 

[NickTaylor]

Ok I have dug around a million tire websites, called the dealer and visited the local ag tire shop. Was hoping for a hybrid tire, but there just isn’t much available for little tractors like the 770. Very few R-1 setups I could find that support the needed MFWD 1-4% lead. Closest I could find was BKT TR-171 for front (25.0 diam, rolling circ 76.9) and TR-135 for rear (diam 37.8, rolling circ 112.3). By diameters, the lead is 1.04, by rolling circ the lead is 1.07.

Anyone have experience either these BKTs? Too aggressive for mowing hilly pastures and trails? Too much lead?

Interested in any other available combos people have recently installed?

 

[Jaygyver]

I got my front tires from Amazon and I believe they were also listed as for Kabota and a couple of others so I would try to find another tractor brand with similar size front/rear tires and go from there. Find the tractor that has the same size ratio and find that tractor brand's R-14 tire/rim combo? (They do list a Kabota 7100 as having the same tires but if you look up its spec sheet it shows it has 6-12 NOT 6.00-12, so much for that.)

There's very little information on our JD 770's out there for some reason. I guess we got the perfect tractors?

Again, I was at least 10 years past changing my front tires and haven't had any issues, as of yet anyway. Either way you go just use the 4x when you need it and being in the dirt shouldn't be an issue when you do use it. We are not doing 70+ mph/kp or pulling 8 plows behind us to worry too much about it. There has to be a little bit of leeway to account for wear, like in my instance of bald front tires and 50+% rear tires.

The R-1 front tires I got, the brand is Max-Auto and they are 6.00-12.
I couldn't find the R-1 6.00-12 MaxAuto on amazon now, only the 6-12, but there are a couple of other brands it seems but they just list the tire size and not tractor brand fitment. Maybe on their own website. They were one of only a couple outfits that actually had a warning stating that 6.00-12 and 6-12 were different sizes.

 

[jyoutz]

It really sounds like all of your tractor uses would be best suited with traditional R4 tires. If you are not doing any serious ground-engaging work that requires the most traction, then R1 tires may not be the best choice. Seems like you already know this...

That said, I just replaced the R4s on my 20-year-old JD 3520 (tires starting to dry-rot) with the following on the front: Carlstar Trac Chief 6 ply, and Carlstar Ground Force 400 R4 14 ply G rating on the rear. All have great reviews, and I've been happy with them so far for the same uses as you. I've also used them for tilling with my reverse-rotation tiller and they have better traction than the original Galaxy R4s. Most of my tractor use is bush hogging and loader work.

No experience with the R14s, and they look interesting, but wonder why you think you need them based on what you use the tractor to do. If the majority of time on your tractor was tilling, discing, plowing, chiseling (working the ground), with a little bit of the bush hogging and loader work, then traditional R1s would likely be best.

My opinion is to look for the highest-quality R4s you can afford. Titan, Galaxy, Goodyear, Calstar all have lots of models and sizes. BUT, this may well require different rim sizes for the R4s.

My biggest issues with the new tires were actually finding a reseller that had my sizes in stock, and then finding someone to install the new tires. And, there was the cost of it all...

Good luck with whatever you decide!

Agree. For what the OP is doing the R4 tires have the stiffest, toughest sidewalls.

 

[jyoutz]

You know, if the lugs on the R-4's were a bit deeper I think that would help, at least until they got worn. Maybe I'll try the tire groover, $1500 a couple years ago to switch wheels/tires can wait a bit more.

The new Kubota R4 tires are grooved. Maybe check those out.

 

[kenacp]

Will have to replace my original 770 tires before too long. Keep posting the options.

 

[jyoutz]

Will have to replace my original 770 tires before too long. Keep posting the options.

The options are going to be based on your wheel sizes. Can’t change to R1 tires if you have R4 tires/wheels now. And vice versa.