Tires John Deere 770 R4 tires?

[lhobson]

If you want to have the same match for the front R4's that Deere uses on the 790 you'll have to do as Deere does and use 15-19.5 R4 tires on the rear..Of course you'll need new rear rims..or you can do what Whitey did and just realize your frt tires are a little bigger than spec.. Here's a link to the proper titan R4 rear tire. Titanï½® Tire catalog
With the 25x8.50-14 R4s on front you're a little closer to spec with the turf tires on the rear than if you bought 12.4-16 R4's..With your 13.6-16 turfs use these sizes for the ratio formula. Rears = 113" / Front = 79" .. That's the sizes that you have now.

With 15-19.5 on the rear use these sizes Rear = 117" Front = 79" this is the official Deere recommendation.

With 12.4-16 on the rear use these sizes, Rear = 110" Front = 79"

With 12.4-16 R4's and 23x8.50-14 the numbers are Rear = 110" Front = 71" ... ratio is 1.549 this equals 1.4% lead on frts..

Front wheel lead is used to aid in traction..everything I've read from experts leads me to believe that using Front assist is for needed traction, not for use all the time..unless you live in a traction limited area ie: mud, loose dirt. snow..etc. use 2WD until 4WD is needed. Less wear on the front differencial that way. Bottom line as long as it's fairly close and you use 4WD only in limited traction situations you'll be fine...leave it in 4WD all the time and you will put excessive wear on the front differencial.

Thanks for the explanation! If I want rear R4s I'm going to have to go with the 12.4-16. The 15-19.5 has about a 40" diameter. There wouldn't be enough clearance for the belly mower. People have modified the belly mower to sit closer to the front wheels to accomodate the 15-19.5, but I'm in 4 wheel drive maybe 15% of the time. I last question. Where did the 71" figure come from ?

 

[irwin]

Thanks for the explanation! If I want rear R4s I'm going to have to go with the 12.4-16. The 15-19.5 has about a 40" diameter. There wouldn't be enough clearance for the belly mower. People have modified the belly mower to sit closer to the front wheels to accomodate the 15-19.5, but I'm in 4 wheel drive maybe 15% of the time. I last question. Where did the 71" figure come from ?

Originally posted by irwin
With 12.4-16 R4's and 23x8.50-14 the numbers are Rear = 110" Front = 71" ... ratio is 1.549 this equals 1.4% lead on frts..

On this page... Titan?ｮ Tire catalog On the right column, rolling circumference for the 23x8.50-14 is 71".

The rear R4 15-19.5 rolling circumference is 117" the best match for that tire is the 25x8.50-14 @ 79" rc (or 75" depending on the R4 tire see Titanｮ Tire catalog) , using the formula (see last link) the front wheel lead is 6%, (or .06% for the 25x8.50-14 that's 75" rc), the acceptable lead is normally 1 to 5%. in the case of the R4's on the 790 and 3005 apparently less than 1% or 6% is okay too.

Sorry if this is a little confusing.. To find all your numbers you can look up the exact tire that you have (or want) and find the rolling circumference on line.

Can I use a different size tire on my 4wd tractor

 

[lhobson]

On this page... Titan?ｮ Tire catalog On the right column, rolling circumference for the 23x8.50-14 is 71".

The rear R4 15-19.5 rolling circumference is 117" the best match for that tire is the 25x8.50-14 @ 79" rc (or 75" depending on the R4 tire see Titanｮ Tire catalog) , using the formula (see last link) the front wheel lead is 6%, (or .06% for the 25x8.50-14 that's 75" rc), the acceptable lead is normally 1 to 5%. in the case of the R4's on the 790 and 3005 apparently less than 1% or 6% is okay too.

Sorry if this is a little confusing.. To find all your numbers you can look up the exact tire that you have (or want) and find the rolling circumference on line.

Can I use a different size tire on my 4wd tractor

Does anyone make a 13.6-16 R4 ?

 

[irwin]

Does anyone make a 13.6-16 R4 ?

Sorry, nope. At least no one made one when I searched a couple years ago. The closest size that can be used on a 16" rim (11"wide) is the 12.4-16 R4.

 

[Roger Ellis]

I have a 1991 John Deere 770 with Ag tires that need to be replaced. I mostly mow lawn, some bush hogging (in some wet areas and hills), driveway snow removal and some dirt moving. I have been told that changing to R4 dires will decrease cutting into my lawn yet still give me better traction than turf tires. It looks like Indiana Deere has done this in 09. How do you like your conversion? Other comments and experience would be appreciated. Thanks in advance.

 

[Berryfarmer]

I have 1996 John Deere 770 with the Ag type tires on it and would like to put new R4 tires on my old Deere. The front ag tires are very whimpy when doing loader work with heavy loads. I would like to hear from anyone who has made the switch from Ag tires to R4s. I've looked at a lot of posts and I think I can use my rear rims, but will need to get new front rims for the loader tires. I believe I read where someone used front rims from a 790. Please give me the rim sizes and tire sizes you used. I really don't use the tractor for any farming, just for discing up a small food plot. Mainly dirveway maintenance, clearing trails in woods and some bush hogging.

Hi, I have brand new ag4 tires for jd770 but would like a set of ag tires. In addition I have a set of new turf rear tires for jd 750 and a used set of turf tores in excellent shape for a jd 770. Call Rod at 651-674-8765.