John Deere 770 tires??

[deeregirl85]

Hello everyone! I am having quite a problem with a company tractor and I am hoping someone can help!

I work for college that has a JD 770 CUT 4WD that is used for landscaping purposes and just recently had some parts in the front end go Bang! Well now that the tractor is all back together I am having some serious doubts that the tires on the front of it are not the correct size...

The tires are 155/80R12 passenger car tires and I don't think these are the right size?! I have gone to the dealer and was informed that the original tires are obsolete so no help there..

Can someone please tell me the correct size that goes on the front of this tractor? I do not want to put on the traditional tires as I know it will tear up our grounds so I am hoping to find a lighter duty/turf tire, I guess, to put on the front.

Thanks in advance!

 

[arrow]

Turf tires for this tractor measure 13.6x16 rears and 23x8.50-14 fronts

 

[deeregirl85]

Turf tires for this tractor measure 13.6x16 rears and 23x8.50-14 fronts

Thank you very much for responding to my post

But the size you listed above 23x8.50-14 will not fit the rims on our tractor..? As per the dealer this tractor came with either 5.00x12 or 6.00x12 tires but that was all the info I could find..?

 

[irwin]

Thank you very much for responding to my post

But the size you listed above 23x8.50-14 will not fit the rims on our tractor..? As per the dealer this tractor came with either 5.00x12 or 6.00x12 tires but that was all the info I could find..?

Not sure where that dealer is getting his info. The 770, 790 and the 3005 all have the same front wheel lead ratio: 1.571 .. you might have to buy new rims for the front if you go with turf tires... rear= 13.6-16, frt= 25x8.50-14.. if the 3005 has different sizes listed you should be able to use them..

You MUST have the proper front wheel lead or serious damage to the front axle or the drive for the front can occur.

You haven't told us what type of tire is on the rear. R1? R3 (turf)? or R4? If you have R1 (ag) tires you will need to be very careful putting anything other than the corresponding front tires on. Take a look at the rear tires and post here what size and style they are.

I did a lot of research on my old 770 when I changed tire type from R3 to R4. Here's a couple links to older threads that have info that might be useful.

http://www.tractorbynet.com/forums/parts-repairs/96441-turf-tires-should-go-industrial.html

http://www.tractorbynet.com/forums/john-deere-owning-operating/99396-790-770-mfwd-ratio-r4.html

 

[deeregirl85]

Not sure where that dealer is getting his info. The 770, 790 and the 3005 all have the same front wheel lead ratio: 1.571 .. you might have to buy new rims for the front if you go with turf tires... rear= 13.6-16, frt= 25x8.50-14.. if the 3005 has different sizes listed you should be able to use them..

You MUST have the proper front wheel lead or serious damage to the front axle or the drive for the front can occur.

You haven't told us what type of tire is on the rear. R1? R3 (turf)? or R4? If you have R1 (ag) tires you will need to be very careful putting anything other than the corresponding front tires on. Take a look at the rear tires and post here what size and style they are.

I did a lot of research on my old 770 when I changed tire type from R3 to R4. Here's a couple links to older threads that have info that might be useful.

http://www.tractorbynet.com/forums/parts-repairs/96441-turf-tires-should-go-industrial.html

http://www.tractorbynet.com/forums/john-deere-owning-operating/99396-790-770-mfwd-ratio-r4.html

Sorry I am still new in the JD world lol! Our tractor has R1's on the rear (12.4-16) I will post a picture of it when I get home tonight.

I have read a few posts on here regarding tires and I already understand the improtance of having the "right size" tires for any application. Especially 4WD's. (just like my pickup that had 4.10's in the rear and 3.73's in the front when I bought it and didn't know...)

So this is why I ask if the tires that are on it are any where close to the size they need to be or not? I have a very tight budget to stick to on getting tires for this tractor since we just put over a grand in repairing the front end.

If it ends up me having to find 4 tires for it then so be it but I am/was really hoping that I don't have to go that route...

 

[scrappy isb67]

Turf tires for this tractor measure 13.6x16 rears and 23x8.50-14 fronts

this is also the size for the R4's I believe

Thank you very much for responding to my post

But the size you listed above 23x8.50-14 will not fit the rims on our tractor..? As per the dealer this tractor came with either 5.00x12 or 6.00x12 tires but that was all the info I could find..?

The 5.00x12 and 6.00x12 are R1 sizes

The tires on the frontend now are too short I would bet. but if you aren't in 4wd ALL the time , it shouldn't cause an issue

 

[grsthegreat]

this is what tractor data shows

TractorData.com John Deere 770 tractor dimensions information

4.0-15 front and 9.5-24 rear

My old 870 had the same "go bang" front end and i think the bill was about $1,300 to repair as far as i remember.

 

[deeregirl85]

The 5.00x12 and 6.00x12 are R1 sizes

The tires on the frontend now are too short I would bet. but if you aren't in 4wd ALL the time , it shouldn't cause an issue

I honestly do not know how often it is in 4WD or not...I'm just the mechanic so I don't ever see our equipment till something goes wrong haha. Which hopefully will not be for quite a while with the JD...But regardless if these tires will work for now or not they are almost shot and I Do Not want to put passenger car tires on it again...especially if they are too small. I can get the R1 tires easy but unfortunately they can't go on it because they are afraid of messing up the campus with them :-/

 

[deeregirl85]

Here is a picture of our Deere

 

[sriddle1ny]

Deeregirl85,
I recently purchased a "04 JD790 and have been doing research on its operation. The old saying "Don't know what I don't know" applies with me so proper ballest and weight distribution came to mind whenlooking at the 770 picture you posted with the Loader, I don't any wheel weights nor a ballast box if you're doing any heavy lifting. I noticed grsthegreat mentioned the "go bang" front end, you might want to read this thread, again not sure if it applies to the 770 or the tractor pictured is 4WD..........

http://www.tractorbynet.com/forums/john-deere-owning-operating/171692-jd-790-front-end-problems.html

 

[deeregirl85]

Thank you everyone for all of your replies and helping me out! But sorry to say that I am now more confused then when I first posted...seems like everyone is saying a different size for the tires so I'm not really sure where to go from here....?

The front end went bang and chewed up 2 of the gears in the right hub/spindle and snap rings were broken every where in it. The ring and pinion survived without even a scratch thankfully

I have been working here for a little over a year and a half and as far as I know the rims have never been changed out on the tractor and by the dealer parts list it would suggest that the rims are the originals or at least the original size...?

I know that the front end went either because of too much weight in the front or from them never taking it out of 4wd. It is used on campus so it sees grass, dirt, concrete, rocks, etc everyday. I have already talked to the department and told them they must be careful with the weight they throw in it but the tire issue still really concerns me...

 

[arrow]

There is no tire with the amount of flotation you are looking for so as to not scrub up the turf that will fit your present rims in the front. There is a company ( Hoye Tractor Parts) that will create your proper size wheel and turf tire set for around $1300 for all 4's. If you are looking for just the fronts, they will accommodate you as well with your information about the tractor. They can duplicate just about any compact tractor rim with proper sizing for correct lead.

 

[sriddle1ny]

I am now more confused then when I first posted...seems like everyone is saying a different size for the tires so I'm not really sure where to go from here....?

I know the rims have never been changed out on the tractor and by the dealer parts list it would suggest that the rims are the originals or at least the original size...?
...

deeregirl85 ,

Although you can access the John Deere Web Site's Parts Catalog and look these parts up, I went ahead and pulled the recommended (3) differeing types of tire/rim combinations for the 770. Hope this helps, you can look at each rim and tire details for sizing info.

 

[grsthegreat]

as to the front end.... i was told that there is /was a defect in the front axle, and ALOT of 770,870 and 1070's had this issue.

After one side of my front axle failed, i had JD dealership open up the other side and it was a few weeks away from failing also. Something about a retainer nut that has no locking ring/pin in it and was backing out. I ended up paying about $1,300 in repairs that was for all intense and purposes a factory defect.

 

[irwin]

All you need is 2 12" tires that have the exact same rolling circumference as 5x12 R1's.

Really, if you can find a set of 12" tires that are close to the rolling circumference and are careful with 4WD usage you'll be fine...

BTW.. I just found these... here's a link to 5x12 R1 tires. https://www.kenjones.com/Scripts/XListSearch.aspx?XGID=REARTRAC_5x12&calledFrom= I thought there would be someone still making them...