Hi Jim. You can tell "as manufactured" tire codes on 1966 though very early 1969 year tractors (the cut off was production before November 25, 1968). The sales bulletin I have showing this though only lists GT-3, GT-4, GT-5 & GT-6 tire type codes for 140 models. I have a price list dated 6-24-74 and in it that actual GT-7 tire code isn't used even at that time yet, but a dealer could mix & match tire sizes/types to suit whatever the customer needed. That is why even on older tractors where this info is on the serial number plate, it does't mean the tractor was sold to the first owner with those tires on it (as a dealer could mix and match tires off of tractors in his inventory to suit a customers needs) and that is why I always say that it may have been built with a certain tire type code, but wasn't necessarily sold with those same tires still on it.
so is that to say that the gt-7 option was not offered in 1969 ? because in my less than 30,000 manual i believe that their is mention of a gt-3 through gt-7. (although it was sat. night when i read it and i was "unwinding" at the time)
My 1968 & 1969 owners manuals do not show GT-7, but my 1970 & 1971 manuals do, then the 1972-1974 manuals do not. So, that must be why it wasn't shown in my dealer price sheet for 1974. BTW, keep in mind that JD printed a different owners manual for each year during the production run of 140's, so having an under 30,000 owners manual is misleading as there were three versions depending on the serial number of the tractor. So, it looks like GT-7 was an "official" option for 1970 & 1971 models, and any other years it would have been something a dealer made up before selling (unless somebody has some dealer sales sheets that show it for other years, as 1974 is the only dealer price sheet I have for 140's).
How do you tell what the tires look like for each GT-# option. I have a 69 140 with model & serial number T0583 012501. What should it have for tires? It has Goodyear 10.5" turf tires on it now with the solid center rear rims? This is an interesting topic. Thanks for the help.
Hi Brad. Although you have a very early 1969 140, unless you have had a serial number research done through Two-Cylinder magazine, I have no idea if it was built before the Nov. 25 cutoff on the scans above. If it was, then it should have GT-3 tires on it, which are 16x6.50-8 front and 23x8.50-12 rear turf tires. As to the different GT codes, that info is in some owners manuals, sales manuals, price sheets and sales bulletins. A breakdown of them is as follows-
GT-1 4.00/4.80-8 2ply front 6-12 turf rear
GT-2 4.00/4.80-8 2ply front 6-12 traction rear
GT-3 16x6.50-8 2 ply front 23x8.50-12 turf rear
GT-4 4.00/4.80-8 4ply front 23x8.50-12 traction rear
GT-5 16x6.50-8 2ply front 23x10.50-12 turf rear
GT-6 16x6.50-8 2ply front 23x8.50-12 traction rear
GT-7 4.00/4.80-8 4ply front 23x10.50-12 turf rear
GT-8 16x6.50-8 2ply front 23x10.50-12 traction rear
For the 400 the following two codes were used
GT-12 18x8.50-8 2ply front 26x12-12 turf rear
GT-14 18x8.50-8 2ply front 26x12-12 traction rear
So far these are the only tire codes I have found, but I haven't spent a ton of time going through my library looking for them either, so I'm not sure if GT-9, GT-10 or GT-11 were ever used (I'll be honest and say I am a bit suprised that there wasn't a 4.00/4.80-8 4ply front 23x10.50-12 traction rear listed where I looked).
The print date of an OM can be estimated based on the cover style used, which has been changed several times over the years. If you could possibly post a picture of the front cover I am sure either Kent or myself can give you an approximate date (or at least narrow it down to a decade).
The GT codes specified a tire size & basic tread type however not the actual tire manufacture or tread pattern. And while Goodyear was most likely the primary supplier, there were others including BFGoodrich and Firestone to name a few. Here are pictures of a few of the different “turf” type tires offered from that period…
Hi Bob. It is interesting that they used those suppliers for the turf tires, but I have yet to see anything other than Goodyear brand bar tires pictured in all my sales literature. It is interesting to note though that my mid 1970's 140 parts catalog does list the Firestone 23 degree bar tires as a parts item (and the Firestones had been around since the mid 60's as my dad has an old farm magazine with a Bolens ad in it, and it clearly has the Firestone bar tires on the back of it).
hi kent my manual number is sm2086 (aug-70) copyright 1970 it is grey with 6 green stripes running through it horizontally and the manual states "gt-6 and gt-7 tires are also available.gt-6 tires are gt-3 front high flotation tires and gt-4 traction rear tires.gt-7 tires are gt-4 front studded tires and gt-5 rear high floatation tires" thank you for your help jim
The rear Goodyear tires pictured in my previous post are the 23x8.50-12 size. Don't remember for sure but I think the wider 23x10.5-12 size alternated the tread orientation similar to these smaller sized ones...
That cover style was used during much of the 1990's so I would say your SM was printed then.
Hi Jim. I thought you were talking about an owners manual, not the service manual. Anyway, as Bob said, it is a newer printing with that cover style, and with the August 1970 copyright, that makes it the "newest" information that was printed for 1968-1970 model 140's.
Hello all, I'm in a slow process of restoring a 1971 140 H1. Eventually I will be buying new tires. I've never really understood all of the GT-3, GT-4, etc. I'm going for looks and want to stay original as possible. I really like the looks of the Goodyear turf tires. Just like the ones Bob Decker posted on Oct. 4. Does anyone know if those kind of tires are still available by suppliers? I have to get all four tires. My mower type is T0581 and serial number is 034631M. Thanks for any help anyone can provide.
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