4020 Rear Tires

plowman1926

New User
I've got a 1964 Johne Deere 4020 Row Crop model that my son is going to restore for an FFA project. It has 15.5x38 tires on the back and we were thinking of going with the bigger 18.4x34 tires. We just don't want to get dinging at any of the shows he takes it to. Can you tell me if the bigger tires were an option in 1964 or is that something that came out later?
 
I have an early 1965 ? gas model and it has the 18.4-34 on it.
I would think the 15.5-38 would really be too small for this big of a tractor. Many models do offer optional tire sizes.
 
Our late model 4010 diesel came with 18.4X34 tires right from the factory. I would go ahead with putting the 18.4X34 tires on your 4020 and have a sharp looking tractor.
 
Just went and looked at jdparts.com site and there are 5 different rims listed for Row Crop (RC) models ! various 34 and 38 inch ones. All would be legit options.
 
The later 4010's had 34 inch rears as an option. 4020's could be had with 38's or 34's. Many people who did alot of cultivating bought the 15.5X38's and you also needed them for a mounted corn picker. I think the 34's look about the best on a 4020 but we have one with the 15.5's and I like that for chores as well.You should be able to trade your cast centers even up for a set of 34's and good used 15.5x38 sell good as well so it shouldn't cost alot to trade up. I do not like 18.4x38's on a 4020 as it makes the hitch height to high,even 16.9x38's if they are on the narrow rim don't look right to me. Tom
 
Thanks for the info. The current tires are about done for and the rims are rusted from the CaCl that was used for ballast. My son is just nervous because one of his class mates did a tractor last year and got dinged by the judges at several shows for stuff he thought was minor. I've looked at a bunch of 64's online and most of them have the 18.4's. I'm just trying to make him comfortable. Also trying to get backup info so if the judges do say anything he has the info to back it up.
 
I have a 1964 4020 and also a 1971 4020. The early one originally had 18.4-34 tires while the late one had 16.9-38's. I always liked the way the later one looked over the early one. I have since put 18.4-38 on both of them and get along with them just fine. I also have 11:00-16 front tires on both of them. Both tractors look balanced (in my opinion) and also ride better with the larger tires on both ends. I did have to extend the steps on both. I've seen many 4020's with 18.4-34 rears and 11L-15 fronts. I always thought they looked "dumpy". That is the way my early 4020 came to me. I like it much better now. You will likely get as many opinions as there are people who post. This is my opinion. Mike
 
An operators manual or shop manual should list the most popular tire options. I suspect the most popular rear tire sizes on 1964 4020's included 15.5-38, 16.9-34, 18.4-34 and 23.-30. I would check when other tire sizes were introduced. I think 18.4-38 was introduced later with the IH 1206 and 20.8-34 with the JD 4320, and 16.9-38?
 
Isn't that a lot of trouble? You would need new rims and cast wheel centers to swap.
 
18.4-34s are very common on 4020s. If a judge knocks that, they shouldn't be a judge. All three of my 4020s came with 34s when I bought them. My PS 4020, I wanted it to look different from the boring drab looking 34s that are on every other 4020, so I put 38s on it and now it looks stellar (also with 11:00-16s up front). But 18.4-34 is the smallest tire size I would ever have on a 4020.
 
The 16.9x38 came later but being you already have the castings I would go with 16.9 on a 16in rim.The 18.4x34 is on the majority of 4020s and look fine also.I always thought the 18.4x38 were a little too large for the original 4020 fenders.Personally I would put what you like.Depending on what state you are from Titan Tire has supported 4-H and FFA tractor projects by supplying 4 new tires for tractor projects.I have seen many nice tractors and a decal being 1/4 inch out of place or some of the little things the experts find wrong doesn't bother me at all.The main thing is do it right.
 
For older two cylinder tractors you can get the shipping information to find out where the tractor was shipped and how it was equipped. I don't know if that's possible on a new generation tractor. You might have to balance "originality" with how you plan to use the tractor after the contests are over. Will you keep the tractor or sell it to a collector at the fair? Worst case you can always change the wheels and tires next year if you need something non-original.

Look into the Titan(?) tire offer. Some of those rear tires have a center rib that could reduce traction in soft ground, but would be a smoother ride at road speeds.
 
Thanks for all the feedback. He's going to show it in the Spring and then I imagine we'll take it to a few shows later. My guess is 2 years down the road it will be pulling a 15' bush hog and pulling a renovator in the hay field so we probably need to setup the tires for that.
 
Personally, I hate 18.4-34 tires, and wouldn't own a tractor with them on. The sidewalls feel like they're gonna buckle when working on sidehills. I borrowed a 4040 with 18.4-34s while my 4430 was in the shop a month ago. I pulled a 10 foot Gehl 2365 disc mower/conditoner with it, and it was a nerve racking experience when turning downhill. I was sure I was gonna roll them off the bead, and I had 25 lbs air in them. Too much sidewall. Stay with the 38" rubber. 16.9-38s are a good match, even though they don't fit the year. A lot of guys around here have 18.4-38s on 4020s, but I think they're a *little* too much rubber.
 
(quoted from post at 00:39:10 07/17/16) Personally, I hate 18.4-34 tires Stay with the 38" rubber. 16.9-38s are a good match, even though they don't fit the year. A lot of guys around here have 18.4-38s on 4020s

On Firestone super all traction rear tractor tires
18.4X34 overall dia is 65.1'' - 34''=31.1 divided by 2=15.55''
18.4X38 overall dia is 69.7'' - 38''=31.7 divided by 2=15.85''
therefore I see little difference in sidewall height of either size. 16.9X38 tire wasn't listed where I found other tires listed.
 

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