John Deere 4020 on 20.8 X 38s

Not wanting to hijack the other threads about 4020 rear tires choices......Just wondering what people's experience has been with running 20.8 X 38 tires on late model 4020s?

We're currently running 18.4 X 38 tires on our '72 4020D(no 3pt. hitch) & they are getting in rough shape along with the rims which are corroded.

Only reason I was curious about the 20.8 X 38s was that there are times when we could use a bit more traction & since we will be replacing the tires & rims anyway............

Thoughts?

TIA

Never had that large of a tire on a 3020 or 4020. We installed 16.9 x 38 rear rubber on a 3020, which was a wonderful upgrade for the that tractor from the original 15.5 x 38 rear tires. I would tend to think 18.4 x 38 rear rubber should be more than adequate to hold down the horsepower of a 4020 and especially so if you went with radials. The 20.8 tire is a monster of a tire, particularly for a 4020, in my opinion.

If you need more traction, first choice is to go with a more fancy tire, for sure not a 18.4-38, but a radial carcass.

I had 600/65R38 Michelin XM108 on my 4020 and it was sticking to the ground. Those are same height than the 18.4R38 but they are 600mm wide (23 inches wide).

I would recommend to go that way. You can also go with 520/70R38, that would be a low profile 20.8R38. If you can afford the latest Michelin Xeobib in 650/60R38 format, you will have a nice looking tractor and a lot of traction.
Those tractors allows to run at very small pressure, particularly on a 4020 (lightweight). You will have to get special rims with smaller diameter tolerances so the tire does not spin on the rim. But you will like it!!!

This one tractor is not mine, but I had same tires on mine:
https://www.youtube.com/watch?v=70VDNEhn-1w

Thanks for the info.

The 18.4 - 38 tires that we are running now work fine for the majority of the work we do. Just the occasional job where we are working in a field where the ground is more sandy & bare than usual is where we could use a bit more traction / flotation.

We'll definitely be looking at radial options when the time comes.

(quoted from post at 20:12:16 08/01/17) Never had that large of a tire on a 3020 or 4020. We installed 16.9 x 38 rear rubber on a 3020, which was a wonderful upgrade for the that tractor from the original 15.5 x 38 rear tires. I would tend to think 18.4 x 38 rear rubber should be more than adequate to hold down the horsepower of a 4020 and especially so if you went with radials. The 20.8 tire is a monster of a tire, particularly for a 4020, in my opinion.

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Thanks for the info.

The tires in the video look just about perfect on that tractor & the Xeobibs are pretty cool although I'm not sure they'll fit our budget when the time comes. LOL

Regardless, we'll be going radial when the time comes......

(quoted from post at 23:37:23 08/01/17) If you need more traction, first choice is to go with a more fancy tire, for sure not a 18.4-38, but a radial carcass.

I had 600/65R38 Michelin XM108 on my 4020 and it was sticking to the ground. Those are same height than the 18.4R38 but they are 600mm wide (23 inches wide).

I would recommend to go that way. You can also go with 520/70R38, that would be a low profile 20.8R38. If you can afford the latest Michelin Xeobib in 650/60R38 format, you will have a nice looking tractor and a lot of traction.
Those tractors allows to run at very small pressure, particularly on a 4020 (lightweight). You will have to get special rims with smaller diameter tolerances so the tire does not spin on the rim. But you will like it!!!

This one tractor is not mine, but I had same tires on mine:
https://www.youtube.com/watch?v=70VDNEhn-1w

Click to expand...

Will the three point clear tires that big?

(quoted from post at 10:41:06 08/02/17) Thanks for the info.

The 18.4 - 38 tires that we are running now work fine for the majority of the work we do. Just the occasional job where we are working in a field where the ground is more sandy & bare than usual is where we could use a bit more traction / flotation.

Click to expand...

Sounds like you need duals, not larger singles.

20.8x38 are the same height as 18.4x42.One problem would be fender clearance unless you have the bigger fenders that came on 4320/4620. The gearing would also change a few MPH.18.4x38 seem large on a 4020. I prefer the 16.9x38 or18.4x34 w/duals.

Neighbor we traded help with and farmed 80 acres together with had 15.5x38 Firestone Deep Treads bias tires for 8-10 years on his '70 4020 with M&W turbo. He didn't even run wheel weights, just his Year-a-Round cab, pulled 5-16 IH plow, 15-16 ft disk. Heven did a lot of road work with the tractor too, used it to grind hog feed 2-3 times a week and run a mile to other farm to do chores and come the mile home.

We had 15.5x38's on our 4010 and for doing all fieldwork mounted up 13.6x38 M&W direct axle duals with JD hubs. No weights or fluid. We only pulled a 12-1/2 ft disk and on plowed ground slippage was near 0%. It was such a gutless wonder if we shifted down to 3rd gear and tried to pull an 18 ft disk it would still have near 0% slippage. Problem was our JD dealer tech, he maybe wasn't the wizard of injection pumps he thought. New pump guy paid us a house call one night and in 2-3 hours we went from 60-70 hp to 105! Went from 5th to 7th Gear disking! Still near zero slippage with the duals.

Most good running non-turbo'ed 4020'd run in the 105-115 area and 18.4X34's in a good Firestone all traction tread is normally enough tire to make it all work,,38's work out well too..20.8"s are a bit much..

Tractor doesn't have a 3 pt. hitch.....

(quoted from post at 13:57:54 08/02/17)
Will the three point clear tires that big?

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The lack of traction only happens in certain conditions which are few & far apart. IMO, it wouldn't justify having duals in our situation.

Sounds like you need duals, not larger singles.

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The 18.4 X 38s fit fine on our '72 but the final ratio is certainly less than our '68 that's running 18.4 X 34s.

Have to run the '72 in 4th & the '68 in 5th.....

(quoted from post at 04:36:12 08/03/17) 20.8x38 are the same height as 18.4x42.One problem would be fender clearance unless you have the bigger fenders that came on 4320/4620. The gearing would also change a few MPH.18.4x38 seem large on a 4020. I prefer the 16.9x38 or18.4x34 w/duals.

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Duals would be ideal but we don't do enough work, where traction is an issue, to justify them. Unless we happen to find the time / money someday to put boost on the 4020 & get some bigger implements.....that could be a different story. LOL

(quoted from post at 07:38:25 08/03/17) Neighbor we traded help with and farmed 80 acres together with had 15.5x38 Firestone Deep Treads bias tires for 8-10 years on his '70 4020 with M&W turbo. He didn't even run wheel weights, just his Year-a-Round cab, pulled 5-16 IH plow, 15-16 ft disk. Heven did a lot of road work with the tractor too, used it to grind hog feed 2-3 times a week and run a mile to other farm to do chores and come the mile home.

We had 15.5x38's on our 4010 and for doing all fieldwork mounted up 13.6x38 M&W direct axle duals with JD hubs. No weights or fluid. We only pulled a 12-1/2 ft disk and on plowed ground slippage was near 0%. It was such a gutless wonder if we shifted down to 3rd gear and tried to pull an 18 ft disk it would still have near 0% slippage. Problem was our JD dealer tech, he maybe wasn't the wizard of injection pumps he thought. New pump guy paid us a house call one night and in 2-3 hours we went from 60-70 hp to 105! Went from 5th to 7th Gear disking! Still near zero slippage with the duals.

Click to expand...

Thanks Tim,

Our 4020s have only ever ran on bias ply tires. I imagine switching to 18.4R38s would be make a significant difference & would probably be all that we would ever really "need"........

That might change though if we ever find the time / money to install a turbo. LOL

(quoted from post at 07:59:25 08/03/17) Most good running non-turbo'ed 4020'd run in the 105-115 area and 18.4X34's in a good Firestone all traction tread is normally enough tire to make it all work,,38's work out well too..20.8"s are a bit much..

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Glen, Here are pictures of the 4020 with the Michelin 600/65R38. Those tires are specially made to fit on narrow rims so you do not have to change rims. They are made for 18 inches wide rims and can also do 20 or 21 inches wide rims.
Those tires give this old tractor a boost of traction that was unbelievable. I could get them for about a 1/3 of new tires, so I did not pass on them.

You can also see the hydraulic trailer brake valve right under the rear light that I installed from a salvaged 4430, and the welded extra plates welded on the lift link to increase the lift power (while decreasing stroke). The red trailer hold 9.5 metric tons of grain and the brown one hold 14 metric tons and is super heavy to pull. It sure makes the 4020 work out going up-hill, and you got to know how to shift that syncro range.

Tractor does not do any row crop work, so the center to center distance between tires is 80 inches. The fenders were raised using a very thick tube about 2 inches tall. That tractor is not pretty but it is earning her keep and the oil is changed every 100hrs. He now has the muffler back on, because that setup was too noisy, and tires are down to 520/70R38 (18.4R38 height with 20.8R38) width because the 600/65 went on another tractor.

Thanks for the pictures. It's nice to see the older equipment in action.

Those tires look good & certainly must have some bite to them!

That said, I'd need to get the same type of deal on the price as you otherwise I'll have to wait for the lottery to kick in.....LOL

A p-shift trans. in the 4020 would make the grain cart work a little nicer I bet.

Sure it will be nicer. But the syncro is not bad at all if you know it.

I bought the rear end of a late 4020 PS in southern France and the front end of a 4320 in the US. Now I need to put that together...

When you have the 4020/4320 bolted together you'll have your new grain cart tractor.

Even better will be when your 6030 Powershift project is complete you can hook all of the grain carts together! LOL