16.9 x 38 vs 15.5 x 38

I am new here so I apologize if this in the wrong forum. I have a John Deere 2640 that needs new rear tires. The tractor currently has 15.5 x 38 on it and a few years ago I bought some nice used 16.9 x 38. I was about to put the 16.9's on this weekend when a friend said it wouldn't pull nearly as good. Now after some research I realize the 16.9 is a good bit taller than the 15.5's (never bothered to measure either before). The tractor is kind of slow on the road. Would the 16.9's be a good fit on the rear of a 2640 or should I find some 15.5's? This might be a silly question for someone who already owns a set of tires to ask but this will probably be the last set of rubber this tractor will ever need and I don't want to be disappointed. Thanks in advance.

i'm not real familiar with that tractor but do you mean 16.9 x28. 38's are a very tall tire for utility tractor. I assume the 15.5 are 28 s as well.

Since you already have the tires I would put them on and see what you think. A lot of it depends on if you are out of engine or out of tire. If you are out of engine then you may not want to go bigger but if you are out of tire as I suspect you are with that much hp on those tires the 16.9s should work fine.

I don't know the tractor at all, but do you have 4x4? You could run into problems with the rear pushing the front end around, and eventually gearbox failure on the front end.

Checked some sites and found that 16.9 x 28 is the standard tire for your tractor and was the tire used in the Nebraska tractor test. Unless someone swapped rims out or the 15.5 was an available option, the 16.9 should be right. I checked the Titan Tire site and found the 16.9 x 28 takes a 15 inch wide rim. They don't list a 15.5 x 28 but a 15.5 x 38 takes a 14 inch wide rim. If your rims are 14 inch I'm not sure how they will fit but in the past we have up sized tires keeping the narrower rim width without problem, but those were tube type. Not sure if you are using yours tube type or tubeless.

I had a 3020 with the 15.5 38 tires that were worn badly and replaced them with 16.9 38 tires. I vaguely remember that the only problem was one implement didn't have enough clearance to hitch up because the tires stuck out farther to the rear. You may need to drop one gear to get the approximate travel speeds similar but overall it worked well enough. A 3020 and 2640 should be very similar in power (70 pto hp) so since tires are so expensive I would give it a shot after comparing the length of the lower hitch arms.

Your friend's opinion does not match up with my experience. swapping to 16.9x38 tires from 15.5x38 will make a big difference in traction in most conditions. They are an acceptable fit on 14" rims. You already own them, put them on. The same swap made a huge improvement on a 4010 I once owned.

Ignore the guys who think you can't read numbers on a tire sidewall. 38" tires were optional on most Deere utility tractors and certainly were available on a 2640.

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Originally Posted by RickB

Your friend's opinion does not match up with my experience. swapping to 16.9x38 tires from 15.5x38 will make a big difference in traction in most conditions. They are an acceptable fit on 14" rims. You already own them, put them on. The same swap made a huge improvement on a 4010 I once owned.

Ignore the guys who think you can't read numbers on a tire sidewall. 38" tires were optional on most Deere utility tractors and certainly were available on a 2640.

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I would agree and add that 38" rims were very popular for 2640 tractors and other older models. Now I see alot more tractors with smaller diameter with wider rims and tires in the newer tractors.

When that tractor was made many of them were set-up for cultivating which required ground clearance and a narrow tire. To change out to the 16. RichB is right on! better ground speed as well as a big gain in traction. I wouldn't worry about filling them if you really want to enhance the performance unless you have a loader.

Just curious. John Deere doesn't list 38" tires as an option. Standard rims are 15" width by 28" diameter. Operator says tractor is slow. If someone put 38" tires on it would be very fast. Unlisted option by Deere or is my info obsolete?

Yeah, a 28 inch rim to a 38 inch rim would make that thing really go!