JD 2640 Tire/Wheel Size Options?

[Almonzo]

Have 18.4 x 30's on Dad's 2640 right now, but tires are showing small cracks on sidewalls, and are likely from 1980's era, so would like to replace, with decent used, if I can find some.

Inner axle bolt pattern is 8 bolts, on 9.5" diameter 'hub', outer wheel edge has 9 bolt pattern, on approx 32.25" diameter rim.

I notice tractordata shows 16.9 x 28's for the 2640.

Wondering what size(s) I can safely replace with? Is there a range of width x radius ratio's I can use, or is it also a factor of torque/hp?


Majority of used tires for sale in this area currently are 18.4 x 38's -- have been told those are likely too big for this tractor's hp (60-70).

Would any of these work?
16.9 x r28
18.4 x r26
19.6 x 28
23.1 x 26
23.1 x 34



Thanks for any advice.

 

[Tx Jim]

I've never seen a 19.6 X 28 rear tractor tire. I think 16.9X28 & 18.4X26 will fit a 2640

 

[Almonzo]

Thanks for the reply.

Meanwhile, found the following in the 2440/2640 manual:

"The travel speeds shown are for tractors with 16.9-28 or 18.4-30** rear tires. Speeds would be 4% slower with 13.6-38 tires, 3% slower with 14.9-28* tires, 3% faster with 15.5-38 tires, 9% slower with 16.9-24 tires, 5% slower with 16.9-30 tires, and 2% faster with 18.4-26 tires. Differential drive ratio is different for tractors equipped with 30 or 38-inch rims."

Below this, another note says ** is for 2640, * is for 2440 only.

So to sum up, looks like the 2640 can take the following rear tire sizes:
16.9-24
18.4-26
16.9-30
18.4-30
13.6-38
15.5-38

Now need to figure out what front tire sizes match these...

 

[oldnslo]

Is this a 2 wheel drive or front wheel assist? If 2 wheel front to rear size is of less importance.

 

[Zebrafive]

If no problems with your wheels (such as rusted through) I would stay with a 30" tire. For that size tractor, I would pick the 16.9-30
IIRC these were only 2-wheel drive tractors. If it needs front tires too, I would replace with the same as equipped. I would only change if it's a loader tractor and the current front tires are undersized for a loader.

 

[JD3520Turbo]

Agreed with above. If your current wheels are fine, I would use them. Since you have 18.4-30's now, you more than likely have 16 inch wide wheels. A 16.9-30 will not like being on a wheel that wide. If you are tubeless, then you will have a difficult time getting that tire to pop out. If you tube them, you could do it, but they won't look right, and the sidewalls will be more vulnerable to cuts and snags.
I would stay with the size you have, because it will be cheaper to get tires only, instead of wheels and tires.
Good Luck