What's the smallest tire that will fit on a 20.8 x 38 rim?

Is the question - "What is the narrowest tire that will fit on the rim a 20.8 came off of?"

If so, that would likely be an 18" wide rim. Would be really hard to seat an 18.4 on it even...

I got a 4440 and 4640 with 20.8 x 38 tires that I would have liked to put 380s on.  Guess I will have to change rims also. That's gonna break the piggy bank for sure.

If you're looking at 380's on a 44/4640, I'm not sure you'd really be impresssed with 380-38's. Short, and not much load capacity, especially if you want to lift a planter with them.

Suggest you look at 380-46's.

Buy a 46" rim shell, then have someone with a plasma table cut the step-down rings out of ~ 1/2" plate with a hole pattern to bolt right onto your castings.

I did the same with a set of 340-46's that mount on 34" castings...

Sure, it was a few sheckles, but far less than buying a new set of tires with a tractor thrown into the deal!!

Luke

I was thinking along the same lines as Luke. I was thinking about conversion rims to get to 46" also, OR Unverferth stub-disc wheels/rims to get to 46".


A taller tire, but narrow, should help get a little more tire/tread onto the ground. Plus it should help keep the tractor "more level". I will still have to measure, for clearance, from axle to cab fenders, to insure you still have clearance with the "possible" 380/90R46 tire.  

Yes, but Clay was contemplating a 380mm (14.9") tire onto an 18" rim.

He might have done it, but would have taken 4 buckets of Murphys and 6 Bead Cheetah's all syncronized perfectly to get the bead to seat.

Luke

I have the large castings for centers. Can I bolt rims to that or do I also need to replace the hub? 

(1979 JOHN DEERE 4440 100 HP to 174 HP For Sale At TractorHouse.com-202127.png)

1979 JOHN DEERE 4440 100 HP to 174 HP For Sale At TractorHouse.com-202127.png (84KB - 682 downloads)

Here's some links:

http://www.umequip.com/wheels/step-up-conversion/?tab=features


Click on blue highlighted titles. (for Unverferth)




Wold rims, have double bevel rims and single bevel rims that are called "conversion rims". I just installed some from 36" to 38" from Wold. {Went from 13.9 x 36" tire to 15.5 x 38" tire}   

http://www.woldinc.com/tractor-replacement.html





On the 3010 tractor rims, it is kinda hard to see, but there is an additional bump/rib inside there, where the clamps go.
     
  

(3010 tractor tires 015.jpg)

DOUBLE BEVEL_Wold Rims.pdf (914KB - 745 downloads)

3010 tractor tires 015.jpg (47KB - 771 downloads)

Hey, that's slick. Didn't know such a thing existed. I'm gonna have to look around locally and see what I can find. Shipping will probably kill me otherwise.

iseedit:

Those rims happened to be 42" up to 46" , in the ad. Poster would probably have to buy step-up clamps, also to make them work, on his cast hubs(38")




Note: Maybe you noticed it, or maybe you didn't, just thought I would mention it.   


  

MIchelin is a little more 'forgiving' on rim sizes than most, might check their site.