BIG WHEELS KEEP ON TURNING

dagger dog

New User
My TO35 Delux 1959 has 12.4 X 28 rear tires on the turn out wheels. I read the Nebraska test info and the rear tires on the tractor for the tests was 11X 28's and 10 X 28's.

This is where I need some input from the guru's. Are the 12's helping or hindering? I do know that the gearing is set up for the original tire size, and that a larger tire can make the maxium torque and horsepower come in at a different rpm, or possibly different gear . Being very new to tractors the two speed trans is a new thing to me.I have read the section in the operator manual, about using the correct gear for the job (plowing , ground engagement equipment etc.) My tractor was purchased with the TRACTORMETER missing and the generator has been converted to a Delco alternator. Would a standard tachometer, help out in selecting the correct gear and rpm?

:D many thanks for any input
dd
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I think I have the maths correct........ :?:

An 11 x 28 tire has a no load diameter of 50 inches and a rolling circumference of 13.82 feet.

An 12.4 x 28 tire has a no load diameter of 52.8 inches and a rolling circumference of 13.09 feet.

Therefore a 12.4 x 28 tire has a 5.6% longer rolling circumference than an 11 x 28 tire.

I'm not sure of the correct tire size on a TO35, but I seriously doubt 5.6% difference in rolling circumference would be noticeable or seriously affect tractor working performance. Theoretically, the tractor should have a 5% faster top speed! :lol:

If you don't want to convert back to a generator and the original Tractormeter, there are any number of low cost electronic tachos available that you could install.

Or you could do what the rest of us do - open up to three quarter throttgle and get on with the job.

Good luck!

Bob in Oz
'53 TEA20
 

Bob,

Thanks for the info. I think I'll just install a electronic tach. Also I have a real good deal working on a new set of 12.4 chains, as I plan to use the Ferguson this winter to remove snow.

thanks Drue (aka dagger dog)
 
Not to confuse the issue...

Modern 12.4 28 tires are equal to the old 11 28 size. Old 10 28 would be 11.2 28 now. Those 12.4 28 are just what the old girl needs...
 

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