YM276D located and in garage

[California]

rScotty posted a YM276/YM226 sales flier on another thread. According to one page of that flyer, power steering is optional.... Here is the link to the page rScotty posted.

http://www.tractorbynet.com/forums/files/yanmar/516270d1500817842-ym226-ym276-original-sales-flyer-orig-adv_ym226-ym276_pg-10-jpg

Thanks! I should have looked at that thread.

After reading that brochure, I want one!

 

[richriddle]

Now I am even more confused. While specs on agricultural tires remain constant from all sources, the same can't be said for turf tires. According to the following sources different tire sizes are stated:

Rear Turf Tires...........Front Turf Tires....................Rear Ag Tires.............Front Ag Tires
16.1L x 16.5..............25-8.50 x 14 Skid Steer ................................................. (Current Configuration)
16.1L x 16.5..............25-8.50 x 14.......................11.2 x 24...................7-14....(Tractor Data)
16.1L x 16.5..............25-7.50 x 15.......................11.2 x 24...................7-14....(YM276/YM276 Yanmar Flier)
11.2 x 10-24.............27-8.50 x 15.........................11.2 x 24.................7-14....(YM276/YM276 Yanmar Manual)

Your wisdom and help is appreciated.

 

[rScotty]

For what it's worth I am having trouble getting to the last page on this thread so I may not respond. Sorry about that, of course some may be happy.

I am having that same trouble getting to the last page as well. But today it all seems to work better. Apparently there is some problem with the site; in the "forum/forum" they say they are working on it. Oddly enough, the problems crop up on Sundays....of course.

Winston, thanks for that info you posted. Using your post as a guide, I looked in my old factory repair manual for the YM336 and found that it has those same axle ratio figures, too. So they did publish the numbers - my mistake - and after all these years we've finally found those figures! It's been 25 years since I did the math to set up our YM336D, but from what I remember the number I came up with in my measurements is either the same or very close to the number shown in your attachment as the "FRONT AXLE TO REAR AXLE SPEED RATIO = 1.638 : 1" . That's about on the middle of the page
I need to see if I an find my old notes doing the calculations, but that number does seem familiar.

There's a lot of information on that page. Including is something called "FRONT AXLE PRE-RUN PERCENT = 0 and 6%. My interpretation of that spec is that it is weird translation of a concept from the Japanese designer. What he seems to be referring to is what we would call the minimum and maximum percentage of deviation for the front axle to turn faster than the rear axle. As we noted, the front to rear ratio of the tires "running circumference" would be best if it exactly matched the front to rear axle ratio of 1.638:1 ratio. If the ratio of running circumference F/R matched the internal axle gearing F/R exactly, then that would be 0% overrun. That would be perfect, and in fact I did once build a Yanmar to 0% overrun. It was an eye-opener. I could shift from 2wd to 4wd and back again while flying down the asphalt road in top gear ... and the shift was smooth as silk. No lurching and no noise.
But the problem with 0% overrun is if the front tires wear faster than the rears then you are in danger of going into negative overrun. In that condition the rear tires try to overrun the fronts and steering quickly suffers. On the positive side at about +6% overrun is about where most new tractors are set up. At that much overrun, the main thing that one will notice is that the 4wd shifter binds up and is hard to shift to 2wd. This happens worst if you drive in 4wd on a high traction surface. Don't do that!.

Apparently there were a lot of wheel/tire options available for the 276. Just by matching the tire rolling circumference ratio to that axle ratio allows even more options.
rScotty

 

[winston1]

I am able to get the last page today. Rich, I cannot find the 25-8.50-15 tire anywhere, are you sure that is the correct size. I was wanting to do a little math on your setup but need the rolling circumference of that tire.

 

[clemsonfor]

Here are some pictures that better illustrate the condition and the tires on the tractor at this time.

View attachment 516196
This the front tire.
View attachment 516197
That is the back tire.

Here are general pictures.

View attachment 516198 View attachment 516199 View attachment 516200 View attachment 516201 View attachment 516202

As you can see, it has a Rhino gear-driven tiller. Some think it's a superior style compared to the older Yanmar chain models.

I thought the yanmar tillers are gear driven?

 

[winston1]

I thought the yanmar tillers are gear driven?

Some are, some aren't, depends on model

 

[California]

re 'overrun', 4x4 front tires leading rear tires - some design theory: A little overrun will help pull the nose around for a sharp turn.

Not too important on a farm tractor because braking one rear wheel can help this, but for an offroad jeep more is better for critical maneuvering in tight spots among trees, boulders, cliff edges etc where you can't just plow forward. (That assumes traditional 4x4 without a differential in the transmission).

Ok, school's out.

 

[richriddle]

I am able to get the last page today. Rich, I cannot find the 25-8.50-15 tire anywhere, are you sure that is the correct size. I was wanting to do a little math on your setup but need the rolling circumference of that tire.

I am absolutely positive you are correct and the tire size previously stated was wrong. See the two included pictures. It's a 25/8.50-14 mad by Trac Chief. Sorry about that. The rear tires say nothing but the tire size and Goodyear along with "tubeless".



Oh the joys of finding the right tires for old tractors. Thanks for all your help.

 

[richriddle]

I see Goodyear makes a front tire to compliment the Goodyear rear tire: Goodyear Softrac Mower Tire, Size:25-8.50-14, Ply:6, item number 4SR-327. They are certainly proud of them.

 

[winston1]

For what it's worth, here are some calculations. I'm unsure what you have on the back but if it is a 16.5-16.1 the circumference would be 109. Should measure about 40.3" tall. If that is the case a matching front tire would be a 25-8.50-14. Circumference 68". Doing the math that would give you a 2.187 front lead.