F16D Tire Replacement

[jd123-HT]

Hi All!

I am trying to replace my F16D tractor tires. Since it's 4x4 I am trying to maintain the drivetrain ratio. But I have the following problems:

1. I cannot find specs for my original tires (OHTSU 8.3-20 and 5.00-12). They are worn...so I am not sure what their o.d. or running circumference is...
2. I cannot find the drivetrain ratio for my tractor.
3. Truthfully, I am having a hard time finding specs for any tire from japan or china.

So, I really can't find the right diameter tires for replacement if I do not know what the o.d. of my old tires when new. I also can't calculate % slip if i am missing drivetrain ratio of my tractor or lack tire spec.

I have purchased BKT 8.3-20 for the rear...and am looking for the proper fronts to pair them with.

I have searched like crazy and am in a pickle. Can anyone help me out!?

Thanks!!!

 

[winston-HT]

How about getting on the cement or asphalt, mark your tires and cement, roll 1 revolution, mark the cement, measure distance and you have appx rolling circumference. Do this with front and back. Divide rear by front and you have your ratio. I believe most of the Yanmars are suppose to have 1 to 4% lead with the fronts. I'm going to look for your new tire circumference but if I don't find it just roll it just like you did the tractor.

 

[jd123-HT]

Thanks winston. The problem is, i have the new rear tires mounted already and looking for fronts. If I still had the old tires on...I would do what you suggested. Looking back...I should have done what you said before having the new tires mounted...but I am all new to this and am learning as I go.

Also, my old front tires were really worn...rears 80% remaining I guess. With that wear on the front...I don't think I would come up with the proper ratio would I? I did find the rolling circumference of the BKT 8.3-20....I have to look that up again.

Thanks for the help.

 

[jd123-HT]

I found the rolling circumference of the BKT 8.30-20 as 2670 mm.

I cannot find any specs of my old OHTSU 8.3-20 and 5.00-12 tires though... <E</E>

 

[Norm-HT]

"I cannot find specs for my original tires (OHTSU 8.3-20 and 5.00-12).

Am I missing something, or why not just replace the original 5.00-12 tires on the front? Why do you need specs?

 

[winston-HT]

The repair manual I have for a 220/226 gives front to rear ratio. Have you considered buying a manual or maybe you already have one. Don't know if there is one out there for the f16? I found some 5.00-12 tires with a circumference of 1705mm or 67.12598". That won't do you much good without the ratio. If you used those with your new 8.3-20 tires your ratio would come out at 1.56598. Take your old tires and roll them a revolution on the cement. Measure the distance. Divide the large by the small and see what you come up with. Norm is probably right in his thinking. I think this match is important if you use your 4 wheel drive much. I do and sometimes on hard ground.

 

[Norm-HT]

You are making this harder than need be, just replace with original size. Original sizes had to be correct. No matter if changing from rice to ag tires.

 

[jd123-HT]

Yea...I may be making all this harder than it needs to be <E>:?</E> I have a tendency to do that. I do have a murray manual...but nothing about drive ratio. I am also hesitant to derive a ratio rolling my tires and assuming that reps my true spec of my tractor....the front are really worn...and I am sure it would be off.

Norm the reason I am concerned about just replacing the front with any 5.00-12 is that the O.D. or rolling circumference differs quite a bit from manufacturer to manufacturer. This is what affects your drive ratio. I also cannot find all tires from the same manufacturer...the tires I have are somewhat hard to find.

I also am in 4x4 all the time. I do mowing on rough hilly ground...and it's needed quite a bit.

But I asked the shop where I bought my tractor and they said to just replace front with a 5.00-12 and that it would be fine. Although O.D is different from manufacturer to manufacturer...the range of slip that's acceptable in the front axle usually absorbs any O.D. differences among manufacturers. They sell a lot of small tractors and this is what they do...

I welcome anymore thoughts from folks though...

 

[Norm-HT]

Where did you hear that? There is nothing that would cause any significant difference in rolling diameter. 5.00-12 is 5.00-12 no matter who makes it and ag tread is ag tread. I have been reading about people replacing tires on 4wd for 10 years on 5 different forums, and that issue has never been addressed. Hoye sells at least 2 different brands of tires, and the only siginficant different in a particular size is price. One mfg's vulcanizing equipment could be thousandths of an inch or fractions of mm's different but nothing to be concerned about.

 

[winston-HT]

Compare these two. <LINK_TEXT text="http://www.petesti...e-shopping&amp;utm_medium=organic</LINK_TEXT> <LINK_TEXT text="http://www.firesto...conv=1&amp;subref=22&amp;subid=22</LINK_TEXT>

 

[jd123-HT]

Thanks winston...there are differences in the specs between those tires. Not much but goes to show that not all tires have the same O.D. specs.

Norm there is quite a bit of info on the web about maintaining your drive ratio for 4X4 tractiors...but i am beginning to think that slip percentage range needed in the front end is enough to take into consideration of minor differences of O.D. between manufacturers.

The damage caused by some folks must be placing improper sized rims...rather than tires.

I have found some 5.00-12 online and will order them today.

Thanks for the help guys.... <E></E>

 

[Norm-HT]

No, the difference in those tires is only 1.5% overall, .3" difference in diameter, not even worthy of mention. Safe allowable variance is 5%.

 

[Aaron-HT]

If you think about it - look a the depth of the tread... especially on the "rice" tires. You could easily have <U><s></s>5 inches <e></e></U>of difference between the diameter of a new rear tire vs a worn rear tire. Are you going to replace the tires once they have wore down 1/2" just so they still match the factory specs? As long as you start within 5% and, most importantly, use 4wd only where it is needed you will be fine.

We have seen several tires, like the 6-14 for example, that can be as much as 2" difference in diameter just because of the brands (one brand might be 1" bigger than the normal and one brand 1" smaller). I'm not sure why.....

 

[winston-HT]

OK everybody, I'm not trying to be unreasonable, however, if I were looking to get new tires I would make ratio one of my shopping prioritys. As JD123 and I have both stated we use our 4 wheel drive a considerable amount. Just my belief you can't go wrong trying to get the best match possible. Just my opinion. <E></E>

 

[Norm-HT]

<QUOTE author="Aaron"><s>

</s>If you think about it - look a the depth of the tread... especially on the "rice" tires. You could easily have <U><s></s>5 inches <e></e></U>of difference between the diameter of a new rear tire vs a worn rear tire. Are you going to replace the tires once they have wore down 1/2" just so they still match the factory specs? As long as you start within 5% and, most importantly, use 4wd only where it is needed you will be fine.

We have seen several tires, like the 6-14 for example, that can be as much as 2" difference in diameter just because of the brands (one brand might be 1" bigger than the normal and one brand 1" smaller). I'm not sure why.....<e>

/e></QUOTE>

A 6-14 is not the same tire size as a 6.00-14, although I don't know what the difference is. Tire dealers sell 6-14 and 6.00-14, or 5-12 and 5.00-12, If that's what you are referring to..

 

[jd123-HT]

yep...like i said i am new to all this.

And I have thought about the wearing down of tread issue....

When researching tires, i came across this drive ratio thing....and the concerns about it. I have determined that as long as you are in that percent slip range you are fine....and differences in any O.D. would still be within that range, providing you got the right spec tire.

Problems folks must be having with this ratio thing must be from guys re-gearing or putting on different sized rims....i don't know... <E>:roll:</E>

Also, the sized tires I have are hard to find. It appears that a lot of manufacturers have stopped making them...

 

[Hoogy-HT]

I just bought a 147D and was looking at the idea of upgrading tires for it. All the talk about percentages and ratios is somewhat confusing me. I thought that just piking a tire that would be close to the original would be fine. Is that not correct? <E>:?:</E>

 

[alan-HT]

Let me restate what Aaron said.

If you drive on a dry road in 4WD, you need perfectly corresponding (both size and pressure) fronts and rears, a straight line on a level road, and luck to not eventually stress your driveline to the point of damage. Conversely, you can mount widely discrepant fronts and rears (even two fronts different from each other) if you never put in in 4 except on a slippery surface. You should use 4WD similarly to how you use the rear differential lock.

Even new from the factory, drive in 4 for a bit and you may find it hard to move the lever out of 4. It's the beginning of lockup so drive a couple of feet in the opposite direction to remove the pressure.

OK?

 

[Hoogy-HT]

Thanks Alan, It sure helps an old guy like me if I hear or read something more than once. <E>:idea:</E> <E></E>