QUESTION: any problem adding larger front tires?

[ovrszd]

My quote about the warranty issue was based on the fact that if you've modified anything of significance on your tractor the dealer has the right/obligation to report that to the manufacturer, who could void that Serial Number's warranty. That could cause you to not get warranty coverage on an item that is not affected by tire size change. Just making the point that when you take your tractor to a dealership you risk that happening to you.

Same thing applies when you take your truck or car to the dealership if it has current warranty coverage. You can label that however you want. I think of it as the manufacturer looking for a way out of warranty service. My Sons all work at auto dealerships and see this daily. I personally saw one instance where a Ford Super Duty warranty was voided because the packaging and instructions for a programmer were found in the glove box although it wasn't installed and the truck's computer had no record of it ever being installed. Call it what you wish. the owner bought an engine. 6.0L diesel, which everyone knows has issues. Ford's loophole was what they found in the glovebox.

 

[MikePA]

Wow, very authorative answer...the only correct thing?

Asking the dealer, and the manufacturer, whether they recommend changing the front tire size is the only way to get the authoritative answer from the people who designed, made, sell and service the tractor. Obviously, they've determined what tire combinations they will sell and warrant. Just as obviously, they have better ways to spend their time than debating the topic.

As I mentioned in my second post, the OP has sufficient information to decide what he wants to do.

 

[GManBart]

Then in your experiences over the past 30 years what did you find to be the acceptable variance without damage???

My experience has mostly been in other 4WD applications. You said you didn't think I had "changed gear ratios or tire sizes in a modified vehicle of any type" and I have.

I've seen where Deere recommends 1-6%, and Firestone suggests 0-7%, and some others suggest 2-5% lead being acceptable. I guess the conservative view would be 2-5% so it's within all the common ranges suggested.

 

[GManBart]

The OP already made his decision, but Gman's going to argue it into the dirt anyway.

Time to unsubscribe from this one.

I said very early on that it wasn't worth changing (at least in my opinion). The rest has simply been a discussion of the technical aspects, not an argument. If you're not interested in the topic, there's no reason to get bent out of shape about it.

 

[GManBart]

Asking the dealer, and the manufacturer, whether they recommend changing the front tire size is the only way to get the authoritative answer from the people who designed, made, sell and service the tractor. Obviously, they've determined what tire combinations they will sell and warrant. Just as obviously, they have better ways to spend their time than debating the topic.

As I mentioned in my second post, the OP has sufficient information to decide what he wants to do.

The authoritative answer from 10 dealers who said they don't know, and can't answer the question? That's pretty funny!:laughing:

Very early on I said I didn't think the change was worth doing, but people seem interested in the technical side of it...not sure why so many folks are getting butt hurt over a technical issue....lighten up, it's just a discussion.

 

[ovrszd]

It's never just a discussion with you. Or maybe it's just the wording you use. Over and Out.

 

[GManBart]

So, after the finger pointing, people getting upset over a simple technical discussion, dealers that can't answer basic questions, and all the other histrionics, has anybody even tried to run the numbers?

Unless MF uses a transfer case with a fairly high ratio, all of their current tire combinations appear to be producing a LAG in the front tires. I'm not saying they are producing a lag, but they can't tell the OP what the mechanical ratio is, and nobody has actually measured one in the real world (at least in this thread), so nobody knows, but the math does look funny.

Using the same brand, model, and tire style, these are the numbers.

R4 10x16.5 has a Rolling Circumference of 89".
R4 14.9x24 has a Rolling Circumference of 143".

For a baseline, I'll use a very common Mechanical Ratio (1.3-1.4) to get an idea what things look like. The formula is to multiply the front tire RC by the MR, and divide that by the rear tire MR. That gives us:

89x1.4/143 = .871 That says the front tires would be lagging if the MR is less than about 1.65 or so.

What if we use that same math and look at the R1 tire option they offer?

R1 9.5x16 has an RC of 101"
R1 13.6x28 has an RC of 158"

101x1.4/158 = .894 which means the front tires would be lagging if the MR is less than about 1.6 or so.

Now, what if we got totally crazy, and substituted the larger front tires TSO was interested in?

The same make and model R4 12x16.5 has an RC of 98", so we'd get:

98x1.4/143 = .959 or a slight lag unless the MR was around 1.5 or so.

If the MR on the machine in question is actually 1.65, so that the stock 10x16.5 and 14.9x24 combo has a lead, what would the math look like?

89x1.65/143 = 1.026, or a 2.6% lead, which is right around the ideal number most people/companies cite.

What would happen if the 12x16.5 tires the OP asked about were substituted in this scenario?

98x1.65/143 = 1.13, which would be 13% lead, and higher than what normally gets recommended, but it wouldn't cause lag, which is what hurts driveline parts. Too much lead wears front tires faster, and can disturb soil excessively when turning, but it doesn't cause the gloom and doom problems everyone is afraid of.

 

[GManBart]

It's never just a discussion with you. Or maybe it's just the wording you use. Over and Out.

Oh well, I guess I'm just not for the touchy, feely types.

BTW, there is no such thing as "over and out"...it can't be both. Out.

 

[DarkBlack]

All you wanna-be mechincal engineers crack me up. 7 pages later, and not one poster showed a true understanding of the physics.
One poster was getting warrm, alluding to present tire wear and loading ,which is very relevent.

Revelation question of the day: What is the actual effective circumfrence of a high lug tire in soft land? What is it on hard land? Is it the same?
What is the effect of weight on effective tire circimfrence? Is the effetive circumfrence of a tractor front tire on soft land the same with a loader load vs empty? Hmmm...

 

[MikePA]

The authoritative answer from 10 dealers who said they don't know, and can't answer the question? That's pretty funny!:laughing:

I've spoken with about 10 different Massey dealerships, & I also called AGCO directly ... each place has said not to change the tire size...

What part of 10 dealers and the manufacturer 'said not to change the tire size' by 10 dealers and the manufacturer is not authoritative?

BTW, there is no such thing as "over and out"...it can't be both. Out.

But you're not argumentative. That's pretty funny. :laughing:

Out.