Tire help

[bikerdib]

Tire help ~ yes I'm bringing it up again

My B7300 has turf tires; front 21x8-10, rear 31x15.5-15.

I'm sure those of you with the same size tires have come against the same problem as I; finding tires that will work.

The rear on my machine are not too bad but my front are pretty dry rotted. I went to Firestone's website and found that the TL G-2 is discontinued. I'm looking for solutions (like many others). I know about the trailer tire option but I want more traction. The 21x8 actually has a mounted diameter of 20.5 and I read on another forum that someone has used a Carlisle All Trail in 20x10-10 which is supposed to have a mounted diameter of 20.1; I'm just not sure if that is a good option.

Of course I have the expensive option of switching out the wheels to the 6x12 front and 8.3x16 rear but I'm afraid that tires for those rims might become hard to find also. Can someone give me the tire sizes for those rims. I wouldn't mind having ag type tires anyway.

 

[Vitster]

Try Ken Jones Tire @ KenJones.com. May not have what your looking for, but maybe they know where to get it, or to refer you to?

 

[Vitster]

Say, Bikerdib look at grandv8's post today 10/4 title'd: to those looking for 20.5 x 8-10 tires. Looks like he might have a solution for you to with Carlisle for your sizes. Click on his links.

 

[bikerdib]

Thanks for the tip. However, I already knew about the All Trail from Carlisle; in fact I now have some on order through my cousin's auto mechanic shop (should be in today). I think the All Trail should work. I'll know later today after I get them mounted (I have a tire changer in my shop because I do most of my own motorcycle maintenance).

 

[/pine]

Are you mounting the 20x10-10's on the original (21x8-10) rims?

also, do you mind saying how much the 20x10-10's cost ?

thanks...

 

[bikerdib]

Yes, I'm using the original rims. On Carlisle's web site they say the 20X10-10 are designed to mount on a 6X10 rim, which is the stock size on my B7300 (and I think the B7100 used the same rim size but different bolt pattern). The 21X8-10 Firestone Turf & Field were actually 20.5 mounted (my measurement). The Carlisle are supposed to be 20.1 mounted. I'll post the actual measurement I get after I mount them this afternoon. I also plan on measuring the ground to rim height of both the old and new tires when the tractor weight is on the tires (this will be the most critical check).

Here is a link to their website:

http://www.carlisletire.com/products/atv/all_trail/index.html

 

[/pine]

Thanks...

I have a 1995 B1700 with 21x 8.00 -10 front and 31x 15.5 -15 rear...these are the original (industrial) tread tires....
...after an exhuastive search last year I found that that size (front) tire is simply N/A...because the trctor is 4x4 I was told that is paramount to maintain the same ratio of "rolling circumferences" to prevent damage...

I have still been unable to find any tire that would maintain the (exact) same ratio without changing out the rear tires which means changing out all 4 rims...

comments?

 

[bikerdib]

Just got the Carlisle All Trail 20X10-10 tires mounted so I thought I'd give a report.

Before taking the wheels off the B7300, I checked the air pressure (because of my FEL I normally run 25 psi). I measured the static load radius of the Firestone Field & Turf that were on my tractor. This measurement is the ground to center of axle distance with the weight of the tractor being supported by the tire. It was hard to measure from the concrete to the exact center of the axle so instead I measured from the concrete to the bottom lip of the rim but this will give the same effective check since I was only concerned with the difference between the old and new tires. With the Firestone, this measurement was 4 & 1/16 inches on one side and 4 inches on the other (difference in wear?). After removing the wheel, I measured the outermost mounted diameter of the tire with no weight and found it to be 20 & 9/16 inch (so like others have said, the 21X8-10 is actually still a 20.5X8-10). For our needs I think the static load radius is the most crucial.

I dis-mounted the Firestones and mounted the Carlisle. Aired the tires up and measured the outermost diameter of the Carlisle. It measured 20 & 3/16. I got worried, maybe this was going to be too small a tire after all. I put the wheels on the tractor and measured the static load radius. I got 3 & 15/16 inches, a loss of only 1/8 to 3/16 of an inch (allowing for measurement errors). That should work, at least for me since I only use 4X4 on low traction surfaces. I think uneven tire inflation and tread wear can cause a bigger differences than I'm getting between the old and new tires.

The Carlisle have almost 200 lbs more carrying capacity than the Firestone so I think that might account for the reduction in sidewall flex so the Carlisle might be even better when hauling a load in the FEL. This should mean even less of a difference in size between the loaded Firestone and the loaded Carlisle.

BTW, I tried the test of putting the tractor in 4X4 and the trany in neutral then pushing the tractor. I couldn't tell much of a difference between the old and new tires but this test if not very accurate because I had no way of measuring the amount of force needed to move the tractor.

 

[bikerdib]

Slash Pine, apparently you posted while I was typing. As you can see from my post above, the Carlisle is slightly different. So, if you use 4X4 on pavement you might have a problem but if you only use 4X4 on low traction surfaces (like me) I think they should be OK. In fact, I VERY seldom drive my tractor on pavement even in 2X4.

I went through the same dilemma, change all four to the ag type tires and wheels or experiment with the Carlisle. I prefer the wider footprint the turf type tires give so I decided to experiment. I hope I made the right choice, only some seat time will tell.

 

[/pine]

Just got the Carlisle All Trail 20X10-10 tires mounted so I thought I'd give a report.

did you measure the rolling circumferences of the old and the new tires ?

 

[bikerdib]

No I didn't measure the rolling circumference, I thought it would be subject to too much variance (knowing exactly when I made a complete revolution).

After I already changed the tires, I thought about it, I could have made a mark on the tires using a level then going one revolution to that point again but it's too late now. I really don't feel like dis-mounting the Carlisle, re-mounting the Firestone, then probably again dis-mounting the Firestone and re-mounting the Carlisle.

Doing a little math, it looks like the Carlisle will be about 0.4 to 0.5 inch shorter rolling circumference than the Firestone.

Like I said in my previous post, I think more difference can be had by say replacing worn fronts with new tires while not replacing worn rears (I'm referring to same size old and new). This would especially be true if you had R1s front and rear and replaced worn fronts but not the worn rears (and I have seen people do that).

 

[/pine]

FWIW...
I got this from another forum in regard to replacing 21 x8.00 -10 tires

Glad to have dropped in tonight and hopefully save you some grief & aggravation.The Carlisle 20x800-10 will not match the rolling circumference needed.Been there done that paid the price!...

 

[bikerdib]

But I think he was talking about a different tire in 20X8-10, I used a 20x10-10 All Trail that has a mounted diameter of 20.1 inches compared to 20.5 for the Firestone Field & Turf. However, if you look at my report you will see there is even less difference in the static load radius when the tire is supporting the tractor; only 1/8 to 3/16 inch difference. A few psi under inflation of the Firestone can make that much difference in static load radius since they seem to have a lot of sidewall flex.

There is also this option if you don't mind loosing some traction:

Look at product 511116
Carlisle Tire & Wheel Company

They have a mounted diameter of 20.8 so all you would have to do is lower the inflation slightly and you'd probably have the same rolling circumference as the Firestone.

 

[/pine]

They have a mounted diameter of 20.8 so all you would have to do is lower the inflation slightly and you'd probably have the same rolling circumference as the Firestone.

this is the same justification (to use the Carlisle tires) buy the OP on the other forum when advised that the r.c. was not the same...

if you look at my report you will see there is even less difference in the static load radius when the tire is supporting the tractor; only 1/8 to 3/16 inch difference. A few psi under inflation of the Firestone can make that much difference in static load radius since they seem to have a lot of sidewall flex.

There is also this option if you don't mind loosing some traction:

Traction is not my real concern...
To prevent damage to the drive train...my understanding is that there is really only one significant measurement and that is the rolling circumference...

 

[bikerdib]

this is the same justification (to use the Carlisle tires) buy the OP on the other forum when advised that the r.c. was not the same...


Traction is not my real concern...
To prevent damage to the drive train...my understanding is that there is really only one significant measurement and that is the rolling circumference...

And that's my point, the rolling circumference can be directly affected by the static load radius of a tire. Rolling circumference is related to the mounted outside diameter of a tire as well as that tire's static load radius. If you use the original tire but only run say 10 to 15 psi, the static load radius will be smaller (and therefore the rolling circumference is smaller) compared to the original tire running 25 to 30 psi. Vice versa, if you have a tire with a slightly smaller mounted diameter but one that has a static load radius that is very close in size to the original tire then the rolling circumference is likewise close to being the same as the original. Remember, the outside diameter of a circle (or in our case the rolling diameter) is pie times the radius (in our case the static load radius) times 2.

I know the All Trail is not an ideal replacement (that would be the no longer made Firestone Field & Turf) but it was the closest I could find with a traction type tread.

The mounted diameter of tires from different manufacturers can vary for the exact same given size and in fact it can even vary between different lines of tire from the same manufacturer.

Take for instance the All Trail I used in 20X10-10, it has a mounted diameter of 20.1. While the tire I gave a link for, the Turf Saver in 20X10-10 has a mounted diameter of 20.8. Same manufacturer, same given size but with a different mounted diameter and possible different static load radius and rolling circumference.

That's why I'd like to see manufacturers give the static load radius of tires. Then we could compare directly to see if a tire will suite our needs.

 

[/pine]

That's why I'd like to see manufacturers give the static load radius of tires. Then we could compare directly to see if a tire will suite our needs.

Again...I have seen no mention of "static load radius" (other than in your posts) in regard to the proper rolling circumference....IMO "fiddling" with tire pressure is not the answer to prevent damage to the 4x4 drive train...all the techincal data I have read states that it is paramount to maintain the correct rolling circumference...nothing else...

If you feel comforatable with what you have...that's fine...but until I can find the correct combination I will continue to seek other options...I can't see taking the risk of damaging the gear train for the sake of tires...

 

[bikerdib]

You are missing the point of my explanation of the static load radius. If you know the static load radius, you can do some simple math to find the rolling circumference of any tire. Most likely, that is the way manufacturers find the rolling circumference, they know the static load radius and do the simple math to get the rolling circumference. You think they mount each tire type and roll it along the floor under load?

I know you don't see mention of static load radius on most manufacturers websites; you also don't see mention of rolling circumference on their websites.

Firestone is one of the few that give good info on their tires, such as here:

http://www.firestoneag.com/tirelist_pop.asp?ref=168&load=0

 

[bikerdib]

BTW, I wasn't trying to promote using inflation to adjust rolling circumference. I was pointing out that inflation pressure will affect the rolling circumference of any tire; even the original tire used from the factory.

I'm also not trying to talk you into anything. If you find a direct replacement tire that gives the exact rolling circumference of the original tire, please let me know.

 

[/pine]

You are missing the point of my explanation of the static load radius. If you know the static load radius, you can do some simple math to find the rolling circumference of any tire. Most likely, that is the way manufacturers find the rolling circumference, they know the static load radius and do the simple math to get the rolling circumference. You think they mount each tire type and roll it along the floor under load?

I know you don't see mention of static load radius on most manufacturers websites; you also don't see mention of rolling circumference on their websites.

Firestone is one of the few that give good info on their tires, such as here:

http://www.firestoneag.com/tirelist_pop.asp?ref=168&load=0

As for a "static load"...is that before or after an FEL is added?...and every different attachment connected to the back of the tractor is going to change the load on the front wheels...so are you suggesting changing the tire pressure every time a different implement is attached? or adjusting the pressure for different loads in the FEL?

I got your point...but my point is...someone (quoted from another forum) that used the same tires you have "paid the price"...to me, they are not worth taking the risk especially if you can't run at recommended pressures...

sorry I just don't accept your speculations based on everything I have read about the problems finding replacement tires of that size...you could be 100% correct but IMO with so many people with the same issue i just think there would be more factual data to support the use of those (Carlisle) tires and there isn't...

 

[/pine]

If you find a direct replacement tire that gives the exact rolling circumference of the original tire, please let me know

ditto...

...to date the only absolute way to remedy the problem is to replace both front and rear wheels and tires...which is what I am considering...