I just put a set of bear claws on my "00" Kodiak 4x4 size 25x8x12 front and 25x10x12 rear the problem is that the fronts are 3/4 of an inch shorter than the rearsI can't find a number for Kenda to inquire about this. Any help would be greatly appreciated.

Y2K Kodiak 2000lb Warn Winch Gun Boot and racks Kenda Bear Claws and a 50mm ammo can full of accessories.

 

Some small irregularities are common in any atv tire. Tire pressure and rim width will also affect the overall height. If you are using your stock rims try raising the pressure in the fronts slightly and lowering it in the rears. If you are using aftermarket rims and the front rims are wider than the stock ones and the rears are not it could account for the difference in height.
Let us know what they say if anything. I have Claws too and have to run slightly different pressures to keep them even heights.

 

While measuring the overall height of tires gives data useful for many applications, the critical dimension for front-to-rear drivetrain ratio
matching is the "laden rolling radius."

If you look at the tire mounted on the quad, you'll notice the tire is slightly flattened on the bottom--let all the air out, and the tire becomes plumb flat, on one side. Thus, the bottom radius is shorter than the top radius, or any other radius on the tire. Add a rider, and that bottom radius becomes shorter still.


The distance between the center of the wheel and the ground when you are riding the quad, comparing front wheel and rear wheel, may be proportionally a lot closer than their two static overall height measurements.


Bottom line: small differences in tire measurements may not be noticeable in operation. The geometric mis-match is resolved by ground slip and by tire flexibility (a sort of "push me-pull you" dynamic exchange of bulges, front to rear). For example, 4X4 truck drivetrain builders accept up to 10% difference in differential ratios for off-road applications.

All tires NEVER roll the same distance with the same radii, in the real world. Variations in terrain, tire compression from loading (suspension oscillation), distortion from acceleration/braking torque, different turning paths for all four wheels, etc., cause operational variations for even the most closely-matched tires. Thank goodness for flexibility of rubber and the compressibility of air, absorbing the consequences of all these variations!

I'll bet your Kenda Claws are sized "close enough for government work" and you'll have no problem.

Tree Farmer

 

Tree Farmer....

Your wisdom is often grossly overlooked.... but once again you came to the rescue....

 

Tree Farmer,

That sounds great but I have a question: Take a solid steel wheel, say 12" in diameter. For every revolution of the wheel, its vehicle moves 3.14' (Pi x D). Make that wheel hollow rubber with the same circumference and squish it down some under load. The vehicle still moves 3.14' for every axle rotation does it not?
(Would there have to be a tiny allowance for increased psi because of load?)
Let's take a steel-belted road tire and bleed it down from 30psi to 10. The "flat spot" increases considerably, laden rolling radius decreases (if I understand what that means), but the car will still move the same distance per wheel revolution because every inch of tread corresponds to a certain unchanging point on the axle, and every inch of tread also corresponds to an inch of travel surface.
Now atv tires aren't steel-belted, so the tread expands/contracts more than the car tire (not talking about changing psi here) but isn't the difference that's due solely to load just about irrelevant? The circle has changed shape, not circumference...so it's no longer a circle but you know what I mean.
I've been guilty before of missing the forest for the trees (pardon the weak pun) and will again, so have I done so here? I probably haven't made proper allowance for the theory vs. real world fudge factor.

Gooch

 

Maybe you're right, Gooch!

In which case, even a flat tire covers the same distance with every revolution as its fully-inflated mate . . .

You raise an interesting concept, a tire as a "conveyer belt" instead of a wheel.
Considering nominally inflated tires, with the small differences between the unladen radius and the laden rolling radius, I imagine the differences are taken up by some ground slip and some tire flexing, as happens when the tires take paths of different length (i.e., becuse of terrain variations, different turn radii, etc., as discussed).

Since the vertical diameter of a tire is squished somewhat from the load, maybe a wheel travels farther than pi times the height with each revolution, more like pi times the horizontal diameter.

Thanks for bringing up an interesting perspective on the issue. Ozark can measure the inflated circumference of his tires and get an idea of the front-to-rear mismatch per revolution.

I thought common laden rolling radiuses are critical front-to-rear with mechanically-linked
tires, maybe not as critical as the tires' circumferences, considering your comments.

Tree Farmer

 

Ok here is what I've come up with. First I made sure air pressure was equal in all tires (5psi).
Then I marked one front & one rear tire on the same side. Without any weight on the wheeler I rolled it forward untill one tire made one full revolution and noted any differance. The rear tire came up 1/2" shorter revolution than did the front. I also rode it some yesterday to see if there was any noticeable problems. In 2wd none, in 4wd none I could tell other than there might be some slight growling from the front diff. I still think I'll contact my tire dealer and see what he thinks. Till next time Happy Wheelin.

Y2K Kodiak, 2000lb Warn Winch, Gun boot & Racks,
25" Kenda Bear Claws, 50mm ammo can of accessories.

 

Ozark, you should talk to "The Rock", he's usually in the Yamaha Forum.... Anyway.. he had the same problem with his 25" Bear Claws and after some investigation found out that it was because they came from an older batch of bear claws made form an old mold. The place he bought the tires replaced them. *Don't* drive your Kodiak in 4WD with those tires for long distances, Especially if you notice your top end seems slow. Ask the dealer for a serial number of the old tires and check it against yours.

2000 Kodiak
26" Bear Claws
Kimpex f/r bumpers
Kimpex fender guards and pegs
Warn 2000 with rollers


http://www.geocities.com/y2kerplunk/kodiakleft.jpg

 

I do remember therock having this problem. I have
e-mailed him on it but no responce as of yet. I'll try again.

Y2k Kodiak,2000lb Warn Winch,Gun Boot & racks,25"
Kenda Claws, and a 50mm ammo can full of accessories