Hi all,

I would be interested in gathering data to put into some sort of spread sheet that lists different tires "loaded radius" or the distance between the ground and the axle center. I think there are so many variables out there in tire sizes. Example...I had a set of 25" Dirt Devils on my Prairie 400 and they were at least 2 inches shorter (diameter) than the 25" Goodyears on a friends Polaris 600. I need to put new skins on my Prairie 650 and was leaning towards the 26" Dirt Devils, but I saw a post where the 25" radial Maxxis Bighorns were taller. Since what I'm mainly interested in is ground clearance, the "loaded radius" should be helpful to decide which tires to buy. If everyone will submit their front and rear tires sizes along with an ACCURATE measure of the distance from the ground to the axle centerline, I'll organize them and make them available to everyone. Also, I'm going to pull tire weights off different websites and add that to the database. If you have an accurate scale, and know the weight of your tires, post that too.

For me, I'm thinking the 25" Maxxix Bighorn radials will have the same or taller "loaded radius" as the 26" Dirt Devils and will end up weighing about the same. Guess we'll see!

To keep the variables to a minimum and the measurements consistent, let's do the following:

1. Measure using a square from the concrete to the axle (rear) itself behind the tire. The distance to where the square touches the axle should give you a pretty accurage measurement. On the front it will be easy to misalign so try to be precise to the center of the hub.

2. Measure with no one on the ATV itself.

3. How 'bout we air up to 6 lbs.? Seems most guys run from 5-7 lbs., so 6 will hopefully be a happy medium. I know different ATV weights and air pressures will affect our measurements, but hopefully we'll be able to get some idea. On my Prairie 650, going from 5 psi to 7psi on the rears increased the "loaded radius" by 5/16".

4. Let's try to keep the data base for new tire measurements. If your tires are worn 1/4", then just add that to your measurement.

Post the following info:

Tire size, make and model... loaded radius measurement...make and model of ATV it was measured on and ATV weight if you know it...and an accurate tire only weight if you know it.

Here is an example...

'02 Prairie 650 (approx. 600 lbs.)

stock tires @ 6 psi

Front:
Dunlop KT121A 25X8-12 11.75"

Rear:
Dunlop KT127A 25X10-12 12.25"

Give me a few days to create the database and a link.

Thanks in advance!

Larry

 

Larry,
I'll send you some info. later in the week if wanted. I'm working 12hr shift and don't have any spare time right now. Mike

 

Sounds great to me. I know I'm overly analytical at times, but I think it will be helpful to alot of people when we get a bunch of tires in the database. Seems like there are a ton of questions about tire height...one tire vs. another. If we can get this put together, it might save a bunch of frustration and time. Also, I think at least part of the tire weight difference is that the taller tires will obviously weigh more...I'm talking taller tires when they are both labeled 25", but one is 2" taller.

I remember 30 years ago when I was looking in a Dick Cepek catalog and there was a picture of Dick's Armstrong 12.00x16.5 and it was three inches taller and and inch wider than the "competitions" 12.00x16.5. I think the same thing is going on in some of the ATV tires today.

 

Larry,
Here's what I got. The measurements(?) are on hard pack gravel no concrete yet and at 6psi, I normally run at 5psi but aired up for comparison.

Front:
Bridgestone Mudhook Xtreme11 26x9x12 12"

Rear:
Bridgestone Mudhook Xtreme10 26x12x12 12 3/8"

There on an 03 Prairie 360 around 603#

Kimpex box with gear around 60# on rear

Fuel pak and small storage box 40# on front

Hope this will be of use. Mike

 

Thanks Mike...one of my riding buddies just put a second set of 25" Dirt Devils on his '02 Kodiak 400. I'm going to try to measure them in the next week. Everyone talks about diameter (by simply looking at the numbers on the sidewall...which aren't always accurate), but I'm more interested in the distance from the axle center to the ground. I'll try to start on the database this weekend. Thanks again.

 

This may help with some of your research.

 

Thanks tons Prong...I'll use the weights for sure. The diameters look to be just the tire sizes. Sure hope we can get some actual radius measurements from everyone.

 

BIGHORN'S, 25x8-12/ 25x10-12

front, 24 1/2" tall
rear, 24 3/4" tall

i couldnt find my pressure gauge, i had 3.5 lbs in front and 4lbs in rear.

 

Thanks Deerchopper for the help, but I'm looking for the "loaded radius"...the distance from the center of the axle to the ground. Suppose I could talk you into measuring this for me? I'd really like to have the Bighorns in the database. Are your Bighorns radials? Thanks!

 

yes they are radials. its 1:40 am wright now, if it wouldnt hurt anything could i measure them in the morning. LOL