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Flotation experiment

Posted: Sun Dec 09, 2012 7:15 pm
by Nobody
Finally got a chance to do a little experiment that I had been wondering about. I wanted to see best "theoretical" floatation that could be achieved with one of my tires. The snow conditions were about 3 feet of fresh powder. The snow had not compacted at all, making conditions prime for this experiment.

I went for a quick walk in my snowshoes. I didn't measure, but I was sinking nearly a foot while wearing snowshoes!
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My bronco tires were aired down to 2psi. I pulled off to the side of the road in some fresh snow. Tried to maintain as much floatation as possible. I was sinking about 21-22 inches.
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Then I broke out my 36x12.50R15 spare tire and rolled it from my existing tracks onto the fresh snow. The tire climbed right up. It was sinking about 11 inches. I did notice that as the snow packed lugs rolled around the tire seemed to float even more. I put my 190+ lbs on it and it didn't seem to sink any more.
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Since my bronco is pretty nose heavy, I backed in my bronco into the fresh snow by the spare tire. I was in a hurry since it was getting late, so I didn't take a measurement. It appears that my back tire did come up a bit.
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So what can we extrapolate from this experiment? Well, I was trying to demonstrate why taller tires are better. I'm not sure I acheived that with this test...maybe I just need to pack a lighter lunch. However, had I been running 40's or 44's, I would have been pushing much less snow. And, a vehicle running 31's would be dragging diffs even if it weighed zero lbs.

Hopefully one of these trips we can get some floatation comparisons between wide and narrow tires.

Re: Flotation experiment

Posted: Mon Dec 10, 2012 12:28 pm
by n16ht5
what size tire are you running?? Interesting.

I remember when I had better rigs I noticed that there seemed to a be a sweet spot for having enough flotation.. weight to tire size ratio. I noticed once I got to 36+" tire range at 4,000lb I hardly got stuck. I had a BroncoII, started out on 31s, then 33s, then 35s, then finally 37s. It weight 4,000lbs gassed up. Once I got to 37s it did extremely well in deep snow, a very noticeable improvement from 35s. My friend has a Suburu brat on 29s all lifted, it weighs ~2000lbs. It does surprisingly well, but has a hard time getting forward traction

Re: Flotation experiment

Posted: Mon Dec 10, 2012 7:11 pm
by Nobody
n16ht5 wrote:what size tire are you running?? Interesting.

I remember when I had better rigs I noticed that there seemed to a be a sweet spot for having enough flotation.. weight to tire size ratio. I noticed once I got to 36+" tire range at 4,000lb I hardly got stuck. I had a BroncoII, started out on 31s, then 33s, then 35s, then finally 37s. It weight 4,000lbs gassed up. Once I got to 37s it did extremely well in deep snow, a very noticeable improvement from 35s. My friend has a Suburu brat on 29s all lifted, it weighs ~2000lbs. It does surprisingly well, but has a hard time getting forward traction
My tires are 36x12.50R15 super swamper TSL radials. The tread width is only 9.5 inches which is pretty narrow. I too grew from 31's to 34's to 36's. 36 inch was definitely the magic number to be able to get out and break trail.

Re: Flotation experiment

Posted: Mon Dec 10, 2012 7:36 pm
by n16ht5
Nobody wrote:

My tires are 36x12.50R15 super swamper TSL radials. The tread width is only 9.5 inches which is pretty narrow. I too grew from 31's to 34's to 36's. 36 inch was definitely the magic number to be able to get out and break trail.

I thought so, couldn't remember. how much does your truck weigh all gassed up?

Re: Flotation experiment

Posted: Mon Dec 10, 2012 7:38 pm
by Nobody
I think it's in the 4,200 - 4,300lbs range. Pretty nose heavy though. I think my V8 Bronco II was much better balanced.

Re: Flotation experiment

Posted: Mon Dec 10, 2012 7:58 pm
by Samurai19
We can do a weight comparison next time out as I now have the same 36x12.5 tsl radials on the Samurai now. I have yet to weigh it yet but I'm hoping less than 3,000 lbs with the Toyota axles.

Re: Flotation experiment

Posted: Mon Dec 10, 2012 8:04 pm
by Nobody
Sounds like a plan. I look forward to seeing the results.