Here is a good replacement for the original OEM tires.......These are bead lock wheels which would be great with running that low of PSI in the tires.....
Richard's Relics sells Parts for Amphibious ATV's
www.richardsrelics.com
Appreciate the link, BUT...... They don't make these any more and that site takes full advantage of people that don't know where else to source parts. They want $100 each for those tires. Shop on-line a little and you can buy them for $60. They want $35 for a 10' choke cable you can buy from Stens for $10. Sells 5' of Chinese made #50 chain for $60 ($12 per foot), you can buy #50 U.S. made Diamond brand chain all day long for $6 per foot at Motion Industries. $28 each for 21x11x8 tubes you can buy for $12. List goes on and on..... Every part they sell is way over priced and available some where else.
It's like the "Willys Rear Axle Seal" for $30 you see on some of these specialty Willys sites. Willys didn't make that axle, it's a Dana 53. Seal is $6, in stock at NAPA. $700 of a "front disc brake conversion kit"..... Once again it's a Dana 25 front diff, just like the ones that came on Chevy 4x4's from the mid-70's to the mid-90's. All the parts at NAPA add up to $250.
Don't even get me started on ereplacementparts.com for mower parts..... You can pay Google to have your website pop up first in a search and these sites make a lot of $$$, doing just that, off people that don't have experience looking for parts/components and just buy what they need from the 1st site they see that claims to have it in stock.
I do my best on this forum to share my parts sources just to screw this type of web-site out of sales as much as possible... Most of the time when you see me posting on this forum, it was because I was sitting at the keyboard anyway..... Looking for parts