Last weekend, I went riding in some sandy terrain and I was sliding all over the place and washing out (25 psi). This coming up weekend, I will be riding riding in even deeper sand. My question is, what is the lowest PSI I should run on my tires without rim locks? Can I get away with 15 psi? Thanks

 

I have run 15 on very rocky trails with no problem. I'd assume you would be fine in sand at that pressure.

 

Thanks, I like riding my bike and not using it as a workout machine.

 

(When the rim pops off the bead, you're running too low psi.)

 

Actually it all depends on how you ride your bike. If you're hard on the throttle, you like to fishtail ,heavy acceleration and braking then you'll be sorry you went down to 15psi. there's nothing Much worse than having a flat in the middle of nowhere in these scorching heat.

 

Depends on tire too. but 15psi shouldn't be a problem, or at least never has been for me. Had the back at 12 many times. Keep and eye on the stem and don't use the stem nut. Never seen one slip so far in one event that it tears the stem. It usually happens a little at a time or right after mounting the tire doing stoppies in the driveway. If tire has been on there awhile its pretty well set.

 

I had a failure with my dot knobbies at 14 psi. I was pushing it in a turn on asphult and it moved enough to slice off the valve stem. Enough of a deal for me to install locks soon after.

 

I've flogged the crap out of my bike at 15 psi (with the nut on) with no problems, but the tire and tube had seen lots of miles (and weather) together already.
It made such a huge difference riding at 15psi!
Made me order rim locks so I could air down even further. I now run 8/10 psi (F/R).
Letting some air out gives you a little softer suspension feel because you roll over, instead of bounce over, trail obstacles.
In sand and gravel you gain a much wider contact patch, instead of the tire trying to knife through on edge and making the bike all squirrelly, it's more like using the flat of a blade to spread butter, so you float across. It's like being on a magic plush carpet.
Just do it and have fun........and maybe take a spare tube if you're inclined to grab a lot of throttle.