I recently bought a Gravity-Base Camp 1.0 (I know not even close to a great bike) and I'm having problems with my feet hitting the tire during turns. I want to try a shorter crank (maybe 160mm) and minimize that. I want to make this a better bike for me and be happy with what I have at the time. Does anyone have any suggestion? Aside from this I've had some issues with chain coming off when I jump bigger jumps, could I take a link or two out to help with this? Thanks for the response in advance :-)
You could try adjusting the "b" screw on the rear derailleur to put a little more tension on the chain. There are only three adjustable screws on Shimano RDs. Two of them, side-by-side adjust the maximum throw of the RD in and out. The other one moves the cage back and forth. I'd do this before taking out a link as the manufacturer probably had the chain length right.
Heel strike is pretty common for those of us who ride short wheelbase recumbent bikes. You get used to knowing it is there and will automatically position the cranks so that you don't hit the wheel in a sharp slow speed turn. Just takes a bit of practice. You can buy shorter cranks but there is less power delivered to the rear wheel in the most powerful part of pedaling when you do it.
I don't know about mountain bikes, but on hybrids and road bikes, toe overlap is relatively normal. Since most turns happen when you are going fast enough to steer by leaning instead of turning the wheel, we just learn to ride in a way where toe overlap doesn't impact us.
For mountain biking, you would be better asking in the mountain biking forum. My guess is that there may be more need for low speed cornering, but I am not sure if a mtb riders tend to address the issue in the same way. However, if you are set on a new crank, to make it easier, seek out a crank that you can use with the existing 113 mm square taper bottom bracket. You will need a crank removal tool, but otherwise, it is a pretty simple change.
The earlier message you didn't understand was refering to the usual method of coasting through the corners to avoid toe overlap issues, but you can't do that if you are riding fixed gear...
The 'B' adjustment isn't for chain tension, it's for adjusting the clearance between the top jockey pulley and the largest cassette/freewheel gear. Although if you're not watching the right place, it might look as if the tension is being adjusted.
Going to 160mm cranks will help toe overlap -- if you've only got 0.4" of overlap right now. I'd suggest just learning to live with it.