I'm having problems with fast descents where there are parts with lots of sand. When I'm riding down the hill and there is a lot of sand I lose control of my front wheel. My front wheel just starts to slide diagonally and it's very hard to stay on my bike (luckily I have avoided major accidents so far).

Is this newbie kind of thing or are there some tips and rules I should follow to fix this issue.

I don't know if this matters but my bike has 26 inch wheels and front tire is 1.95 and rear tire is 2.0.

Try, fatter tires less pressure, get yer but back behind the seat, less front brake or none, start there.

good advice above -speed is your friend also, weight back, let the bike drift some if it wants, don't try to steer or brake much if at all, pedal hard if losing momentum, keep your eyes down trail on your destination not on whats directly in front of you

keep your weight far back
fatter tire goes up front
and run less pressure

when this happens to me, i try to get the bike steered in the right direction, before i hit the sandy section, if possible, or try to steer with the process of leaning your body rather than steering the handlebars , and try to be prepared mentally if you have to make the jump off the bike

I remember asking a similar question as I was just learning about modern MTB.
I got a lot of the same advice, and it was good then too.

what you have to do is trust your line - lean back like noted and visualize your front wheel tracking right where you want it to.
look up the trail - nothing good ever came from staring at a sandpilie while hauling ass - you gotta trust it tho

Let'er drift to the side/edge of the trail, often a bit-o- grip there where fewer have plowed the road XD
azz back and keep the power on,

DON'T Chop wood,, That's too low of a gear. Spin Is IN but It's gotta produce some forward go motion...

Get stronger,
My trick,
Anything that gives me trouble, I stick to that till I break something or get it right...
Every time I see sand I go right into it, yeah I crash well

I'm also the first Idiot to go for the mud puddles,
If I comeback to the trail head on wet rides without mud stripes from my ankles to my neck front AND back I call it a wuss ride..

Down hill in the sand is very very hard. don't break yer neck and if ya go over the bars, tuck that shoulder and roll.

stick your hand out to break yer fall and you may break yer wrist,
forget to tuck that shoulder and snap goes the collar bone....

I'm going to go against the grain and NOT tell you to get your weight back. That is old school and wrong. You want a LOW, neutral position on your bike, staying loose to absorb trail changes. You want to keep some weight on the front wheel. If you don't, your won't keep its tread anchored for grip. Being back on the bike lessens one's control. https://www.youtube.com/watch?v=Dwrs...hQywQ&index=32 And yes, fatter tire up front. I run a 2.35 F and a 2.0 R.