I don't know anything about training for downhill beyond getting out and riding your downhill bike, but I do know how I've got upto my current level of fitness for 24 hour racing.

Firstly, get out and ride XC a couple of times a week. It builds your singletrack skills, and good route choice means you can built in good staged warm ups, warm downs and some properly tough climbs that'll get you working. Tough climbs followed by rewarding singletrack in a one hour to 1&1/2 hour route will keep you interested and fit. XC is a fun sport, if you're finding it boring, you're doing it wrong

Still with me? Right, search your local newspaper or your local XC/Road forum. Someone will be selling a road bike of some description for pennies. Pick one up, use it to replace the car for getting to work. It'll have paid for itself pretty quick, and you'll arrive at work having made an effort towards building your fitness without even having to get muddy.

So, you're doing a couple of XC rides a week, riding to work on the days you're not riding XC, but you can't be bothered to ride XC tonight as it's going to be filthy/your XC bike is borked/you just can't be bothered. Plan a road ride.

Yeah. That's right. Road ride. Out and back for no more reason than turning some pedals. But, before you doze off, plan your route. Get off the A roads, stay off the flat. Keep it interesting. Seen a 30mph speed camera? Can you trigger it on the bike? It's possible on the flat once you've got your fitness up, 36mph is the trigger speed if you fancy a go. Mix your overall distancey endurance with speed camera sprints and some tough climbs that'll help you build the sort of fitness that'll get you to the top of the hills the best singletrack starts from.

So, you're riding road and XC, and still getting out on the DH bike every weekend. Your fitness is getting better and you can sprint your local track without being out of breath? Time to shave some seconds in the technique department then.

You can get a DMC moto-trainer, but they're expensive and designed for circuits, not sprint events. What you want is a Sportcount 90030 stopwatch which is identical in form but doesn't record 100 laptimes and hence costs £22 less. I'm pretty good at remembering the number of seconds my last run took and the £22 I didn't have to spend is much better spent on bike parts that'll actually make me faster, like a tyre with some tread on it.

I've been doing all of the above for about six months, and I've gotten bored of all my local XC loops, bored of riding on the road on my own and I still have the fear on the DH tracks.

My latest tool is Rollers. All you need is some friends with roadbikes, a doorframe, rollers and bike computers attatched to your roadbikes. Then start competing for who can
A) stay upright longest without touching the doorframe (for newbies)
B) Get the highest top speed on the rollers without walking it across the room, or falling off (more about pedalling technique than raw power, though it helps!)
C) Complete impossible interval sessions, like a minute at 20mph, 30 seconds at 30 and 20 at 40, then back down again. (This hurts so very much)

Congratulations. You are now a cycling freak.

quite simply do Royal Marine Commando training then when you come out you will be fit as an olypic athlete until you touch beer 

And as downsides go, thats a pretty big one

Why does everyone think dh training is soley cardio? Whenever training is mentioned it is simply 'oh, go out and slog on the road bike for miles.' 

Strength training is also very necessary in the correct form.

If making your own plan for dh you should have a balance of cardio and strength training throughout the week.

only if your built like a 12 year old girl

i was workin on it haha, and it lets me hold onto a crosser for 20 mins solid 5 or 6 times a day every weekend so can't be too bad, and you boys are worried about strength for a 4 min Dh run

Why are you on this forum? Piss off to an mx one 

I find riding without a chain the easiest way to practice as it highlights your errors and forces you to lay off the brakes in corners.  You will try it and hit a corner badly and come out at walking pace, then by the end of the day you will be coming out of the same corner pinned and keeping your speed everywhere without pedalling and it feels so much better.  If you can be fast without pedalling its ideal because when your knackered at a race it wont affect your performance as much

plus its quiet and you dont beak mechs

also just have as much two wheeled fun as possible, bike skills are so important and its better learning them on a BMX/motobike than on your downhill bike.  Its insane how good all the pros are just pissing about on bikes; manualling round hairpin bends, riding trails, riding minibikes etc.  You think road bikes are gay, try wheelying one for 100 meters clipped in. 

And its way more fun being on a bike the whole time than in the gym