As long as the fire road isn't gravel - I hate gravel & it's more dangerous than a rooty trail.

Pick something with no major climbs/descents. Teach them unweighting your front wheel, how to brake (distribution between front/back matters more on loose dirt) & definitely the "look where you want to go - not at the tree".

You'll be able to tell pretty quickly their abilities/tolerance for more technical trail. Road biking does not translate into MTB skills, but comfort on a bike should help a bit.

If they have good bike handling skills (group rides, crits, etc.), then don't go too easy on the terrain.

Find a trail that will highlight the fun of mountain biking: some swooping corners on a gentle descent, a few easy obstacles to get that instant feeling of accomplishment. You want them to love the difference between mtb and road/TT.

One of my bestest buddies got me mtbing last year and the key things I got from the first ride we did are as follows:

• Your seat's too high. (Damn triathlete)
• WTF is there so much air in your tires? (Damn triathlete)
• WTF is there no bounce in your front fork? (Damn triathlete)

Followed by:

• Get your arse in the air! (Damn triathlete)
• Get your elbows out! (Damn triathlete)
• Spin for fuck's sake! Get into that small ring and ride a gear lower than than you think you should at all times (Damn triathlete)

Once I'd mastered those basics and got over the mental hurdle that I wasn't on 110PSI 20mm, I had a ball:-) Love it.

If your pals are in New England, they should check out some of the clinics from NEMBA (http://www.nemba.org/). Some of those are women's only clinics for different levels of riders.

If they are not here in New England, check out your local MTB association and I would bet they have skills clinics. I'd recommend your friends use that as an intro to mountain biking.

BrokenSpoke

+1 on the gravel and braking ... find a gentle incline to try it out before actually heading out onto the mtb trails. On my first ride I flew down a steep gravel incline that had a really nice curve at the bottom. Got some serious air as I tried to navigate the curve (braking) and crashed hard. When I got up my saddle was facing sideways and my shoulder was broken. Everyone around here laughs when I tell this story. Right up until the second my shoulder hit the ground I was trying to wrestle my bike back to vertical - because you can do that if you are skidding out of control on a road bike.

Thanks for sharing.

Have you taken them out yet?

I started mountain biking last year after we moved to Bend OR. (Front door brag.) I LOVE it and don't care if I ever get on my road bike again.

I started with an all women's week-night ride then took a skills clinic, which helped immensely for building confidence. Butt back, pedals at 3 & 9, elbows and knees out for descending was one of the most helpful hints. As was keeping eyes on the trail ahead and just learning that my bike can roll over lots of bumps, so trust it.

Have fun!