As rated by the IMBA: http://venturacountytrails.org/TrailMaps/TrailSymbols.htm
What column fits you best?
For me, the double black diamonds would best describe my favorite conditions. Most of the trails I ride, from Santa Barbara to San Diego would be the single and double diamond rating. [B]
[/B]How about you?
So why is the average trail gradient is described as no more than 20%, when the maximum is 15%? The average couldnât be higher than the maximum anyway!
I prefer a mix. A trail thatâs all double-diamond is fun, but itâs more of a Trials ride than a MUni ride.
Weâll put this to the test at Northstar in a few weeks I guess⌠
Haha yeah I thought the same thing! 
Well, in some cases it might seem very âtrialsyâ, but most of the double diamond stuff is quite ârollableâ; you just canât bomb it as fast as if it were smooth XC stuff, which I also enjoy. I made this video recently, which is a compilation of the more technical trails Iâve ridden over the past couple years.
A little hopping here and there, (Which I rather enjoy and it keeps me in practice for doing more precision moves) but I rolled most of it. The various trails highlighted in this video are 95% rock, with a predominance of double diamond terrain. 
PS: has anyone else noticed the new âgoogle searchâ bar at the top right?
Yea, I rode the double diamond trail at NAUCC for (fun/no points) Tech Muni on my 20" Trials and I won, because I had 0 falls. I rode it like a trials course :D. It would have been more fun on a 24" though.
Hereâs another basic ratings guideline. Most riders can easily tell where they best fit in:
Easy Trail
Short distances and smooth surfaces. Suitable for novice riders including kids. Kind of like a sidewalk, but made out of dirtâŚ
Beginner Level
Still pretty smooth and easy, but the trail may have a few rocks, some tight and twisty sections and maybe some steep ups and downs. Nothing too hairy, thoughâŚ
Intermediate Level
Tougher than Beginner. These are ârealâ mountain bike trails. The trail will have a combination of one or more of the following: rocks, tight, twisty stuff, steep ups and downs, drops/ledges and hard climbsâŚ
Advanced Level
Tough trail for more experienced riders. Expect lots of rocks and drops, the possibility of extended climbing, fast down hills and plenty of opportunities to inflict bodily and bike damage
More detail:
Easy and Beginner Rides
Geared for people looking for conversational paced riding with stops to regroup and/or discuss technical sections and/or offer riding advice. Also good for new comers to learn trails and meet people to ride with. All Beginner rides have a âSweepâ - an experienced rider that rides at the back of the pack to insure that no one gets dropped. The rides are usually 5-10 miles in distance and can last 1.5 - 4 hours. Some of these rides will also incorporate âSkills Clinicsâ, where weâll help new riders develop the needed skills to tackle more difficult terrain.
Intermediate Level Rides
Geared for the more advanced rider capable of a fairly fast pace with good technical skills. Good for experienced riders new the area to learn the local trails and meet people to ride with. Fewer stops to regroup but usually wait at trail intersections. These rides often split into smaller groups of faster and slower riders. There are no sweeps on intermediate rides, so it is possible to get dropped. This is rare, but it has happened - so be prepared. Ride length and time vary greatly depending on terrain.
Advanced Level Rides
Same as above but âon steroidsâ. Very technical, longer distances, slower riders may get dropped. Feel free to drop the ride leader as well!
And hereâs a good one from dirtworld: This and the previous guide do factor in trail length and climbing.
Something For Everyone
A mish mash of trails that will entertain riders at every skill level. Youâll find a combination of flat perfectly manicured trails to tight turns to steep and rocky climbing and plain old scary descents. Beginners and Weekend Warrior riders, take extra care so you donât get over your head.
Beginners
Non technical trails suited for riders who have not spent much time in the saddle. Trails are generally smooth and flat. Basically one-step away from riding on the road. If you havenât biked off-road before, this is the place to start.
Weekend Warriors
A collection of semi technical trails. Trails include some roots, rocks and swithcbacks. These tend to be singletrack trails and can get narrow in places. These rides are for intermediate-level riders in good aerobic condition with some technical handling skills. The majority of mountain bike enthusiasts fit into this category.
Advanced Skills
Roots, rocks, switchbacks, steep drops, burly climbs and tight twisting ribbons of dirt. Our advanced trail rating lists all the tough trails that are generally under the 20-mile mark. While they are over rowdy terrain their distance is easy to handle for most advanced riders. Some advanced rides receive this rating because they are less technical, but extremely long. Good aerobic condition is a must.
Masochistic
More roots, rocks, switchbacks, steep drops, burly climbs, and tight twisting ribbons of dirt. However, the trails listed under Masochistic are bigger and uglier than most any trail you have ever been on. Ride lengths are longer, climbs are deadlier and descents are down right dangerous. Masochistic trails are for semi pro riders and pro riders only.
I like this rating system because I sometimes feel guilty that I canât manage some of the âhairierâ stuff. On my unicycle I fit into the intermediate area for general skill. Downhill I can do the advanced but not the masochistic. And to veryify, I am likely to UPD on the advanced downhill but will continue. On my mountain bike I am generally advanced, however, Iâm not fast up or down.
I canât climb 20% grade but can descend 20% grade. 15% grade I can climb if itâs the white and green circle. So depending on what the trail is I can mix it up.
The other day I took my daughterâs boyfriend on a hilly off road ride and had a good time. We climbed up part of our intended trail and he had to stop and barf. I know I am mean but it made me feel good to âoutclimbâ a 22 year old male. After a few weeks of conditioning he would likely outride me but I was happy to steal the moment. Heâs a better unicyclist than me but Iâm in better condition (for now).
You keep going great guns! Thereâs so few hardcore MUni riders compared to other riding types, let alone those over 50! So letâs here it for all of us middle aged kids!!! 
Wow, middle aged. I consider myself practically geriatric. But, youâre right. We need a cheer for MUni geezers and grannies. Woooooooooo!
That works for those of us on the west coast, but having mountain biked on the east coast, too, I think you need to include ârootsâ each time you say ârocksâ above. Those New England technical trails are a whole different animal, and the roots are an amazing challenge!
Ha Ha, I love it. Those moments are meant to be enjoyed!
Haha â at 54 I feel exactly the same. But somehow that adds spice to the achievement.
All the trails in my local trail system have sign posts at the trail intersections indicating the âdifficulty level.â I believe they are using the same system that MuniAddict already posted. Iâm not sure I agree 100% with the rating some of the trails in the park were given, but nobody asked my opinion! So based on that Iâm pretty much riding black and double black trails most of the time but over longer distances it probably averages out to single black (if I trace some of the 20 mile + rides Iâve done in this park)âŚ
Just depends on the day and what youâre into I guess⌠Iâm happy to go Coker MUni some green circle trails too!
Yes, rocks vs. roots. As bumps, not too different. But get them wet, and they really start showing their character. Also the way the dirt erodes around themâŚ
The thing with trail ratings is that itâs hard to indicate how much of a given trail contains the features described in the ratings. Naturally in a double-diamond trail youâd expect large amounts of the hard stuff. But what about one small, really hairy section in an otherwise beginner trail? Mostly itâs something in-between. So ratings sytems like this are good for getting a general idea, but they still leave a lot of room for variations between trails with the same rating.
Our local trail advocacy group, FATRAC, uses a trail rating combined with an overall ride rating to give people an idea about which rides may be too much for them. Some are on not-so-hard terrain, but itâs at 6000, or involves tons of climbing, or is just plain long, etc.
Haha thatâs great of them to do that so less experienced riders can at least know what to expect.
And NOW I can see where you got your username!
You got it! 
Plus the fact that I live right in the heart of that trail system, just outside the picnic area. All I do it go out my back gate and Iâm right in the park!