9.8 miles
Distance
1,902 ft
Climb
-1,891 ft
Descent
2,659 ft
High Point

MTB loop for Chumash UH to Rocky Peak DH to Undertow DH

Detailed Description
Chumash-RockyPeak-Undertow is a 10 mile moderately popular expert route located near Simi Valley California. This mountain bike only route and has a moderate overall physical rating. This route includes 5 trails. This route climbs 1,902 ft with a max elevation of 2,659 ft then descends -1,891 ft.
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51 Reviews & Comments

  • + 0
thechrisfr (3 days ago)
Trail The Grudge
Great trail indeed. It takes several laps to start feeling comfortable though. To go fast here, you either need to disconnect your brain or be really good!
[Reply]
  • + 0
jimmckenna23 (Jan 2, 2023 at 16:34)
Trail The Grudge
Great trail. More challenging than Hummingbird for sure but I wouldn’t say hardest in the area. Was really wet today, can’t wait to send it when dry.
[Reply]
  • + 0
Jadeeyes1113 (Dec 10, 2022 at 18:36)
Trail Hummingbird
Not really worth the climb on a sketchy road except for the views. Looks like it used to have some fun berms but no longer maintained. Some sections that are super steep and rutted instead. Very confusing with multiple trails going different directions. Meh.
[Reply]
  • + 0
Verdugist (Sep 25, 2022 at 13:00)
Trail Undertow
After having tried this trail for the 3rd time today and just returning from black and double black trails in Whistler, this is definitely a double black. Much more technical and intimidating than Snow Summit 10 ply (minus the gap jumps) with high risk/consequence in at least 3 sections (all steep tech rollers). Especially now in the extremely loose sandy/dusty conditions. Very steep in some sections and generally constant tech as well as off camber sections to keep you on your toes. If you know the lines the overall flow of the trail is very good. Wear full face and chest/back guard.
[Reply]
  • + 0
bigchipero (Jul 30, 2022 at 15:31)
Trail Undertow
this trail was definitely for the advance rock rider! serious drops that will put u in da hospital if u don’t know watcha do’in. Also even on a eBike u are going to want to shuttle cuz there are no good uphill options back to the top !
[Reply]
  • + 0
Dogl0rd (Jul 4, 2022 at 13:42)
Trail The Grudge
Could argue all day about what's harder, this or Undertow...
[Reply]
  • + 0
Gkarma15 (Jul 4, 2022 at 11:24)
Trail The Grudge
Happy
[Reply]
  • + 0
Johneracer (May 4, 2022 at 16:25)
Trail The Grudge
Very dry. Excellent trail. Black diamond for sure. I find hummingbird as hard as grudge (if you don’t skip anything) so not sure why hummingbird is considered easier. All 3 rides and equally hard. Hummingbird got harder after rains. Advanced riders only. If you want easier route look into sideaction.
[Reply]
  • + 0
nofunstravaguy (Apr 26, 2022 at 21:05)
Trail The Grudge
So sweet! A world class trail. 'Hard Black',, some might say double black. This is a rock slab, roll and drop Techy wonderland. Highly recommend. On average, a little harder than Undertow. I recommend both. Hike back up and play on the fun alt lines.
[Reply]
  • + 0
nofunstravaguy (Apr 26, 2022 at 21:03)
Trail Undertow
This trail is rad! Definitely a 'Hard Black'. There are fewer difficult features than The Grudge, so I'dsay slightly easier overall. However, there are a few large rock rolls and steeps sections which are harder than The Grudge. I'd say The Grudge has more bang for buck - more stacked with rollers jumps and slabs. Both are AWESOME.
[Reply]
  • + 0
Condor69 (Jan 15, 2022 at 19:16)
Upper section is more technical than a blue but about half way down it mellows out quite a bit. Liked the trail and will come back. Bell saved a few crashes with hikers coming around corners
[Reply]
  • + 0
BiggDiehl (Dec 15, 2021 at 8:56)
Trail Hummingbird
Popularity has really taken it’s toll on the Hummingbird. The switchback sections have been pretty much obliterated by straight shot chutes that are being rapidly eroded into deep rocky ruts with every rainstorm - in fact, the deep ruts from too much traffic are a problem on every section now. Mystery junctions that divert into multiple sidetrails that seem to go nowhere also abound. Just not as much fun as it used to be. To each his/her own I guess, but it would take a massive trail building effort to make it fun again. After many years of riding the trail, I’m looking elsewhere for single track.
[Reply]
  • + 0
Jkheiss (Dec 4, 2021 at 15:40)
Rode down on a gravel bike, a few (~4?) gate keeper sections at the top I had to walk, then turned into a pretty flowy trail down. Prob wouldn’t ride down on a gravel bike, totally rideable on a hard tail.
[Reply]
  • + 0
Michaeltal59 (Oct 30, 2021 at 15:49)
Trail Hummingbird
Feels like between black to double black diamond. Maybe I took the harder lines by mistake lol
[Reply]
  • + 0
Marcpelosi (Sep 21, 2021 at 12:54)
Trail Undertow
I would definitely rate this a double black. Has some ride arounds but a couple features makes this a double black. Best trail I’ve ridden in LA so far for downhill/enduro
[Reply]
  • + 1
blindstuff VKBC (Sep 20, 2021 at 10:53)
Trail Undertow
By far the hardest of the three trails off rocky peak road. A few rock rolls on this one are quite technically challenge, definitely not let go and hang on like you can do on some on the grudge. If you're an advanced rider and want a challenge this is it, unless you're really good it'll take a couple of rides through to clean the trail top to bottom
[Reply]
  • + 1
blindstuff VKBC (Sep 20, 2021 at 10:51)
Trail The Grudge
Intermediate or above riders will be able to get down this, but flowing through it will most likely be for advanced riders. This is one of those trails you have to ride a few times to fully understand, there's so many alternate lines with varying degrees of difficulty that make is great but also hard to ride blind. Most of the commiting spots have ride arounds. Super well built.
[Reply]
  • + 0
blindstuff VKBC (Sep 20, 2021 at 10:47)
Trail Hummingbird
Easiest of the three long descents off rocky peak road. I think the single diamond rating is accurate. Easiest way to access is park at the hummingbird trailhead and pedal up Santa Susana pass road and up rocky peak road. It's steep at times but doable with a 12sp.
[Reply]
  • + 1
CCS414 (Aug 7, 2021 at 0:03)
Primarily smooth flow single track with some advanced sections at the top. It's an enjoyable climb and the technical sections are climbable if you still have any strength left. Some blind corners when coming downhill fast so be aware of hikers and other riders coming up through those sections.
[Reply]
  • + 0
PzzxQX (Jul 25, 2021 at 23:20)
Trail The Grudge
Pretty silly series of comments above. This is clearly an advanced ride. The downhill trails at Rocky Peak Park are perhaps the most advanced in the whole LA region. Intermediate riders will be fine but only an advanced rider can make the whole run without walking down several sections. There are drops, jumps and rock gardens that keep these downhill trails offering new challenges time after time.
[Reply]
  • + 0
kevinjc85 (May 1, 2021 at 17:15)
Trail Hummingbird
*I have ridden* ...sorry for the typo
[Reply]
  • + 0
kevinjc85 (May 1, 2021 at 17:15)
Trail Hummingbird
This should be a double black diamond in my opinion. It's have ridden double blacks and pro-lines at bike parks that were less difficult than this. It's hike-a-bike most of the way up, and very steep rocks with no optional side routes.
[Reply]
  • + 1
roaminghazard (Mar 6, 2021 at 8:00)
Trail The Grudge
Should remove or cover all the stupid hiker arrows/rabbits that lead to the dumb swing. Redo them so they lead all the hikers off the mtb routes or maybe off a cliff.
[Reply]
  • - 2
yourfrienderik (Feb 21, 2021 at 17:46)
Trail The Grudge
just send it
[Reply]
  • - 2
yourfrienderik (Feb 3, 2021 at 19:27)
Trail The Grudge
the grudge is easy guys
[Reply]
  • - 3
yourfrienderik (Feb 3, 2021 at 19:27)
Trail The Grudge
see?
[Reply]
  • - 2
ClarkecY5E9J (Jan 31, 2021 at 20:57)
Trail The Grudge
My bike is small
[Reply]
  • - 3
ClarkecY5E9J (Jan 31, 2021 at 14:34)
Trail The Grudge
Bike
[Reply]
  • - 1
yourfrienderik (Jan 31, 2021 at 14:23)
Trail The Grudge
oh my
[Reply]
  • + 5
nomadshred (Jan 10, 2021 at 17:11)
Trail The Grudge
This is the definition of GNAR. AM and Trail bike maybe inadequate depending on skill level. Recommend FR or DH bike. Ungroomed trail with not much flow or jumps. A lot of drops into technical rocks where you can't build much speed without the travel. Technical with up and down transitions into steep descent at the end. This is borderline double black diamond.
[Reply]
  • + 1
Stlc (Jan 7, 2021 at 10:29)
Trail Undertow
Of the three main trails Undertow is the most difficult. Then the Grudge and Hummingbird is last on the list...
[Reply]
  • + 0
KevinAlvarezMtb (Nov 29, 2020 at 12:11)
Trail The Grudge
This trail is no joke. Steep rock slabs drops everything. Don’t recommend riding alone for the first time.
[Reply]
  • + 1
seanharanmtb (Sep 13, 2020 at 15:02)
Trail The Grudge
One of the best trails out there
[Reply]
  • + 0
crucialsworld (Jun 26, 2020 at 18:55)
Steep climb but you get to hummingbird and the grudge in about 10 minutes
[Reply]
  • + 0
crucialsworld (Jun 26, 2020 at 18:09)
Trail The Grudge
Super dry rn but the drops were sick
[Reply]
  • + 1
rodeodon (May 28, 2020 at 23:25)
Trail The Grudge
Why are E bikes Discriminated against using the trails? There are plenty of people like myself with injuries or disabilities that can only access the trails with the help of an E bike.
[Reply]
  • + 1
pumpjumpnflow (May 29, 2020 at 9:59)
Trail The Grudge
Are you asking about Rocky Peak specific trails or E-Bikes in general? Personally, I think Rocky Peak is the most acceptable for E-Bikes because most of the trails are downhill only and no one is biking up Santa Susana for fun (unless you're on a road bike)...
[Reply]
  • + 0
seanharanmtb (Dec 1, 2019 at 11:18)
Trail Hummingbird
Easiest of the black trails at rocky peak, start here if you aren’t sure you’re ready for the other trails yet
[Reply]
  • + 1
dantepetri1 (Oct 27, 2019 at 18:01)
Trail Undertow
Super fun trail, little bit of everything and great hard pack traction
[Reply]
  • + 0
dantepetri1 (Oct 27, 2019 at 18:00)
Trail The Grudge
Agree with below comment, this trail is a step above the adjacent black diamonds. scout the blind rollers first if you’re not a high confidence rider
[Reply]
  • + 0
Karlosb10 (Jan 19, 2019 at 20:15)
Trail The Grudge
Definitely only a trail for advanced riders. There are some huge slabby rock obstacle course drop offs that are not for everyone.
[Reply]
  • + 0
dynamatt (Jan 13, 2019 at 19:35)
Trail The Grudge
Perfection, traction is all time right now. Gritty dirt doesn’t get too slippery on the rocks
[Reply]
  • - 2
dynamatt (Jan 13, 2019 at 19:34)
Trail Undertow
Next level conditions, loads of traction, trail drains well
[Reply]
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Trails in Route

Details

  • Riding area
  • Primary Activity
    Mountain Bike
  • Difficulty rating
    Black Diamond
  • Route Type
    Loop
  • Bike type
    DH, AM, XC
  • Physical rating
    Moderate
  • Ridelogs
    2
More Stats for Chumash-RockyPeak-Undertow mountain bike route
  • Altitude min
    1,039 ft
  • Altitude start
    1,322 ft
  • Altitude end
    1,332 ft
  • Grade max
    -94.6%
  • Grade min
    64.7%
  • Distance climb
    5 miles
  • Distance down
    4 miles
  • Distance flat
    2,572 ft
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Recent Trail Reports Along Route

statustraildateconditiondescription
Chumash Trail
Jan 2, 2023 @ 4:37pm
Jan 2, 2023
Little damp but dirt is real nice
The Grudge
Jan 2, 2023 @ 4:32pm
Jan 2, 2023
About 1/2 of this was a slippery muddy mess today (last rain 36hrs ago). Probably best to wait 2-3 days after rain.
Hummingbird
Dec 22, 2022 @ 11:48pm
Dec 22, 2022
Little rutty from the rain but not to bad
Undertow
Dec 10, 2022 @ 7:38am
Dec 10, 2022
Light rain. Perfect dirt. All time conditions, this is what we dream about out here
Rocky Peak Trail
Nov 11, 2022 @ 10:06pm
Nov 11, 2022
more reports »
  • By Verdugist & contributors
  • #11128 - 1,894 views