Open in App
Get this trail on your phone instantly.
more stats
1,365 ft
Distance
-132 ft
Descent
00:04:29
Avg time
-134 ft
Altitude change
842 ft
Altitude min
976 ft
Altitude max
976 ft
Altitude start
843 ft
Altitude end
-9.8%
Grade
-34.6%
Grade max
-1.8%
Grade min
1,365 ft
Distance down
00:04:29
Avg time
B-17 Extension Details
-
Activities
- Mountain Bike
- E-Bike
- Hike
- Trail Running
-
Riding AreaTamarancho
Fairfax, California -
Difficulty Rating
-
Local Popularity
-
Global Ranking
-
State Ranking
-
Trail TypeSingletrack
-
Bike TypeXC
-
DirectionBoth DirectionsPopular In Reverse
-
Dogs AllowedYes
-
eBike Allowed
-
Land OwnerBoy Scouts of America
No community description for B-17 Extension trail has been added yet!
AI Generated Description
B-17 Extension is a highly rated 1,365 ft popular blue difficulty singletrack trail located near Fairfax California. This mountain bike primary trail can be used both directions. On average it takes 4 minutes to complete this trail.
Local Trail Association
-
-
-
Please consider joining or donating to the local trail association to supportDonate to earn trail karma!
trail development & maintenance.
Traditionally Indigenous Territory
Recent Activity on Trail
Past Week
- 16 rides
- 14 miles average
6 Months
- 335 rides
- 14 miles avg distance
All
- 2,165 rides
- Last: Nov 11, 2026
| c1 | c2 | c3 | c4 |
|---|---|---|---|
January | February | March | April |
May | June | July | August |
September | October | November | December |
B-17 Extension Trail Reports
more »
close
3D
Trail Conditions
- Unknown
- Snow Groomed
- Snow Packed
- Snow Covered
- Snow Cover Partial
- Freeze/thaw Cycle
- Icy
- Prevalent Mud
- Wet
- Variable
- Ideal
- Dry
- Very Dry
Trail Flow (Ridden Direction)
Trailforks scans users activity logs to determine the most popular direction each trail is ridden. A good flowing trail network will have most trails flowing in a single direction according to their intension.
The colour categories are based on what percentage of users are riding a trail in its intended direction.
The colour categories are based on what percentage of users are riding a trail in its intended direction.
- > 96%
- > 90%
- > 80%
- > 70%
- > 50%
- < 50%
- bi-directional trail
- no data
Trail Last Used
Trailforks scans activity logs to determine the last time a trail was ridden.
- < 2 days
- < 1 week
- < 2 weeks
- < 1 month
- < 6 months
- > 6 months
Trail Ridden Direction
The intended direction a trail should be ridden.
- Downhill Only
- Downhill Primary
- Both Directions
- Uphill Primary
- Uphill Only
- One Direction
Contribute Details
Colors indicate trail is missing specified detail.
- Description
- Photos
- Description & Photos
- Videos
Trail Popularity ?
Trailforks scans activity logs to determine which trails are ridden the most in the last 9 months.
Trails are compared with nearby trails in the same city region with a possible 25 colour shades.
Think of this as a heatmap, more activities = more kinetic energy = warmer colors.
- most popular
- popular
- less popular
- not popular
ATV/ORV/OHV Filter
Max Vehicle Width
inches
US Cell Coverage
Legend
Radar Time
Activity Recordings
Trailforks uses anonymized public activity data.
?
Activity Recordings
Trailforks uses anonymized public activity data.
?
Winter Trails
Warning
A routing network for winter maps does not exist. Selecting trails using the winter trails layer has been disabled.
Missing Trails
Most Popular
Least Popular
Trails are colored based on popularity. The more popular a trail is, the more red. Less popular trails trend towards green.
Jump Magnitude Heatmap
Heatmap of where users jump on trails. Zoom in to see individual jumps, click circles to view jump details.
BC Backroad Status
![map legend]()
Service Road Atlas is a free to use, community-driven service for viewing and creating reports on the numerous back-country service roads around B.C. and Alberta.
Slope Aspect
Direction the slope faces
Trails Deemphasized
Trails are shown in grey.
Only show trails with no bike usage.
Suggested Layers
Based on selected activity type
Save the current map location and zoom level as your default home location whenever this page is loaded.
Save
Directions to b17-extension trailhead
(38.000390, -122.626220)
Photos
1 more »
Videos
1 more »
Trail Lists
Routes with this trail
more »
★ 3.5 • 7 miles • 1,254 ft • 10 • Loop •
Great loop around Tamarancho Trail system!
★ 3.5 • 19 miles • 2,965 ft • 11 • Loop •
Begin the Tamarancho loop via Alchemists Trail then take Dead Heifer Fire Road at the bottom of the Endor...
★ 3.5 • 4 miles • 877 ft • 4 •
Quickest Route to Endor: Park at White Hill Pass Bridge on SFD Blvd Need a Friends of Tamarancho Pass to...
Trail Products
Spindelatron
North Shore Skills course repaired today. Can you ride all the progressive lines?
Tonymosa
Careful not to confuse with Endore Flow downhill! Look for (lack of) berms and jumps to assure you are on the right trail.
We hope you've been enjoying Trailforks!
Create a FREE account to view all trail reviews and much more.
Nearby Trails
- Endor (flow Trail) 312 ft
- Broken Dam Trail 774 ft
- Dead Heifer Road 1,273 ft
- Porcupine Trail 1,778 ft
- White Hill Trail 2,966 ft
- By TheBikeNerd
NWTA & contributors - #20426 - 3,166 views
- Follow/Subscribe
- login to download gpx or kml files.
Hit the Trail
Download Trail
Save to wishlist, Garmin & download.
Find Related Routes
Find routes and users activities that include this trail.
You must enter a description before submitting.