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HomeMt Tam Double Century

Mt Tam Double Century


The 200 Mile Mt. Tam Double Century is limited to 300 riders. Double Century riders are encouraged to register early.  

Riders registering before July 12 (cutoff subject to change) will receive Concierge Mailing Service as part of their entry fee!  About two weeks before the big ride, we will mail your rider bib number and route map.  Head straight to the starting line – avoid the registration area for the 5AM mass start!  

Double Century riders registering after the cutoff date will be required to check-in at registration before riding.


New for 2017
The MTDC is no longer  a timed event.  
Course has changed from previous years.  Please read course description carefully.  
Use only official maps and cue sheets. 

Mandatory Mass Start:  5:00 AM Saturday, August 5, 2017

  • Check in for Mt. Tam DC riders without a bib and rider transfers is 4:00 AM – 4:45 AM.
  • Riders registering before July 12 will receive their registration materials in the mail and are to report directly to the start line.
  • NO BIB TAGS will be collected.   You must check in and have your number recorded at EAST PEAK Checkpoint or you will be DNS

Cut Off Times and Checkpoints

  • No rider will be allowed to start before 5:00 AM.  

  • There are 4 mandatory check points 

    • East Peak (top of Tam)
    • Platform Bridge and Petaluma Pt. Reyes Rd.
    • Valley Ford
    • Coleman Valley 
  • Checkpoints are identified on the route map and cue sheet and RWGPS.

  • Failure to sign-in at checkpoints will result in a DNF. Check the open/closed times.

    • Bay Hill/Coleman loop closes at 3:00 PM.  Failure to make this cutoff will result in DNF.  No exceptions.
    • Course closes at 10:00 PM. Anyone on course after that time will be SAGed and/or have their bib revoked, resulting in DNF and no Triple Crown credit.
    • Official finish is at the check-in table at Start/Finish at the Marin County Fairgrounds.  
    • Anyone on course at that time will receive a DNF, will not earn Triple Crown credit and will be SAGed.
    • All riders please check in at the finish even if you SAGed in or DNF.  
  • If you are riding slower than 11.5 mph average, you may not make the Coleman Valley Loop Cutoff at Valley Ford. You will have the option to bailout onto the Century Course return. Any SAG or bailout options will result in a DNF.

Light Requirement

  • The Mt. Tam Double Century will begin at 5 AM in the dark and could, depending on your speed, potentially end in the dark.
  • Working lights are mandatory for the start of the Mt. Tam Double Century - NO EXCEPTIONS.  No lights = DNS (Did not Start)
  • Sunrise is approximately 6:15 AM and sunset approximately 8:15 PM.  Also, keep in mind, some of the valleys will be dark after sunrise and before sunset.
  • Lights are mandatory after 8:00 PM. 

Lights & Drop Bags

The Marin Cyclist club will provide paper bags and marker pens  for you to drop your lights and forwarded for later pickup.  Here are the options:

  • Pine Mt to Laguna School (2nd to last stop)
  • Pine Mt to Marin County Fairgrounds (Finish)
  • Stinson Beach School to Laguna School (2nd to last stop)
  • Stinson Beach School to Marin County Fairgrounds (Finish)

Any bags not picked up, as the course closes, will be SAGed to the finish.  Bags not picked up after the event will be returned to riders via mail ($10 fee). 

Aero Bars

Aero bars are permitted but not recommended. Please do not  use aero bars when riding in pace lines.

A full color water resistant map with cue sheet will be provided in your rider packet.
Ride with GPS map is available here.  This link was updated on 7/20/17

Course Description

The MTDC begins on flat-to-rolling terrain before a 1.4 mile, 430-foot climb to the Big Rock summit of Lucas Valley and a thrilling descent through the redwoods into the ranches and grasslands of West Marin. Here the route parts ways with the other courses, wending its south and east to the town of Fairfax and the ascent to the top of Mount Tamalpais (Tam), which begins on Bolinas-Fairfax Road. The narrow and twisting road levels out as it approaches a golf course and begins to climb again to the top of Pine Mountain, site of the first rest stop.

From the here the road descends in a series of tight left turns with a decreasing radius to four miles of rolleurs ending at a dam at Alpine Lake. A three-mile ascent takes riders to a left-hand turn onto Ridgecrest Road, which offers sweeping views of the Pacific Ocean and golden grass hillsides for the six miles of rolleurs, some with challenging grades, up to the top of Tam. At the very top is a checkpoint and the turnaround.

Riders now descend three miles that they just ascended and must take care to avoid riders finishing their climb to the top of Tam. They continue descending south to Pantoll with  a sharp right onto Panoramic Highway—both roads have  sharp technical turns that require extreme caution. 

Here the course changes from previous years and we continue on Panoramic all the way to Hwy 1 at Stinson Beach.  

We turn north on Highway 1 just before the town of Stinson Beach, just past town we reach our second rest stop at the Stinson Beach School as we pass the Bolinas Lagoon toward Olema and into Pt Reyes Station, where riders find their third rest stop.  the course continues north on Highway 1 to a right on Point Reyes/Petaluma Rd, following the flat creekbed inland to Platform Bridge Rd. where we make a right turn to our second CHECKPOINT and then travel over to Sir Francis Drake  and up and over the hill to Olema and back into Pt. Reyes Station.   We repeat this part of the course to Platform Bridge, this time making left onto 
Point Reyes-Petaluma Road, and travelling inland past the Nicasio Reservoir. After a short climb (1.4 miles and 380-foot gain) and gentle descent past the Marin French Cheese Factory, the course continues onto to Petaluma, site of the fourth rest stop . Leaving Petaluma, riders find the entrance of beautiful Chileno Valley Road, which takes them to a left turn on Tomales-Petaluma Road. The course continues to Highway 1 and the small town of Tomales. At town center, the course turns left on Dillon Beach Road and continues to Valley Ford-Franklin School Road and a right turn on Highway 1 (away from Bodega) that takes riders to Valley Ford, site of the fifth rest stop and third checkpoint. Riders who do not reach this point by 3:00 PM will not be permitted to do the Coleman Loop and will be DNF. NO EXCEPTIONS will be made. 

The course continues on Bodega Highway west to Bay Hill Road, which offers a grand Pacific Ocean vista from the crest. A quick descent on rough road leads to some highly scenic miles of coastline before the route turns onto Coleman Valley Road and a long and steep climb with false summits and stunning views. (Look south from the top for a far-off Mt Tam.)

At the top of the Coleman Valley Loop  riders will find  the fourth checkpoint in small rest stop stocked with water, Gatorade, and energy supplements (gels, bars, etc). A 400-foot descent leads to yet another climb and a long and technical descent on Joy Road. USE EXTREME CAUTION on this winding and potholed stretch, which eventually leads to wide-shouldered roads and the sixth rest stop in Valley Ford.

The ride continues over scenic and sparsely traveled roads to the short but steep Middle Road climb with another thrilling descent to the S curve at Whittaker Bluff.  It then crosses over Highway 1 to become Fallon Two Rock Rd. which we follow to a right turn at Alexander Rd. and then a left back onto Tomales-Petaluma Rd for the  trip back down  Chileno Valley Rd.   A rest stop awaits at the historic Laguna School  before you climb back over the Wilson Hill to Hicks Valley Rd.    USE EXTREME CAUTION DESCENDING. THERE IS A SHARP LEFT TURN AT THE BOTTOM OF THE HILL.

The route continues along the rolling hills of Hicks Valley Road before turning west on Pt. Reyes-Petaluma Road, taking riders past the Cheese Factory to a slight climb and a very fast descent to Nicasio Reservoir and Nicasio Valley Road. A relatively flat stretch lead to the fifth and final rest stop at the Nicasio Schoolhouse.

A few miles later, riders begin the climb back up Lucas Valley Road to Big Rock. Riders should exercise caution on the DEMANDING DESCENT FROM BIG ROCK AT LUCAS VALLEY ROAD. This descent has several sharp left-hand turns with a decreasing radius. The remainder of the route is almost all downhill to the finish at the Marin County Fairgrounds.

Rest Stops & Rest Stop Food

  • For the Mt Tam Double Century riders only, each rest stop will have Hammer Gel (bring your own flask) and Sustained Energy (SE) in addition to the normal fare.
  • There will be an assortment of sandwiches and/or burritos available at the Valley Ford Rest Stop for the Double Century riders as well.
  • Some sandwiches and burritos MAY be available at Petaluma, however, this is not guaranteed.
If you need a particular item or drink, please bring it yourself.  We can not guarantee volumes or availability and work hard to avoid food waste.


SAG and Course Marshals

Course Marshals are only on the Century sections of the DC course.  There are SAG vehicles on the entire DC course.  Please keep in mind, it's a long course and the SAGs become very spread out on the DC sections of the course as the day progresses, so response times are longer than that on the Century sections of the course.

Check-in at Finish

The official finish is at the check-in table located at the Start/Finish at the Marin County Fairgrounds.  All riders please check in even if you SAG in or DNF so we don't spend  resources  or volunteer time trying to find you on course.  Failure to check in may result in exclusion from future Mt Tam Double Century events.

Post Ride Meal

Naturally, most of the Century fanfare wraps up around 6:00 PM. We will have a hot meal for DC riders who arrive after 6:00;  however, certain menu items may not be available.

Ride time results

Announcements will be made on Facebook and Twitter when the results are posted to our website a few days after the event.  Be sure to follow us  for updates and news before the event.

DC Jersey  
can be preordered at registration, added after registration or purchased after the ride.   
Jerseys are for DC finishers only and will be awarded upon completion of the event (at the finish check in).
Those that received a DNS or DNF will receive a refund for preorders.

DC Volunteers and Triple Crown Volunteer Credit

The Marin Century and Double Century are organized and run by volunteers.  Only volunteers.  So, we love volunteers....especially those with riding experience.  You know the challenges cyclists face and what cyclists appreciate!  

DC riders may earn Triple Crown Volunteer Credit for volunteering at the Marin Century.
Volunteer opportunities that specifically support  the  DC are available here.  
Other volunteering  opportunities  are also available here.  

Workers Ride
Volunteers are welcome to ride the Workers Ride which includes a Double Century.  The Double Century Workers Ride qualifies as a Triple Crown event.  Registration for the Worker's ride will open on August 6.  Please see the Calendar on our website to register.


California Triple Crown

Click here for more info on the CA Triple Crown