2018 Grizzly Peak Century

We are not offering a mixed terrain option this year. All of the information on this page pertains to a mixed terrain option we have offered in the past, but this option is not being offered this year. We hope to offer this option again in the future.


The regular paved course for the Grizzly Peak Century goes through and around many of the East Bay Regional Parks. In fact, three of the rest stops are located at picnic areas within the parks. We have devised two experimental routes (78 miles and 100 miles) that take advantage of this to follow dirt fire roads for some portions of the ride. The short option has about 18 miles of dirt and the long option has about 28 miles.

In between the dirt sections, the mixed terrain routes join up with the regular paved century route as much as possible. All of the dirt roads are wide fire roads where bicycling is permitted. The mixed terrain routes use the same start/finish and rest stops as the regular century.

The mixed terrain courses will be much harder than the standard course. The dirt portions can be very steep and rutted. Ordinary on-road bicycles and tires are not advised. A carbon frame could crack, racing wheels could warp, skinny tires sink in the dirt, and most road cleats will wear down or break during the parts of the course where you have to walk your racing bike.

Essential Limitations

You will be given a phone number for SAG support, but there will be no physical support on the dirt portions of the ride. If you have a mechanical breakdown, you will have to go back or forward to the nearest location where the route is on paved roads. For this reason, it is advisable to carry a map and cue sheet of the standard course.

If you arrive at a rest stop after its official closing time, then you must revert to the regular paved century route. We are required to conduct a sweep of certain sections of the course and we need to be certain that all mixed-terrain riders have passed before we begin.

Turns for the regular paved century routes are marked on the road surface, but that will not be true for the mixed terrain routes, even in locations where the routes are on pavement. In some places you will need to ignore the route markings in order to stay on the mixed terrain route. You will need to be able to navigate using maps, cue sheets, and/or GPS devices.

Rider Limit

This is an experiment! In order to avoid problems and minimize impact while we learn how mixed terrain riding might fit into our century we are limiting this inaugural event to only 50 riders. We ask that you do not register for the mixed terrain option unless you are already experienced with this type of cycling and prepared to be self-sufficient.


  • Please be courteous to other trail users when riding within the parks. Follow all EBRPD Rules for Bicyclists.
  • Just like the regular century, you can start either mixed terrain ride at Campolindo High School or at our alternative car-free start in Tilden Park.
  • Just like the regular century, you can start anytime that registration is open. This is not a mass start event, and we are counting on mixed terrain riders being spaced out to minimize impacts on other park users.
  • There is a 15 mph speed limit on park roads.
  • Yield to pedestrians and call out when passing.
  • When approaching equestrians call out and stop whether you are seen or not. Ask for instructions on how to pass safely.
  • Shut cattle gates after you pass through them.
  • Riders should ride in groups of no more than 5, and in general try to keep groups separated by a minimum of 50 yards.
  • This is not a race or a timed event. Nobody is keeping track of when you start and finish. Take your time, enjoy the rest stops, and be safe, especially on the dirt portions of the route.
  • Try to keep some space between yourself and other riders when on the dirt roads. If someone falls don't make it worse by running over him or her.


After the century you will receive an email from us asking for your feedback. We send this to all century riders, but it is especially important that we hear back from you if you choose to ride the mixed terrain routes. You can help us shape our future events.


All queries about the mixed terrain option may be directed via email to Craig Hicks, hicks111at hotmaildot com with the subject containing the four capital letters GPCX.