Northern California - Rock Spring / Lagunitas Road condition?

I was plotting a Marin ride to possibly do this Saturday if it isn't raining. I like doing loops but since Fairfax-Bolinas road is closed I broke out the Marin bicycle map (http://www.marinbike.org/Map/Index.shtml) and started looking for a suitable dirt trails to use as a connector instead. There's a trail called Rock Spring - Lagunitas Road and it looks like it might be doable on a road bike with 23mm tires. Anyone have experience with this? I'd be riding it south to north (from Ridgecrest to either Bon Tempe Lake or Lake Lagunitas) and looks like it climbs about 200 feet before descending 1500. From what I can tell the vertical profile looks pretty smooth.

I have ridden the dirt section of Montebello on a road bike without trouble so if it's anything like that (or easier) then I should be all set.

I haven't ridden Montebello so can't compare. There are parts of Rock Springs/Lagunitas that are very rideable on a road bike, and parts that will be challenging, especially with 23c tires.

That initial climb is fairly steep; could be tough depending what your gearing is. But it's also very short, so even if you have to hike a bit, it won't take long. The route I take ends up putting me out on Fairfax/Bolinas Rd. (not anywhere near the section that is closed). While it is mostly downhill to there, there are a couple of uphill stretches, including one that could be tough on a standard double crankset, if that's what you have on your road bike. But again, it's a pretty short stretch.

The descents are fast, twisty, and occasionally fairly bumpy. There's also one section with a lot of loose gravel that could be hard to get through on 23cs. I ride it on a fully rigid mountain bike with 1.7 inch tires, don't go all that fast, and there are still stretches where I feel like I'm getting slammed around pretty good and feel like i could lose it any second. But I'm a cautious rider, and not all that great of a bike handler. I've seen people on cross bikes absolutely rocket down it, but they were probably riding 28cs at the least, and maybe wider.

If you have wider tires, I'd recommend that. If you don't, it's probably still doable. But bring some spare tubes, a good pump, and a taste for adventure.

Here's an example of one of the more technical stretches. It's steeper than it looks, but as you can see, there are usually lines you can take that allow you to avoid the rockiest parts. (I.E., don't take the line my friend in the photo took...)

http://farm3.static.flickr.com/2060/2411220210_67b066b9a5_o.jpg

Thanks a bunch for such a detailed write up! It looks like it would be passable if I was willing to go slow or even get off and walk here and there. I think I just might go for it sometime although a weekend where there's a good chance of rain probably isn't the best choice.

Hey Ben,
Another loop worth considering would be to make your way over to Stinson Beach (either via Muir woods/beach or Panoramic/Pan Toll), then catch the west side climb of Fairfax-Bolinas up to Ridgecrest.... climb to the top of Mt. Tam, then descend back via Panoramic..... all paved and a great route !!!
:giver:

Yeah I was thinking of doing Stinson beach and then the west side of Fairfax Bolinas in addition to Rock Spring :)

Here is the loop (http://www.bikely.com/maps/bike-path/Marin-Loop229859) I made but coming back from Mt. Tam directly via Panoramic Hwy would be a good bailout option.

Hey Ben,
Normally I ride up Rock Springs to Rocky Ridge, then down & out across Bon Tempe Dam.... but I have ridden down Rock Springs as well, usually turning off on Rocky Ridge as well. The other way out is what I beleive is in the pic above, where you pass along the north (or west) shore of lake lagunitas....while the part in the pic, and just above around the curve is steep & rough I think the steepest & roughest part is just below the turn off to rocky ridge..... I couldn't imagine riding it on a road bike..... If you survive I'd be interested in hearing about it.... and don't worry, I won't mind waiting 'till you get out of the hospital..... :roflmao2:

Good Luck !!!
:giver:

Hey Lou, I'm not sure I understand which part you're saying is steep. Here's the route I intended to take (click bigger):
http://i465.photobucket.com/albums/rr12/scurvy_lubber/marin-640.jpg (http://i465.photobucket.com/albums/rr12/scurvy_lubber/marin.jpg)

I'll start at the bottom and go up to "Bay Tree Junction" and then take the left fork to Bon Tempe dam. Are you saying the left fork is rough or the right fork? Or the section before the fork? I get confused with the similar sounding trail names and the fact that I've never been on any of them.

Anyway I am tentatively planning to do this ride on Saturday with my brother. Whether or not I do this trail will depend on the weather and how much sense of adventure I'm feeling at the time :) If anyone wants to join we'll most likely meet up at the south end of Golden Gate Bridge at 9am

OK, from Ridgecrest to "Bay Tree Junction" isn't that bad.... it's really not to much of a climb either... and you probably loose elevation by the time you reach the junction..... keep your eyes peeled because the turn onto Rocky Ridge is easy to miss.... it's like a downhill 180 degree turn on your left.... my "normal" ride is to climb up lagunitas rd. (what I call Rock Springs btw) to Rocky Ridge.....there is some real steep stuff maybe 1/2 to 2/3rds of the way up..... that's what I was refering to..... Now Rocky Ridge is something completely different (btw, it's one of my favorites....) It is appropriately named.... very rough in places....(awesome views too !!!, saw an Elk up there once, 10+years ago.... but I digress...) the upper part, 'till about the 1250' mark on your map, is the worst.... and there is one short pitch, that you turn left into, that I can rarely get up without losing traction and having to walk.... you'll know it when you get there (and are walking up it :) ) the descent is relatively smooth, but relatively steeper as well.... I love this trail !!! But I would NEVER try and ride it on a road bike myself..... I can't wait to hear your report.... but don't say I didn't warn you :ride:

Cheers !!! (preferably post-ride at the Marin Brewing Co.)

P.S. If it was me I'd take a road bike and a Mtn. Bike, and park at the intersection of Panoramic & Ridgecrest, or at Pantoll, and then do 2 separate loops, one road, one mtb.... much better odds of living to tell your grandkids about it.....

Ok, you gotta check this out.... this is Rock Springs/Lagunitas Rd. NOT Rocky Ridge.....

http://www.youtube.com/watch?v=LRdPffEoZF8

Too Cool !!!

This one is not Rocky Ridge either.... but it's close in terms of the "trail".....

http://www.youtube.com/watch?v=weXQJPJRR1A

Yep, no problemo !!!

Looks very cool ... for a full suspension mtb. I'm definitely having second thoughts about this plan which is sad because that trail looks so innocuous on the map. I mean it never even gets to the triple arrowhead depicting "very steep" and still it looks like more than I could handle :cry:

Looks very cool ... for a full suspension mtb. I'm definitely having second thoughts about this plan which is sad because that trail looks so innocuous on the map. I mean it never even gets to the triple arrowhead depicting "very steep" and still it looks like more than I could handle :cry:

the marin bike map reserves the triple arrowhead for only the most insanely steep stuff.

if you take the rock springs trail, then turn right at lagunitas rd. (rather than left at rocky ridge), you won't run into anything that requires suspension. but like i said in my first reply, with 23c tires, there are parts that would be pretty tough. also, if you have rims with low spoke counts and super-lightweight components, this route isn't ideal. If I were doing it on a road bike, I'd like 700 x 32c minimum, and wider if possible. and i'd want rims with at least 32 spokes. In other words, the route is more suited for touring/brevet/cross/all-rounder-style bikes rather than racing-oriented ones.

if you're interested, here is a route sheet (http://bike.duque.net/assets/files/SF-Mixedterrain-RutaLocaRandonnee.pdf) from a longer ride that includes this rock springs/lagunitas stretch. The relevant section starts at the 25.5 mile mark and ends at the 34.9 mile mark, aka Fairfax-Bolinas Rd. You'd turn right there to return to downtown Fairfax.