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  1. #1
    Family, Health, Cycling Lanceoldstrong's Avatar
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    Acceleration Junkies: Ski Jump Thread

    Pete introduced me to what he called the Ski Jump in San Francisco last summer. A hair raising descent down California St. toward Embarcadero Bart if I remember right.

    What is your favorite ski jump?


    Here is my local Ski Jump:
    A 15% grade starts things off in a hurry. Acceleration to 50 MPH is possible in just 1400 linear feet. Yipeee!!

    My best is 46 MPH but I am working on it.


    East bound Muir Rd. in Martinez along HWY 4 where Muir meets Pacheco Blvd.

    Last edited by Lanceoldstrong; 01-15-09 at 03:45 PM. Reason: East not west oops
    In Ascensu Est Verum

  2. #2
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    I've gotten up to 50mph on Los Trancos Road in Portola Valley. It's a smooth, moderately steep road with a long run out at the end.

    The steepest downhill that I do regularly is Conzelman Road in the Marin Headlands (heading west). It is steep for a good distance, but it is so steep and winding that most people are too afraid to build up much speed.

  3. #3
    Senior Member silentben's Avatar
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    Crestview going southbound. Steep and wide and not very twisty so theoretically you should be able to go all out without hitting any brakes. But there's a stop sign 1/3 of the way down and the pavement is pretty bumpy. You can still hit 50 without too much trouble though.

  4. #4
    Direct Hit Not Required BlastRadius's Avatar
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    In Millbrae, Larkspur between Skyline and Helen Dr is steep and fast. Only problem is the intersection at the bottom is pretty busy and there's not much stopping time if there's traffic there. Oh yeah and the 3-way stop in the middle of the descent is a bummer too (unless you don't mind running it ).

    http://maps.google.com/maps?f=q&sour...98311444652903

  5. #5
    Senior Member silentben's Avatar
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    At the risk of suggesting something totally reckless and irresponsible ... it would be fun to have a downhill time trial and/or top speed run on one of these hills some time.

    Top speed would best be measured by gps to rule out calibration difference between wheel-revolution based computers.

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    Quote Originally Posted by silentben View Post
    Crestview going southbound. Steep and wide and not very twisty so theoretically you should be able to go all out without hitting any brakes. But there's a stop sign 1/3 of the way down and the pavement is pretty bumpy. You can still hit 50 without too much trouble though.
    Anyone who tries that is trying out for a Darwin award. There is a stop sign at the bottom of Crestview and moderately heavy cross traffic that does not stop. A good "ski jump" road needs to have a long run out at the bottom (like 1 mile of flat road with no stop signs). You cannot stop a bicycle from 50mph to 0 in just a few seconds with your hand brakes.

  7. #7
    Dolce far niente bigbossman's Avatar
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    Not exactly a ski-jump, and not exactly local, but - the descent off of Sagehen Summit southeast of Mono Lake. It is about a 10 mile roll-out in high desert, with altitude and sweeping, unobstructed vistas.

    The upper half is a big sweeping curve, followed by a few rollers. Then the second half drops off down into a red rock canyon, so you get a relatively straight roll with excellent sight lines and (usually) no wind It is in the second part of this descent that you can easily hit 50-60mph coasting, if the conditions are right. My personal best is 56mph.

    The trace:


    The big sweeping curve is out of frame to the left, the rollers are about where the visible road disappears, and the dark ridges just beyond that that hide where the real fun lies:

    "Love is not the dying moan of a distant violin, itís the triumphant twang of a bedspring."

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  8. #8
    Senior Member gpelpel's Avatar
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    Rheem between Orinda and Moraga: my max is 47 mph.
    Pig Farm Hill (westbound) in Martinez: max at 49 mph.

    Too gradual to be a ski jump but a lot of fun is Monitor Pass in the Sierra: max at 51 mph.

  9. #9
    Senior Member JTGraphics's Avatar
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    We do 44 -45 regularly down some short decent of 6 -7 % grades fastest was 49 mph I seem to spin out around that speed using 53x12
    It may not be fancy but it gets me were I need to go.
    http://www.jtgraphics.net/cyclist_bicycles.htm

  10. #10
    Senior Member silentben's Avatar
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    I guess I should clarify that I stop at all stop signs. You can hit 50 on the bottom portion of Crestview (between Brittan and Edgewood) and still stop in time for the final stop sign because the slope does flatten out at the bottom.

    I think if you choose to run the stop sign the cross traffic will be less of a concern than the fact that Crestview doesn't continue past Edgewood

  11. #11
    Senior Member silentben's Avatar
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    I got curious about braking distances on a bike. The wikipedia article states you can get 0.5g of deceleration out of the front brake before you hit your limiting factor of pitching over the handlebars. Let's say that out in the real world you're actually applying a constant 0.3g of braking though. This is 2.95 m/s^2 (9.82 m/s^2 * 0.3)

    Say you're cruising along at 50mph (22.4 m/s) and you need to come to a full stop. This will take 7.6 seconds (22.4 m/s divided by 2.95 m/s^2). During that time your average speed is 11.2 m/s and so you travel about 85 meters (11.2*7.6). This is a little over 0.05 miles.

    Of course that assumes you're on level ground. Maybe double that stopping distance if you're going down a reasonable (6-7%) hill? That's still just a tenth of a mile to go from 50mph to zero.

  12. #12
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    Quote Originally Posted by johnny99 View Post
    The steepest downhill that I do regularly is Conzelman Road in the Marin Headlands (heading west). It is steep for a good distance, but it is so steep and winding that most people are too afraid to build up much speed.
    I am one of the afraid people on this road -- how fast do you get going on it?

    For less scary descending, Red Hill going north to south (i.e., from Petaluma toward Marin) is a great stretch to try to achieve maximum speed on. Then, just a short while later, there's the descent on Point Reyes Petaluma toward Nicasio. Both are long downhills with only the most gradual of turns, and also long flat stretches at the bottom to decelerate safely on.

  13. #13
    phony collective progress x136's Avatar
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    That section of Highway 1 (going North) right before Tunitas Creek is always a pretty good recipe for mid-40s or so. Never a problem taking the lane to cross that bridge, that's for sure.

  14. #14
    moth -----> flame Beaker's Avatar
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    For me - South Park Drive in Tilden FTW. Easy to exceed 50mph even with braking, that straight part in the middle is the key:

    http://www.bikely.com/maps/bike-path...uth-Park-Drive

    Good news is it's quiet, with not many cars, generally wide turns and smooth tarmac. Unfortunately it's closed until Mar or Apr to protect migrating newts...

  15. #15
    crazy bike girl msincredible's Avatar
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    I passed a truck on Edgewood in the shoulder at 45 mph...drafting it let me get up to that speed (usually I can get up to about 40 if I don't have my jacket on).
    Countries I've ridden in: US, Canada, Ireland, UK, Germany, Netherlands, France, China, Singapore, Malaysia
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  16. #16
    Senior Member powpow's Avatar
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    South Park Drive in the Berkeley hills will get you going. After a few curves there is a long, straight, fast section with good pavement. Good climb too.

    http://www.calcycling.org/?q=node/367#southpark

  17. #17
    crazy bike girl msincredible's Avatar
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    Bonny Doon is a nice fast descent too...got up over 40 mph on my old hybrid there.
    Countries I've ridden in: US, Canada, Ireland, UK, Germany, Netherlands, France, China, Singapore, Malaysia
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  18. #18
    moth -----> flame Beaker's Avatar
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    Quote Originally Posted by powpow View Post
    South Park Drive in the Berkeley hills will get you going. After a few curves there is a long, straight, fast section with good pavement. Good climb too.

    http://www.calcycling.org/?q=node/367#southpark
    Great minds think alike

    Interesting link, I'm trying to find as many climbs in the area as I can, but I'm not sure I agree with all of the descriptions though - descending Wildcat isn't much fun, huh??? I need to try Marin for the reasons stated though.

  19. #19
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    I finally got to go down S. Park in Tilden Regional Park when it was closed to traffic - steep and fast! My computer was out, so I'm not sure how fast I was going. Only a couple of people walking dogs, and no salamanders were hurt on the run. There's a stop sign at the bottom, but it seemed to flatten out and you can see it coming from at least a quarter mile away.

    Another oldie but goodie is Palomares going South to North (ie, from Niles Canyon to Castro Valley). Not super steep, but long enough and straight enough to get up close to 50 without trying.

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  20. #20
    Senior Member
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    Quote Originally Posted by Beaker View Post
    Great minds think alike

    Interesting link, I'm trying to find as many climbs in the area as I can, but I'm not sure I agree with all of the descriptions though - descending Wildcat isn't much fun, huh??? I need to try Marin for the reasons stated though.
    Oh, I have to disagree - descending Wildcat is a lot of fun - just kind of technical, so you get to work on your skills!

    JB
    "Poor Reverend Hamilton! He worked so hard, got a mountain named after him and now all anyone wants to do is complain about his backside!" Overheard while climbing Mt. Hamilton

    Check out my cycling blog.

  21. #21
    moth -----> flame Beaker's Avatar
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    Quote Originally Posted by jonathanb715 View Post
    Oh, I have to disagree - descending Wildcat is a lot of fun - just kind of technical, so you get to work on your skills!

    JB
    No, we're in agreement, it was the link that claimed it wasn't fun.

    For South Park, I have to say I prefer the descent when it's open. Climbing is fine year round, but I find because the road is closed to traffic, folks walk across the breadth of the road, often with dogs not expecting to meet anything on wheels. Makes me a bit jittery.

  22. #22
    slow up hills kudude's Avatar
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    1) Whoever said Pig Farm hill - I've seen excess of 50, and it has a great runout that takes you onto Bear Creek
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15

    2) South park is fun and all, and maybe the fastest, but the one right curve near the top always makes my heart skip a beat. Definitely above 50 mph, though.
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15

    3) Wildcat is a blast, in the same way south pinehurst is a blast. You can practice high speed cornering over and over and over and over
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15

    4) The backside of papa bear is fast, but really, really long, not much of a ski jump
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15
    5) Who doesn't love Claremont?
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15
    6) Marin -- you can go 0 to 30 to 0 in the course of a block, for about 6 consecutive blocks
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15
    7) Joaquin Miller is fast, plus you get that sign blinking at you telling you you're speeding.
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15
    8) If you come back OVER mama bear (from pumphouse), that one will get you flying in a hurry
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15
    9) Someone mentioned something about Orinda->Moraga. I don't know if it's the same road, but Orindawoods Drive has got to be one of the steepest uncontrolled (no stop signs/lights) roads around. You can get to it going towards wildcat from el nido ranch road
    http://maps.google.com/?ie=UTF8&laye...59.961462&z=15
    Any others around the hills in that area that I'm missing?
    Last edited by kudude; 01-16-09 at 10:24 AM.
    Quote Originally Posted by mr_tom View Post
    Cycling isn't a sport. It's more like a really, really expensive eating disorder.

  23. #23
    moth -----> flame Beaker's Avatar
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    kudude - two more:

    10) Shepherd Canyon the other side of Skyline/Pinhurst is pretty good, there's a nice long straight stretch that can get you well into the 40's - only done that a couple of times.

    11) Hiller is pretty insane - I'd put that in the "too steep to be fun" category, as it finishes in a stop sign before becoming Tunnel that put my HR through the roof the other week.

  24. #24
    Senior Member powpow's Avatar
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    Quote Originally Posted by Beaker View Post
    Great minds think alike

    Interesting link, I'm trying to find as many climbs in the area as I can, but I'm not sure I agree with all of the descriptions though - descending Wildcat isn't much fun, huh??? I need to try Marin for the reasons stated though.
    Got me by nine minutes!

    I agree, Wildcat is a fun descent, though the pavement on some of the lower turns could use some work.

  25. #25
    slow up hills kudude's Avatar
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    Quote Originally Posted by Beaker View Post
    kudude - two more:

    10) Shepherd Canyon the other side of Skyline/Pinhurst is pretty good, there's a nice long straight stretch that can get you well into the 40's - only done that a couple of times.

    11) Hiller is pretty insane - I'd put that in the "too steep to be fun" category, as it finishes in a stop sign before becoming Tunnel that put my HR through the roof the other week.
    +1 I forgot about Shepherd Canyon. I don't know if I've ever done Hiler -- is it the steep as **** road if you take a left instead going right up tunnel?
    Quote Originally Posted by mr_tom View Post
    Cycling isn't a sport. It's more like a really, really expensive eating disorder.

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