# 50mph Downhill Speeds?!!



## austincrx (Oct 22, 2008)

so i'm hearing alot about people hitting 50 mph and over on the downhill sections of their rides. Is this normal? I've tried to get that speed, but my bike will top out at 45 mph, sadly i've only recently seen 42 mph. Is 50 mph common? Is this more common going down a mountain or just hitting a quarter mile downhill section. most of the hills in my area are <10% grades, and not more than a mile long. My gears are 53-39 chain rings, and 11-23 rear cassette. I know my friend has an Allez w/ a 57 tooth large chain ring, but also a 12-27 rear cassette.

thanks!


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## John Nelson (Mar 10, 2006)

Yes, you'll probably get a hundred people here tell you that they have exceeded 50--some have exceeded 60. It's not hard. All you need it a hill that is steep enough and straight enough and long enough. I have found that although the bike accelerates very quickly down a hill, that the speed does keep increasing the longer the hill is (within limits). I doubt you would need more than a half-mile, however, to get to top speed on a steep hill. You of course need to stay off the brakes, and it helps greatly to streamline your body (i.e., get low). Pedaling is not usually a factor here as very few people have the gears and leg speed to allow them to pedal up to 50 MPH.

Use reasonable caution. Don't try it on windy days. Find smooth roads that you've been on before. Watch carefully for animals. Don't do it if there are side streets from which cars may come. If there is a sharp turn or stop sign ahead, slow down well in advance. Keep your weight back and be sure your bike is rock steady at high speeds (you should know whether it is based on how it handles at slightly lower speeds). Read up on the ways to mitigate high-speed wobble just in case it does happen (e.g., put a knee or two on the top tube).


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## andulong (Nov 23, 2006)

I have been riding basically all my life and have hit 52 MPH once only. My normal top speeds for rides are in the low 40's or upper 30's. To hit 50's you need a big hill, nice roads and a bike in top condition (to avoid any potentially catastrophic failures at speed). I have learned that big hills are for coasting down and resting. That 57 tooth big ring you speak of is not very common. If you spin your ass off you should be able to do it with your current setup...if you find a big enough hill.


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## JCavilia (Sep 12, 2005)

It's pretty much all a matter of the length and steepness of the hills, and aerodynamics. Nobody gets to 50 mph by pedaling (with a 53x11, you have to turn over 130 rpm to go 50 mph -- that's doable, but it's hard to produce much power spinning like that.)

But it's even more about bike handling, reliable road surface, and knowing the road well. My advice is not to shoot for any particular speed, and never go faster than you're comfortable with given your experience and the road conditions. And resist the temptation to look at your computer -- you need to watch the road.

The bike has to be well-maintained to be safe. The front end is especially critical -- headset, fork, front wheel, front tire, brake. If something goes wrong up there at high speed, it's big trouble.


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## Bocephus Jones II (Oct 7, 2004)

austincrx said:


> so i'm hearing alot about people hitting 50 mph and over on the downhill sections of their rides. Is this normal? I've tried to get that speed, but my bike will top out at 45 mph, sadly i've only recently seen 42 mph. Is 50 mph common? Is this more common going down a mountain or just hitting a quarter mile downhill section. most of the hills in my area are <10% grades, and not more than a mile long. My gears are 53-39 chain rings, and 11-23 rear cassette. I know my friend has an Allez w/ a 57 tooth large chain ring, but also a 12-27 rear cassette.
> 
> thanks!


Not that uncommon here in CO--you need a long, steep, relatively straight road though. My fastest is 56 down the Dallas Divide in CO--I may have been able to go faster, but a truck was in my way so I had to brake.


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## Blue CheeseHead (Jul 14, 2008)

I have yet to break 50, but did 49.7 on a short (1/3 mile) hill with a 15%+ gradient. Pedalling past 42 mph is pointless for me with a 52-12. It is spooky as all get out as any little furry critter could change your life.


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## GerryR (Sep 3, 2008)

Bocephus Jones II said:


> I may have been able to go faster, but a truck was in my way so I had to brake.


Should have honked at the driver for impeding traffic.


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## iliveonnitro (Feb 19, 2006)

Madison is hilly, but the short, steep kind. No mountains. But there are quite a few places that 40+mph is just easy, and a couple that 50mph is simple, too.

Every single week for the past 14 weeks I've broken 40mph, and 5 of those were >45mph. My fastest is 59.4mph (damn!), but that was in North Carolina in the mountains.

Here is a pic from 55+mph in madison. The gradient was approx -18%.


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## Creakyknees (Sep 21, 2003)

since this is the beginner forum... I have to say, it's not the going that's a challenge... it's the sudden stops that sometimes happen.

bikes behave differently at speed. small pavement problems can slam you to the ground with no warning. animals, branches, cars etc appear with no warning.

just make sure your bike is in tip-top shape and you have the confidence and handling skills. always be looking way ahead - it's surprising how long a stop can take and how fast things happen.


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## wasserbox (Mar 17, 2002)

Bocephus Jones II said:


> Not that uncommon here in CO--you need a long, steep, relatively straight road though. My fastest is 56 down the Dallas Divide in CO--I may have been able to go faster, but a truck was in my way so I had to brake.


Heh - I passed a cop coming down that last year. There was a moment of "Should I? Shouldn't I?'

The only times I have gotten rolling that fast was in a group. Solo I max out around 50ish.


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## MerlinAma (Oct 11, 2005)

JCavilia said:


> ............Nobody gets to 50 mph by pedaling (with a 53x11, you have to turn over 130 rpm to go 50 mph -- that's doable, but it's hard to produce much power spinning like that.)..............


Then call me "Mr. Nobody".

I hit 50 (very briefly) a couple of years ago using a compact crank and a 11 tooth cog.

We were on a big tailwind ride and I cranked up to 140 rpm (very, very, very briefly) and saw the computer read 50mph. Yes - it was flat.

Did I day it was windy that day? Ridiculously windy. There was no way to go into that wind hence the tailwind ride!


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## JCavilia (Sep 12, 2005)

*You go, Dude.*



MerlinAma said:


> Then call me "Mr. Nobody".
> 
> I hit 50 (very briefly) a couple of years ago using a compact crank and a 11 tooth cog.
> 
> ...


Not a lot of big descents in the Panhandle  Wind must serve.

I'm pretty sure I've gotten the cadence up to 150 a couple of times, descending on a fixed gear. It's a whole other zone, and I certainly couldn't do it for long. On a geared bike you at least know you can coast if you blow up; on the fixed you have to be thinking ahead to how you keep it together through the slowdown period.

On the other hand, I wasn't having to anticipate whether a side gust was gonna toss me in the ditch.


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## Cory (Jan 29, 2004)

andulong said:


> I have been riding basically all my life and have hit 52 MPH once only. My normal top speeds for rides are in the low 40's or upper 30's. To hit 50's you need a big hill, nice roads and a bike in top condition (to avoid any potentially catastrophic failures at speed). I have learned that big hills are for coasting down and resting. That 57 tooth big ring you speak of is not very common. If you spin your ass off you should be able to do it with your current setup...if you find a big enough hill.


Me, too: Almost 40 years on the bike, and I've gone over 50 just once, when I looked at the speedo on a steep downhill and saw I was at 48. Couldn't be that close and not touch 50, so I pedaled hard for a few yards and got to 51. Then it dawned on me that everything on the bike was bought for the lowest possible price and installed and maintained by me. I'm pretty comfortable at 35-40, but I have no desire to go faster.


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## austincrx (Oct 22, 2008)

Yeah, i have to agree with you Creakyknees.

I do some autoracing during the spring and summer months, EVERYTHING behaves differently at high speeds. you'd be surprised how hard it is to control a Honda at 140mph, or even 100 for that matter. once you add in the super stiff suspension, race tires, lower it to 3.5 inches, etc. then go around a 180 degree turn at 60+, it's ridiculous and yet, AWESOME!!! 

Speed is not something i'm scared of, 80mph on a bike would be at my limit, but i think i'm ok it i was going 60mph. And holding the brakes is not something i do much either. i find that you go faster if you let them go (haha joke). It just seems odd that me and my friends can spin up to about 45 in aero position, and will have plenty of hill left, but don't accelerate by coasting (guess the hills aren't steep enough). Then again, mountains are mountains, and we don't ride in them, only an hour south of them though, haha. it's intimidating when you see a mountain in the distance and think "can't wait until I can ride those hills!"

But yeah, just always wondered about this. Don't see how i could get any more aero, other than getting my face into the stem, and that really hurts my neck if i do it for more than 1 min. (tried it once, didn't last long on the rest of the ride and still only made it to 28 mph, from rest with no pedaling just to play around).

Speaking of animals- saw three Deer run out about 100' ahead of me on my last ride, pretty neat, tried to catch up with them to see them run across the field beside the road, but couldn't go fast enough to see them go throught the trees on the other side of the field. Then got chased by a pit bull, and watched my friend pedal right past him and the darn dog didn't even move, just watched; haha.


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## george costanza (Nov 3, 2008)

140 in your CRX? that must be nuts. i wouldn't do over 120 on a sub 2200 pound car. i'd be scared of any type of cross wind.


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## cxwrench (Nov 9, 2004)

austincrx said:


> so i'm hearing alot about people hitting 50 mph and over on the downhill sections of their rides. Is this normal? I've tried to get that speed, but my bike will top out at 45 mph, sadly i've only recently seen 42 mph. Is 50 mph common? Is this more common going down a mountain or just hitting a quarter mile downhill section. most of the hills in my area are <10% grades, and not more than a mile long. My gears are 53-39 chain rings, and 11-23 rear cassette. I know my friend has an Allez w/ a 57 tooth large chain ring, but also a 12-27 rear cassette.
> 
> thanks!


57, huh? sounds like he's got some serious inadequacy (is that correct spelling?) issues. i'm sure he was spun out on the bike path w/ his 53...


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## austincrx (Oct 22, 2008)

yeah, 140 has only happened once. Most tracks we just barely reach 110mph. and yes, the crosswinds play a HUGE role in where your car goes. Because all vehicles have some amount of 'play' in the steering wheel whether it is 1 degree or 20 degrees of movement before the vehicle moves; it becomes very unstable for a vehicle with ANY play when you get above 120mph. But what is cool, at 140 the gap between the side mirrors and the window begins to almost make a whistling sound!!! SWEET!!

Now the crx has been un-modified to keep the gas mileage up. Almost 40 mpg on the interstate (crx is my street car, I have a civic that I road race, not to confuse anyone).


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## jlandry (Jan 12, 2007)

I'm scared just thinking about it. While going fast down hills, I'm always concerned that my front wheel will explode.

Anyone heard of this happening?


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## danl1 (Jul 23, 2005)

Yes, it's possible. Not for the faint of heart or ill-equipped, and discretion is the better part of valor here. 

One note about the pedaling: At speeds much above 40, getting into a tight tuck usually nets more watts than one is able to provide by opening up enough to pedal. 

Obviously, crazy wind conditions change that math somewhat. I've been blown to a dead stop by a canyon headwind going down an 8% grade. Was on an out-and-back route on the California coast headed into Gualala, and actually went up the hill faster than I was able to go down.


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## wmayes (Aug 8, 2007)

The course I ride every other day has a decent 3-4% downgrade for a 1/2 mile and I regularly get to 40-42 mph, plenty fast for me. Let me just put in my .02, the ground isn't any harder at 50 than 20. You just slide/tumble farther and hit way more stuff!


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## Blue CheeseHead (Jul 14, 2008)

wmayes said:


> The course I ride every other day has a decent 3-4% downgrade for a 1/2 mile and I regularly get to 40-42 mph, plenty fast for me. Let me just put in my .02, the ground isn't any harder at 50 than 20. You just slide/tumble farther and hit way more stuff!


Yep, but it's that tumbling that will rip skin, break bones and dislocate joints. Plus the impact with an immoblie object (deer, tree, car) is a bit harder at 50 than 20.


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## phoehn9111 (May 11, 2005)

I found this year, after having my wheels trued by an expert, most of my
earlier fears were due to wheel wobble. I didn't notice it until it was
gone. For me, downhills are something I have to put up with to get
to uphills. Max speed downhill is meaningless to achieving training
goals other than bike handling skills.


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## JCavilia (Sep 12, 2005)

> For me, downhills are something I have to put up with to get to uphills.


Downhills are the big adrenalin payback for the uphill effort (though I enjoy the climbs, too).




> Max speed downhill is meaningless to achieving training goals other than bike handling skills


.

Thank goodness I don't have "training goals"! I agree max speed is generally meaningless, but going fast is FUN.



> Let me just put in my .02, the ground isn't any harder at 50 than 20. You just slide/tumble farther and hit way more stuff!


The real issue, IMO, is the decreased margin for error and other difficulties. A bump or bobble or bad spot in the pavement that is easily handled at 20 is a whole different animal at 50. You gotta be solid.


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## Oldteen (Sep 7, 2005)

JCavilia said:


> The real issue, IMO, is the decreased margin for error and other difficulties. A bump or bobble or bad spot in the pavement that is easily handled at 20 is a whole different animal at 50. You gotta be solid.


+1111111!!!!!

I'm in Midwest so no mountains. But there are short but steep (15-20+%) grades so doing 50+ is very possible in my area.. At least on hills with reasonable pavement. 
Descending is a biking skill, and, like DH MTBing, errors can be severely punished. You must have a stable, balanced, relaxed, & aero (tucked) position. You must scan the road well for any upcoming problems- pavement (ruts, potholes, etc.), traffic (cars & other bikes), animals, upcoming turns, etc., etc. A minor rut or pavement crack may be no prob @ 20mph, but literally life-threatening at 50+mph. If you hit a rough patch, level your pedals & raise your butt off the seat silghtly (MTB "attack" position to let legs act as shock absorbers). Danl1 is right that above low 40's mph you are prob better off in a tight tuck. For most, trying to pedal faster than that just makes you less stable (more prone to crash) & less aero (watts produced don't overcome increased drag). 

Don't push for top speed on downhills until you gain experience and are very familiar with the particular road. Stay in control & let speed happen. Avoid the rougher patches of pavement. You will find yourself riding the same hills faster, but ALWAYS in control. Doing 50+ is nothing if you don't finish the ride intact 

FWIW- I rarely hit 50. On local roads my testosterone levels usu. max @ low-mid 40's.


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## waldo425 (Sep 22, 2008)

I got up to 45 on my bike and it scared the crap out of me (my bikes a little shaky.) As much as I try I just cant go any faster on my bike on the hill I am going down. I think that the only hill I could go faster down around here goes straight into main-street traffic; no slow down, just car fender.


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## SkiRacer55 (Apr 29, 2005)

*What he said...*



Oldteen said:


> +1111111!!!!!
> 
> I'm in Midwest so no mountains. But there are short but steep (15-20+%) grades so doing 50+ is very possible in my area.. At least on hills with reasonable pavement.
> Descending is a biking skill, and, like DH MTBing, errors can be severely punished. You must have a stable, balanced, relaxed, & aero (tucked) position. You must scan the road well for any upcoming problems- pavement (ruts, potholes, etc.), traffic (cars & other bikes), animals, upcoming turns, etc., etc. A minor rut or pavement crack may be no prob @ 20mph, but literally life-threatening at 50+mph. If you hit a rough patch, level your pedals & raise your butt off the seat silghtly (MTB "attack" position to let legs act as shock absorbers). Danl1 is right that above low 40's mph you are prob better off in a tight tuck. For most, trying to pedal faster than that just makes you less stable (more prone to crash) & less aero (watts produced don't overcome increased drag).
> ...


...I ski race in the winter, and have been clocked at 74 mph in a downhill. I've also come unglued at that speed, which wasn't great...however, I gotta say that falling on snow is a _hell_ of a lot better than taking a trip to McDonald's, which is what happens when you come unstuck from your bike on asphalt...


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## saccycling (Sep 30, 2004)

It all depends on the road. I've done 49 on a long straight road with no problem. On a road with twists and potholes. 40 is screaming. I've fallen off a skateboard doing 35 when I was a teenager. I bounced. A lot of pain. No broken bones but sure felt like it.


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## TWB8s (Sep 18, 2003)

Ahhh speed. It's a wonderfully addictive drug. There a few hills here in Wisconsin where 40+ mph happens and if you sprint at the top you can hit >50 mph. When I lived in Colorado it was hard to show restraint on descents. My favorite is highway 24 from Woodland Park to Manitou Springs. 2000 feet of elevation change in about 12 miles made more fun by the twisties mid-way down. The sheriff used to sit at the exit into Manitou Springs waiting for speeders. We frequently were ticketed for speeding on the bicycles as we came down at speeds greater than 60 mph with 72 being my personal 'record.' Never did pay those tickets either. They were more concerned with us being in control of our bikes than the speed. As as Creaky said, being a beginner you should try to maintain control.


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## waldo425 (Sep 22, 2008)

I'm probably going to try and go for some higher speeds in the coming weeks. This week Ill be getting a new rear wheel which should help a lot. My wheel right now is wobbly and the bearings are grinding. Ill be very happy when I have a new setup in the rear. All Ill need is a dry day; I find that above 30 MPH a slight drizzle feels like needles, then theres that big drop from a tree that pegs me right in the forehead --- ouchies.


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## Gnarly 928 (Nov 19, 2005)

I've hit 50+ quite often on mountain roads. Love it, but usually if I am just training or riding I simply tuck and my top speed seems to top out around 45-50. You have to actually try to get over 50 but on a long steep hill, it's not hard. 

I get a kick out of making all the climbers PAY in a roadrace by going balls-out myself on the downhills..They hate that. I always hear, "hey a**hole, where the hell do you think you're going? Attacking on the descent never works...mellow out." etc etc etc. But it's sapping their energy, cranking it waay up on the downhills, which may make it easier for me to hang in on the last climb of the day...works like that sometimes (rarely) anyhow, and I love all the 'whining' 

With a group, you can all coast over 50 if you draft each other just right..but you need to be pretty confident with the other riders.

Don Hanson


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## Angelracer (Dec 12, 2004)

50mph is easily attainable, yeah watching out what is in front of you is very important. I do lots of gap rides, where its miles and miles to the top, and miles to the bottom. Hit a decent with 15-20% or more 50 mph is nothing. But heck a 10% grade decent for only 1/2-1 mile long hitting 50 mph is a bit of work. But man...going 50 mph down those steep descents I just get in a stable areo position and hold it, don't think, no sudden movements and just ride it out and think, I want to do this again and end up climbing back up to the top and laugh at tourists clapping at me as I go up the mountain again.


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## EMB145 Driver (Aug 17, 2006)

It's really all about True Airspeed and Density Altitude. The reason everyone can go faster in the mountains (Rockies) versus a 1/2 mile hill in TN of the same grade has everything to do with air density. When you start at 9,000 feet and end at 6,000 feet, the air is still much less dense for the entire descent. Starting at 1,000 feet and ending at 400 feet, is basically the same air density, and you never had the aerodynamic chance of going as fast as you do at altitude. Warm, summer air in the mountains, and you'll go even faster.


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## mercsport (Dec 14, 2008)

One aid to hitting 50+ mph not mentioned up to now on this thread is to *be overweight* - by a good margin ( such as myself ) - and you'll certainly scoot down those hills with considerably less effort than that of the skin 'n' bone hollow chested mountain climbing hero . It has to be said that that would seem to be about the only virtue to being a fatty on a 'cycle .
At 62 I can still hit 50mph on occasion ( I live in a hilly area ) but am considerably more circumspect at 'letting go' as I've discovered it seems to hurt a heck of a sight more with increasing age when you lose it and get decked .


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## JCavilia (Sep 12, 2005)

*"true airspeed"*



EMB145 Driver said:


> It's really all about True Airspeed and Density Altitude. The reason everyone can go faster in the mountains (Rockies) versus a 1/2 mile hill in TN of the same grade has everything to do with air density. When you start at 9,000 feet and end at 6,000 feet, the air is still much less dense for the entire descent. Starting at 1,000 feet and ending at 400 feet, is basically the same air density, and you never had the aerodynamic chance of going as fast as you do at altitude. Warm, summer air in the mountains, and you'll go even faster.


Only a pilot would use that term.

I just figured out your screen name. I've ridden in a few of those. Which line do you fly for?

The altitude/density factor is a major point. You're probably too young to remember the 1968 Mexico City olympics. Everyone talked beforehand about the adverse effect of the altitude (>7000 feet) on the endurance events, but hardly anyone anticipated the positive effect on the speed events. Bob Beamon broke the long jump record by nearly 2 feet, and his record stood for over 20 years (and It's only been broken that one time, in 40 years).


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## Muaythaibike (Oct 26, 2007)

The fastest I ever went was 42. This was down a mountain pass in NH.. I was so scared that I had my hands on the brakes and 100% concentration.

You fall at 40+ and you have some issues....


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## austincrx (Oct 22, 2008)

well, got 48 mph yesterday. felt awesome!!!


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## Camilo (Jun 23, 2007)

andulong said:


> I have been riding basically all my life and have hit 52 MPH once only. My normal top speeds for rides are in the low 40's or upper 30's. To hit 50's you need a big hill, nice roads and a bike in top condition (to avoid any potentially catastrophic failures at speed). I have learned that big hills are for coasting down and resting. That 57 tooth big ring you speak of is not very common. If you spin your ass off you should be able to do it with your current setup...if you find a big enough hill.


My top recorded speed was about 48 mph and I wished I'd just given it a little more rein (let it roll a little more, gotten down lower and for longer) and hit 50. I tend to be ultra paranoid and really only let 'er loose on long straight sections w/ perfect visibility in all directions. Any little thing (intersection, even if it's empty, any appearance of gravel or leaves, etc.) causes me to feather the brakes. I usually feel that 40 is plenty fast, thank you.


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## WWU (Oct 7, 2008)

Hurricane Ridge on the Olympic Peninsula of Washington State.

59 miles per hour by the time I got to the bottom of the hill.


And I almost wiped out when I hit a golf ball sized rock in the middle of the road.





Needless to say it was a pretty sketchy ride. I was riding my Fuji Touring, so I had a somewhat more relaxed geometry and wider tires, which made me feel somewhat safer, but I nearly wore through my brake pads both front and back trying to stop near the bottom of the hill. I had to stick towards the middle of the road because there's no guard rail for much of the descent, and it's several miles long, but it was the most fun I've ever had on two wheels, and I plan on doing it again this summer.


If you plan on hitting 50+ anytime soon, I'd suggest a full tuneup and checking your brakes, just in case, as well as looking a long ways ahead to check for obstructions, as the smallest pebble could drop you and make a nice red streak down the hill.

I'll post the pics as soon as I can find them.


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## John Nelson (Mar 10, 2006)

If you're going to ride 59 MPH, I suggest you steer around golf ball size rocks.


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## hoehnt (Nov 7, 2008)

I regularly hit the mid 40s. There is one hill I get low 50s but I dont ride it often (too far)


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## lalahsghost (Aug 27, 2007)

I've hit 62 going on a half mile downhill, hunched over into cyclo-fetal position being piss scared, not thinking my brakes would hold up when I start wanting to slow down. Of course I only tried this extreme speed after doing the hill four or five times (in the past, not on the same day)


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## Mr. Versatile (Nov 24, 2005)

I've been a little over 50 on a single, a little over 60 on the tandem. Very scary ride on the tandem that day.


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## raymonda (Jan 31, 2007)

For bragging rights, I use to hit 60 or more down Sugar Loaf Mnt. Rd outside of Boulder when I live in Co. back in the early 90's. 64.5 was the fastest I went. Around Ithaca I can only top out at 51 or 52.

I really enjoy the super fast down hills!!!!!! It is part of the ride I really look forward to.


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