Shibboleth - Member62 on a mountain bike?? I'd go as far as to say you should throw that Cateye out... It's obviously completely f*****d. The only way a mountain bike would do 62mph is on the roof of a car.
N0B!!
[url= http://http://en.wikipedia.org/wiki/Cycling_records#Speed_record_on_a_bicycle ]On 14 September 2007, Stöckl rode an Intense M6 mountainbike down the ski slope of La Parva, Chile, reaching the current record of 210 km/h (130 mph).[/url]
Years ago I managed an indicated 54 mph coming down the top section of 'Kloser's climb' in Vail while we were out there for the '94 world championships (marshalling, not competing). Measured on a Cateye computer.
Altitude was about 12,000 ft so much reduced wind resistance, a mile straight down fairly steeply on a wide fireroad and a tailwind obviously all contributed. Nearly killed myself by completely mis-judging how long it takes to lose speed afterwards though, the first corner was seriously sketchy.
Happy days.
Regularly get mid to late 40s (mph) coming down Butser Hill. That's without pedaling or adopting a particularly aerodynamic position so I'd imagine an extra 10 mph would be achievable if you wanted to put the effort in.
52mph coming down Hartside on a yr2001 marin east peak with xc pros while doing the C2C a few years back. I would hate to think of the speeds possible on a road bike coming down there!
On the long descent from the top of rosedale chimney bank I had the wind behind me and a spun out my very top gear which I have never done befor. No speed so I am not able to tell you the exact speed but I guess a bit faster than 52:12 can spin.
edit 42 mph
There appear to be 3 of us with faulty Strava apps, GPS's and bike computers on different days.
[url=app.strava.com/rides/9703401#172722773]app.strava.com/rides/9703401#172722773[/url]
Managed 29mph down the lockerbrook descent down to ladybower last Sunday and 28mph down the big descent into cwm rhader recently.
Doubt it's accurate but Sunday I had 40mph. Not quite sure where or how.
@shibboleth, yeah i had more frontal area for sure, and no i wasnt pedalling, 46/12 gave me a max pedalled speed of about 45mph, and i wouldnt be providing much power at that speed i dont think.
thor hushovd did 68 mph on a shallower slope, with less weight pushing him along, without the benefit of a massive tailwind.(afaik)
if i regularly recorded that type of speed then yeah id be sceptical myself, but it was a one off event, ive been back on that road many times as it was a regular route to my grandparents house, i didnt acheive that type of speed again. also, i didnt experience that type of tailwind again either, i think that was the deciding factor.
you obviously dont believe its possible, fair enough, go try it for yourself.
http://maps.google.co.uk/maps?hl=en&bav=on.2,or.r_gc.r_pw.r_qf.&biw=1093&bih=500&wrapid=tljp1343824778236038&um=1&ie=UTF-8&q=killhope+lead+mining+museum%2Bmap&fb=1&gl=uk&hq=killhope+lead+mining+museum&cid=0,0,4037845047115118006&sa=X&ei=lSMZUOb4IISr0QWc5IDwBg&sqi=2&ved=0CI4BEPwSMAA
heading east towards this place.
Come on Marty, every time you tell a lie, a fairy dies. Let's just admit that your Cateye was waaaay out and stop the killing!
Just checked FB and the two fairies I know are still alive.
it could have been out, i said that at the very start, no computer is truly accurate is it.
im on holiday in 2 weeks, and im seriously considering taking the cx bike and full susser down there, be interesting to see how much slower a fat git goes. (i mean me btw)
i dont have the same bike any more unfortunately, just a full susser and a cx bike, but could take them both for comparison.
Did 32mph last night in the gathering gloom down a rutted field - felt rather sketchy... Haven't been faster than 40mph on-road.
Here's a video someone shot of hitting 48mph on Devil's Dyke, where I mentioned earlier. Definitely worth checking out if you're on the South Downs near Brighton and feel the need for speed 🙂
Not sure about all time, but clocked 59.3kmh last week sometime (new to Strava so unsure how to see speed vs location) during a couple of loops of Innerleithens' Red route.
48.9 down Drum Mountain but overtaken by a fat bastard who had more gravity 😉
TBH not much difference in speed but he must have touched 50...fried the brakes when we tried to stop....it is bowling green smooth though
46mph on the geared bike and 41mph on the rigid singlespeed down the same hill. I'd say faster is possible but there are a few blind corners at the top of the hill followed by a steep straight section and a mini roundabout followed by a t junction at the bottom so only a hundred yards or so to get your speed up. I could go faster if I could slow down faster!
Shame on all those who think that weight has a bearing on descending speed: acceleration due to gravity is 9.81 m/s/s regardless of mass.
If you are fatter then you will have a greater force due to gravity, but a greater mass to accelerate.
Managed 52mph years ago, on a DH bike, riding steep fireroads in the Alps that wouldn't have looked out of place on the old Mammoth Mountain Kamikaze race of the 90's. Scared me a lot, I have no desire to do that again! For reference, 160mph on a motorbike (on pretty narrow back roads) felt safer!
Have only managed 48.6mph on the road bike strangely! Mind you, never ridden it anywhere especially steep by comparison.
Shame on all those who think that weight has a bearing on descending speed: acceleration due to gravity is 9.81 m/s/s regardless of mass.
If you are fatter then you will have a greater force due to gravity, but a greater mass to accelerate.
Dear god man this has been done MANY times before.
You're not taking into account wind resistance and drag, which is proportional to the contact patches of the tyres and the frontal area of the rider.
A fat man may weigh 50% more than a skinny man on the same bike, with the same pressure in the tyres, but his frontal area will probably only be 25% larger as will the tyre contact patches.
The fat man is therefore subject to proportionally more accelerative forces than the skinny man, thus his terminal velocity without pedalling will be higher!!!
PLEASE only enter into scientific arguments if you actually know what you're talking about...
EDIT: I have simplified this greatly, obviously there are many more variables in the equation, but the point is that gravity is not the only force acting on the rider, and as such, people with a greater weight to frontal area ratio (ie. fatties) go faster downhill.
So the fat man has a higher drag and more rolling resistance, and this will make him faster?
(Edit: drag, not CD)
42 mph recorded on a cateye computer on my old firemountain on a smooth and steep forest road binned it when I went for the brakes though. Bounced a long way in the nice soft gorse but was still a mess at the end of it, probably still over 20mph when I came off.
Got a road descent where I reckon 60mph is possible just need a spotter as it involves straight lining a corner. Very smooth quiet road in the middle of nowhere.
Please not again, someone make him stop!
Matt
shibbolath,look
http://en.wikipedia.org/wiki/Cycling_records
78 on the road bike.45 on the mtb.fire/gravel road.
63 on the flat on a road bike behind a truck.
that's km,not miles.
43 mph on the road, prob only high 20s/30 off road though.
48 mph down the minor road from Nant-yr-arian to Penrhyncoch one night, and have clocked 38 mph on the bottom of the moorland section of the Summit Trail there. Latter was a tad dodgy as there were sheep about doing their usual random sprints across the trail
Okay, I was talking rubbish.
Just did the maths though (will this get me banned?), and terminal velocity appears to be proportional (assuming identical CD) to the square root of area over mass, i.e. sqrt(A/M).
Assuming that increased mass results in simply a bigger person (same density just bigger in very dimension), then area will scale as M^(2/3).
This results in terminal velocity (if my maths is still good at this time of day) varying with M^(-1/6).
Therefore doubling mass gives ~0.9 times terminal velocity.
A gross simplification perhaps, but it's a bit better than fatter=faster.
A gross simplification perhaps, but it's a bit better than fatter=faster.
This pleases me... You may continue! 😉
49.8 according to my Garmin.
Arggg, doing too many bits of simultaneous maths..
Terminal velocity goes as sqrt(M/A)...
So for scaled up identical density people V_t = kM^(1/6)
Doubling mass leads to a 12% increase.
I'm trying to do something really quite complex at the same time as this, either this excuses my poor efforts at very basic aerodynamics, or I'm going to be spending the next month debugging a truly awful model as I'm in no state to be working...
Ive been eye watering fast whatever speed that is?
that depends if you were wearing goggles/glasses or not.
49.2mph according to cateye down Winnat's Pass on the road bike. Endomondo said 60!
58mph, 1995, Kona Hahanna, lycra, Corney Fell.
6 riders in full on tucks all registered between 55 -60mph on various makes of computer so I reckon it's as accurate as anything else.
We tried it again the next day in the wet and 3 ended up in hospital...
[url= http://app.strava.com/rides/14840179 ]If its not on Strava etc etc[/url]
76.7 kmh on road, with road bike - full tuck, spinning out the gears. Reckon the only way to go quicker is to find a steeper, longer hill and have an operation to pin my ears back
53 and a bit on Kirkstone pass on the roadbike. Awesome descent on this years' Fred Whitton. Hooning past other riders on the wrong side of the road with no regard for safety of any kind. 8)
MTB I have no idea. Maybe 40 with a favourable wind.
thanks folks always thought i was megaslow/self preservation so on yeti asr 7 with 2.35 tyres
on road 41.3
off road 30.2
the on road was passed by SO and daughter...........
Dunno exactly how fast but descending Ventoux I overtook an Audi I estimated doing 30+ mph fairly rapidly so maybe high forties? More excitingly I also overtook a roadie who very nearly shat himself on hearing the ridiculous roaring of my knobblies up his rear. He actually pulled over to let my only vaguely in control vibrating 26" mess hurtle past. I love disk brakes 🙂
51mph, Mammoth Mountain Kamikazi downhill run, circa 2003.
Long long long dead straight fire road at about 15% gradient.
I absolutely sh1t myself to be honest. I like going fast, but that was something else. Knowing that someone had recently died nearby (Earthquake Jake Watson) from a supposedly 50+ mph crash was enough to stop me trying any harder.
Seem to recall that some years ago the cops radar trapped a lad on the Berridale braes in Caithness at 70mph. Made the local papers - "lucky to escape a ban - blah,blah"
Just did 40 mph on me full suss cannondale (slicks) into a headwind down the Brae from Daviot to Inverness. Reckon 50+ would be possible in still conditions - in fact may go back and let you all know what the crack is, see if anyone could crack 70 on a road bike!!!!
A while ago to push the limit, on a hill from Mijas To Fuengirola in southern Spain
72kph on the back wheel for quite some distance... Kona Dawg supreme custom
A Mountainbiker Guide's greatest skill is to wheelie and manual everywhere if nothing else...
(Adrenaline seeking is fun but respect the limit)
Regularly cracked 40mph on the fireroad run-out on the blue at Avoriaz last week, verified by four of us with different speed devices (GPS and normal computer). Locals said 50 was possible if you cleared the small drainage gully jumps at speed. Fun watching them bottom out their DH rigs just on the shallow compression! Fastest on road was 57mph according to one of those matrix signs.
I've done 48 mph down Ripponden Bank on my XC bike, and only just beaten that by a tiny margin on my road bike. I once clocked just over 38 off road on a fire road but wouldn'nt want to go much faster than that....
Clocked 36mph yesterday, but I am going to try and top that judging by some of these speeds 😉
