Hmm that WOUld have ben beter wiv raNdom CAPs and no grammer
Anyway those of you that really have done 60mph on a road bike - I salute you
Bike Forum
Compared to the slowest descenders in the peloton - how would most of us compare
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Posted 10 months ago #
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Buzz-lightyear - Cadel didnt win two world cup races - it was two world cup series that he won.
Posted 10 months ago # -
Yes of course we would be shite but I think the relative position still exists further down the food chain. When I go out with my roadie mates several of whom are good triathletes, they thrash me into tiny pieces on the climbs but on the downs they are like a pensioners bingo outing. They do realise this and are taking lessons from a motorbike racer in an attempt to go down faster [oops]. Unfortunately the time I lose flogging up a big long climb is far more than they lose going down, still it's nice to be in front once or twice a day.
PS wouldn't disc brakes allow everybody to descend faster?Posted 10 months ago # -
Careful now, things of different masses will roll down the hill in the same time. It's just the ratio of mass to surface area that causes heavier riders to go quicker.
I think
That's what I am saying. Taking arbirtary units, that ratio would be 1:1 in any given rider, and 4:9 in a rider twice the height.
Posted 10 months ago # -
I have peaked at 55mph riding off the Mendips on a tt bike with tri bars using 55x11. The fastest I have done was 60mph coming off Dartmoor after the finish of the Devil Audax
Posted 10 months ago # -
We'd be rubbish and slow, just like trying to keep up with Cav on the climbs, he'd still hand you your ass
Posted 10 months ago # -
Mph. The first few bends down have reasonable straights before the next village bit.
You can get 60 mph down a small hill in to Otley, Leeds too its not really the length that matters its the steepness and getting speed up quick.
Posted 10 months ago # -
Re the Physics
Lets put two rider with the same bike at the top of the same hill.
With no air resitance, the only work they receive is the work of gravity:
for rider one:
1/2m1*Vendofthehil²=m1*g*height of the hill
for rider two:
1/2m2*Vendofthehil²=m2*g*height of the hill
As you can see you can remove the weight in both equation, therefore they will it the bottom at the same speed.
Now perform this on earth you must add wind resistance: F 1/2*S*C*V².
so for rider one:
1/2m1*Vendofthehil²=m1*g*heightofthehill-1/2*S*C*V²
and for rider 2
1/2m2*Vendofthehil²=m2*g*heightofthehill-1/2*S*C*V²Which arise the question, whom, of the two rider has the biggest S*C coeff
Posted 10 months ago # -
I have done one big alpine pass. I was descending at 50 ish mph in places, these guys do 70 mphish.
None of us could get close to them
Posted 10 months ago # -
C.Boardman, I think, attributed Cadel's excellent descent yesterday to his mountain bike skills
well Chris Bordman is talking out of his arse as the two skills are very very different. Was Lance MTBer first? Was Salvodeli, Hushovd, Spartacus? Cadel is a good descender because he has those skills and no doubt works at them having been a top mtber has no influence on it at all. Millar was a BMX racer and mtber in his youth and was shocked by the speed of the descending in the pro races.
Its just a lazy line that presenters use.Posted 10 months ago # -
On an inclined plane a riders weight will have an effect on how quickly they accelerate horiontally (it's not the same as freefall), a smaller rider however will be likely to be more aerodynamic, and will thus have a higher "terminal velocity".
Gravity Assisted tarmac racing anyone?
Posted 10 months ago # -
Oloivered - nope - the bigger rider will go faster as they are heavier. The increase in weight is greater than the increase in air resistance.
Try free-wheeling downhill alongside a mate - the fatties go faster - thats why tandem are a lot faster downhill - 60% higher terminal velocity
Posted 10 months ago # -
TJ is right - this time
Posted 10 months ago # -
I agree fatties accelerate faster, and this has the larger effect. (Probably wasn't clear on this before) but the terminal velocity is dictacted solely by the drag and eventually would favour the skinnies (altough this is probably a long way past where mortals fear to tread)
Posted 10 months ago # -
Do all pro roadies spend a lot of time descending ?
Do they all go off training in mountains etc ? (can't be for the altitude benefit, since their haematocrit is "optimal" anyway)
Surely it's not that helpful for the majority of races (or are there one day pro races that go up & down mountains ?)
Posted 10 months ago # -
Well yesterday's tour stage went up and down a mountain, as did today's, and tomorrow's goes up three mountains and down two. So I'd say it's a pretty helpful skill to have, yeah.
Every stage is a one day race, winning a stage on the tour is bigger than most one day races (classics and monuments excepted).
Posted 10 months ago # -
so, here are the assumptions on my part:
in a really good pro's year there might be what, twenty or possibly thirty big mountains (if they ride 2 big tours) ?
of all riders in the big tours, maybe 5-10 can REALLY make a big showing there
if descending skills probably hardly ever actually win races (look at today - 20 secs to contador and then he got caught by a chaingang), the only way it's worth picking them up is as a side-effect of climbing long hills, rather than training specifically
I reckon if I was in charge I'd make my team concentrate on riding flat & rolling stages rather than poncing about on big mountains, unless I had a genuine GC contender or an already proven climber
if these assumptions are true, why/how do pros learn to descend so much better than amateurs ?
Posted 10 months ago # -
I'm about 4/5 stone heavier than my mate, i always roll faster than him, by quite abit too. In general I find it much easier to get away from or to overtake him on a downhill, conversely he destroys me uphill by a huge margin, it really doesn't balance itself out in that respect!
so if it's noticable on rough mtb ground, the difference on the road must be much more pronouced.
Posted 10 months ago # -
I agree fatties accelerate faster, and this has the larger effect. (Probably wasn't clear on this before) but the terminal velocity is dictacted solely by the drag and eventually would favour the skinnies (altough this is probably a long way past where mortals fear to tread)
Terminal velocity is a free falling term I think, so not to get confusing I'll say max velocity.
Max velocity occurs when acceleration = 0 - the forces are balanced. So you will have a weight component, and an air resistance component.
The rider with the bigger weight will be able to go faster if the air resistance is the same between both riders.
If it's different, then it depends on how different it is, but in real life, I think bigger riders have a higher maximal velocity - within reason.
Posted 10 months ago # -
So whoever is more dense can go down hill faster?
Posted 10 months ago # -
Posted 10 months ago #
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On the tandem we have twice the mass but only the same wind resistance as I do on a solo. we go much faster downhill. s a slope I hit 40+ on the solo we hit 50+ on the tandem- both times reaching terminal velocity for that slope
Logic as real man says
Posted 10 months ago # -
Following two mates on a tandem down Kirkstone doing the Whitton a few years back we klicked 58.9mph i would have not gone that fast if i had not been in the slip stream Tandems rock down hill.
Posted 10 months ago # -
As far as I'm aware 50mph (or 60mph) is the same speed wether you do it on the Quantocks or the Alps, and it still surprises me that people post on here that they've never been faster than 45mph etc.
Posted 10 months ago # -
I think i'd go faster if people didn't keep calling it terminal velocity.
Posted 10 months ago # -
So whoever is more dense can go down hill faster?
Yep, a 15st muscle man will be faster than a 15st lardy, in theory.
Posted 10 months ago # -
I have two points to make 1:ex mtbers are better descenders my arse and secondly most people on here talk complete shite about anything relating to road riding.
YOU WOULD ALL BE SHIT COMPARED TO THEM ALL end of storyHave you read the thread? No one is actually saving normal riders would stand a chance.
PS wouldn't disc brakes allow everybody to descend faster?
A good set of road brakes can lock up the wheels fairly easily, why would you need any more than that? Suspect the amount of usable power from discs would be pretty minimal as you really don't want to lock brakes on the road. Guessing they will start appearing on low end bikes soon as they will be a lot more confidence inspiring than crap road brakes for new riders.
The pros will have trained how to corner at some point in their career, the descending skills will come from that and time spent doing it. If a pro was so slow they were always getting dropped they either wouldn't get a team ride or would be given training to sort it out.
Posted 10 months ago # -
if these assumptions are true
they are not end of story. Whilst being shit hot at descending can not often win you a race being shit can easily stop you winning it.
Just look at the places most pro' choose to live and train to get an idea of the terrain they train on. Some of the one day races have some terrifying descents on cobbles for example, you need skill to ride them even if they are not super long alpine descents.Posted 10 months ago # -
A good set of road brakes can lock up the wheels fairly easily
In the rain? I doubt it.. admittedly I only have 105 brakes but in reasonable rain I pull the brakes and literally nothing happens at all for a good ten or twenty yards. I'm guessing it could be different with new rims, new blocks, and dura ace though.
Posted 10 months ago # -
In the rain? I doubt it.. admittedly I only have 105 brakes but in reasonable rain I pull the brakes and literally nothing happens at all for a good ten or twenty yards. I'm guessing it could be different with new rims, new blocks, and dura ace though.
Ultegra ones don't seem to have much of a problem with it. Then again, in the rain I will be pulling the brakes on early and really trying not to lock up. Haven't had the same 'shit, I'm not stopping' moments I used to get with Tiagra brakes anyway.
Posted 10 months ago # -
I have done one big alpine pass. I was descending at 50 ish mph in places, these guys do 70 mphish.
Yeah, but they have drop bars and an aero position. See also how them hitting 60+ regularly (let alone 70) is BS. Anyway, it's not the speed on the straights that's the issue, it's the speed they corner at (and managing that for 15-20 minutes continuous when knackered from the climb).Posted 10 months ago # -
I'm way too scared to go past about 45 kph on any bike in any kit on any surface/trail.
Posted 10 months ago # -
... although we would all easily be faster than Andy 'Boo Hoo, Pedallling Down a Big French Hill is Really Dangerous' Shrek
Wouter Weylandt RIP. This may be why they are a little sensitive.
No one here would touch the slowest in the peloton.
Haven't had the same 'shit, I'm not stopping' moments I used to get with Tiagra brakes anyway.
Change of pads and a degrease of the wheel rim sorted my 105s that were a little tame to start with. Still not brilliant in the wet, but I mince about in the rain anyway.
Posted 10 months ago # -
if these assumptions are true, why/how do pros learn to descend so much better than amateurs ?
They ride a lot more than amateurs. See if you can find the GPS tracks of the pros in training on Strava or a similar site; they really do put the miles in and if they're going up hills, they're coming down a lot too.
Posted 10 months ago # -
Stokes theorem states that for a sphere falling througha viscous liquid the terminal velocity is proportional to the radius.
It proably not too hard to go from there to the idea that larger riders will reach a higher terminal velocity than smaller riders, all other things being equal
Posted 10 months ago #
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