Over 50 mph??

oldwelshman

Most important factors in order of effect on speed:
1) Gadient and length of slope (presuming no bends!)
2) Wind resistance ( affected by weather and your position.
3) Rolling resistance ( least resistance on good smooth surfaces and with decent tyres and wheels)

If you realy want to improve your top speed on your particular hill, go with someone else and sit behind them about 2 bike lengths and as they hit max speed you will still accelerate due to slip stream and go past them, even without pedalling.

nasahapley

teagar wrote:

How much does weight make a difference?

I'm a weenie 56kg and always get dropped on the descent. I like to think it's my weight, but I might just be rubbish.

Happens on all decents -technical or not.

Hi teagar,

The question of how weight affects the top speed you can reach on a descent was dealt with in this thread: http://www.bikeradar.com/forums/viewtop ... sc&start=0

In a nutshell the terminal velocity you'll reach by freewheeling on a descent is proportional to the square root of your mass, so all else being equal a heavier rider will descend quicker than a lighter one. Of course in the real world all else isn't equal - heavier riders will also be bigger (with a greater frontal area) and so be subject to greater air resistance. However, it will usually be the case that a bigger rider's greater mass will more than offset the increased air resistance they are subject to. You can compensate by working on your aero tuck, but the fact remains that physics is unkind to lighter riders on descents (it also takes a hell of a lot more power for every extra mph at, say, 40mph than it does at 20mph).

Console yourself by flitting past us 80kg+ carthorses on the uphills!

nosmo-king

I mentioned in an earlier post that I just topped 50mph about twenty odd years ago. Looking back now it seems scary. I tend to brake at 30- 35mph now just to keep in control.
A gust of wind or a pothole or could have drastic consequences, so being older and wiser ( that's not saying much!) I'll stick to a safe speed.

Climber_Andy

Did 49mph down either Bulmer Bank or Terrington Bank in a TT, presumably the latter and with a tailwind. Still not sure if that's right, but then again, it is pretty steep. Only found out at the finish... rest assured, if I'd known, I'd probably have grabbed for the brakes

dennisn

sub55 wrote:

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What are we looking at here?

Dennis Noward

kettrinboy

like quite a few on here i,m stuck at about 42/43 mph which ive done several times ,here in Northants there are loads of short steep hills but no long steep hills , unless ive missed one,which you need to get over 50 from where i live in Kettering it looks like i would have to get up to Derbyshire to find any hills like that

kettrinboy

like quite a few on here i,m stuck at about 42/43 mph which ive done several times ,here in Northants there are loads of short steep hills but no long steep hills , unless ive missed one,which you need to get over 50 from where i live in Kettering it looks like i would have to get up to Derbyshire to find any hills like that

STEFANOS4784

hipjazzcat wrote:

Out on a ride in Australia i was giving it large portions on a nice descent at around 82kph when i was overtaken by a kid about 16 years old. He looked across at me, gave me the peace sign and left me for dead. At the bottom of the descent with a busted ego i had a massive reality check and realised i just dont have what it takes to be a race winner. Still enjoy the riding but just descend slower.

:roll: righto, so you were going in excess of 50 mph and some kid past you??? With one hand off the bars :roll: Pics/ vids please :roll:

feel

STEFANOS4784 wrote:

:roll: righto, so you were going in excess of 50 mph and some kid past you??? With one hand off the bars :roll: Pics/ vids please :roll:

I can just imagine hipjazcat being overtaken thinking "WTF - hold on a minute, i'll get my video camera out and film this youth"

STEFANOS4784

Sorry but is quite un-believable :roll: Probably me just being an un-trusting cynic though :oops:

trickeyja

Beat my record speed today - 46.7 down Leckhampton Hill - such a rush!!!

I am in the process of gaining confidence round that critical corner... I am sure that hill has 50mph potential in the right conditions.

Richard891

Breaking your top-speed record is always good, but please be careful posters! Would suggest that you know the descent well. Even roads you've been down before can be dangerous, say if farmers have been in and out of a field a few times or you suddenly find yourself behind and much slower vehicle or a car driver tries to overtake you (there's a cyclist! must get past him!) despite your speed or some gravel or a new pothole appears.

Also good to avoid looking at your computer on the way down, get one that logs the top-speed for you!

I was doing a few hill climbs on the Church Rd out of Hollywood (Northern Ireland) in the summer and enjoying the descents, think I hit 47mph once, but one time got the speed wobbles. I've had this a couple of times on my bike (Giant SCR 2) and have both times managed to steady her up by gripping the top-tube with the inside of my thigh.

The wobble on the Church Rd scared the be-flipping jeezus out of me though and I started thinking about how stupid I would feel having done loads of hard training, got myself fit etc. if I was to come off at speed and wreck myself and my bike and have to spend the rest of the summer watching big brother or some crap.

Fair enough if you're a pro and you have to take such risks to win races, even then, they have the benfit of closed roads.

Not worth chasing it too hard IMHO

alfablue

I used to top 50mph coming down Bannerdown Hill in Batheaston, thinking the bend was fun as it took some skill - having broken my pelvis coming off at 20mph I now think I was stupid!

Bengdogg

I once did 42mph off road on my mtb down hill but the best ive had out of the road bike is 41.9 even with longer gearing than the mtb (50/12Road and 700c tyres vs 44/11 on the mtb with 26" tyres) its all about how fast you can roll, the hill i was mtbing down was a very long flowing track that was steep as hell, i do remeber thinking in I f**k this up im gonna die lol

Jez mon

nasahapley wrote:

teagar wrote:

How much does weight make a difference?

I'm a weenie 56kg and always get dropped on the descent. I like to think it's my weight, but I might just be rubbish.

Happens on all decents -technical or not.

Hi teagar,

The question of how weight affects the top speed you can reach on a descent was dealt with in this thread: http://www.bikeradar.com/forums/viewtop ... sc&start=0

In a nutshell the terminal velocity you'll reach by freewheeling on a descent is proportional to the square root of your mass, so all else being equal a heavier rider will descend quicker than a lighter one. Of course in the real world all else isn't equal - heavier riders will also be bigger (with a greater frontal area) and so be subject to greater air resistance. However, it will usually be the case that a bigger rider's greater mass will more than offset the increased air resistance they are subject to. You can compensate by working on your aero tuck, but the fact remains that physics is unkind to lighter riders on descents (it also takes a hell of a lot more power for every extra mph at, say, 40mph than it does at 20mph).

Console yourself by flitting past us 80kg+ carthorses on the uphills!

This is all correct, however, I do find that with a bit of effort, I can keep up with most of my club on descents despite me being 55/56 kgs. However, in order to do this you have to get pretty compact, which is uncomfortable and dangerous. I once went over a load of gravel at 40 tapped the brakes and found I was skipping all over the road...nearly s*** myself. Sat right up and my body's area managed to slow me down to 30 ish and I regained control. The key thing with descending, and cornering, at any speed is to be aware of road conditions, on a nice day, on a good gravel free road, you can go very fast round corners with no worries. But in bad conditions it can go very wrong, very quickly

hipjazzcat

STEFANOS4784
Sorry mate cant give you a video of me being overtaken. But heres the lat and long of the hill. 32"53'26.36" S 151"32'21.54" E. Have a look on Google Earth Its a place called Mt Sugaloaf (Sugarloaf Range Rd) outside of a town called Newcastle Australia. The Rd is often closed in the summer to vehicles and all sorts of cyclists get up there to give the hill a run. With a tail wind stupid speeds are possible. Is the reason you doubt it happened because perhaps you couldnt do it? Oh for the record, the dude who passed me went on to podium finish at the Aussie titles in downhill MTB so he was no mug on a bike.

hipjazzcat

STEFANOS4784[/b] Sorry but is quite un-believable Probably me just being an un-trusting cynic though

Sorry mate cant give you a video of me being overtaken. But heres the lat and long of the hill. 32"53'26.36" S 151"32'21.54" E. Have a look on Google Earth Its a place called Mt Sugaloaf (Sugarloaf Range Rd) outside of a town called Newcastle Australia. The Rd is often closed in the summer to vehicles and all sorts of cyclists get up there to give the hill a run. With a tail wind stupid speeds are possible. Is the reason you doubt it happened because perhaps you couldnt do it? Oh for the record, the dude who passed me went on to podium finish at the Aussie titles in downhill MTB so he was no mug on a bike.

STEFANOS4784

hipjazzcat wrote:

STEFANOS4784[/b] Sorry but is quite un-believable Probably me just being an un-trusting cynic though

Sorry mate cant give you a video of me being overtaken. But heres the lat and long of the hill. 32"53'26.36" S 151"32'21.54" E. Have a look on Google Earth Its a place called Mt Sugaloaf (Sugarloaf Range Rd) outside of a town called Newcastle Australia. The Rd is often closed in the summer to vehicles and all sorts of cyclists get up there to give the hill a run. With a tail wind stupid speeds are possible. Is the reason you doubt it happened because perhaps you couldnt do it? Oh for the record, the dude who passed me went on to podium finish at the Aussie titles in downhill MTB so he was no mug on a bike.

I did say on a later quote it was probably me being an un-trusting cynic, but 1 hand c'mon that's pretty messed up, he must have been going 55mph at least, and you only said he was "some kid". Apologies if i offended :roll: