How much faster would I do a Sportive in on a Carbon Bike?

[meic]

Lance Armstrong: It's not about the bike.

Nope, according to the US Anti-Doping Agency it was about the doctor and the medicine

Innocent until proven guilty eh?

Obviously you are guilty when you commit an offence, the courts are just incompetent in terms of speed and accuracy.

Nothing to do with Lance Armstrong, just that particular cliché.

PS: Is Osama Bin Laden still innocent?

[Tonyf33]

Seeing as the now legendary Dutch postie gave the Radobank boys a pasting on his pannier laden sit up and beg it certainly it is always more about the person than the bike
Enjoy again, I love watching this time & time again http://www.youtube.com/watch?v=VN54oOMVrXQ

I'll do the downhill test later today, I have the same computer fitted to the Prinny as my Spesh Globe Pro (flat bar) so it will be interesting...lol

[Ayesha]

Have you ever been out with a pro team in training?
As soon as cameras appear, they suddenly become hopeless and slow up to touring pace.
The postie just happened to be in the right place at the right time to get on telly.

[stewartpratt]

By not taking account of the rest of my point you are comparing cheese with apples I'm afraid. Doesn't matter how forgiving the bike is - if it encourages you to over do it at the start you will suffer later.

Sorry - I was just trimming the quote, but I did take it into account. My alu/carbon very much encourages enthusiastic riding, whereas my previous steel bike positively didn't - yet I still found the former left me in better shape. It's quite possible that keeping a good speed up a moderate hill on a lighter and stiffer bike is actually more efficient than falling into plodding speed on a heavier and less stiff bike.

[Graham O]

All things being equal, I see no reason why, when getting on a lighterweight bike, there is any reason to go off too quickly and suffer later in the ride. And on longer rides, although the ride is harsher, I certainly don't suffer for it any more the next day than on the steel tourer.

[Tonyf33]

Have you ever been out with a pro team in training?
As soon as cameras appear, they suddenly become hopeless and slow up to touring pace.
The postie just happened to be in the right place at the right time to get on telly.

So the obvious exertion/effort was all in my mind then? I've watched pros 'in training' and I know what effort looks like and that is hard to falsify in any case. Whilst I'm sure they weren't all out it was a funny video which given the discussion I thought was fairly relevant, shame some are unable to take it for what it is!

[stewartpratt]

All things being equal, I see no reason why, when getting on a lighterweight bike, there is any reason to go off too quickly and suffer later in the ride.

My faster bike only really comes alive when it's in the big ring and doing at least 20mph, and it's also much easier to keep momentum up over undulations to keep the speed up anyway. It just incites you to put the hammer down, it feels lively where its stablemate feels reluctant and indifferent.

It's a combination of weight, stiffness and geometry, but bikes seem to have a curve of "grin against effort" - and those bikes where the graph rises steeply somewhere above pootling effort are the ones where you're naturally more inclined to find yourself shifting up gears insetad of down.

IME.

[Graham O]

My faster bike only really comes alive when ......... etc etc

IME.

I agree completely. It was really just the comment above that on a faster bike you WILL set off too fast and suffer later. I have found on the tourer, that if I try to ride it aggessively, then I suffer for it. In other words, you get fit and strong at riding one bike in a typical manner and if anything changes, (health, energy, bike, style) then you may get "sub optimal" results back.

On a fund raising ride from Manchester to Chester last year, a guy on a carbon bike looked at my steel tourer with rack pack, lights and mudguards and asked if I was going to be all right doing 50 miles on a heavy bike? Leaving 10 minutes before the end of the start window, he never did pass me.

[Si]

Don't get hung up about it Graham, it was intended as a humorous story....not as serious training advice or an account on which one should base the purchase of a several £K bike

If you ride a flash bike and find it improves the enjoyability of your cycling then good for you - nothing wrong with that!

[Tonyf33]

Right test done, knackering as I was out delivering charridy magazines on the bike this afty too so gettng back up the hill was a chore. Tests done within 25 minute window, Computer is Raleigh Echo W1

Bike 1: Principia Rex Ellipse Project, Wheels Mavic Ksyrium SSC 20/18 bladed spokes, Schwalbe Stelvio Light tyres. Total Weight 111.6kg Seat height from floor 102cm, hood height 95cm
Wind Speed very light 0-3mph
Average terminal velocity 30.4mph

Bike 2: Specialized Globe Pro (Flat bar) Ultegra/Open pro rear, Sansin sealed/Mavic MA2, 25mm Gatorskins + wide mudguards. Total weight 117.8kg (including panniers, large front light & heavier shoes). Seat height 101cm, top of grip height 97cm
Wind Speed very light 0-3mph
Average terminal Velocity 29.9mph

Conclusion, I'm faster going downhill on the race bike with no pedalling despite the weight 'advantage' of the Spesh

[Vorpal]

How many samples did you take? I'm not convinced that the difference is statistically significant.

[Tonyf33]

How many samples did you take? I'm not convinced that the difference is statistically significant.

Enough!

[fatboy]

How many samples did you take? I'm not convinced that the difference is statistically significant.

Enough!

Especially with all the pot-holes on that road!

[iandriver]

Average terminal velocity 30.4mph


Average terminal Velocity 29.9mph

Baldock Lane descent.JPG

Sounds about right. If you are racing in the alps, that half a mile an hour is priceless. Personally believe lightweight bikes are faster, it's by how much that seems to be the contention, it's not way faster. I've seen so many people in the club buy uber bikes and be disappointed they haven't shot off like a rocket.

[[XAP]Bob]

In theory it make no odds what the mass of a bike is when going downhill.

Of course that ignores two things:

Friction
Air resistance

Friction tends to increase linearly with load, but far more significant is the quality of the bearings - a "race" bike will likely be fitted with better bearings.

Air resistance increases by the cube of speed and has no relationship with mass - different bikes of course have different aerodynamics and encourage different body positions.


The reason a heavy bike is "faster" downhill is that the same aero force is applied to a larger mass, and therefore has a reduce effect. The only fair test of course is to set yourself in plaster and then add wet sand into the tubes on half the runs



Going on the flat the same applies (you'll roll further if you weigh more), but there is no benefit to top speed for a given power input (although it will take longer to accelerate a heavier vehicle (noting the differing effects of mass on moving parts)


Going uphill then a heavier bke will, for the same power input be slower.

Of course as the results above show the difference in the all up weight is only a few percent - not a huge factor anywhere.