What makes a fast bike fast?

[mikesbytes]

Back on topic. Last year I did the NSW Masters ITT champs on a road bike with clip-ons, then I borrowed a TT bike and some head 3 spoke wheels, took them down to Victoria for the Australian Masters ITT champs. Carefully comparing the data with the other NSW riders I concluded that I was 3/4 kph faster on the ITT / tri spoke than my road bike with clip-ons.

A TT bike alone will trump a road bike with clip on bars every time simply because of a better aero position you can achieve on a TT bike (assuming the set up is correct). I'm not sure about 3-4 km/h difference though. You could be comparing apples with oranges, e.g different weather/road conditions, different form/fitness level , different distance (perhaps) etc.

Sorry by 3/4 I mean 0.75

A lot of analysis was done to determine this figure and cross check it

Ride position was the same, the only difference of note was 0.25mm of crank length.

Anyway the point was that for me, no bike was going to make the 4kph being looked for

[ValleyForge]

A lot of analysis was done to determine this figure and cross check it

Ride position was the same, the only difference of note was 0.25mm of crank length.

Oh noooo! Now the thread will all be about crank length I suppose it's better than being about chain lube.

[Nobody]

Oh noooo! Now the thread will all be about crank length I suppose it's better than being about chain lube.

And cadence.

Since you mention it.
[hijack]

My favorite articles on crank length:
http://www.ecovelo.info/2010/04/19/taki ... nk-length/
http://www.pezcyclingnews.com/?pg=fullstory&id=8845

I run 165 or 170mm cranks on all my bikes.

[/hijack]

[Nobody]

... assuming the set up is correct...

I often wondered how people know their set up is correct? All without objective wind tunnel testing. Every one have developed the eyes of an aerodynamic engineer?

I thought it would be as easy as a flat piece of ground, a windless day, a computer and a power meter. Just trial and error.

[toolonglegs]

2.5 mm ... 0.25 mm is not much

[ni78ck]

... assuming the set up is correct...

I often wondered how people know their set up is correct? All without objective wind tunnel testing. Every one have developed the eyes of an aerodynamic engineer?

you need to sit comfortably on a bike to rode fast as well. its pointless being in an aero position if it is unsustainable for a period of time.

[Alex Simmons/RST]

Nothing....bikes don't go anywhere without a rider pushing the pedals. There are many factors that go into why one bike feels faster than another, eg. fitting. Wheels make a difference but it's marginal.

Sorry, I disagree. For reasons the LBS Owner doesn't want to discuss, I rode my frame on consecutive days with two wheelsets, Mavic Kysrium SL vs Mavic Cosmic SL, which negated my positon related aerodynamics.

Both days I rode the same route home to get a clear idea of the difference between the two. Both days I rode into a headwind with the Cosmics copping a 5kmh stronger breeze (15-20kmh vs 20-25kmh). Both days I rode at the same time of day.

The results? The Cosmics delivered a 3kmh faster average speed into a stronger headwind.

Not bad for a flimsy Corbon Fibre fairing!

Well a few uncontrolled variables there, but having said that, it wouldn't be hard for any wheel to be somewhat better aerodynamically than a Ksyrium, which is one of the worst wheels, aerodynamically speaking. It's a good wheel otherwise.

[Alex Simmons/RST]

Back on topic. Last year I did the NSW Masters ITT champs on a road bike with clip-ons, then I borrowed a TT bike and some head 3 spoke wheels, took them down to Victoria for the Australian Masters ITT champs. Carefully comparing the data with the other NSW riders I concluded that I was 3/4 kph faster on the ITT / tri spoke than my road bike with clip-ons.

Perhaps, but too many uncontrolled variables to make any firm conclusion. The error bars would be larger than the difference you are suggesting.

[kosh]

I put new Zipp bar tape on and I swear the dimples are making me faster.

[Nikolai]

... assuming the set up is correct...

I often wondered how people know their set up is correct? All without objective wind tunnel testing. Every one have developed the eyes of an aerodynamic engineer?

Life without wind tunnel testing and power meters, imagine that...

[Nikolai]

Ride position was the same, the only difference of note was 0.25mm of crank length.

2.5mm you mean? At any rate, this would be kind of hard to achieve, the same position I mean. TT bikes have different frame geometries with a steep seat tube and a more rearward BB. Front end is different too but also the cockpit set up of a TT bike is impossible to replicate on a road bike with clip on bars and this is one of the most important areas to get right for better aerodynamics.

[mikesbytes]

Agree that body position is particularly important to good aerodynamics. I did a lot of work on getting that position right for me (ok I didn't have a wind tunnel) and that contributed to me taking Bronze in NSW. When I borrowed the TT bike it was so much easier to setup

[steveo]

So would I be better the campagnolo eurus at 1500 grams or heavier campagnolo bullet 50 carbon clincher at 1750 grams. I was always chasing lighter maybe aero would be better?

[Mulger bill]

Depends what you're doing Steveo, lighter is better in the hills or if there's lots of speed changes.

[ValleyForge]

Depends what you're doing Steveo, lighter is better in the hills or if there's lots of speed changes.

+1. I'd add direction change in there too. Ploughing down a twisty mountain with high profile aero wheels always feels to me like trying to steer a container ship. Most city rides with a bit of drafting I think are better with medium to low-profile wheels. Course/highway/long straight/solo - then high profiles would be better.

I know there are exceptions to the rule - I've got a couple of friends who swear the new Zipp Firecrests are fine for the twisty/speed up/slow down stuff for example.

[ray]

So would I be better the campagnolo eurus at 1500 grams or heavier campagnolo bullet 50 carbon clincher at 1750 grams. I was always chasing lighter maybe aero would be better?

Or the bullet ultra 50 instead?

[Cardy George]

Depends what you're doing Steveo, lighter is better in the hills or if there's lots of speed changes.

+1. I'd add direction change in there too. Ploughing down a twisty mountain with high profile aero wheels always feels to me like trying to steer a container ship. Most city rides with a bit of drafting I think are better with medium to low-profile wheels. Course/highway/long straight/solo - then high profiles would be better.

I know there are exceptions to the rule - I've got a couple of friends who swear the new Zipp Firecrests are fine for the twisty/speed up/slow down stuff for example.

I'll second that. The Ksyrium SLs I mentioned earlier accelerate like a cut cat compared to the Cosmics I run now

[BarryTas]

the word "fast" makes the fast bike fast



it did read "fats"

[ratter]

the word "fats" makes the fast bike fast

wow, so if I put some "fats" stickers on my bike it will become faster



sorry could not help myself

[Pedal-Pusha]

Personally i have found :
rolling resistance ..tire pressure , tire manufacture and rims . Ie: the difference between Fulcrum racing five vs Fulcrum racing zero
Seated position
stiffness of frame

The are so many variables from bike fit , to route taken , wind , ect ect .
Some swear by ceramic bearings , like myself , or those who only run carbon rims.

I believe get a pro bike fit done to your Ridley , get a full strip and rebuild , get your shoes pro fit done and then put pen to paper and work out if the difference in cubic dollars.
I have owned a 2010 Damoclese and it was a brilliant bike , it did get better after a pro fit up.

[donncha]

That's the plan. I had a pro bike fit anyway, but the bike is due for a strip & rebuild so am going to book that in. Also planning a nice pair if wheels for some extra zing

[Pedal-Pusha]

If you do some research into your model Ridley you will find that it was the last of the Noah re badged , prior to the new Noah shape , so your foundation is good .
Your feet and position effect how your knees run / valgas /vargus will determine how your feet/hips/back work prior to seat adjustment stack height angle of the bars ect.
for $250-$350 for a pro fit it is money so well spent when your bike works properly

[Parrott]

For the two bikes compared by the OP it is the wheels making the most difference. IME carbon wheels are noticably faster. They tt faster and I am fresher at the end of a handicap race using them, have to be blowing a gale before I'd swap them out.

[BarryTas]

Back on topic. Last year I did the NSW Masters ITT champs on a road bike with clip-ons, then I borrowed a TT bike and some head 3 spoke wheels, took them down to Victoria for the Australian Masters ITT champs. Carefully comparing the data with the other NSW riders I concluded that I was 3/4 kph faster on the ITT / tri spoke than my road bike with clip-ons.

A TT bike alone will trump a road bike with clip on bars every time simply because of a better aero position you can achieve on a TT bike (assuming the set up is correct). I'm not sure about 3-4 km/h difference though. You could be comparing apples with oranges, e.g different weather/road conditions, different form/fitness level , different distance (perhaps) etc.

Sorry by 3/4 I mean 0.75

A lot of analysis was done to determine this figure and cross check it

Ride position was the same, the only difference of note was 0.25mm of crank length.

Anyway the point was that for me, no bike was going to make the 4kph being looked for

interesting.....

i have done both a 20km TT and a 60+km TT on a top of the line TT bike with pointy helmet, shoe covers tri spoke wheels - and a top of the line roadie with, tear drop helmet, shoe covers and some 404s.............. each time the roadie smashed the TT bike. the TT bike was set up for me (it was borrowed) but the roadie is about 2kgs lighter

[Parrott]

interesting.....

i have done both a 20km TT and a 60+km TT on a top of the line TT bike with pointy helmet, shoe covers tri spoke wheels - and a top of the line roadie with, tear drop helmet, shoe covers and some 404s.............. each time the roadie smashed the TT bike. the TT bike was set up for me (it was borrowed) but the roadie is about 2kgs lighter

Were you riding a hilly course?
My tt bike is minutes faster over a 40 k tt than the roadie on a flat course.