Aero - don't believe the hype?

charlie_potatoes

Simon Masterson wrote:

6.8kg bikes are underengineered enough as it is.

How sure are you about this Simon?


Just wondered

Strith

Charlie Potatoes wrote:

Simon Masterson wrote:

6.8kg bikes are underengineered enough as it is.

How sure are you about this Simon?


Just wondered

I would also like to know where people come up with this stuff. How can you suggest a bike is underengineered based soley on its weight. I don't see people on lightweight carbon bikes stuck at the side of the road everywhere because they're bikes have suddenly failed.

As already said, the gains available from lightweight or aero bikes are small and sometimes insignificant for some people, but thats not to say manufacturers claims are not valid. If a frame saves you 10W at 40kmh or could help you climb a hill 10s faster then it is what it is. How people use that information is up to them.

When it comes down to it if people can afford fancy 'high performance' stuff they will buy it. I don't see a problem with that.

bernithebiker

It's the fake claims that cheese me off though. 30w here, 20w there - if you picked the stuff with the most lary claims you would only need to produce 100w to ride at 40km/h all day long....!

Strith

If they are making fake claims then I'd agree with you, but I've not seen any. What are the lairy ones you mean, I'm honestly curious as to how sneaky they may be.

All the manufacturers whose websites I've read state that their tests are done wind tunnels, as you would expect. If people interpret that incorrectly, well thats their own fault.

VTech

Strith wrote:

If they are making fake claims then I'd agree with you, but I've not seen any. What are the lairy ones you mean, I'm honestly curious as to how sneaky they may be.

All the manufacturers whose websites I've read state that their tests are done wind tunnels, as you would expect. If people interpret that incorrectly, well thats their own fault.

I was speaking to one of the guys in tech earlier today and we have had several bike companies use our wind tunnel, I never knew about this (I do work really) so I guess some take it serious.
Having said that, it is sometimes the case that companies test products and due to the amount of costs they have spent, they can be more willing to bend the results to aid sales.

Strith

Well giants propel marketing 'hype' claims you could be up to 36 seconds faster over a 40km TT at 40kmh when compared to what you could do on competitors 'aero' bike.

They're not really claiming you're gonna win the tour are they?

People need to apply a bit of common sense when they're reading this stuff.

keef66

36 seconds over an hour is a suspiciously precise figure which works out at exactly 1%. Marginal gains and all that bollocks!

bernithebiker

Strith wrote:

Well giants propel marketing 'hype' claims you could be up to 36 seconds faster over a 40km TT at 40kmh when compared to what you could do on competitors 'aero' bike.

They're not really claiming you're gonna win the tour are they?

People need to apply a bit of common sense when they're reading this stuff.

'Up to' is the classic advertising get out clause. (cf. Broadband up to 10Mb/sec......)

Given that Scott, Specialized, Cervelo, etc. all claim to have the fastest aero road bike, and now Giant saying theirs is 36 seconds faster still, you have to wonder where the truth is......

ShutUpLegs

It's the Boardman, Chris posted on here that the Geometry wasn't plucked out of Thin Air.

Strith

keef66 wrote:

36 seconds over an hour is a suspiciously precise figure which works out at exactly 1%. Marginal gains and all that ****!

Exactly my point. It's very little and at lower speed the gains are gonna be even less. Like I said they're not claiming you're gonna win the tour if you buy their bike are they. I don't see anything implausible in any of their claims. People need to apply some common sense.

The claim up to is just that, up to. If people have difficulty understading what that means it's their problem. I'm still waiting to see anything totaly unbelivable.

Grill

bernithebiker wrote:

Strith wrote:

Well giants propel marketing 'hype' claims you could be up to 36 seconds faster over a 40km TT at 40kmh when compared to what you could do on competitors 'aero' bike.

They're not really claiming you're gonna win the tour are they?

People need to apply a bit of common sense when they're reading this stuff.

'Up to' is the classic advertising get out clause. (cf. Broadband up to 10Mb/sec......)

Given that Scott, Specialized, Cervelo, etc. all claim to have the fastest aero road bike, and now Giant saying theirs is 36 seconds faster still, you have to wonder where the truth is......

Much of this is dependent on yaw angle. Some bikes are faster/more aero at different angles.

bernithebiker

This from Specialized;

The Venge’s competition-crushing combo of Tarmac-inspired stiffness and light weight with Shiv-inspired aerodynamics keeps them ahead of the competition.

This from Cervelo, (for the S5)

UNMATCHED AERODYNAMICS ALLOWS YOU TO RIDE FASTER

And yet the Giant claims to be 36 seconds faster than both. Someone's telling porkies.......

VTech

I think the real issue is that the true costing of finding out wether or not you have a great aero product is so high, it beggers belief that unless there was a potential to sell many hundreds of a certain model there would be a high risk of never being able to recoup the costs of design.
We are forever altering carbon only to find it does not improve dynamics and so the development is an ongoing process. I just dont know if these funds are spent in cycling ?
What I mean by that is in general, when testing aero dynamics we see around 3% positive compared to 97% failure.

philwint

bernithebiker wrote:

This from Specialized;

The Venge’s competition-crushing combo of Tarmac-inspired stiffness and light weight with Shiv-inspired aerodynamics keeps them ahead of the competition.

But which competition? They will be able to truthfully claim to be faster than a Carrera Tdf for example....

This from Cervelo, (for the S5)

UNMATCHED AERODYNAMICS ALLOWS YOU TO RIDE FASTER

...ride faster than you could on one of our cheaper less "aero" bikes for example....

And yet the Giant claims to be 36 seconds faster than both.

And it may well be

Someone's telling porkies.......

Not necessarily - as I've demonstrated, these could all be truthful and compatible statements... depending on what they are actually comparing with. It is all just marketing: find a comparison that favors your product and base some advertising on it.

I would hope that most bike consumers were sophisticated enought to see through all this.

You just have to be honest with yourself - my new bike has Ultegra Di2 on it. Not because i think it will go faster, or add any significant tangible benefit to me over standard ultegra. But because I think it's cool and I like the gadgetry of it, understanding that I made my value judgement. i.e. was that worth it for me, for the price?

simon_masterson

Charlie Potatoes wrote:

Simon Masterson wrote:

6.8kg bikes are underengineered enough as it is.

How sure are you about this Simon?


Just wondered

The most light frames are intentionally made without 'excess' material; any material that doesn't 'need' to be there isn't. The effect of this on the actual strength of the frame will be variable, but this is of course one of the benefits of carbon fibre monocoque construction. The hubs and rims that go on the lightest wheels aren't primarily made with durability in mind either. Whether or not some aspect of the bike actually fails in use doesn't really come into it; it is, in a manner of speaking, underengineered. You could easily put together a very fast bike with bits that will last for decades (excluding crash damage or neglect), but I doubt it would be the lightest.

charlie_potatoes

Simon Masterson wrote:

Charlie Potatoes wrote:

Simon Masterson wrote:

6.8kg bikes are underengineered enough as it is.

How sure are you about this Simon?


Just wondered

The most light frames are intentionally made without 'excess' material; any material that doesn't 'need' to be there isn't. The effect of this on the actual strength of the frame will be variable, but this is of course one of the benefits of carbon fibre monocoque construction. The hubs and rims that go on the lightest wheels aren't primarily made with durability in mind either. Whether or not some aspect of the bike actually fails in use doesn't really come into it; it is, in a manner of speaking, underengineered. You could easily put together a very fast bike with bits that will last for decades (excluding crash damage or neglect), but I doubt it would be the lightest.

So a 6.8kg bike manufactured by a large company and used by top teams in top races is under engineered?
Compared to what? A bloke in a garage who welds a few steel tubes together?

N.B. My apologies and respects to frame builders who work from their garage :oops:

VTech

I "think" maybe he was referring to build quality (strength) which of course isnt needed as much if you have access to replacement parts should an item fail.
Maybe in racing its more important to keep weight down that worry how long a frame will last ?

charlie_potatoes

VTech wrote:

I "think" maybe he was referring to build quality (strength) which of course isnt needed as much if you have access to replacement parts should an item fail.
Maybe in racing its more important to keep weight down that worry how long a frame will last ?

I see

But many major manufacturers are building bikes for sale that weigh around 6.2kg. So doesn't it follow that you can factor in greater reliability/longevity with the 'spare' 600 grams? A few extra spokes and a slightly heavier but stronger group set etc.
How long does a lightweight carbon frame last?
How often do steel frames fail?

And how long is a piece of string? (before anyone else asks)

VTech

Charlie Potatoes wrote:

VTech wrote:

I "think" maybe he was referring to build quality (strength) which of course isnt needed as much if you have access to replacement parts should an item fail.
Maybe in racing its more important to keep weight down that worry how long a frame will last ?

I see

But many major manufacturers are building bikes for sale that weigh around 6.2kg. So doesn't it follow that you can factor in greater reliability/longevity with the 'spare' 600 grams? A few extra spokes and a slightly heavier but stronger group set etc.
How long does a lightweight carbon frame last?
How often do steel frames fail?

And how long is a piece of string? (before anyone else asks)

Ohh, Im not trying to argue the case, I just dont know the answers or enough about the subject to be critical.
I know at work they they are happy to make a change on carbon development based on weight reduction but rule changes have meant that items need to pass strict strength testing so as to avoid the dangers of "light but weak" products being used.
I reckon this should be adopted to bikes if it is the fact that they are overly weak or dont stand up to rigourous usage. ?

smidsy

Charlie Potatoes wrote:

And how long is a piece of string? (before anyone else asks)

Now that one I can answer..it's twice the distance from its middle.

simon_masterson

VTech wrote:

Maybe in racing its more important to keep weight down that worry how long a frame will last ?

Exactly. Gear for the pro ranks only has to last a few races, if only just a single stage.

As for lightweight carbon frames, they can fail. Steel frames can also fail. I think both are great (though I only own the latter at present), but purely in longevity and durability terms, were I presented with an old steel bike and an old carbon bike, both of which had seen a great deal of active service, I would trust the steel one with my life more, simply because steel frames don't tend to fail suddenly like carbon ones do, and the signs of impending doom tend to be much more apparent. Steel also copes better with non-design loads, and is much more easily repaired (particularly if it's a lugged frame) than carbon fibre.

None of that would deter me from buying a carbon fibre bike, but if I had a choice of a 6.8kg all-carbon world tour level bike and an 8-9kg 953 bike with slightly heavier hubs and metal parts, I would have more long-term confidence in the latter. I'm aware that now I've said that someone will prove me wrong.

VTech

Simon Masterson wrote:

VTech wrote:

Maybe in racing its more important to keep weight down that worry how long a frame will last ?

Exactly. Gear for the pro ranks only has to last a few races, if only just a single stage.

As for lightweight carbon frames, they can fail. Steel frames can also fail. I think both are great (though I only own the latter at present), but purely in longevity and durability terms, were I presented with an old steel bike and an old carbon bike, both of which had seen a great deal of active service, I would trust the steel one with my life more, simply because steel frames don't tend to fail suddenly like carbon ones do, and the signs of impending doom tend to be much more apparent. Steel also copes better with non-design loads, and is much more easily repaired (particularly if it's a lugged frame) than carbon fibre.

None of that would deter me from buying a carbon fibre bike, but if I had a choice of a 6.8kg all-carbon world tour level bike and an 8-9kg 953 bike with slightly heavier hubs and metal parts, I would have more long-term confidence in the latter. I'm aware that now I've said that someone will prove me wrong.

I dont think anyone would/could try to prove you wrong. I purchased my bike as I like the look of it so my opinion in the whole is worthless but from a tech point of view carbon can be lighter but it wont give like metals will and on the whole I would punt towards the side of a steel bike for sudden knocks.

charlie_potatoes

A bit like a diesel family hatchback compared to a light weight sports car with a tuned K series engine.
The diesel is going to do everything that you need it to do and last for ages.
The K is going to need lots of TLC.

But when it comes to an early morning blat through the lanes............ 8)

VTech

Charlie Potatoes wrote:

A bit like a diesel family hatchback compared to a light weight sports car with a tuned K series engine.
The diesel is going to do everything that you need it to do and last for ages.
The K is going to need lots of TLC.

But when it comes to an early morning blat through the lanes............ 8)

The good o'l K series, brings me back to me yout

john1967

Get on the aero bus now,destination the future.You can't argue with physics.

simon_masterson

VTech wrote:

Simon Masterson wrote:

VTech wrote:

Maybe in racing its more important to keep weight down that worry how long a frame will last ?

Exactly. Gear for the pro ranks only has to last a few races, if only just a single stage.

As for lightweight carbon frames, they can fail. Steel frames can also fail. I think both are great (though I only own the latter at present), but purely in longevity and durability terms, were I presented with an old steel bike and an old carbon bike, both of which had seen a great deal of active service, I would trust the steel one with my life more, simply because steel frames don't tend to fail suddenly like carbon ones do, and the signs of impending doom tend to be much more apparent. Steel also copes better with non-design loads, and is much more easily repaired (particularly if it's a lugged frame) than carbon fibre.

None of that would deter me from buying a carbon fibre bike, but if I had a choice of a 6.8kg all-carbon world tour level bike and an 8-9kg 953 bike with slightly heavier hubs and metal parts, I would have more long-term confidence in the latter. I'm aware that now I've said that someone will prove me wrong.

I dont think anyone would/could try to prove you wrong. I purchased my bike as I like the look of it so my opinion in the whole is worthless but from a tech point of view carbon can be lighter but it wont give like metals will and on the whole I would punt towards the side of a steel bike for sudden knocks.

And there's no wrong in that. I love steel bikes. I'd like to own a carbon bike too (though I'm nostalgic and aethetically I rather like the aluminium bikes of the late '90s when it comes to recent racing machines). Titanium bikes are also beautiful things. The problem is trying to use that one on the wife.

VTech

My wife is away tomorrow for a few days with the girls topping up their tans so I've played the "come on love, it's only fair" card several times already

simon_masterson

john1967 wrote:

Get on the aero bus now,destination the future.You can't argue with physics.

It would be nice if it were that simple, wouldn't it?

Yes, some "aero" innovations can represent a significant performance enhancements, but others are minute, and little more than statistics generated by wind tunnel experiments (rather like the experiments that allow Lucozade to claim a 5% performance increase, or whatever); as has already been discussed, at its worst "aero" is the new marketing buzzword to persuade gullible punters to hand over more money. Unless you are in a wind tunnel with a group of scientists controlling the variables, it's better to take these claims with a large pinch of salt.

(and most cyclists could go much faster by improving their posture on the bike. You can't argue with physique. )

simon_masterson

VTech wrote:

My wife is away tomorrow for a few days with the girls topping up their tans so I've played the "come on love, it's only fair" card several times already

Well played!

VTech

Years of practice my friend