Aero - don't believe the hype?
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DesWeller wrote:Aero is important. Going as fast as you can, on a flat road, that's where almost all of your power is going. The UCI-mandated diamond-shaped frame limits the improvements that can really be made. And since the chord of an aero feature has been limited in regulations the improvements that can be found are even smaller.
That's a very good point. I wonder if we'll see more bikes like the Specialized Shiv, which they make in a UCI and non UCI version.0 -
greasedscotsman wrote:Surely the braking surface isn't going to last that long even if the rest of the wheel does. That might change if disc brakes become more common place, but at the moment, that's not really the case.
If you are buying a pair of wheels 'for best' then you can expect the braking surface to last for decades potentially. IME, the vast majority of break surface wear occurs between November and February - when there is enough rain to wash lots of abrasive crap onto the roads which gets picked up by the pads and turns them into coarse wet and dry paper. If you only use your posh wheels on dry roads, you'll be able to knock up enormous mileages with little wear.Faster than a tent.......0 -
It would be great to view the reports of the aero testing although in reality I doubt they would ever release the info.
I also wonder if a circular wind test in a lab on an aero bike would prove better than that is a traditional non aero type bike.Living MY dream.0 -
greasedscotsman wrote:Simon Masterson wrote:We may not be talking about grand tour level bikes, I grant you - no prototype parts and not quite as blingy specs (etc) - but fundamentally the same principles apply. I commonly read of extremely light rims (eg. those on extremely light factory wheels) developing cracks within relatively few miles, and for that reason I do think there's a lot to be said for a fair few road cyclists these days deeming very short service lives to be normal and acceptable, but nevertheless I'm not suggesting that every bike that has fairly flimsy hubs in order to allow the wheels to be as light as they are (for example) is going to need new ones within two years; merely that they probably aren't going to withstand decades of hard use, as will something slightly heavier and stouter.
I agree with you, I don't want to buy parts that only last a couple of years, but also I don't think I would be expecting a pair of wheels to last decades. Surely the braking surface isn't going to last that long even if the rest of the wheel does. That might change if disc brakes become more common place, but at the moment, that's not really the case.
You have a point, and I agree. I was more suggesting that you probably won't be taking them out day in day out and relacing those featherweight hubs time and time again until you're old and grey. But this obviously depends on the rims; stout old touring type rims are much more likely to last eons than light racey ones. I have two old bikes with 1 1/2 sets of original wheels, and the rear wheel that died demised on account of the axle snapping (which hurt); the 27" Weinmann front wheel still spins fine and the other set is cheap old steel rimmed Raleigh junk.0 -
Rolf F wrote:If you are buying a pair of wheels 'for best' then you can expect the braking surface to last for decades potentially. IME, the vast majority of break surface wear occurs between November and February - when there is enough rain to wash lots of abrasive crap onto the roads which gets picked up by the pads and turns them into coarse wet and dry paper. If you only use your posh wheels on dry roads, you'll be able to knock up enormous mileages with little wear.
Yeah, that's fair enough, but then surely you could get greater longevity out of a light pair of wheels if your using them less.0 -
This post has gone through all the aero/lightweight issues
Im going to see if I can get time on the tunnel and test my aero against my non aero and see which one comes out best. Im actually quite interested now in what the outcome will be.Living MY dream.0 -
This post has gone through all the aero/lightweight issues
Im going to see if I can get time on the tunnel and test my aero against my non aero and see which one comes out best. Im actually quite interested now in what the outcome will be.Living MY dream.0 -
Simon Masterson wrote:You have a point, and I agree. I was more suggesting that you probably won't be taking them out day in day out and relacing those featherweight hubs time and time again until you're old and grey. But this obviously depends on the rims; stout old touring type rims are much more likely to last eons than light racey ones. I have two old bikes with 1 1/2 sets of original wheels, and the rear wheel that died demised on account of the axle snapping (which hurt); the 27" Weinmann front wheel still spins fine and the other set is cheap old steel rimmed Raleigh junk.
It would be interesting to know what sort of life span people expect from their bikes. I'm sure it varies quite a bit. I buy some things only expecting to keep them for up to about 10 years. But then I also have a custom steel bike that I will keep as long as I can still ride a bike.0 -
VTech wrote:This post has gone through all the aero/lightweight issues
Im going to see if I can get time on the tunnel and test my aero against my non aero and see which one comes out best. Im actually quite interested now in what the outcome will be.
Doesn't matter. You could do a different test and get the same result0 -
Aero bikes only matter if your body is as thin as the bike frame.0
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Froomes Edgar wrote:VTech wrote:This post has gone through all the aero/lightweight issues
Im going to see if I can get time on the tunnel and test my aero against my non aero and see which one comes out best. Im actually quite interested now in what the outcome will be.
Doesn't matter. You could do a different test and get the same result
Of course, but it will be the first time many forum members will have had access to reliable data to base their opinions on. It will also prove or dispel theories about which is better given the variables, again great info for those interested in the debate.Living MY dream.0 -
VTech wrote:Froomes Edgar wrote:VTech wrote:This post has gone through all the aero/lightweight issues
Im going to see if I can get time on the tunnel and test my aero against my non aero and see which one comes out best. Im actually quite interested now in what the outcome will be.
Doesn't matter. You could do a different test and get the same result
Of course, but it will be the first time many forum members will have had access to reliable data to base their opinions on. It will also prove or dispel theories about which is better given the variables, again great info for those interested in the debate.
But haven't you already stated that wind tunnel data doesn't necessarily translate into the real world? All that you will prove is that one of your bikes is faster in a wind tunnel than another. Doesn't mean that the same bike will be faster on the road. I'm not sure what this will prove.0 -
It will (I think) prove that it doesnt matter what bike you have, if it feels good to ride and your comfortable it wont matter wether its aero or not.
At the moment you only have data given by manufacturers for the good, ive been unable to find negatives published on any tunnel testing of a particular brand ?Living MY dream.0 -
VTech wrote:It will (I think) prove that it doesnt matter what bike you have, if it feels good to ride and your comfortable it wont matter wether its aero or not.
At the moment you only have data given by manufacturers for the good, ive been unable to find negatives published on any tunnel testing of a particular brand ?
Are you sure? Won't it just prove that one bike is quicker in a wind tunnel than another? How is that going to translate to the road? Do you not need to do some testing on the road as well?
Also what bikes are you going to test? You have a Felt AR4, that's quite an old design, how about testing something newer. Like a Scott Foil which uses a different profile for it's down tube. Or what about something with integrated brakes?
You also seem to be suggesting that an aero bike might not be as efficient with fat bloke compared to a skinny one. Who is going to be sitting on your bike in the wind tunnel, hopefully you'll have a number of people lined up.
And finally you seem to want to prove an aero bike won't make any difference, so how can we believe any results you come up with? In the same way a manufacturer wants to prove their bike is better.0 -
greesdscotsman, your arguing my points yet you seem to believe your arguing against me ?
I only have a finite time so testing would have to be identical over frames, I think if you took the rider out of the equation it would give better results as no one will ever be the same so if you had a definitive answer as to wether an aero design by its nature was better or worse than a non aero it would be of at least some interest to at least one person here, after all, every magazine I have read have been far from scientific with no basis to make an assumption yet they still sell thousands !
I also asked for advice earlier hence asking what you guys would want to see so as the assumption was fair.
Lets face it, a cross wind tunnel test is better than no test, at least it will answer some of the questions debated on aero design.Living MY dream.0 -
I think you have to have a rider, to see how the drag is split between frame and rider, and how the flow field around the frame is effected by the presence of a rider.You live and learn. At any rate, you live0
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VTech wrote:greesdscotsman, your arguing my points yet you seem to believe your arguing against me ?
Don't really know what you mean there.VTech wrote:I only have a finite time so testing would have to be identical over frames, I think if you took the rider out of the equation it would give better results as no one will ever be the same so if you had a definitive answer as to wether an aero design by its nature was better or worse than a non aero it would be of at least some interest to at least one person here, after all, every magazine I have read have been far from scientific with no basis to make an assumption yet they still sell thousands !
I also asked for advice earlier hence asking what you guys would want to see so as the assumption was fair.
Lets face it, a cross wind tunnel test is better than no test, at least it will answer some of the questions debated on aero design.
Sorry, I think this test is too limited to be meaningful. Couple of bikes in a wind tunnel without a rider, think you'll end up with more questions than answers. But hey, go for it. Do other people want to see this?0 -
greasedscotsman wrote:Sorry, I think this test is too limited to be meaningful. Couple of bikes in a wind tunnel without a rider, think you'll end up with more questions than answers. But hey, go for it. Do other people want to see this?
Two bikes, similar geometry, one aero, one not, same rider on both. That would be mildly interesting and mildly informative as a bare minimum. Wouldn't be definitive but interesting all the same.Faster than a tent.......0 -
Rolf F wrote:greasedscotsman wrote:Sorry, I think this test is too limited to be meaningful. Couple of bikes in a wind tunnel without a rider, think you'll end up with more questions than answers. But hey, go for it. Do other people want to see this?
Two bikes, similar geometry, one aero, one not, same rider on both. That would be mildly interesting and mildly informative as a bare minimum. Wouldn't be definitive but interesting all the same.
Ok, if thats whats wanted ill do that.Living MY dream.0 -
It's been touched upon a few times, but surely any test without the rider is largely meaningless... My TT bike *should* be more aerodynamic than my road bike, in some small part due to the shape of tubes, wheels etc etc but mainly because of the position it puts me in. I'd guess I make up >80% of the frontal area of the system, so frankly even if the tubes were round and the wheels low profile, it would probably still be more aero (whatever that really means) then me sitting on my R5.0
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I don't think this is about rider position. As Rolf F says, geometry (or rider position) should be the same. You still need the rider there though as it will still have an effect on how the air flows around the bike. For example, is an aero bike better at coping with the turbulence created by the movement of the riders legs.0
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greasedscotsman wrote:I don't think this is about rider position. As Rolf F says, geometry (or rider position) should be the same. You still need the rider there though as it will still have an effect on how the air flows around the bike. For example, is an aero bike better at coping with the turbulence created by the movement of the riders legs.
On the ideal aero bike you'd be recumbent and faired-in, to reduce XA and have feet and wheels running out of the airflow as much as possible.- - - - - - - - - -
On Strava.{/url}0 -
greasedscotsman wrote:I don't think this is about rider position. As Rolf F says, geometry (or rider position) should be the same. You still need the rider there though as it will still have an effect on how the air flows around the bike. For example, is an aero bike better at coping with the turbulence created by the movement of the riders legs.
Yep. From my perspective things we know are effects of rider position (as tested exhaustively) and the aerodynamics of the frame (based on all those manufacturers claims). What we need to know is whether the frame aerodynamics translate to anything measurable in the real world. The rider position probably doesn't matter that much but I think it makes more sense for it to reflect a normal riding position rather than eg a TT position. I guess this is about whether an aero bike provides any advantage to us average cyclists doing our average cycle rides.
I'd just go for a normal setup with the rider on the drops (since we can assume that any benefit is maximised at speed - though it would be interesting to see how things vary between say 15 and 25mph).Faster than a tent.......0 -
Ok, so now were getting serious I do think there is a lot to be learned here. I agree with a lot of the above as you guys will know more about what matters on the road than me!
My original though was to circular the bike and do a flow test around a 360 degree axis, maybe 10/20/20/40/50kph and see if the benefits are clear on an aero but then you have one issue that I kept thinking of which was the energy used to keep balance when the wind is blowing side-on, surely this would also be important when taking into account a 50km to 100km ride ? Any wasted energy will matter over time ?
I also think the points above about the bike putting you into an aero position bears a lot of weight and shouldnt be dispelled, it will reduce drag from design alone.Living MY dream.0 -
I think you're right about the cross-wind. Couple of weeks ago I did a 30 mile out and back trip which was all east - west but there was a stiff, cold wind coming down from the north. That took a lot more out of me than I had expected.0
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I spoke with a couple of guys in tech for the wind tunnel and although they cant prove it (as they have never tested a bike themselves) they "think" that if you circulate air around the bike to take into account the different directions that you would be cycling, you will almost certainly end up worse off than standard round tubes ?
Of course this is guesswork at the moment.Living MY dream.0 -
I think I've heard that before too. But standard round tubes are the norm on bikes - manufacturers would struggle to get a premium price for them.
TBH - I really think the drag on an aero bike isnt really worth us worrying about. In the real world - it wouldnt make any significant difference.0 -
cougie wrote:I think I've heard that before too. But standard round tubes are the norm on bikes - manufacturers would struggle to get a premium price for them.
TBH - I really think the drag on an aero bike isnt really worth us worrying about. In the real world - it wouldnt make any significant difference.
I think your absolutely right, at the same time however im not sure they truly make a significant gain ?
Personally, I think they look great
Living MY dream.0 -
VTech wrote:I spoke with a couple of guys in tech...
What's their take on latex inner tubes?0
