Extra speed from deep section wheels...really?

AllezAllezAllez

Is the correct?

The following was taken from a wheel builder:

"50mm is going to be a bit faster for a novice rider, wanting to get up a group in chaingangs etc. Average speeds can increase 2-3mph over box-section wheels".

Sounds a lot. But does it happen?

noodleman

2-3mph is very hopeful in my opinion. I only gain 1.5 mph average on a good day on my full on TT bike.

kettrinboy

Not for me really , ive got a 2006 Scott CR1 pro with Ksyrium SL box section wheels and a 2014 Specialized Venge Expert with DA 9000 C50 wheels and at my speeds of 16-20 mph I havnt found my ave speeds 2-3 mph faster but more like 0.2-0.3 mph I reckon , but on one local fast downhill the Venge will hit 50 mph where the best I can get out of the Scott is around 45 mph so at high speed there is a definite increase but obviously some of that is the bike,you probably need to average over 20 mph to get the best out of aero wheels or even 25 to get big improvements on your ave speeds, the C50,s do look bloody good though.

ianSWBB

definitely some 'free' speed to be had from riding deep section wheels

2-3mph might be a little optimisitic!
as a %, probably around the 7-8% level
So if your average ride is 15mph, then it becomes 16mph ish
If your average is 20mph, then it becomes 21.5mph ish

and more importantly, deep sections sound great!

i've got campag 80mm on mine, have to be careful when the wind is over 15mph

Anonymous

That author is writing utter censored . I would say the 7-8% is about right. For me its nearer 5% (once up to 20mph) but probably less than that switching between zondas and 50mm carbons. The faster you go the more effect they have.

carbons look and sound awesome though. Performance increase for a beginner would be minimal if not non-existent.

bigmat

Also if you're riding in a group aero issues become less critical as you should be spending most of your time in the slipstream. I do find 50mm wheels seem to hold their speed better on fast sections, particularly noticeable on the kind of long gradual descents where you don't need to worry too much about braking, but only a real benefit if you are attacking off the front, trying to get back on the back (more of an issue for me!) or time trialling. Their number one benefit is that they look good!

964cup

It's not just wheels, though, it's position, kit, frame etc. I reckon I get about 5-6kph "free" on my S5 with 808s compared to my winter bike on Pacenti SL23s, but the winter bike has panniers, a dynamo, mudguards and about 4cm less saddle to bar drop.

DKay

My non-aero Cayo Evo has 5800 105 and SL23s or H Plus Sons fitted to it. My aero Foil has 6870 Di2 and 50mm carbons. The difference between my average speeds on both bikes is minimal and certainly not 2-3mph. Imagine a novice rider being able to improve his average from 15mph to 18mph just from a change of wheels. If only!

Which wheel builder said this btw?

cycleclinic

When I stuck a rack and a bag on my computer my pace really dropped the extra few kilo and extra drag is significant.

2 to 3 mph from aero wheels won't happen and it depends what you are comparing them too. When riding at 30 kph on a mavic open pro 32h with thick spokes and then a good aero wheels et over 40km sums indicate a 20 to 30 sec time saving. That 0.2kph. At tt speeds the speed increase is higher but still not 1 mph. Power saving is small handful of watts. It real but the claim made by the wheel builder is bogus.

neeb

Less than 5% I reckon even at a 20mph average, my guess is about 2-3% (rather than 2-3mph...) based on how the relationship between average power and average speed varies (on average...).

imposter2.0

There's evidence to suggest that deep rims offer more of an advantage to slower riders than faster riders, so the author is definitely NOT writing 'utter censored '..

DKay

But certainly not a 2-3mph increase. I'm calling it 'utter censored ' too.

Anonymous

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714404#p19714404]Imposter[/url] wrote:

There's evidence to suggest that deep rims offer more of an advantage to slower riders than faster riders, so the author is definitely NOT writing 'utter censored '..

I disagree. My uninformed opinion thinks that the faster you go, the more difference it makes, thus less relevance for a beginner

imposter2.0

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714416#p19714416]coriordan[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714404#p19714404]Imposter[/url] wrote:

There's evidence to suggest that deep rims offer more of an advantage to slower riders than faster riders, so the author is definitely NOT writing 'utter censored '..

I disagree. My uninformed opinion thinks that the faster you go, the more difference it makes, thus less relevance for a beginner

There is no magical aero 'switch' that gets turned on at speeds over 25mph. The same wheel that gives you a benefit at 25mph will still give you a benefit (albeit a proportionally smaller one) at 15mph. Which is why, on a 10m TT for instance, a slower rider will see (proportionally) more of a benefit than a faster rider, as they will be riding them for longer.

DKay

Yes, but drag increases to the square of velocity.

cycleclinic

It is not true that aero kit benefits slower riders more tha faster ones.

Take a 40km TT done a 20 mph and 28 mph with non aero wheels and then aero wheels. The 20 mph ider will have a bigger time saving in seconds over the 28mph rider but as a percentage of time saved vs total time the faster rider gets a higher % saving.

So lets get the interpretation of the numbers right. Dkay sit down and do the maths it is the only way you will understand it. I have posted before with calculations it took time I am not doing it again.

Aero wheel give a benefit it is small but it way bigger than the time saved by saving 300g of the wheelset.

the number I gave came from data on the cycling powerlab website. I hope they are right.

foggymike

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714368#p19714368]thecycleclinic[/url] wrote:

When I stuck a rack and a bag on my computer my pace really dropped the extra few kilo and extra drag is significant.

2 to 3 mph from aero wheels won't happen and it depends what you are comparing them too. When riding at 30 kph on a mavic open pro 32h with thick spokes and then a good aero wheels et over 40km sums indicate a 20 to 30 sec time saving. That 0.2kph. At tt speeds the speed increase is higher but still not 1 mph. Power saving is small handful of watts. It real but the claim made by the wheel builder is bogus.

This looks about right to me and matches what I find in reality switching between 404's and Ksyrium SLs. Like noodleman switching to a full TT set up pushes me up around 1 1/2 mph, but the wheels are a small part of the gain to be had there.

imposter2.0

2-3mph is ambitious, I agree. However, there was a study linked and discussed on this forum previously which showed the benefits to 'slower' riders actually outstripped the benefits to faster ones. I'm sure someone will find it, I can't...

term1te

I think we underestimate the psychological effect of new kit. I'm sure sticking a number on my back gives me an extra 5%, and I suspect new deep section wheels will have a similar effect, at least initially. I've been told that there is also an advantage to having red kit, so red deep section wheels are the way to go. I put red handle bar tape on my bike in the spring, and almost immediately got a PB in a local hill climb TT, QED

mpatts

My boras are significantly faster than my shamals - I'd say by up to 5mph*



*Note, this is not true, but it helps to justify the price tag.

cycleclinic

imposter it has been dicussed many time and the conclusion was what I stated in my last post not what you took away from that thread. I am not doing the calculations again it takes too long to write up the formulas and go through the workings suffice to say you got the wrong end of the stick. re read my last post for how aero kit changes the speed of slower riders compared to faster ones. It applies to all aero kit on any bike.

markhewitt1978

For a beginner? For aero to really make a difference you need to be spending sustained periods >20mph, beginners won't be doing that so much, especially if riding on their own, unless they live somewhere completely flat. Beginners IMO benefit more from light wheels for climbing rather than aero.

imposter2.0

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714581#p19714581]thecycleclinic[/url] wrote:

imposter it has been dicussed many time and the conclusion was what I stated in my last post not what you took away from that thread. I am not doing the calculations again it takes too long to write up the formulas and go through the workings suffice to say you got the wrong end of the stick. re read my last post for how aero kit changes the speed of slower riders compared to faster ones. It applies to all aero kit on any bike.

I'm not drawing any conclusions - I'm just stating that there was a study which concluded that aero benefits favoured slower riders. It's great that you think you know better than the guys who compiled the study, but unless either of us can actually find the original document, then it's meaningless.

slowbike

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714593#p19714593]Imposter[/url] wrote:

I'm not drawing any conclusions - I'm just stating that there was a study which concluded that aero benefits favoured slower riders. It's great that you think you know better than the guys who compiled the study, but unless either of us can actually find the original document, then it's meaningless.

Take a moment to think about that logically .... if aero benefits slower riders more than faster riders then a child on their first bike would be better off in the TT position ...

Or think about drafting another rider - at 5mph there's no point, at 10mph you can barely feel it, 15mph it starts becoming noticable and at 25mph it's very nice to take the rest - and if you have a peleton in front of you then you could hold that 25mph+ all day - until you reach an incline of course ....

Fact is - the faster you go, the more drag you are exposed to, so the more you can reduce this the better.

imposter2.0

FFS - I'm not making any judgements - logical, illogical, or otherwise. I'm simply saying the study is out there.

slowbike

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714627#p19714627]Imposter[/url] wrote:

FFS - I'm not making any judgements - logical, illogical, or otherwise. I'm simply saying the study is out there.

Yes - however, you're either mis-reading the study conclusions or the study is flawed - as it's blatently obvious that the slowest riders don't benefit from aero gains.

noodleman

Aerodynamics come into play at speeds. The faster you go, the more you push against oncoming air. The smaller and more aero you make yourself, the less power you need to produce for a given speed. There may be a study that says the slower rider will benefit more than the faster rider but it makes no scientific sense. These studies are forever being proven and then disproved. The latest one being the case for 25 tires having better rolling resistance than 23. Only a few years ago you would have been ridiculed for suggesting such a thing.
Could this latest aero theory be created by manufacturers to persuade inexperienced novices to part with large chunks of cash in the belief they need to buy expensive kit they dont need in the hope it will suddenly make them 2-3 mph faster overnight? Maybe

imposter2.0

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714639#p19714639]Slowbike[/url] wrote:

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714627#p19714627]Imposter[/url] wrote:

FFS - I'm not making any judgements - logical, illogical, or otherwise. I'm simply saying the study is out there.

Yes - however, you're either mis-reading the study conclusions or the study is flawed - as it's blatently obvious that the slowest riders don't benefit from aero gains.

This is totally bizarre..

From memory, I'm fairly sure I didn't mis-read it and the study may indeed be flawed. But, as I have repeatedly stated, I am not drawing any conclusions, other than to say that the study exists, out there, somewhere. Jesus.

stevie63

I think that the point was kind of made earlier in that slower riders can save more time by getting aero but the fact is that isn't going to just come from some aero wheels you would also need tri-bars, a tt helmet etc (in fact you would get more benefit from these rather than the wheels, which is why you see these recommended first, then wheels, then bike). However the speed advantage is going to be higher at a faster speed.

So let's assume that your aero wheels are going to boost you 5% and your current average speed is 15mph. 10 miles currently takes you 40 minutes. The 5% boost is going to up your average to 15.75mph and drop your time by 2 minutes to 38. Now let's do the same for 20mph. 10 Miles takes 30 minutes, the boost takes you to 21mph but you save only 1.5 minutes on your time.

However all the above is cobblers because there are too many other factors involve to draw straight conclusions and it is highly unlikely that a wheel is going to save you 5% whereas a change of position might. It also doesn't take into account that the increase of air resistance is not linear.

bad_ash

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714627#p19714627]Imposter[/url] wrote:

FFS - I'm not making any judgements - logical, illogical, or otherwise. I'm simply saying the study is out there.

Rider 1 rides 40km TT in 60 minutes without aero wheels. Aero wheels save them 60 seconds which is 1.7%.
Rider 2 rides 40km TT in 80 minutes without aero wheels. Aero wheels save them 70 seconds which is 1.5%.

So in explicit terms rider 2 gets a bigger saving, 70 seconds compared to 60 seconds.
But in relative terms rider 1 benefits more with a 1.7% improvement compared to 1.5%.

I completely made these numbers but, it demonstrates that that you can say either rider improved more, but you have to clarify on what basis that improvement is.

I would think most people would think % improvements is most relevant.

agnello

[url=http://www.bikeradar.com/forums/viewtopic.php?p=19714506#p19714506]DKay[/url] wrote:

Yes, but drag increases to the square of velocity.

I thought the relationship was cubic