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Have you wasted money on super light new wheels?
Ok, so I'm currently researching a new set of wheels, I was primarily looking at the weight of the wheels but during my research I came across a number of articles that would imply that 250g's off a set of wheels would make a minimal difference.
Here is an article backed with scientific research: http://www.biketechreview.com/index.php/reviews/wheels/63-wheel-performance it shows that reducing a wheelsets weight by 50% has a sub .5% difference in performance. The main gains that can be made by a wheel are in it's aerodynamic ability.
So I thought well, I will need a 40mm+ set of wheels to reap the aerodynamic benefits, then I stumbled on the following research: http://www.cyclingpowerlab.com/ComponentAerodynamics.aspx this data would suggest that the Campagnolo Zondas are a more aerodynamically sound choice than a Mavic Carbone SLR!
If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.
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80 comments
It is very simple.
Yes the rolling resistance is simple which will save you 0.2 - 0.3 watts going from 23c to 25c, but aerodynamic implications are closer to 6 watts dependent on wheel rim width.
Sorry guys simple solution:
Running, there has been so many" innovations" with running, and yet its proven training gains far out way any performance clothing gains.... Most performance gains from clothing ie compression only give the perceived feeling of better performance.
To sum up, aero=feeling of less effort thus can push harder =actually going harder
Training's free.
The thread was about whether spending money on lighter and/or more aerodynamic wheels is worth it or not. All other factors being equal.
Wheel upgrades have made a difference for me, therefore it's worth spending money -to a point. This point will vary for everyone.
No amount of science or theory can convince though, you just have to try them out.
Testing rolling resistance using smooth steel drums and air resistance of wheels/tyres using a TT bike "ridden" at 25-30mph in full aero position is as far to typical riding conditions as it gets.
It makes a very effective marketing, though.
Testing rolling resistance using smooth steel drums and air resistance of wheels/tyres using a TT bike "ridden" at 25-30mph in full aero position is as far from typical riding conditions as it gets.
It makes very effective marketing, though.
All this stuff about rotational weight/rotational inertia. Read what Jobst Brandt has to say about it:
http://yarchive.net/bike/rotating_mass.html
His engineering/physics is spot on. The point is, rotational inertia only causes any negative effect when accelerating significantly. It might even have positive effects at a steady speed.
The sensation of surging forward with each push on the pedals does not mean you're going faster - you might just be slowing down more between pedal strokes due to reduced flywheel effect!
It can be very hard to tell what is actually faster without timing things and having some evidence that you're putting out an equal effort (ie power meter). Even then you can't control for wind conditions and other factors.
What is more simple is that saving weight on the bike or on yourself means you can ride up hills faster at the same speed (terminal velocity is higher - try coasting downhill next to someone heavier than you). The steeper the hill, the bigger the effect. You'll also go down hill more slowly, but the net effect going up and down is that you'll be quicker.
Saving weight also slightly reduces your rolling resistance at any speed.
I think the maths is off in the first linked article because the speed uphill is high (I think because it isn't very steep). This makes the aerodynamics far more significant than it is when you're grinding up a steep hill at low speed. Weight becomes the dominant factor at lower speeds.
So true. It's predominantly the emotion and the magpie syndrome. After all, Bradley Wiggins could ride my current bike way faster than I can so there's nothing wrong with my bike
As Dave128 posted, swapping to much lighter wheels (Ksyrium Elite) allowed me to grind up the very steep hills in my area with noticeably less effort (before that, I could not even get up some of them without dismounting). On the flat though, I seemed to lose some flywheel effect. Changing to 28mm tyres at 90 psi made a massive difference in ride comfort over the appalling roads (breathtaking views though), ultimately making me 10% faster on typical 3 hour mountain rides.
I believe that wheel manufacturers have only scratched the surface, the advent of disk brakes, wider rims, tubeless tyres will increase their design freedom. 5 years down the road, our wheel/tyre combinations will look very different.
Summing up: lighter rims make a real world difference when climbing, same as wider tyres on comfort; aero gains probably kick in above 35 km/hr overtaking the fly wheel effect. The truly interesting times in wheel/tyre development lay still ahead.
On two occasions this year I have heard local guys banging on about their super light new wheels. One also has DI2. And you know what? They still aren't as fast as me.
Of course, if I had the money, no doubt I would be buying the same equipment.
I bought some Swissside Hadron deep section wheels based on as scientific a trial I could be bothered with. I tried a set for a week or two and rode the same short flat TT course numerous times with those wheels and measured them against what I could do on my old Askiums. I found I was around 1mph (21mph vs 20mph) quicker over the course with deep sections on, for the same HR effort, in reasonably similar wind conditions.
We're all individuals here, we make our choices and move on.
Aaah - but are they as blessed with hubris as your good self ?
.... because that's the kind of research that bike manufacturers are going to commission.
This thread is another variation of the age old debate between "I can afford it so why shouldn't I buy it, notwithstanding that I probably could realise similar improvement another way" and "spoilt rich dentists are ruining our sport by pretending to be pro, the true soul of cycling is 7 speed screw on blocks and steel frames".
I ride my bike cause its fun. I suspect the vast majority of users on this website are not paid to ride their bikes and so are in the same boat. For me, sometimes going fast is fun and I am "guilty" of buying loads of shiny stuff that I think will make me go faster (including some PX carbon wheels). Sometimes fun isn't going faster (hence fat bike), but rather doing something different. Have more fun. Trying to justify your fun by some kind of scientific metric is kind of sad; trying to guilt people out because they have chosen to get their kicks a particular way (e.g., via the purchase of carbon wheels) isn't any better.
These discussions tend to go round in circles because those who want/can afford new kit justify it and those who do not want/can't afford argue against it. To paraphrase (incorrectly) Lance, it's a lot about the bike. Part of the enjoyment for many is the machinery, and nothing wrong with that. Even for the Eroica guys and gals, it's still about kit to a large extent
I like shiny things
nothing wrong with a bit of Gucci on your bike 
I'm not sure about the aerodynamics, but as for mass it only affects acceleration and climbing, and in the case of acceleration it depends where on the wheel it is.
The power required for acceleration on the flat is a linear combination of the total mass of the wheels and their moments of inertia. With a bit of mechanics and maths you can show that making the hubs 100g lighter translates to a power saving of ~0.3W when accelerating from 0 to 30km/h over 10 seconds (~250W for a 70kg rider on a 10kg bike, neglecting air resistance). If you move this weight saving to the rim, it (roughly) doubles to 0.6 W because of the reduced moment of inertia of the wheel (the spokes and hub contribute almost nothing to this).
So if you were to take 200g off a wheelset with 100g saved at the rims and 100g at the hubs, you'd save about 1W in those circumstances, and it would increase in proportion to the rider's acceleration. Small, but perhaps noticeable in situations where acceleration is significant and important (e.g. crits).
I certainly doubt it would make any measurable difference under normal riding conditions, though, where acceleration isn't so relevant.
The physics is quite clear (wheel weight doesn't make much difference).
As a experiment I suggest people try seeing how much effort it takes to spin their front wheel by hand. It is laughably easy, pretty much effort free - and that is accelerating from a standstill, and the full weight of the wheel is being accelerated.
Most riding is mostly steady state and the difference in weights across different wheels is only a few hundred grams at most.
New wheels may look cool, might make a nice sound and make you feel like the king of the road but they won't make you much faster on their own.
As Dave said further up, tribars are probably one of the few equipment changes that will genuinely make you a lot faster. Like some other posters, I also like more expensive tyres, although I am happy to admit that to an extent they may just 'feel' better.
That doesn't mean that people shouldn't buy expensive wheels, just that they might be disappointed if the only reason for buying them is that they now think they will fly up the hills.
not totally bike related but Dr Hutch finds tests a aero bike and a regular road bike to see the difference at the same power.
http://www.cyclingweekly.co.uk/news/latest-news/how-much-faster-is-an-ae...
My zondas must be slowing me down, because I love to stop pedaling and listen to the awesome freewheel.
do get some good climb times on them though.
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