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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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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.
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.
.... 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.
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.
I've just changed from cosmic carbone sl's to borrowing a pair of cheap old hoops from a mate with no real noticeable difference, the only difference is when there is a cross tail wind I can't use the rims like a sail to power on.
Re quality of hubs, good aero and weight rims will be made by zipp, hed, sram etc all expensive with good build quality
There's been too little mention of the importance of the hubs and the overall wheel build in this thread...
There's ZERO point getting the most aero or lightest rims you can buy if you're going to run them on worthless hubs, or built into wheels that aren't up to the job.
Too much focus on weight and aero, not a single mention of quality...
I'm no mathematician or physicist so cannot comment on the various % gains or losses quoted here but...
Everyone that I know of who has upgraded their wheels experience an improvement in performance to a greater or lesser extent. As to whether our not it's worth it, that will depend on your point of view.
Even changing to my summer tyres this year have given me a noticeable boost in speed
You just have to try it out for yourself in the real world! You'd be surprised at how much difference weight and aerodynamics can make to the effort required to power on the flat or sprint up a hill.
Perceived benefits and the "feel" has very little to do with actual performance. The best example are tyre pressure and perceived rolling resistance. Pump up a 23mm tyre to 120PSI and it will always "feel" faster than a 28mm one at 30-40PSI less even though you're likely to be faster or at least as fast on a wider one.
I totally agree on this one. Performance of various tyres can be pretty accurately measured with a drum, pendulum or a simple rolling test and the difference between slow and fast ones can be as much as 20-30W.
IMO it's the only bike component that it's worth obsessing about.
I ride in the real world and over 25years of cycling I've never noticed the measurable performance benefits of lighter wheels. They may feel different but that's all.
The only things that made a positive difference to my average speeds were: picking the right tyres, losing 3 stones, commuting/training regularly all year round and clocking long endurance miles in winter.
Anything else had very little relevance.
I think you'll see I pointed out that the figures are not statistically significant. i.e. useless.
What I have found, like the article you link to (which is interesting) is that there is no evidence to disprove the hypothesis I stated.
Cheers robdaykin but that data is totally useless, here is a link to a test on a climb (where weight would matter most) using a powermeter: http://www.training4cyclists.com/how-much-time-does-extra-weight-cost-on... your seriously suggesting 500g's will effect speed by 8%?
This reminds me of the article about the doc who commuted on his old steel tourer with mudguards and a lightweight carbon bike. He found little difference between them.
http://road.cc/content/news/28400-doctor-claims-carbon-offers-no-benefit...
Also discussed in the CTC's magazine last year (PDF)
As for the aero wheel analysis, it's going to need some time to give objective data in a discussion suitable form as I need to quantify the climbing to support the hypotheses.
Broadly though Aeolus 5.0 D3s weigh the same as the Elites, and on my best bike I am 2-3 mph faster on the flat, across and with the wind and 5mph faster into the wind at 160 bpm. Data based on the first test ride I did. As for climbing, I set a Strava KOM first time up the road from Cayton Bay using the Bontys, which is a climb I normally struggle to hold any speed on as it has a kick up partway through.
At this point however, gIven it's sunny out, I'm going to go get some more data points...
Ok. If you want to accept a model, which is purely academically defined then fine. I personally wouldn't accept this model as anything more than interesting and for discussion only, completely divorced from reality.
Anyway, some data since you ask. Were I to do this as a scientific experiment, with an intention to publish results, I'd get one of those fully wired up Factor bikes and hire a wind tunnel, using a dummy and a motor to regulate effort and provide weight and aero consistency. Sadly I only have my legs for a motor and me for a dummy...
Hypothesis: ignoring gross aerodynamic features such as deep section rims, lighter wheels are more than 0.5% faster per kg rotational weight lost.
Take Shimano RS20 as a baseline. List weight 1817g which we'll accept since we're looking at gross weight changes, not trying to derive a graph of weight vs speed.
Same bike, same tyres, same drivetrain, same weather, same day within a 3 hour period, same route, same traffic conditions (i.e. not affecting speed, so quiet roads with occasional traffic passing at a reasonable speed, but no slipstream from continual traffic). The route in question is round Forge Valley in Yorkshire, and is on Strava as Forge Valley Up. Not very long, but easy to ride with consistent effort. Effort measured by heart rate, since I don't own a power meter, effort being targeted at 150 bpm which I can hold reasonably closely. Rider weight and position on bike is near enough constant. In this case only measuring 1 lap, which does not give enough data points for a statistical analysis. This was done because I had both the Elites and the RS20s out of action due to potholes and fell back to the handbuilts. So when all were up and running again, I did a test because I'd done a long ride on the handbuilts and was subjectively horrified at how slow I'd been.
Handbuilt wheel ~ 2100g (measured, no tape, tube, tyre, skewer, cassette, however scales accurate to maybe +/- 50g) 5.5% slower +/- 0.5%
Mavic Ksyrium Elite 1550g list weight 8% faster +/- 0.5%.
So for the one ride I did to explicitly measure this about a year ago, there is a difference. Whether it is significant is arguable for a single data point, but scientifically you'd note is as interesting and move along.
Riding those wheels over a long period gives more data points, but rider weight, drive train, weather, tyre pressure, effort level, mood (i.e. subjective elements), bike upgrades, traffic and so on influence the data. I've not normalised the results for average heart rate, excluding rides which are influenced by 'extreme' weather such as high winds or rain, and I'm assuming that the amount of climbing or severity of it averages out over time because I tend to ride the same roads, with few variances. Looking at those rides you see a similar correlation.
The handbuilt wheels, ridden from 2003 to 2008, but with data points from 2007 onwards (when I bought a GPS, and so could automatically record to computer for analysis)
412 rides, 6.386% slower with a 19.0% 1st standard deviation on the average
RS20 452 rides 2008 to 2012 0% (benchmark), 1st standard deviation 16.3%
Ksyrium Elite, 2011-2013, 48 rides 3.367% faster 1st standard deviation 10.0%
During the whole time there are periods off the bike due to injury or illness, wildly varying rider weights, since my weight swings wildly (I've been 3 stone heavier and 1 stone lighter than I am now), and there are rides where I'm doing recovery through to hard pushing ones, plus adverse weather and differing loads and positions on the bike.
Since I've moved down south I've been riding the RS20s with panniers on different roads, so those are excluded from the analysis.
A t test on the handbuilt vs the rs20 however gives the results as NOT being significantly different due to the large standard deviation. If I wanted to be rigorous and try to get a better analysis, I'd now go through normalising the data, testing for outliers, ignoring anything with incomplete data (i.e. ridden without heart rate) and so on, chop the data sets into a fraction of their current size doing so, and feed it all into an ANOVA, but that's more work than I'm interested in doing on a bank holiday weekend. So I'm happy to forego that.
Despite the t test, I am not seeing any data which contradicts my original hypothesis that lighter wheels are faster, though I am happy to accept the analysis is not complete.
Frankly speaking I should have stopped reading it at this point but I carried on...
I appreciate your efforts and respect your opinions but sorry I'm absolutely not buying it at all.
I'm a bit of a tyre tart and there was a time I was testing various tyres on my bike (w/ Powertap) on a 3h loop, from 25mm 250g GP4000S to 37mm 600g Contact Sports and even despite differences in rolling resistance I don't recall differences exceeding 0.5-0.7mp in extreme cases.
Few other thoughts.
Rims vary in width/shape/volume and tyre pressure should account for that. A 1mm difference may not seem like an awful lot but it may change the volume of the tyres by 5-10% and affect rolling resistance and the feel.
You know... people claiming that wheels A are more comfortable or roll smoother than wheels B
Also of e.g. 500g difference between wheels most of weight saving will be in the hubs. Most of rims will be in a region of 370-450g. There is not much potential for weight saving here. What it means is that you're only saving about 100-200g of rotating mass furthermost from the centre (at best!).
To suggest it's going to result in noticeable difference in av. speed is madness.
Besides, what most of people debate mostly about is not how much difference lighter wheels make but how does it does it compare to a static weight.
The difference is going to be **** all.
Nope, Trek 1.5 so probably a bigger drop in weight than off the stock wheels on the madone, but definitely a noticeable performance increase.
That said the Bontragers make great winter wheels, absolutely bombproof so far
I'm buying some Shimano 501 30mm clinchers for £80, I was going to go for the Zonda's but I'm gonna save that money instead and stick by the research!
I do think there's a real risk of wasting money on expensive wheels, if you factor in the law of diminishing returns, and the additional complications that come from using high end Wheelsets, for example:
My £300 Zondas feel great, I'm used to how they ride, the summer Vittoria's have bedded in and hum along the road fantastically
My new Reynolds tubulars (paid £1100), freewheel more freely, are a bit faster on the flat above 25 mph, but the installation of tyres was a pain in the arse, I screwed up the mounting first time, they need special brakes and can't be used when it's windy (or at least I'm scared to at present...) And are less comfortable
I may get used to them in due course, but are they worth 4 x the price I paid for the clinchers?
I think not..
@notfastenough - That's a simple matter of handbuilt Vs factory. My 3 sets of handbuilt are rock solid, but all factory wheels I've owned have had lateral flex. Even Lightweights and Mad Fibers.
It's not all about weight, or even speed. I enjoy covering ground quickly as much as the next guy, but my winter wheels weigh a total of 3.15kg with tyres/tubes/cassette/skewers. My christmas present, on the other hand (Mavi Ksyrium Equipes) weigh 2.6-2.7kg fully loaded. However, the difference on climbs is really not that great. They spin up easier, but they also flex under load. I'm going to get the spoke tension checked out, but as things stand, I wouldn't buy them again.
I didn't *waste* money on new light wheels. My new wheels made me very happy.
I spent £400 on a pair of Planet X 50mm aero tubulars, and saved myself both weight, and money over the Fulcrum Racing 1s I was considering getting! They feel great, look great on my bike, and I believe I go faster (according to my recorded times over routes I have cycled tens of times).
With the Planet X wheels they are both light and Aerodynamic so you should see best of both worlds. I think the point SammyG was making is that if they were just light, then it would have been money "wasted".
Have a play with this calculator! http://www.u.arizona.edu/~sandiway/bike/climb.html
It's very interesting.
I completely agree with robdaykin. As someone who spends most of my day reading peer reviewd scientific articles I didn't find the article particularly convincing (although I didn't follow all the maths).
From my personal experience as well, I know I can ride higer gears up the same climbs and keep up with faster riders in my club when using my Ksyrium Elites than the bog standard Bontragers off my Trek.
You did exactly the same as me. Trek Madone I presume. I agree that I ride faster with the better wheels.
Purely objectively, based on measurements taken myself on actual rides, I've found bigger differences than the cyclingpowerlabs, but similar trends. I find lighter wheels are measurably faster with no aero features, and aero wheels give benefit climbing and below 25mph ground speed
I'd ignore the biketechreview article. I don't think it would pass peer review for a science journal is probably the politest way of putting it.
I read a very good article last summer on rotational, dead and active weight, which gave some explanations and equations for why rider weight loss affects speed on the flat less than losing dead weight (the bike) and far less than rotational weight (wheels primarily). Can't find the link, but I seem to remember Chris Boardman either referenced it, or it was in an article talking about incremental gains last summer, which also mentioned him.
Having lost over 20lbs in the last 10 months, lower rider weight helps with climbing, but is far less significant on the flat than you'd hope. Certainly riding on the drops and aero wheels are both more significant than weight loss for me. Though it has helped lots with climbing.
And for me, no I didn't waste money on super light new wheels. I have invested wisely, and have had considerable pleasure from each upgrade I've made so far.
If we are to ignore the Biketechreview article (and many other simulations/calculations confirming their findings) and accept the results of your "purely objective" tests, could you please share your test results and methodology with us?
One factor to think of is that if you get lighter wheels the wheel and it's design need to be just as rigid as a heavier wheel. I used to have Bontrager XL race lites on my bikes. These were light and the bike flew, but I couldn't ride them on back to back runs without them warping.
I got the Ksyeriums which are bullet proof. I hardly ever have to check the spoke tension on them and they run like a dream.
I must admit that I thought that rotational force of the wheel could help (on a flat), so strategically weighted wheels are faster. I seem to remember that the old time trial bikes had ball bearings in them which would allow an athlete to keep their speed up. The only problem is if the speed drops and so not so good for going up hills.
Rolling resistance is incredibly important, and aero wheels are still important at low speeds (see the hill climb data from the original post).
Getting the wheels up to speed will take less effort with less weight. For instance a Zipp 404 will take 118joules of effort to reach 19mph from 0 and a Shimano RS30 will take 143 joules. A bit of a difference, but let's take into account the rider. If the bike and rider weighs 80kg 2800joules of energy will be needed for the acceleration thus making the wheels account for only 5%.
With regards to the bike and rider making up 8% of the effect lets take the same 80kg bike + rider figure and work out what difference a 500g lighter wheelset would make. Just over .5% if you had a 1kg lighter wheelset (super expensive) that would be a 1% difference.
Btw are you selling the Khamsins?
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