Have you wasted money on super light new wheels?

Ok. If you want to accept a
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.

Nope, Trek 1.5 so probably a
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

With the Planet X wheels they
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”.

It’s not all about weight, or
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 completely agree with
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.

Gkam84 wrote:I decided, just

Gkam84 wrote:

I decided, just to get a bit fitter and loose a couple of KG from…..around my waist line :evil:

And how is that going for you?