What to make of 'Stress Testing' and it's results?

Its a common theme on YouTube and since the advent of the 'Does it blend' YouTube channel a lot of people have stress tested and uploaded their results. Often the suspense of what is going to happen next keeps the viewer watching, even more so if its a product they are looking at purchasing.

And that brings me onto Electric Unicycle Stress tests.

Electric Unicycles were first designed to fill a need; the last mile commute.

When Speedy Feet started back in 2014 there were very few decent units on the market, until Ninebot brought out the Ninebot C.

This thing had a massive 450w motor and 320wh of battery power (the model before this had a 210wh from memory and prior to that a China only model with 110wh), it could carry you at a staggering 14mph and do almost 14 miles on a full charge. It was incredible and far beyond anything that had gone before it.

It opened up a new world of possibilities beyond just the last mile commute.

In fact, shortly after Speedy Feet started toying with the idea of doing a massive ride for charity, we played with several designs, which included increasing the battery size. This led to the first 200 mile ride on an electric unicycle. You can see that very expedition here.

200 mile charity ride

We did this trip at an average speed of around 8-9mph over a course of 3 days. Wow, things have advanced quite a bit since then!.

One thing that happened with our sales of the Ninebot C (and subsequent C+, E, E+ and P) was that we had several control board returns a month (yes, you read it right several a month), the cause on almost all of them was not a manufacturing defect but more user error (which from the outside you could flippantly/ignorantly say was a fault), the machines were simply not designed to go flat out at 14mph all the time. They were not built to climb massive hills, they were not designed to carry the heavier than usual rider, or go the distances that the battery could take them in one go

Manufacturers adjusted to the market demand (and continue to do so), lets fast forward to now, we have machines which have 10 times the power, 4000w motors, 3200wh of battery storage and a voltage jump from mid 50v's to double at 100v being chucked through the motors. And you know what? Board failures have dropped drastically, its almost never now, the only exception is riders doing something really silly, but all in all hardly ever have to replace a control board due to an actual failure under normal usage - it does happen, but its rare, across all brands we do. All the components are beefed up to such a standard that you have to be on the extreme end of things (far beyond normal day to day riding) to have issues. The number 1 killer above and beyond all others is going too fast.

I will let you into a little secret, despite all the crazy stuff I have done (200 mile ride, 1080mile charity ride through 5 countries carrying ~15kg over 13 days) and all the mental trail riding, jumps, drops and water crossings; I have not written off a machine or blown a board....at all, not ever since 2014, riding at least 80 different machines over 10,000's of miles.

The only exception was under 2 unique circumstances,

1. Control Board (Actually, thats to broad; it was 5 MOSFETs out of 12 on the board, the rest of the board with all its components was fine) on the 1080 mile charity ride blew at around 6-8mph whilst climbing a very steep hill in Yorshire after my wheel had covered ~800 miles / 1300km (PS Jon who I was riding with wheel was fine the entire trip) and

2. A customers wheel which they had damage failed on me outside Speedy Feet's HQ when I was travelling at no more than 10-12mph, causing one of the worst injuries I have had.

I have broken no bones or done any serious harm to myself, nor machine. Again, thats since 2014 and over 10s of thousands of miles across at least 80 machines. Rain, snow, sun (even in Spain).

Does this make me a super duper rider? Is this my point? No, its doesn't and no its not my point. I ride with a mindset of a rider who is trying to care for his machine but also have fun, and get to where he wants to go as soon as possible. There are many others like me, but there is also another set of riders, riders who wish to go as fast as possible to get the biggest thrill as possible and to have the most fun they can and in the process throwing caution to the wind.

We have seen a switch from several failed control boards each month to several injured people per month (not many are our customers thankfully!), the components have come a long way.

And this brings me on to the stress test:

"Stress testing (sometimes called torture testing) is a form of deliberately intense or thorough testing used to determine the stability of a given system, critical infrastructure or entity. It involves testing beyond normal operational capacity, often to a breaking point, in order to observe the results"

Source: https://en.wikipedia.org/wiki/Stress_testing

Some viewers (voyeurs?) of these stress tests latch onto the results and then laser focus in on the failings and use it to decide how good a wheel is.

On the surface this seems logical, for example if something fails at 25mph and you want to go 30mph and they say it will, then take the warning and steer clear, but sadly the net result tends to be that people will write off a wheel in its entirety, whilst overlooking some important facts in how the result came about. They can even be put down to early release bugs and niggles (sometimes they are).

A wheel failing at 25mph when perhaps for example it should do 30mph is not enough information to get to a conclusion.

There are several factors that we need to take into account to draw a safe/unsafe conclusion:

1. Weight of rider (including clothing).

2. Battery % at the time

3. Tire pressure

4. Elevation (flat or on a hill)

5. Terrain (Tarmac, Sand, Mud, Grass)

6. Temperature

7. Milage on the wheel in total and purchase date

8. On the latest firmware or not?

Once the list is answered then a conclusion can be drawn, if any of the answers are out the 'norm', for example, the temperature was 45c or it was climbing up a mountain (or both perhaps!) then you could rightly say these are outside of the normal and constitute a stress test (intentional or not by the rider).

If you want to lengthen the life of your machine keep all those options in the 'normal' range as much as possible. i.e. no mountains, no running on a almost flat tire, no riding in sand (or salt water to that matter!), no riding in extreme temps, not running on low battery; you can venture into doing one of these things on the list that is outside the 'normal' range, but as soon as you do, be aware you are stressing things out and increasing the chances of a failure and once you start compiling multiples on this list then you drastically compound the issue/s and are highly likely to see a failure.

On the box / on the manufacturers literature, it might say a machine can do 50mph, but this, like all information from manufacturers is the maximum it can do in optimum circumstances - usually in a lab, just like when a car maker says their car can do 80mpg, that test was most likely conducted on a ramp with the wheels of the car off and it running a tick over, I mean, they are not lying, but its stretching it a little, but its a practice that certainly has been regularly done in the past.

So where does this leave us?

Well something we introduced quite some time ago was our series of videos on each wheel to tackle this exact thing, because at the end of the day we want to see people having great fun on their wheels and for those wheels to have a good life span (this comes at great cost to us - financially and in terms of time - we purchase these test wheels, we are not given them, some people dont realise that!).  

We do the first video, second 250km video, 3rd 650km video and lastly the 1000km update and final thoughts.

This gives ample opportunity for any potential bugs to be ironed out / found out.

If we haven't discovered it by that point it has to be said, there really cant be much of an issue can there (if there are niggles they are raised in the review and you can from there decide if its for you).

Can something be missed in these review? Very unlikely, you see the brilliant thing with our reviews is that each wheel, each mile we become experts, more and more so, our horizons are very broad now at this moment and can only get broader as more and more wheels get under our feet and we add more and more miles. When you take that into account, our evaluation with the 4 cornerstone videos we do on a wheel are an incredibly valuable insight to anyone looking to purchase.

Secondly, we dont sell wheels that are junk, it would be crazy, its incredibly costly to maintain a true 2 year warranty if the wheel you get from us keeps on failing, what a silly game it would be to play getting stuff thats junk in and reselling. There is a reason we are still around, and selling junk wheels is not it. (Is it possible to have a wheel that fails from us?, yes, of course; but you can be assured this must be outside the 'norm', otherwise we just wouldn't sell it, again, that would be crazy).

Is there anything wrong with Stress Testing?

Remember: 

"Stress testing (sometimes called torture testing) is a form of deliberately intense or thorough testing used to determine the stability of a given system, critical infrastructure or entity. It involves testing beyond normal operational capacity, often to a breaking point, in order to observe the results"

Source: https://en.wikipedia.org/wiki/Stress_testing

There is nothing wrong with Stress Testing, and it pushes makers of wheels etc to further improve, but where it crosses the line is when the expectations of a wheel not to fail under these extreme conditions takes place, and then it becomes unreasonable. (see list of questions above, combining them outside of the 'norm' range is begging for a problem to happen).

If it leads to viewers rejecting a wheel based on the fact that ultimately it failed in a stress test, then sadly no wheels would ever be sold (I can get 100% of wheels to fail, I know the routes to killing wheels - some of them are that list above - but I use that to ride with due care and attention instead, so I can claim since 2014 the record I currently have). Could that change? Absolutely, a mechanical failure from a manufacturing error could cause that to change, and I could potentially get injured, and I would report as such...and if it happened again on a repaired/second version of that model we would not sell it until it proved reliable.

 

The only real reason to reject a wheel purchase based on a stress test is if you are going to be using it in the exact conditions witnessed in the Stress Test. (which leads to an endless loop of tests having to be done, for example, there maybe wheels that accomplish riding in super hot climates, or that can make it up a mountain, but can it do it 100 times over 100 days? what if it can only do it 10 times and then breaks, is it no longer a viable wheel? Is it no longer good enough? Do you need another form of transport?).

If you are still with me, I would like to say one more potential point:

People are not always accurate in their reporting (hence why we ourselves do 4 big review videos on each model of wheel, just in case the first video we miss something we can grab it on the second, or 3rd or 4th, chances of missing something is unlikely especially over 1000km, of course it also allows things to develop that might not have been in 1,2 and 3 video).

Sometimes there is an alternative motive, unless you know personally the reviewer, how do you know their motive or their experience in such matters? There are only a handful of reviewers out there we would trust in their word based on the experience they have; others we take with a pinch of salt. If a review pops up claiming calamity of a specific brand of wheel, do the same, pinch of salt.

I would highly recommend waiting for our 4 foundational videos to be produced and listen to what they say.

As for stress testing, thats not something we will do (in the same way we dont do top speed tests), there is a place for it, but we will continue to use the wheel in the 'normal' range.

Bless you all and I hope this sheds some light and creates some interesting thoughts and ideas around the subject of stress testing electric unicycles.

Ride safe and keep happy!

Worth reading also our '3 Pillars' approach:

3 Pillars


5 comments

  • Hi Ian – interesting article on stress testing. I watched Marty’s “Overheat hill” video on the Veteran Sherman and left some comments. I do like the videos like this and like Fantomas, whizzing around Moscow at 45mph. Wrong Way – telling you how to climb steps and gradients etc. Better still I like Kuji Rolls video’s amazing talent on a wheel. But do I aspire to doing this myself – Nooooo. It will lead to more durable wheels for sure, it’s very entertaining. But it’s dangerous even for them – lethal for someone without the required skills. I aspire to do what you seem to make look easy. I want to look super comfortable, I want to be able to turn left and right on whim, stop start, forward and backward, not quick but apparently as easily as if I was walking. Your video’s are really informative, even you are doing more than most of your Customers will submit their wheels to I’m sure. Just slightly different perspective. I bit more grounded (if you will excuse the pun), and a bit more relevant to your Customers. Keep up the good work – your doing a great job. So back to the stress testing, there are extreme riders out there (and all power to them) doing some amazing things, but this is not the norm. I think as long as Joe Bloggs realizes he’s Joe Bloggs and not James Bond he will be fine.

    Robin Ridge
  • Nice article Ian. It does make me sad that there will always be people who watch some of my videos and say, “well, so much for buying that wheel. I’m going to buy X instead”. I think the majority see if for what it is and don’t give up on the wheel.

    The two times that I actually broke a wheel (Nikola and Veteran) have resulted in changes to the wheel, so they did serve some function to make the wheels better :-)

    Martin G Backe
  • Great and well-written article. I always take stress-tests, like Marty’s ‘Overheat Hill’ adventures with a pinch of salt, and I’d certainly not let such things influence a purchase. I am NEVER going to come close to duplicating such conditions – even though to be fair, Bath is a steep hilly place with bad roads. Using a wheel for the type of rides I like is more important than buying one for type I don’t!

    Matt McArdle
  • Very interesting and informative read Ian ,as I mentioned on Facebook you are the only seller I know that carries out these tests. You are a credit to the community as a hole Keep up the good work.

    Paul Edward Binney
  • Great blog, anything can be made to fail as you say. I know from my years on fast bikes how reviews have to be read between the lines sometimes and with a packet of salt handy on occasion! Trust in a purchase is necessary and that comes in a complete package with Speedyfeet!

    steve blaney

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