bike without single point of failure

[sjpt]

Rockrider E-ST500 water ingress

Hi, I have owned one of these (v1) for last 3 months and it’s been great. Yesterday the motor stopped working, which looking at reviews is a common problem due to water ingress. I am unable to contact Decathlon so does anyone know how I can rectify. I know it’s either the controller or bottom...

www.pedelecs.co.uk

A post by another member made me think (it happens every now and then) and to ask ...
Any engineer out there like to estimate what a bike without a single point of failure would look like?
How much would it weight?

 

[vfr400]

That's easy:

 

[Andy-Mat]

Rockrider E-ST500 water ingress

Hi, I have owned one of these (v1) for last 3 months and it’s been great. Yesterday the motor stopped working, which looking at reviews is a common problem due to water ingress. I am unable to contact Decathlon so does anyone know how I can rectify. I know it’s either the controller or bottom...

www.pedelecs.co.uk

A post by another member made me think (it happens every now and then) and to ask ...
Any engineer out there like to estimate what a bike without a single point of failure would look like?
How much would it weight?

They are called "Hub Motored" e-bikes, and often "weigh" less than many mid motor bikes! Even cheap ones can be made light!
Regards
Andy
PS. Maybe someone will eventually (if a need is seen) put together a mid motor bike where the motor drives the rear wheel, either with its own chain (bulky), separate from the riders efforts own chain.
Or possibly some other drive system. But they need to be separate as far as possible, to allow the rider with a broken chain, the possibility to use either motor power, or muscle power, to ride home. Not to have to "push".
But the results could make a mid motor bike even heavier, and therefore even less efficient.

 

[01wellsd]

This one above should be ok!


Really every bike type/manufacture/motor style have their strengths and weaknesses.
Just the same as when you buy a car you look around at reviews, talk to people who have the model you're after and then make an informed decision based on preference, risk, support and necessary features.
I think its unfair to label certain drive styles as inferior or "terrible" as I've heard lately. Sure they can all have their faults, they are machines at the end of the day. They do break down!

When I worked at Audi certain 2.0 TFSI engines burnt oil. No idea which ones, just luck of the draw. The fix? Replace all pistons and con-rods. Some even needing a new engine. Of course Audi would foot the bill if the car was in warranty, and even give contributions to the repair if the car was outside of warranty.
Other than that it was a great engine, and people still bought them in their masses, taking into account the educated risk that you could get a lemon!

 

[flecc]

Maybe someone will eventually (if a need is seen) put together a mid motor bike where the motor drives the rear wheel, either with its own chain (bulky), separate from the riders efforts own chain.

Already done years ago, the Swizzbee made in Switzerland uses a high mounted motor just by the seatpost, driving the left hand side of the rear wheel with a toothed belt. The right hand side is driven by a chain derailleur and a differential balances the two drives into the wheel.

This link explains how that works

And this link is to member KirstinS post when he bought an old one
.

 

[01wellsd]

Already done years ago, the Swizzbee made in Switzerland uses a high mounted motor just by the seatpost, driving the left hand side of the rear wheel with a toothed belt. The right hand side is driven by a chain derailleur and a differential balances the two drives into the wheel.

This link explains how that works

And this link is to member KirstinS post when he bought an old one
.

Love the look of that Swizzbee! It seems completely over engineered but so cool!
Must have taken quite a lot of thought to get the belt and the chains RPM to match. I can't get my head round how it works, think it might be something to do with magic!

 

[Darren Hayward]

Why bother. The single point of failure (the chain) fails so infrequently, and the tool and part to repair it on the go is so small and light, it's not a real concern.
A bigger concern for me is the generally poor performance and unnatural pedal action of hub motor/cadence bikes. Having had a front hub bike I can't see myself downgrading back to one any time soon.

We've had a couple of posters with mid drive motors whose cassette/chainring has worn out in only a few hundred miles. Whilst we've never gotten to the bottom of that problem it's not the fact it's a mid drive that's the real issue, its (IMO) cheap knock off or second hand parts. Although I imagine a mid drive motor might make low quality parts a bigger issue.


Darren

 

[Andy-Mat]

Already done years ago, the Swizzbee made in Switzerland uses a high mounted motor just by the seatpost, driving the left hand side of the rear wheel with a toothed belt. The right hand side is driven by a chain derailleur and a differential balances the two drives into the wheel.

This link explains how that works

And this link is to member KirstinS post when he bought an old one
.

I am unnable to find a better picture than this, which appears to have two chains!
At least it does in all the pictures I can find under the name " Swizzbee".
If there is a different setup, maybe someone can post a clear picture or two?
Many thanks for searching that out for us here.
Plus I would really like to see a bike say with shaft drive to the LH side rear wheel for the motor and Derailleur in the usual place, on the RH side. That would be something far better than the present "breed" of mid motor!

Regards
Andy


PS. pedelec screws up the pictures again. If I delete one, both are gone, sorry!

 

[01wellsd]

This is of KirstinS' Swizzbee

 

[Andy-Mat]

View attachment 37082

This is of KirstinS' Swizzbee

That appears to be a genuine vast improvement over present mid motor bikes. Thanks for the far better picture.
Andy

 

[01wellsd]

The only Pedelec I have seen with a driveshaft is The Volta by Byar Bicycles. Looks like it's a driveshaft from the pedals combined with a rear hub motor (Battery encased with the motor), and very pricey starting at 3,500 EUR!

It also comes with regenerative braking to recharge the battery a little, although the process to activate this seems a bit much! You have to pedal backwards for 3 revolutions, and after that it is a "gradual slowing"
Lucky there are hydraulic brakes too!

Full review here...

Byar Volta is a shaft-driven e-bike that might never need charging

Test-riding Byar’s chainless electric bike with all-in-one hub motor and integrated lock

www.theverge.com

 

[mike killay]

In the past 70 years I have had two chains 'break'
Neither actually broke, all that happened was that the connector became undone.
The first was when I was 8 years old. The old type sliding locking clip came off and the fish plate fell away. Luckily an older girl was there and we hunted about on the road, found the missing parts and my father refitted them.
The second occasion was 2 years ago when I had refitted an endless chain and did not get the rivet back in properly.
I now use 'Quik-links' and do not have problems, but always carry a spare one.
I really cannot understand Andy's worry about an alleged 'Single point of failure' when to me the most likely failure on a bike is a bad puncture.
Such a puncture in the rear wheel of a mid motor bike is of little account, but for a rear engined hub motor with disc brake an absolute nightmare if the wheel has to come off.

 

[Nealh]

Kirstin's Swizzbee in now my Swizzbee ( seen here close to the'Old Fort' when I took it back to Shoreham three years ago) this one now has a stable mate as I bagged another one.
The Achilles heel of the Swizzbee is it is obsolete now along with the electronics/brushed motor and the aweful 9sp Sram hub gears.
The motor isn't a coventionall hub with a thru axle, it is a brushed slim motor with a drive shaft on the LHS to carry the Gates belt sprocket.

Talking about shaft drive Kirstin regular commuter is a front hub bike with the Sussex shaft drive.

 

[Amoto65]

I really cannot understand Andy's worry about an alleged 'Single point of failure' when to me the most likely failure on a bike is a bad puncture.
Such a puncture in the rear wheel of a mid motor bike is of little account, but for a rear engined hub motor with disc brake an absolute nightmare if the wheel has to come off.

Agreed the chain paranoia is unfounded(over 50 years of bikes and motorbikes and not had a chain fail) and most likely down to poor maintenance, but as you say the rear hub motor puncture is a real pain

 

[01wellsd]

Kirstin's Swizzbee in now my Swizzbee ( seen here close to the'Old Fort' when I took it back to Shoreham three years ago) this one now has a stable mate as I bagged another one.
The Achilles heel of the Swizzbee is it is obsolete now along with the electronics/brushed motor and the aweful 9sp Sram hub gears.
The motor isn't a coventionall hub with a thru axle, it is a brushed slim motor with a drive shaft on the LHS to carry the Gates belt sprocket.

Talking about shaft drive Kirstin regular commuter now is a shaft drive with a front hub.

I always wondered what the bike in your display pic was, but could never enlarge it enough to see properly!
I am slightly jealous of you!

 

[vfr400]

but as you say the rear hub motor puncture is a real pain

Only for people that don't have a clue about these things. Why would you want to take the wheel off to fix a puncture? I've never had to do that in 10 years and about 20,000 miles.

 

[flecc]

Plus I would really like to see a bike say with shaft drive to the LH side rear wheel for the motor and Derailleur in the usual place, on the RH side. That would be something far better than the present "breed" of mid motor!

The trouble with having a drive on each side of the rear wheels is of course the combination of the more difficult wheel removal and the prevalance of punctures on bicycles. That's probably a major reason why both the Swizzbee and its successor the Dolphin both failed in the market after very short runs.

The general public have an irrational fear of punctures, as vfr400 posted, there's no need to remove a wheel to repair a puncture.
.

 

[Ocsid]

"bike without single point of failure" ???

There is of course no bike without any "single point of failure", the frame, the forks, either wheel, and even a simple puncture, the steering, etc; it is just that some get hung up on the drive and choose to look no further.
And the drive might be far from the biggest issue to live with, the bike still ought to be "scooted" along reasonably well compared to say one with a collapsed wheel or fractured fork, even the quite common puncture.

It is going to be a fruitless quest to invent a "bike" without single point of failure issues. Accepting that and minimising their occurence, impact or time to correct are more rewarding areas to address.

 

[flecc]

Talking about shaft drive Kirstin regular commuter is a front hub bike with the Sussex shaft drive.

Here's KirstinS' shaft drive commuter with front hub motor from Woosh

Link
.

 

[Nealh]

The Swizzbee rear wheel removal can be a pain so I use a Gaadi tube and Marathon tyres. The rear axle nuts have to be loctited on other wise it flies off due to the way the Sram hub with differential works.