chainless bikes, well trikes

[rjb]

Its the future folks. no more black hand gangs or leg tattoo's.
https://www.icetrikes.co/products/pers- ... ist-system




Im guessing that the conversion efficiency is about 85%, which compares to about 95% for a perfect chain system, so a small loss of efficiency may not be noticed in the real world.

[cycle tramp]

Ooooohhh... I like the regenerative breaking through the drum brakes... I wonder if you could fit that to a diamond frame bike...

[Galactic]

Assuming the cyclist has already committed to electrical assistance I think this is really exciting. Of course a huge downside is that if there are any problems with the electrical system there's no way of getting home other than pushing The belt and braces effect of conventional electrical assistance is a nice thing to have and something I've already had cause to be glad of.

I do wonder how this can work together with the legal definition of EAPC ("e-bikes") but I haven't got the headspace to go down that particularly rabbit hole right now (otherwise I'd already be gone).

[Tigerbiten]

My biggest grip with this setup is speed down shallow slopes.
On my ICE Sprint I can easily reach 20mph on just a 2% down slope.
With the Pers setup you reach 15mph and now what .....
Pedalling more/faster doesn't make you go faster as the motor has cut out.
The slopes not steep enough for gravity to accelerate you faster.
So you get stuck at 15mph.

Where I can see it useful is the like of mums doing a school run with kids as no mucky chain.
Or older/disabled riders who just want to get on and go to the local shops or around the block on quiet roads/cycle paths, where they've never ridden before or done so very little therefore gears are a black art and overall efficiency is not a problem.

[Carlton green]

My biggest grip with this setup is speed down shallow slopes.
On my ICE Sprint I can easily reach 20mph on just a 2% down slope.
With the Pers setup you reach 15mph and now what .....
Pedalling more/faster doesn't make you go faster as the motor has cut out.
The slopes not steep enough for gravity to accelerate you faster.
So you get stuck at 15mph.

Where I can see it useful is the like of mums doing a school run with kids as no mucky chain.
Or older/disabled riders who just want to get on and go to the local shops or around the block on quiet roads/cycle paths, where they've never ridden before or done so very little therefore gears are a black art and overall efficiency is not a problem.

It’s really for the manufacturer to answer the question, but there’s only electrical assistance when current is flowing from the battery to (powering) the motor, as such there’s no cap on speed provided either by gravity or electrical power from the (human driven) crankshaft generator.

[axel_knutt]

It's still limited to 250W, so that's now 250W including your legs instead of being in addition to your legs as it would be on any ordinary EAPC. If you put out 100W, that's only 150W of assist left.

[mattsccm]

Practically speaking I find the above mentioned speed limit applicable to normal ebikes as well although that is probably because of the extra weight and drag.

[Brucey]

It's still limited to 250W, so that's now 250W including your legs instead of being in addition to your legs as it would be on any ordinary EAPC. If you put out 100W, that's only 150W of assist left.

yes, but you are still likely to 'get stuck' at 15mph.

FWIW I expect it to be hopelessly inefficient (and a lot more money than a conventional transmission/chaincase).

There'll probably be a market for it, but I would be quite surprised if it was big enough to create any 'economies of scale' worth speaking of.

[LittleGreyCat]

Practically speaking I find the above mentioned speed limit applicable to normal ebikes as well although that is probably because of the extra weight and drag.

I find that my eBike can comfortably exceed 15 mph on the flat or down hill.

It is lightweight, though.

[rareposter]

There'll probably be a market for it, but I would be quite surprised if it was big enough to create any 'economies of scale' worth speaking of.

"the market" appears to be recumbent trikes rather than regular bicycles so it's not exactly a massive market to begin with. If it can make inroads there though and do away with the horrendous system of massively long chains, guide pulleys all over the show and 6ft long shift cable runs then it's already got benefits.

[mig]

i appreciate the technological side of it but wouldn't fancy fixing the thing when it goes wrong. hardly the sort of job that an LBS would tackle easily and any amateur tinkering would invalidate warranties no doubt. looks more suited to 'holiday hire' than long term use.

there's a certain beauty to a bi/tricycle 'as is'.....

[Nearholmer]

Because I’m an electrical engineer, i long-ago envisaged this arrangement, which is pretty much the same in principle as, for instance, a diesel-electric locomotive with supplementary traction battery.

There is no reason why one wouldn’t be able to exceed the capped assistance speed by pedalling, and the way generator and motor ratings work the 250W continuous rating is very unlikely indeed to be a practical limitation. The rating is a thermal one, so they will overheat, damaging the insulation etc, if run “forever” above 250W, but will quite happily dissipate higher powers for shorter durations, especially under less arduous ambient conditions than they are rated at. The exact “rating curve” will depend mainly upon the thermal mass and heat paths of the machine, and all that tends to be a trade off with weight, but I’d be really surprised if the machines used don’t have curves which mean that people other than super-athletes with thighs a mile round could never overheat them.

A lot of the achievable performance will depend upon exactly how the drive is configured and how the controller is set-up, as will the transmission efficiency.

Historically, the reason such drivetrains haven’t been viable in a lot of applications, pushbikes especially, has been weight, but small motor technology has come on in leaps and bounds in the past c10 years, and power-electronics have made control systems much lighter too.

[rareposter]

i appreciate the technological side of it but wouldn't fancy fixing the thing when it goes wrong...

The issue about fixing adapted cycles, trikes, cargo bikes, tandems etc is a common one. Anything out of the ordinary that doesn't easily fit through bike shop doors or into bike workshops is invariably a pain to fix no matter what the drive system or the presence/absence of anything electrical.

[mig]

i appreciate the technological side of it but wouldn't fancy fixing the thing when it goes wrong...

The issue about fixing adapted cycles, trikes, cargo bikes, tandems etc is a common one. Anything out of the ordinary that doesn't easily fit through bike shop doors or into bike workshops is invariably a pain to fix no matter what the drive system or the presence/absence of anything electrical.

whilst i take that point i think this set up would be a pain +1 to fix. looks like a "back to the manufacturer" job to me.

[Nearholmer]

All it is is two rotating machines, a battery, a controller, and a load of cables, so if it’s well weather-sealed the amount of “going wrong” will be very, very small indeed, and you’d expect to remove and replace those major modules, rather than tinker about with .the innards at home or a bike shop.

If I was going to point the finger of suspicion at any module it is the controller, because it will be software-dependant, and manufacturers can’t resist “improving” software, and then ceasing to support superseded versions.