Would riding an electric performance bike

[Twigman]

Originally Posted by Scootabout

The bloke who gave me a Vectrix to test ride the other day

that would've been my mate Trev.

He was T_Revs & Trev918 at the other place.

[Zanx]

Saw a City Sprint Vectrix today, bit whiney, certainly not silent by a long shot.

[Twigman]

Trev came round the other night in the Vectrix van with one of their Burgmannesque scoots in the back. It was dead comfy but I really don't think it's all that practical.

The largest part of the instrument display is the 'fuel tank' LOL which shows on a display how many bars of electric are left. On the other clock it calculates an approximation of the # of miles left 'in the tank'....the bike he had the other night had 2/3 of a 'tank' and an estimated range of 29 miles.

He reckoned it'd do a full charge in 90 minutes..........

Not the most practical bike in the world.

Originally Posted by Twigman

Trev came round the other night in the Vectrix van with one of their Burgmannesque scoots in the back. It was dead comfy but I really don't think it's all that practical.

The largest part of the instrument display is the 'fuel tank' LOL which shows on a display how many bars of electric are left. On the other clock it calculates an approximation of the # of miles left 'in the tank'....the bike he had the other night had 2/3 of a 'tank' and an estimated range of 29 miles.

He reckoned it'd do a full charge in 90 minutes..........

Not the most practical bike in the world.

Sounds perfect for someone with a <40 mile mainly city commute. Cheap as beans to run.

[Twigman]

The strangest thing IMO was opening the seat and seeing the mains lead coiled up in the cavernous boot which I am assured can carry a full face lid plus 18 cans of lager no problem.

[KneeDragonR1]

Originally Posted by Mr. Dazzle

It wouldn't have to be like that, you could put a control device in to make the torque characteristic almost whatever you want...the situation I described is just the most extreme possible.

Gearing wouldn't really effect it that much. If you plot a graph of tractive force at the rear wheel (i.e. the force actually pushing the bike along) against vehicle speed, it's exactly the same shape as torque vs. engine speed, it just gets stretched one way or another depending on the gear ratios.

Similalrly if you had an electric motor that provided maximum torque at minimum speed, you'd always get maximum torque at minimum speed the gearing would just change the magnitude.

True enough.

I helped on an electric car project. The torque at low rpm wasridiculousandhad to be limited because the drive line and tires could not handle it.

It did some wicked burnouts … until we broke another half shaft.

[Zanx]

People make these bikes unduly complex. What's wrong with putting a separate gearbox (the same as a million US cutom bikes) in a large frame holding a 1700w motor and three leisure batteries? Bikes like my Enfield would be perfect, separate gearbox, low c of g, lots of engine space etc.

Originally Posted by Zanx

People make these bikes unduly complex. What's wrong with putting a separate gearbox (the same as a million US cutom bikes) in a large frame holding a 1700w motor and three leisure batteries? Bikes like my Enfield would be perfect, separate gearbox, low c of g, lots of engine space etc.

Would leisure batteries be the right choice? Designed for relatively low rate of discharge, and continual topping up. I'm not an expert on these things, but surely you want a battery half way between the extremes of a typical starter battery and a typical leisure battery?

I agree, though. Simple frame, simple transmission, simple motors... like a mobility scooter on steroids! Would be great.

[Mr. Dazzle]

Originally Posted by Zanx

People make these bikes unduly complex. What's wrong with putting a separate gearbox (the same as a million US cutom bikes) in a large frame holding a 1700w motor and three leisure batteries? Bikes like my Enfield would be perfect, separate gearbox, low c of g, lots of engine space etc.

I don't reckon you'd need a gearbox...bikes only have gearboxes to compensate for the inadequacies of ICE's (narrow powerband & uneven torque distribution). Electric motors don't suffer the same faults.

1700W isn't gonna get you very far either.

Not sure the complexity arguments stands up either....even a full on electric sportsbike is gonna be less complicated than a 'conventional' bike. An engine/gearbox has hundreds, getting on for thousands, of moving parts, all operating in carefully choreographed ways. An electric drivetrain would have 1 moving part...well...ideally it would...a real one would still have less than 100 moving parts, probably less than 50, and all those parts would do is spin.

[Zanx]

Originally Posted by Mr. Dazzle

I don't reckon you'd need a gearbox...bikes only have gearboxes to compensate for the inadequacies of ICE's (narrow powerband & uneven torque distribution). Electric motors don't suffer the same faults.

Great, more room for more batteries or a bigger motor.

[Kneerly Down]

Originally Posted by Mr. Dazzle

I don't reckon you'd need a gearbox...

Probably not.
The Tesla electric car has 2 gears but 1st was only lasting a few thousand miles due to the VERY large torque. With only top gear it still did 0-60 in 5.7 seconds (vs 3.9s with 1st)

[Scootabout]

Originally Posted by Olly

Sounds perfect for someone with a <40 mile mainly city commute. Cheap as beans to run.

Yes, provided that was all they wanted to do. If they ever wanted to go for long rides they'd need a second bike. That would wipe out the economic advantage and leave green-ness only. Unless maybe they wanted two different types of bike anyway - a commuter and sportsbike, for example. In which case it might make sense. (I wonder how many sportsbike riders would be willing to be seen - alive - on a Vectrix? )

[Mr. Dazzle]

Originally Posted by Scootabout

...That would wipe out the economic advantage and leave green-ness only...

And vastly superior performance, if someone where to build a 'proper' electric bike and stop mincing about with commuter machines!