I was riding home this evening, and there was one of those bikes modded with a small petrol engine in the bunch going through the lights at Pyrmont.

I followed him towards Anzac Bridge. As we approached the on-ramp, another cyclist overtook me and tucked in behind him.

We all proceeded up the spiral ramp thing at quite a clip, then at the top the cyclist made his move, pulling alongside the petrolhead to overtake. Petrol guy accelerated, and the two of them proceeded to race up the bridge. I followed for a short while, but couldn't keep up.

The cyclist was out of the saddle and going really hard, but was matching petrol guy.

Part of me salutes the cyclist for some awesome climbing. That was some pace you put on, into a fairly strong headwind.

Part of me thinks the whole thing was inappropriate for an SUP; they were going too fast. To be fair, pedestrian traffic was light, and there weren't any peds on the ramp. But I'm sure there were later on, and I wonder how much attention our two racers were paying to their surroundings.

And part of me is aggravated by those dratted conversions; they are noisy, they smell, and in the main they are ridden too fast by people who have lost their car licenses. (Well, I'm extrapolating that last point from a sample of one, but hey).

Views: 84

Comment by Dougie McGill on May 16, 2009 at 2:37pm
what's the legal status of these things? They seem more motorbike than cycle.
Comment by Dan on May 16, 2009 at 3:28pm
As I understand it, if the motor is 50cc or above, they are not legal. That covers pretty much all of them, I think. By riding one on the path you are doing the following things:
- riding a motorcycle without rego and insurance
- riding a motorcycle without a valid safety certificate
- riding a motorcycle without an approved motorcycle helmet
- riding a motorcycle on an SUP

Those people who got one when they lost their driving license are also operating a motor vehicle whilst disqualified.
Comment by Dougie McGill on May 16, 2009 at 9:14pm
Thanks Dan, I must admit, it's mostly weekender types who use them, rather than folk just trying to get about
Comment by Freewheelin' Franklin on May 17, 2009 at 10:16pm
There sure seem to ba a lot more of them around now than there was even a year ago, is someone pushing conversions? I saw a mower shop down at La Perouse yesterday that had a chalkboard out front saying they worked on pushbikes...
Comment by Dan on May 18, 2009 at 8:42am
I guess it's a business opportunity for the mower shop.

I know my LBS refuses to work on them; I was in there one day and a guy turns up with one. He'd bought the bike from the shop a month or two earlier, fitted an engine and then brought the bike back because the bottom bracket was loose.

The shop refused to have anything to do with it, saying he'd invalidated the warranty, and they didn't service motorbikes.

It was then that I learned he had lost his driving license, and was using it to get to work in Mosman - he said he'd 'started off on just the bike, but it was really hard work, so he'd bought the engine as a kit'.

The LBS also commented that people always seem to fit them to really cheap, entry-level bikes.
Comment by Robert Harris on May 19, 2009 at 10:26pm
He may have been legal. The unknown factor is the power output of his motor.

According to the RTA website "Motor assisted pedal cycles with electric or petrol engines are exempt from registration, provided the maximum engine output power does not exceed 200 watts. These vehicles must have been designed as a bicycle - that is, to be propelled by human power, with the motor attached as a supplementary aid only."

Source: RTA

There is no requirement that the cycle must require pedalling input from the rider for proplulsion. Rather, the formal legal requirments are that:

- The cycle be designed to be propelled primarily by human power, and
- any attached auxiliary motor(s) have a total power output of no more than 200W

So, provided his total power output was less than 200W he would have been legal.

That being said, 200W = 0.2682hp. That's not very much, and It's difficult to see any modern 50cc petrol engine producing less power than that unless it is deliberately limited.

Moves are afoot to raise the power limit to 250W (0.3353hp) and introduce a speed limit of 25km/h.
Comment by Josh on May 20, 2009 at 4:59pm
Well gee, 200W on its own is not bad. Have you going along at 30 km/h on a flat road with no wind. And if you weigh 80 kg, up a 5% slope at 13 km/h (assuming a ~10 kg bike, probably a heroic assumption given the weight of the add-on). It's a reasonably fit young male going reasonably well, say touring pace. Or a not fit young male going reasonably hard.

Typical short term (~10 minutes) power output is about 280-320W for young reasonably fit males, and if you keep that up for much longer you are pretty fit (and if you can do that but aren't racing, you probably could be).

To the extent that the power assist is a "boost" to the rider's own power, you can go very much faster (200W engine plus 300W legs gets you going at an awesome 27 km/h up a 5% hill again for an 80kg unit + 10 kg bike... and if you can put out 500W on your own for 10 minutes or more, you'll be less than 80 kg, faster than 27km/h up that hill and there's some pro teams who would like to speak with you...)

Otoh if the artificial power is used instead of the rider's power, or cuts out at the 200W threshold, then it's not great for serious riders and any reasonable rider would be faster without it. But not THAT much faster.


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