A limerick a week #189

On yer bike!

I’ve embraced an up-and-down cycling route that is close to home for some exercise during lockdown. There’s a couple of uphill drags on the route and a short ramp into one of the vlillages en route, but, what goes up must come down, so there’s a couple of fast downhill sections too.

It struck me that riding it would provide an interesting contrast between my road bike and my electric bike, a Brompton-with-a-battery. Would the benefit of power assistance on the uphill sections be sufficient to allow a folding commuter bike to beat the time set on a road bike over the entire route? Would the Brompton’s commuting pedigree make for a more comfortable ride? Dare I wear lycra on a Brompton? There was only one way to find out!

It wasn’t obvious to me which would be the fastest over the entire route. In UK law, power assistance on a bicycle is only permitted up to a speed of 15mph; at greater speeds it drops out completely. And the electric Brompton isn’t a road bike. It’s a heavy, folding, commuter bike with platform pedals (no toe clips) and on the flat (or slight incline) it takes a bit more effort to maintain speeds above 15mph than on a road bike.

Power-assist should make the uphill drags a bit easier, but on the fast downhill sections I suspected that the Brompton would be outclassed by the road bike due to the latter’s lower gearing, an inability to adopt an aerodynamic tuck whilst riding it, and my cowardice – beforehand, I wasn’t sure if the Brompton’s handling characteristics and brakes were conducive to a reckless downhill thrash.

(The Brompton’s small wheels make little if any difference to performance, per se, as has been shown by the Moulton stable of road bikes – as Cyclist magazine said in 2017: The Moulton bicycle can lay claim to a number of accolades. Jim Glover set the (still unbroken) conventional riding position, unpaced land-speed record at 82.52kmh aboard a Moulton AM Speed in 1986.)

So, this is the route (the lettering indexes the different sections that I found useful to define – two sections, A→B and C→D are traversed in both directions):

Brodie Wood / Maryculter / Blairs – South Deeside

And this is the elevation:

Route elevation (relative rather than absolute as my Garmin’s altimeter was uncalibrated)

The length and ‘classification’ of each section are given below along with the time taken per section on each bike. NB. The weather was similar for each ride, dry and sunny with a fresh easterly breeze, and if the times look modest then be aware that although I am not quite un citoyen âgé, neither am I un poulet de printemps and I carry ‘excess baggage’!

Positive speed & time difference means ‘electric’ is faster

Well, it turns out that for this route, the uphill power-assist trumped the downhill and on-the-flat speed of the roadbike. I was right about the Brompton’s gearing. I spun out at about 30mph on the fast downhills whereas I could have kept pedalling beyond 40mph on the road bike, but there were too many blind corners on the narrow roads to do so safely.

Nevertheless, I was impressed by the Brompton’s handling and brakes when going fast, which meant that I could be braver on it than I thought, so the downhill advantage of the road bike was not as great as I’d anticipated.

Going uphill with power-assist was still quite hard work ‘cos I was giving it a good shot, but it was nowhere near as hard as using leg power alone and the speed advantage was considerable.

Anyway, the Brompton was, on average, just shy of 2mph faster on this route than the road bike, but did it give a better ride? Well, the Brompton was comfier en bas à l’arrière, but that was only noticeable on the most broken bits of tarmac and what let the Brompton down, comfort-wise, in my quest for speed was its gearing. It has a wide range, but only 6 gears compared to the 22 on my road bike.

That made for an uncomfortable ride because too often it was impossible to ride at my preferred cadence. I would either be spinning too fast or grinding it out at too few revs. That doesn’t matter if you are riding purely for recreation because you can modulate your speed to match the gearing and your favoured cadence instead of trying to go flat out all the time.

You also need to take account of trip duration. Full power-assist on the steeper uphill sections and low-assist on the gentler uphills and flat does, of course, eat your battery. I once pedalled the Brompton up a long drag on the Black Isle sans battery and it was hard, hard work, so it’s a good idea not to run out of juice or, as the Moulton people say: “if you want a folding bike, buy a Brompton. They’re really rather good. But if you want to ride a bike, buy a Moulton!”. Battery life aside, platform pedals and power-assist at junctions and roundabouts makes for an altogether more pleasant experience if you are riding around town.

So, in my little comparison, the Brompton won on speed and the road bike provided the more pleasant ride, but, horses for course, and both are more suited than t’other for doing what they do best. 

Here’s the limerick:

A cyclist went out for a ride
And thought t’would be fun if she tried
To freewheel downhill 
And show off her skill, 
By perfecting a motionless glide

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LanterneRouge

😎 - Former scientist, now graduated to a life of leisure. - Family man (which may surprise the family; it certainly surprises him). - Likes cycling and old-fashioned B&W film photography. - Dislikes greasy-pole-climbing 'yes men'. - Thinks Thea Gilmore should be much better known than she is. - Values decency over achievement.

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