Search found 725 matches

by rfryer
26 Jul 2013, 7:48pm
Forum: Does anyone know … ?
Topic: Asymmetric chainrings.
Replies: 137
Views: 8138

Re: Asymmetric chainrings.

Brucey wrote:That no-one has published such test data (I think... anyone know different?) says that such a test hasn't been done, or that the results were either secret for some reason, or (more likely) not conclusive.

I suspect that testing of this nature has been done, and has been conclusive. As far as I know, Bradley Wiggins and Team Sky aren't sponsored by Osymmetric Chainrings, and they make extensive use of technology to identify the "marginal gains" that they employ in an attempt to get the edge on the opposition.

Given this, I can't see any reason that Wiggins would use egg-shaped chainrings unless he had identified in testing that they make a real difference to his performance.

Turning this around, I'm quite curious about why some people are determined to write off non-round chainrings as snake oil. I think that the arguments as to why they should work are quite compelling, and are borne out in practice. Why the reluctance to accept that there might be a benefit?
by rfryer
25 Jul 2013, 2:40pm
Forum: Does anyone know … ?
Topic: To Road Bike Or Not To Road Bike?
Replies: 53
Views: 5327

Re: To Road Bike Or Not To Road Bike?

AndyBSG wrote:Another question to throw in the mix, exactly how much difference is there between a road bike and a cyclocross one?

Looking at a few cyclocross ones online and they all seem to have dropped handlebars, thinner tyres, etc. I guess cyclocross sit in between road and hybrid?

I spent a few years using a Specialized Tricross as a do-it-all bike. This was the 2007 model, with triple chainset and a little racier than the current Tricross.

It did the job well. I could train on it with the local road club, ride 100 mile road events, then get further up the approach roads to Munros than a lot of people managed on their mountain bikes. Compared to a road bike, it had more solid wheels, a lot more clearance for the tyres, and more mud-friendly brakes. The wheels would comfortably take tyres from 25mm to 32mm+, so you could choose appropriate rubber for the ride you planned.

I stopped using it when I got a proper road bike, which fitted my needs more completely for most rides. Then it got stolen, and I replaced it with a more touring focussed bike. That combination suits me better, as I'm really more of a road cyclist.
by rfryer
19 Jul 2013, 11:27pm
Forum: Bikes & Bits – Technical section
Topic: Brake Caliper/Headlight Compatibility
Replies: 4
Views: 364

Re: Brake Caliper/Headlight Compatibility

Thanks - that would work. Any idea which model of caliper that is? Mine has the top left arm coming into the centre of the caliper and it fouls the bracket.
by rfryer
19 Jul 2013, 9:44pm
Forum: Bikes & Bits – Technical section
Topic: Brake Caliper/Headlight Compatibility
Replies: 4
Views: 364

Brake Caliper/Headlight Compatibility

Help!

I'm wanting to fit a B&M Luxos headlight to the fork crown on my road bike. Unfortunately, it's not compatible with the existing (Tiagra) brake caliper; the top arm with the cable stop fouls the mounting arm for the headlight.

Can anyone recommend a (cheap) caliper with space above the centre bolt for the light bracket? From pictures it looks as the Campag ones are generally better shaped than Shimano, SRAM and Tektro, but I've not seen one in the flesh.

Thanks!
by rfryer
19 Jul 2013, 10:38am
Forum: The Tea Shop
Topic: BBC and Cycling
Replies: 35
Views: 4759

Re: BBC and Cycling

I don't think so - you'd fall foul of the "you only use TV receiving equipment that is powered solely by its own internal batteries" rule. On the other hand, if you mount the whole shebang, batteries, inverter and all, into a big carboard box labelled "TV receiving equipment", then maybe you could just about get away with it :lol: :lol:
by rfryer
19 Jul 2013, 9:58am
Forum: Does anyone know … ?
Topic: Asymmetric chainrings.
Replies: 137
Views: 8138

Re: Asymmetric chainrings.

I don't think that magnitude of the pedal force (which I agree is surprisingly high toward the bottom of the pedal stroke) is of much use in this context. What we care about is the force perpendicular to the crank, pushing the chainwheel round, and this is generally accepted to be at a maximum around the 3 o'clock position (I've seen this in literature, and also on the display of a WattBike that I was pedalling carelessly).

So I think that I'd argue with the proposition that "this interia can be (and is) turned into useful work on the pedals", either in the normal case (see evidence above), and with Biopace. I can't see how the major, vertical component of the inertia can add much to the pedal stroke within about 40% of bottom dead centre, when we really start to want that extra power.
by rfryer
19 Jul 2013, 8:56am
Forum: The Tea Shop
Topic: BBC and Cycling
Replies: 35
Views: 4759

Re: BBC and Cycling

meic wrote:According to TVLA "No matter what device you use". They send me a frequent letters on the subject. :wink:

It is quite likely that rumours of handhelds being exempt is due to not needing an additional licence to use one

You're right - you don't need a licence if:
- Your main address is covered by a TV Licence
- AND you only use TV receiving equipment that is powered solely by its own internal batteries
- AND you have not connected it to an aerial or plugged it into the mains.

Sorry to spread misinformation!
by rfryer
19 Jul 2013, 8:23am
Forum: Does anyone know … ?
Topic: Asymmetric chainrings.
Replies: 137
Views: 8138

Re: Asymmetric chainrings.

Brucey wrote:if an oval chainring is oriented so that the leg speed raised on the downstroke vs a round ring (i.e. 'the biopace way') then the argument is that this increases the kinetic energy and inertia available to carry your legs through the dead spot.

I see what you're saying, but don't think Biopace is the solution. The "problem" that both asymmetrics are trying to solve is the lumpy power delivery inherent through using our legs as pistons. This has a tendency to accelerate the bike through the powerful part of the stroke, then slow during the dead spot.

Both types of asymmetric chainring aim to smooth out this power delivery.

Biopace's solution is to use some of that spare additional energy during the power stroke to store rotational kinetic energy in your feet, that will help in pedalling through the dead spot. I'm not convinced by this; my feet aren't massive enough to store the kinetic energy to get me through the elongated dead spot. YMMV :lol:

The more "normal" asymmetrics smooth out the power delivery by allowing your feet to move more slowly during the power stroke (when you can support a higher gear), and then more quickly through the dead spot (when you need a lower gearing). By shortening the dead spot, you smooth the power delivery, and also reduce the time spent in the more fatiguing part of the pedal stroke. More efficient, less tiring, win all round. I should be writing marketing speil for these guys :mrgreen:
by rfryer
19 Jul 2013, 7:44am
Forum: The Tea Shop
Topic: BBC and Cycling
Replies: 35
Views: 4759

Re: BBC and Cycling

Mick F wrote:The licence is for watching television broadcasts as they are broadcast, by any method of reception. ie "live".

As far as I'm aware, you don't need a licence to watch live broadcasts on a battery powered receiver, including phones and tablets.

That leaves a bit of a grey area for facilities like Apple TV, where you can stream video from your battery powered device to your mains-powered TV.


Back on topic, though, I'm quite glad the BBC tends to forget about cycling. Races often occur during the day, so a lot of fans will watch them later, and it's good that the BBC hasn't blurted out the result in the meantime!
by rfryer
18 Jul 2013, 10:58pm
Forum: Does anyone know … ?
Topic: Asymmetric chainrings.
Replies: 137
Views: 8138

Re: Asymmetric chainrings.

hubgearfreak wrote:sheldon's written an article. http://www.sheldonbrown.com/biopace.html

Thanks for the link - I'd not seen this. Having read it, I was left wondering if it was one of his April Fool articles :?: I'm amazed that he seemed to swallow the notion that accelerating the feet through the power part of the pedal stroke would somehow supply a benefit at top dead centre. Most rings these days use the power part of the stroke to accelerate the bike instead, thus easing the transition through top dead centre.

For the record, I have used Rotor Q-rings extensively, but can't ascribe any specific performance gain to them as I changed a lot of my kit at the same time as I started using them (resulting in an overall perfomance gain of around 10% over 8 hours). My perception, though, is that they make low cadence climbing much smoother, and also that I don't fatigue as quickly.
by rfryer
18 Jul 2013, 4:12pm
Forum: On the road
Topic: Beckoning on
Replies: 33
Views: 3309

Re: Beckoning on

I would never beckon another road user to overtake, and when driving, I would never commit to a manoeuvre based on another road-user's beckoning. The former blurs responsibility, and the latter is simply daft :lol: .

What I will do, when cycling and wanting a car to overtake, is to make a point of looking back at the car, and positioning myself clearly in secondary position. That way, the driver can see that I'm aware that they're there, and that I'm comfortable for them to overtake, but the decision to go remains entirely their's.
by rfryer
16 Jul 2013, 8:38am
Forum: Touring & Expedition
Topic: Alfine 11 - a question
Replies: 2
Views: 488

Re: Alfine 11 - a question

My Genesis Day One came with 40/18. That's OK for general road riding, but gets a bit grindy up steep hills. I'd want it a fair bit lower for loaded touring. I certainly don't spend much time in the top 2 or 3 gears at the moment.

I believe that Shimano do 18 and 20 tooth sprockets for Alfine with chain guards, but you can also use Nexus sprockets that are sized anywhere from 18 to 23 teeth. I'd think that 23 would be a good touring option.

At the risk of spreading Fear, Uncertainty and Doubt, it's probably worth pointing out that Shimano recommend a gearing ratio of 1.9, which would mean a 21 tooth sprocket with your chainring. Some people would worry that using a larger sprocket would put too much strain on the hub; personally I'd not be concerned.
by rfryer
14 Jul 2013, 10:32pm
Forum: Does anyone know … ?
Topic: Shimano Alfine 11 oil
Replies: 62
Views: 10992

Re: Shimano Alfine 11 oil

ukdodger wrote:Dunno about that. New parts shed metal. I'd at least flush it at the first oil change.

Exactly. That's why I changed the oil half way through the first service interval. Just didn't flush!
by rfryer
14 Jul 2013, 9:12pm
Forum: Does anyone know … ?
Topic: Shimano Alfine 11 oil
Replies: 62
Views: 10992

Re: Shimano Alfine 11 oil

In case you haven't realized, the flushing oil is the same oil you use in the hub. My preference is to not bother with the flush, and instead change the oil twice as frequently. I think that you have cleaner oil more of the time, that way.
by rfryer
13 Jul 2013, 10:32pm
Forum: Does anyone know … ?
Topic: Shimano Alfine 11 oil
Replies: 62
Views: 10992

Re: Shimano Alfine 11 oil

I'm not sure where the figure of £44 per oil change came from; last time I looked it was more like £12. My personal view is that the Alfine 11 is very expensive and has a dodgy reputation for relability, so I'd rather use the official oil, and somewhat more frequently than recommended.