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by rfryer
1 Jun 2013, 8:43am
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

jfarnhill wrote:Quick note from me that I've given up on my Alfine11 and I'm back on a derailleur'd bike.

Sorry to hear that. Have you got rid of the Day One altogether, or are you converting it to something more interesting? Maybe view this as an opportunity to try out the NuVinci hub???
by rfryer
22 May 2013, 7:17pm
Forum: Does anyone know … ?
Topic: Cadence
Replies: 340
Views: 34058

Re: Cadence

samsbike wrote:I have read the whole thread and still am at a loss at why cadence should be measured at all and how it helps develop performance. Can someone please enlighten me.

Delivering a given power output has different physiological demands at different cadences. It's clear that extreme cadences are impractical - imagine trying to push out 300W at 5rpm, or 300rpm. In between these extremities lie a range of usable cadences which will stress your body in different ways.

Lower cadences will tend to put additional pressure on your joints as the pedals are harder to turn. Also, the natural tendency of the bike is to slow down between the power phases of the pedal stroke, and this slowing and subsequent re-acceleration is inefficient. The lower the cadence, the longer is this period of potential slowing, so the more effort is required to resist it, using less efficient muscles.

In contrast, higher cadences have the potential for a smoother, lighter action (less pressure, shorter periods of low power output), but are likely to be more tiring in a cardio-vascular sense. When cadences get very high, joints again become an issue as the pedalling action becomes less controlled.

It follows that it's worth experimenting with how your own body copes with different cadences, to find out which gear will allow you to cycle most efficiently in a given situation (where "efficiently" might mean "to maximize power" or "to minimize tiredness"). Both the experimentation, and the use of that data, require measurement of cadence (or calculation of same from speed and gear ratio).

[My perspective on this is as a some time road cyclist who has been riding mainly fixed gear for the last year. I really enjoy being forced to pedal at widely differing speeds, and it has noticeably improved my speed on the road bike. So, if you don't want to go through the hassle of measuring your performance at different cadences, just get a fixie and improve all of 'em! ]
by rfryer
15 May 2013, 8:35am
Forum: Bikes & Bits – Technical section
Topic: Oval chainrings (e.g. Biopace)
Replies: 33
Views: 1730

Re: Oval chainrings (e.g. Biopace)

One useful thought experiment is to consider an extremely elongated chainring, ie, a bar with, say, 19 teeth down each side, and one tooth at each end. It's then quite obvious, to me at least, that the amount of chain pulled off the sprocket by a small angular motion will be greatest when the bar is at a tangent(*) to the sprocket, and less when the bar is pointing at the sprocket.

Can't be bothered with the maths, but I'll happily assert that I'm correct! :mrgreen:

(*) EDIT: "tangent"? That's not at all what I meant. :oops: I think that I meant that a line perpendicular to the bar, passing through the top end of the bar, was also a tangent to the top of the sprocket. Or something :?
by rfryer
13 May 2013, 2:57pm
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

In case anyone's interested, I'm now in a position to ship out small quantities of Shimano's snake oil at reduced (though still hard-to-justify) prices.

See my classified ad at http://forum.ctc.org.uk/viewtopic.php?f=32&t=75784
by rfryer
13 May 2013, 9:45am
Forum: Bikes & Bits – Technical section
Topic: bike positioning help please
Replies: 93
Views: 177438

Re: bike positioning help please

I like the methodology described here.

Basically, it's all about positioning the saddle such that your normal riding position, when pedalling with your normal technique, results in minimal weight being carried by the arms. Once you've achieved this, you can simply swing your arms forward and get a feeling for where the arms ought to be.

Unfortunately, to use this at home, I think you need to already have a good understanding for what "feels" right.
by rfryer
11 May 2013, 9:13am
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

Brucey wrote:FWIW I think the flushing procedure should remove most of the metal debris, but only if all the parts are very well demagnetised; otherwise it tends to stick around.

That's a really interesting point. A few weeks ago I stripped the freewheel on my road bike, and discovered that of the three pawls, one was not fully opening and looked as new, one was apparently working and looked like new, and one was hooked, worn at the tip, and quite strongly magnetized. I assume the pawl had been magnetized through wear. But it is a concern that a pawl that is getting worn can become magnetized and attract the abrasive particles that will help finish it off!
by rfryer
8 May 2013, 4:42pm
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

OBH wrote:I'm not attacking the guy. I'm just asking a perfectly reasonable question: how is the cost of the oil justified?

I suspect it's justified by the fact that the seller paid slightly less than that for it, and wanted to make a small profit. Just guessing, though...
by rfryer
8 May 2013, 3:41pm
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

Speaking as someone who may enter the eBAY fray soon, I think it's a little unfair to attack sellers for the fact that Shimano sell a product for which they don't specify a standard oil specification, and for which they mandate only their own oil should be used. It's not as if the seller is insisting that you use it.

FWIW, £12 for 50ml is around the retail price for the oil. In bulk, it reduces to £3.60. I hope to be able to package and ship 50ml for around £6, or 100ml for £9. PM me if you're interested, and I'll firm up the numbers.
by rfryer
8 May 2013, 9:23am
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

That's great information. Sadly, the timing couldn't be worse; I ordered my litre of Snake Oil yesterday!

And one minor correction; you'll need green food colouring, not red, if you want your cheapskatedness to be less chromatically jarring!
by rfryer
5 May 2013, 10:09am
Forum: On the road
Topic: Riding on wooden wheels or M+ tires
Replies: 15
Views: 1318

Re: Riding on wooden wheels or M+ tires

My reading of the Bcycle Quartery ttyre drop graph here is that, assuming the M+ is at 32mm, you "should" be running something around 55psi front and 70psi rear (that is assuming you meant a weight distribution of 45/55).

I tend to up these figures a little to cope with hills and additional pinch-flat protection, but 110psi does seem a little steep.
by rfryer
4 May 2013, 7:41pm
Forum: Bikes & Bits – Technical section
Topic: KMC 'alleged' quick link
Replies: 30
Views: 1756

Re: KMC 'alleged' quick link

Assuming you're talking about a quick link with two identical plates, each with a keyhole for the rivet, I use a pair of needle nose pliers diagonally across the link, catch the edges of the two plates and squeeze them together. Hey presto!
by rfryer
30 Apr 2013, 5:56pm
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

@bobc That's encouraging - I'll stop worrying for the moment!

Do let us know how you get on with the scary departure into non-approved oils!

For the less brave/impatient of us, If I had interest in 500ml or more of oil by the end of this week, I would aim to send out 100ml bottles for no more than £15 including postage by the end of next week. That compares to £24 from Shimano. Otherwise, I'll just buy another teeny, tiny bottle for myself :(
by rfryer
30 Apr 2013, 1:55pm
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

@michael42 - I won't argue with your thoughts about preferring a Rohloff equipped bike if spending 1.7K. If I'd had the option, I'd have been tempted too, although I'm not aware of any Versa-style shifters that work with Rohloff, and I do prefer drops. However, I got my Day One as an insurance settlement, and Rohloff equipped bikes weren't on the menu. I do take issue with Genesis, in particular, who create newer and more expensive bikes based mainly on tubing type, but make no marketing effort to explain the improvements (if any) other than "Oooh, it's got an 853 sticker!". Proper winds me up!

Having said that, I don't agree that "You should be able to cycle like a pro" on any IGH hub equipped bike. Bike pros don't ride IGH transmissions, and there's probably a reason for that. I've no problem with adopting different riding styles on different bikes, to ride them sympathetically. Taking your comparison with car gearboxes, I'd happily change gears under load and high revs in a paddle-shifting Ferrari, in a way that I'd not dream of in a small hatchback. That's because I know the underlying technologies differ and will therefore accept different treatment - and I see a direct parallel with derailleurs and IGHs.

The 200-mile oil change interval was my daft idea (and the oil's only £90 a litre in bulk)! I just feel that there's more likelihood of generating swarf from the gears during the break-in period, so I decided to make oil changes more regular earlier on in order to minimize the risk of particles in the oil causing problems. I'll increase the intervals over time, and as I discover that the oil is generally free from larger particles. Anyway, the oil change process isn't much of a hardship - I'm always curious as to what I'll find in there!

Finally, I've not seen much evidence of the bike industry recommending the cossetting of Alfine 11 hubs. It's mainly been word of mouth on internet forums, and I've used this to establish a regime which I hope will give my hub a long and crunch-free life. Shimano seems to be happily honoring warranties on the these hubs, and I'm sure would be very cautious about admitting that they were inadequate for "normal" use.

PS - I'm thinking of buying a litre of SG-S700 oil for the Alfine 11; would any forum-ers be interested in buying smaller quantities off me at cost?
by rfryer
29 Apr 2013, 11:38am
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 11 - Longer term reliability
Replies: 830
Views: 175164

Re: Shimano Alfine 11 - Longer term reliability

@jfarnhill - I think I'd be looking to get the hub replaced if it was as noisy as your seems to be. It's no good if you can't rely on it.

I did a 70-mile sportive on mine a couple of weeks ago, the flooded-out Tour O the Borders, and it was pretty uneventful. In the gale-force winds and hub-deep floods, it was nice having a solid, dependable bike. No regrets leaving the deep-rimmed carbon road bike at home that day!

But this Saturday, I had my first slip-up from the hub. Sitting comfortably (and quietly) in gear, and had been for some time, when the gears did a quick slip, then instantly recovered. But nothing else bad happened in the next 20-odd miles, so I'm hoping that it was just a one-off rather than the start of my Alfine 11 nightmare!

One other thing on Saturday - I was barreling down Glen Shiel (on my Day One Alfine 11) pedaling into a bit of a head-wind, swooping round the bends, and was surprised to run out of gears. I looked at the speedo, and was doing 40. I hadn't had a clue I was going that fast; the bike is incredibly solid and stable. I'd have been quite nervous doing that on my road bike!
by rfryer
26 Apr 2013, 1:00pm
Forum: Bikes & Bits – Technical section
Topic: eliptical chainring - want to try one?
Replies: 61
Views: 8628

Re: eliptical chainring - want to try one?

Surely some mistake - you don't get the ball of your foot underneath the pedal, do you? :shock: