Search found 1148 matches

by Bez
4 Oct 2019, 4:28pm
Forum: Does anyone know … ?
Topic: Bike frame price increase after order placed and paid for legal?
Replies: 36
Views: 2348

Re: Bike frame price increase after order placed and paid for legal?

Trikeyohreilly wrote:They say Surly have put the price up to £999.


That's their problem. They sold you one for £800. If they took your money then the contract exists and you've fulfilled your obligations under it.

(IANAL)
by Bez
22 Sep 2019, 1:18pm
Forum: Fun & Games
Topic: When Pi doesn't matter...
Replies: 10
Views: 2098

Re: When Pi doesn't matter...

Yeah, of course, it’s a regular polygon. But what I meant was that whatever the OP’s measured, it’s probably not the PCD.
by Bez
22 Sep 2019, 10:56am
Forum: Fun & Games
Topic: When Pi doesn't matter...
Replies: 10
Views: 2098

Re: When Pi doesn't matter...

Let's take one of your examples, the 24t sprocket.

97.7mm is about 3.85".

24t is 24 1/2" links, so the circumference is (approximately*) 12".

12" divided by 3.85" is…

;)

* NB for bonus detail, you need to measure the pitch circle diameter (PCD), and that's not quite what you might expect it to be because it needs to join the vertices of a regular polygon with each side being 1/2", rather than a circle whose circumference is the number of teeth times 1/2". And it's going to be hard to manually measure the PCD.
by Bez
12 Sep 2019, 3:32pm
Forum: The Tea Shop
Topic: An unusual use for old spokes.
Replies: 20
Views: 985

Re: An unusual use for old spokes.

Bladed spokes, innit.
by Bez
2 Sep 2019, 2:23pm
Forum: Bikes & Bits – Technical section
Topic: Front dynamo light mount
Replies: 17
Views: 1971

Re: Front dynamo light mount

You’ve got a mudguard, just get a mudguard mounted light. (The B&M Secula Plus is my preference.)
by Bez
3 Aug 2019, 4:12pm
Forum: The Tea Shop
Topic: Why dont they say killed
Replies: 11
Views: 1165

Re: Why dont they say killed

A small thread of a few exceptions that prove the rule:

https://twitter.com/beztweets/status/89 ... 17091?s=21

The thing about allegedly prejudicial reporting is that some vocabulary gets labelled as prejudicial, and therefore is supposedly wrong to use (when applied to someone driving, less often someone cycling); however the widely accepted and supposedly neutral language which divorces people from responsibility—“the car lost control”, for instance—is never acknowledged as being prejudicial in the reverse manner. The “shizzle happens” culture around driving errors is shored up by this sort of thing, not least by jurors being fed it on a daily basis.

Whichever side of the fence you fall on in terms of the semantics of the word “kill” (or any other), two things are fairly objectively clear: firstly that reporting of driving behaviour and reporting of cycling, walking, scooting or other behaviour differ markedly in their use of such words (hence the above headline stating “cyclist killed pedestrian” during an active court case); and secondly, whilst journalists will claim fear of being prosecuted for contempt of court or libel or somesuch for using such words, I’ve never found any precedent for that.
by Bez
2 Aug 2019, 3:06pm
Forum: Bikes & Bits – Technical section
Topic: "Lightweight" Full Suspension Frames Seem Totally Pointless?!
Replies: 12
Views: 2799

Re: "Lightweight" Full Suspension Frames Seem Totally Pointless?!

Even without the fact that you're just pulling numbers out of a hat rather than comparing like with like, it's not really that simple.

Let's pull more numbers out of a hat and build a hypothetical full suspension bike that weighs 28lb, and then let's build a hypothetical hardtail with the same kit which weighs 26lb. Shave 2lb off of each and you're saving 7.1% from the full sus and 7.7% from the hardtail. Sure, the full sus has less of a saving, but not by much. To say that a 7.7% weight saving is worthwhile but a 7.1% saving is pointless doesn't make much sense.

But weight, of course, isn't everything. When it comes to full suspension frames, stiffness is more important than it is for rigid frames, because suspension works less well when it's mounted on a flexible chassis. Carbon allows you to build that chassis differently (as well as offering other benefits such as resilience in impacts), so I would think that a good carbon suspension frame is at least as much about optimising the performance of the suspension whilst staying under a target weight as it is about saving weight outright. To be fair, hydroforming and other modern techniques mean that aluminium frames can be optimised rather more than they could even a few years ago, which is another factor that may help explain why the weight differences seem less than you might expect, but nonetheless carbon can still be optimised more.
by Bez
1 Aug 2019, 10:12am
Forum: Bikes & Bits – Technical section
Topic: Directional hub dynamos
Replies: 30
Views: 3574

Re: Directional hub dynamos

Mick F wrote:I have a calliper brakeset from Campag, and the callipers are very different. Single pivot rear and dual pivot front. Second set like that, first Chorus, and now Athena.


True, Campag did do that, on the basis that they thought you should have less braking available on the rear than on the front. Obviously the only way to do that with rim brakes (assuming both wheels are the same size) is to put an under-performing brake on the rear; with discs you normally just vary the rotor size (though of course it's possible to use different calipers as well—which seems to be less common than it perhaps used to be).

Mick F wrote:Also, in the old days, the cables came out of the callipers on the same side of the bike, but nowadays they are on opposite sides to make the manufacturing simple perhaps.


That hints at another minor difference of rim brakes: the noodles that come with V brakes are available in different shapes. Normally the front comes with a 90 degree bend and the rear with a 120(?), though it's dependent on factors which aren't simply "front vs rear"; eg if you use the right hand lever for the front brake you're better off with a 120 on the front. Plus of course you can get flexible noodles anyway, which negates the issue.

Either way it's still a matter of the peripheral mounting hardware rather than the brake itself being different.
by Bez
31 Jul 2019, 7:46pm
Forum: Bikes & Bits – Technical section
Topic: Directional hub dynamos
Replies: 30
Views: 3574

Re: Directional hub dynamos

Rim brakes differ because they normally point in opposite directions. Even then, generally they only differ in their mounting bolts: the front takes longer ones (because in the case of callipers the bolt goes through the fork rather than the seatstay bridge, and in the case of cantis/Vs because the rim acts to pull the brake away from the bosses rather than push it into it). There are exceptions, eg self energising cantis. But other than that, I don’t think I’ve had a brake that differs in any way other than mounting hardware.

Disc brake callipers are normally the same at both wheels simply because there’s no reason to male them different.
by Bez
31 Jul 2019, 4:06pm
Forum: Cycling Goods & Services - Your Reviews
Topic: Garmin Varia RTL510 light/radar
Replies: 20
Views: 7063

Re: Garmin Varia RTL510 light/radar

I can't discern even a slight reduction in battery life of the head unit when I use the radar. Last time I used it, I eked out 12 hours from my Explore with a mix of normal and battery saver modes, which is as good as I'd expect without the radar. (NB the radar conked out after about 10 hours, which is the quoted life for my RTL511; IME Garmin's advertised battery times for recent devices seem to be somewhat more accurate than the fantasy figures they used to come out with.)

And I've not noticed any false negatives when someone's cycling behind, though I haven't extensively tested that, and certainly not yet in a tight paceline. I have tried it with some luggage partially obstructing its view, and that seemed to reduce its operating range (ie an approaching vehicle was closer when it first notified me); and in general it won't notify you of an approaching bicycle, but occasionally it will. In fact once when I'd parked a bike on a footbridge it piped up when a bloke with a dog walked up behind it.

The only false negatives I'm confident I've observed so far are motor vehicles behind other motor vehicles. Sometimes it'll spot them, often it'll spot them at closer range than a single/leading vehicle, others it won't really spot it at all, though it doesn't fail to notify for the first in line.
by Bez
30 Jul 2019, 10:57pm
Forum: Bikes & Bits – Technical section
Topic: "Lightweight" Full Suspension Frames Seem Totally Pointless?!
Replies: 12
Views: 2799

Re: "Lightweight" Full Suspension Frames Seem Totally Pointless?!

Manc33 wrote:It saves about 2lbs on the frame which is nothing, since it's carbon. A carbon hardtail is half the weight of an aluminium one.


So you're saying it saves about 2lb from a suspension frame, and about 2lb from a rigid frame…
by Bez
29 Jul 2019, 5:40pm
Forum: Bikes & Bits – Technical section
Topic: Directional hub dynamos
Replies: 30
Views: 3574

Re: Directional hub dynamos

There are almost no forks which place the brake on the right; the only off-the-peg one I can think of is the original Cotic Roadrat fork, which hasn't been in production for several years. The only reason to put it there is as a way of preventing ejection of a QR wheel under high braking loads, but there are other ways of preventing it: changing the orientation of the dropouts, using closed "dropouts" (as per the mk2 Roadrat fork), or using a thru-axle. And provided the parameters don't reach extremes, it tends to be a theoretical problem rather than a real one: it famously manifested itself on a tandem with an inappropriate fork, but I've seen few if any stories of similar failures on solos.

So the market for dynamo hubs with a disc mount on the right is approximately zero, hence no-one makes one.

Mind you, won't a dynamo hub still work backwards? I'm a bit clueless when it comes to electricity, but it's AC, right?
by Bez
24 Jul 2019, 12:57pm
Forum: Bikes & Bits – Technical section
Topic: "Lightweight" Full Suspension Frames Seem Totally Pointless?!
Replies: 12
Views: 2799

Re: "Lightweight" Full Suspension Frames Seem Totally Pointless?!

Manc33 wrote:Having a carbon frame on a road bike or hardtail MTB can save weight but when it comes to FS frames, no.


Except clearly “yes”, as your own figures demonstrate.

What’s your point?
by Bez
9 Jul 2019, 3:50pm
Forum: Bikes & Bits – Technical section
Topic: Cost/feasibility of converting these wheels from V-brakes to disc?
Replies: 17
Views: 1013

Re: Cost/feasibility of converting these wheels from V-brakes to disc?

You could even go a smidge lower: I got some new Shimano M315 hydraulics for my son’s bike on eBay, including rotors and IS mount adapters, for under £45. So about £110 with those wheels from Taylor.
by Bez
26 Jun 2019, 12:58pm
Forum: Bikes & Bits – Technical section
Topic: Please explain this frame
Replies: 24
Views: 2198

Re: Please explain this frame

thirdcrank wrote:There are some reasons why a diamond frame cannot be entirely constructed from triangles


The Delta V sort of was… though obviously the large tube diameters and relatively short head tube (required for the Headshok fork) are key to that "sort of" :)

I had one of these for a while in 1993, it was ace.

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