Search found 282 matches

by JakobW
22 Nov 2019, 7:10pm
Forum: Bikes & Bits – Technical section
Topic: How Old is Your Trangia ..
Replies: 46
Views: 2047

Re: How Old is Your Trangia ..

Sadly over the years they've been cheapened - the old riveted-on strap loop is now a stamped slot which is very difficult to use and I suspect the quality of the aluminium is lower as they seem a little thinner and softer - a real shame. I don't know about softer, but aren't the more modern 'Ultral...
by JakobW
21 Oct 2019, 5:08pm
Forum: Does anyone know … ?
Topic: Bikes and air pockets (General not technical)
Replies: 13
Views: 899

Re: Bikes and air pockets (General not technical)

the Bernoulli principal: half the people argue it keeps planes in the air, the (other) half disagree. Really? What is the counter argument? Air flows over the top of the wing travels faster that below the wing, the pressure difference produces lift. If the upward lift force is greater than the down...
by JakobW
21 Oct 2019, 4:23pm
Forum: Does anyone know … ?
Topic: Bikes and air pockets (General not technical)
Replies: 13
Views: 899

Re: Bikes and air pockets (General not technical)

(Drifting OT...) There's a common incorrect explanation for wing lift that relies on shape of a typical aerofoil. According to this, you imagine two air molecules at the leading edge; if one goes over the top of the aerofoil and one under the bottom and they meet at the trailing edge, then the one t...
by JakobW
15 Oct 2019, 8:14pm
Forum: Bikes & Bits – Technical section
Topic: Amusing video about Cervelo being shoddy
Replies: 28
Views: 1414

Re: Amusing video about Cervelo being shoddy

I notice that Rivendell are also selling Tange cup-and-cone BBs; from a Grant P blog post I understand he convinced them to do a run with spindle lengths suitable for road doubles and triples (apparently most quality cup-and-cone BBs made these days are for track - Keirin? - use). They are things of...
by JakobW
15 Oct 2019, 12:04pm
Forum: Bikes & Bits – Technical section
Topic: Night lights, side of bars?
Replies: 14
Views: 548

Re: Night lights, side of bars?

Yeah, the rationale is that at night people will use the light as their reference point for your position; if the light were all the way over to the left then there could misjudge how much space they had to give you. I think there are similar rules for how far from the body edge car headlights can be?
by JakobW
5 Oct 2019, 7:32pm
Forum: Does anyone know … ?
Topic: A"cute bike" with an acute angle-sadly
Replies: 26
Views: 1027

Re: A"cute bike" with an acute angle-sadly

I suppose about half of my bikes are step-throughs (does a Brompton count I wonder?); for town/utility biking they're far more practical, especially when wearing civvies. OTOH as a tall and fairly powerful rider I prefer the reduced flex of a diamond frame for spirited riding or touring.
by JakobW
4 Oct 2019, 8:11am
Forum: Does anyone know … ?
Topic: Vintage Bicycle Advertisements; good, bad. ugly...
Replies: 550
Views: 17680

Re: Vintage Bicycle Advertisements; good, bad. ugly...

Interesting; did police have to buy their own cycles, or was this just advertising pointing out that you too could own one of these Leviathans?
by JakobW
30 Sep 2019, 11:49am
Forum: Does anyone know … ?
Topic: Carbon v steel frames v Gravity (Non Technical)
Replies: 8
Views: 548

Re: Carbon v steel frames v Gravity (Non Technical)

Gallileo explained all this 400+ years ago. Ignoring air resistance both bikes will descend at the same rate. Well yes, but the OP said nothing about ignoring wind resistance; in the real world it's likely to be the biggest factor in downhill performance. Ignoring rolling resistance, the bikes will...
by JakobW
29 Sep 2019, 3:26pm
Forum: Does anyone know … ?
Topic: Carbon v steel frames v Gravity (Non Technical)
Replies: 8
Views: 548

Re: Carbon v steel frames v Gravity (Non Technical)

Not sure about the balloons, but assuming the steel frame is heavier than the carbon, its potential energy of at the top of a hill would be greater, and therefore - ceteris paribus - you'd expect a greater speed on the descent (like the old tales of lead bottles being handed to riders as they went o...
by JakobW
29 Sep 2019, 2:12pm
Forum: Does anyone know … ?
Topic: Initialisms
Replies: 47
Views: 1519

Re: Initialisms

^ +1. Also, it's not like this is some shocking new development; I've been online for nearly three decades, and netspeak wasn't a new thing when I first started using message boards etc. IOW, do u even internet? :wink:
by JakobW
28 Sep 2019, 9:30am
Forum: Does anyone know … ?
Topic: Initialisms
Replies: 47
Views: 1519

Re: Initialisms

LMGTFY = Let Me Google That For You...
by JakobW
24 Sep 2019, 1:34pm
Forum: Does anyone know … ?
Topic: Vintage Bicycle Advertisements; good, bad. ugly...
Replies: 550
Views: 17680

Re: Vintage Bicycle Advertisements; good, bad. ugly...

But it comes with a free comic book!
by JakobW
16 Sep 2019, 9:30am
Forum: Bikes & Bits – Technical section
Topic: Brompton-esque build; guess the weight
Replies: 22
Views: 1231

Re: Brompton-esque build; guess the weight

Vindicated! (As is Natural Ankling of course :mrgreen: ) Brompton Marathons are ~420g/tyre; the Marathon Racers are ~280g/tyre, and the bling tanwall Schwalbe Ones are ~173g/tyre. I don't know if anyone makes ultralight inner tubes (latex or otherwise) in Brompton sizes, but you could easily shave n...
by JakobW
14 Sep 2019, 9:03am
Forum: Bikes & Bits – Technical section
Topic: Brompton-esque build; guess the weight
Replies: 22
Views: 1231

Re: Brompton-esque build; guess the weight

A standard S2L-X is 10.2 kg. Depending on what the wheels are they may not save much over the stock - indeed lots of custom wheels (silly deep carbon etc.) are a fair bit heavier - and the Brompton chainset isn't too bad (apparently a Ti BB is a better way to save weight). With the heavier saddle an...
by JakobW
8 Sep 2019, 11:35pm
Forum: Does anyone know … ?
Topic: Folding bikes - good Brompton alternatives?
Replies: 25
Views: 1424

Re: Folding bikes - good Brompton alternatives?

Like Horizon I can take or leave the electric assist, but I think the GSD is great, and just the kind of thing that could replace a second (or even a first?) car for lots of city dwellers. OTOH even by cargo bike standards it's not cheap, and I'd only buy one from a specialist bike shop who knew wha...