Search found 32727 matches

by Brucey
25 Mar 2019, 9:52am
Forum: Bikes & Bits – Technical section
Topic: Brompton Electric Conversion Advice please
Replies: 10
Views: 272

Re: Brompton Electric Conversion Advice please

the folding action of a folding bike is a given; that is why they are, er, called 'folding bikes'. Arguably there is no point in a bike folding if you can't then carry/lift the thing, even a short distance; only rarely can it be wheeled (eg half-folded) to where it needs to be. Most folk carry at le...
by Brucey
25 Mar 2019, 9:28am
Forum: Bikes & Bits – Technical section
Topic: 135mm OLN hub in a 130mm alloy frame?
Replies: 19
Views: 452

Re: 135mm OLN hub in a 130mm alloy frame?

frames crack by fatigue because in use, they see an alternating stress. If you 'spring' a frame then you increase the mean stress, and as the plot above suggests, the tolerance for cyclic stresses is reduced whenever you do this, i.e. the frame is more likely to break via fatigue. Steel frames can ...
by Brucey
25 Mar 2019, 9:13am
Forum: Bikes & Bits – Technical section
Topic: Tandem Crossover Chain 3/32 vs 1/8 ?
Replies: 25
Views: 685

Re: Tandem Crossover Chain 3/32 vs 1/8 ?

the thrust loads on the BB are certainly very high and vary with BB configuration; part of the attraction of using larger timing chain chainrings is that the thrust loads on the BB bearings are always reduced. However the torque loads on one BB spindle are very high in a crossover drive and this can...
by Brucey
24 Mar 2019, 9:29pm
Forum: Helmets sub-forum
Topic: My Lidl helmet - and fall
Replies: 14
Views: 253

Re: My Lidl helmet - and fall

it probably did help you avoid an injury. But that won't stop folk from speculating that it a) didn't b) that the presence of the helmet on your head somehow caused you to fall c) that the presence of the helmet on your head somehow caused the kerb to be there, or be more pointy than normal d) that ...
by Brucey
24 Mar 2019, 8:44pm
Forum: Bikes & Bits – Technical section
Topic: Brompton Electric Conversion Advice please
Replies: 10
Views: 272

Re: Brompton Electric Conversion Advice please

the torque isn't that high (like brake torque is) and it isn't 'pulsy' (like pedalling torque is) so it is probably going to be OK. It might be better to build even x1 but if this makes the spokes go into the rim at a funny angle it is a question of choosing the lesser of two evils. BTW I thought th...
by Brucey
24 Mar 2019, 8:39pm
Forum: Bikes & Bits – Technical section
Topic: 135mm OLN hub in a 130mm alloy frame?
Replies: 19
Views: 452

Re: 135mm OLN hub in a 130mm alloy frame?

I agree; quite a lot of frames are not exactly as they are meant to be, and it isn't that difficult to respace wheels to suit.

cheers
by Brucey
24 Mar 2019, 5:52pm
Forum: Bikes & Bits – Technical section
Topic: 135mm OLN hub in a 130mm alloy frame?
Replies: 19
Views: 452

Re: 135mm OLN hub in a 130mm alloy frame?

https://www.researchgate.net/publication/319419768/figure/fig2/AS:533763869818880@1504270631154/A-typical-schematic-showing-Gerber-Goodman-and-Soderberg-lines-and-relation-between-the_W840.jpg frames crack by fatigue because in use, they see an alternating stress. If you 'spring' a frame then you i...
by Brucey
24 Mar 2019, 5:31pm
Forum: Does anyone know … ?
Topic: does anyone remember Westland bikes?
Replies: 29
Views: 2860

Re: does anyone remember Westland bikes?

Gavmoir's and Mikebike's examples both have round section fork blades, i.e. they were built with a 'track' type fork, as was common at one time if you bought a bike meant for 'road/path' use. Again I'd guess that the gear hanger would be a later addition.

cheers
by Brucey
24 Mar 2019, 5:17pm
Forum: Bikes & Bits – Technical section
Topic: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.
Replies: 16
Views: 1795

Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

the (W) 5s hubs the planet gears cannot be removed; they are riveted into the planet cage and the sun pinions are trapped in the 'Atlas assembly' too. Thus you cannot get the planet gears mistimed as in other 5s hubs. FWIW I have seen a 5s hub with marked planet gears in which the markings were not ...
by Brucey
24 Mar 2019, 5:05pm
Forum: Bikes & Bits – Technical section
Topic: Shimano Alfine 8 - sealing & servicing
Replies: 7
Views: 369

Re: Shimano Alfine 8 - sealing & servicing

I know nothing about that SFG so I can't really comment, sorry. I've made my own SFG which works in such IGHs. The closest you can buy to this is the SFG that is used inside land rover front swivels, but a) I have not used this every IGH and b) random mixtures of this and different oils/greases may ...
by Brucey
24 Mar 2019, 5:01pm
Forum: Bikes & Bits – Technical section
Topic: SRAM cassette size problem
Replies: 2
Views: 175

Re: SRAM cassette size problem

According to online references (which tally with my own observations) sram and shimano 'road' 11s cassettes have a pitch of 3.72 to 3.74mm but their 'MTN' 11s cassettes have a pitch of 3.9mm (cf 3.95mm for shimano 10s pitch). I think MTN 11s cassettes need freehub bodies of slightly different length...
by Brucey
24 Mar 2019, 12:19pm
Forum: Bikes & Bits – Technical section
Topic: Problem with light
Replies: 4
Views: 288

Re: Problem with light

apologies if this is B obvious but if there are multiple batteries in series then a) it only takes one duff battery/contact to kybosh the light and b) if just one cell is installed backwards the low battery warning light will soon indicate. worth double-checking the battery contacts are in good shap...
by Brucey
24 Mar 2019, 9:51am
Forum: Bikes & Bits – Technical section
Topic: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.
Replies: 16
Views: 1795

Re: the slightly crazy world of Sturmey Archer single toggle dog-locking 5s hubs.

an old 4s Raleigh roadster would have been fitted with a FW or FG hub. In these hubs gears 2,3,4 work just like 1,2,3 in a 3s hub, and are likely to be just as reliable. The only shift where anything unusual happens in those hubs is 2-1, in which a different sun pinion is locked. That shift is not a...
by Brucey
23 Mar 2019, 10:16pm
Forum: Bikes & Bits – Technical section
Topic: What's the plastic sleeve inside the bottom bracket for?
Replies: 13
Views: 1257

Re: What's the plastic sleeve inside the bottom bracket for?

modern sleeves have 'o' ring seals and BITD they didn't have this feature.

cheers