Cycling UK Forum

Brucey wrote: ↑22 Nov 2023, 6:51pm

SA_SA_SA wrote: Why would symmetrical dps need a linkage: the above u brake with slant cable entry doesn't?

the brake above has either a linkage or a very different MA in each arm [not sure which]. I think that uneven wear is inevitable with either thing.

I presumed the 90 degree bend in one arm didn,t count in terms of leverage, so as long as each arms
Length gave equal leverage all was well? If not isn,t it fixable by redesigning the lengths?

st599_uk wrote: ↑21 Nov 2023, 9:12am

simonhill wrote: ↑20 Nov 2023, 2:53pm I hadn't realised that the UK grant 6 months to EU citizens and no time limit for re-entry. Why the hell didn't we negotiate that on a reciprocal basis.....

There was a quote doing the rounds from, I think, Oliver Letwin that it was offered, but we turned it down.

But what else did the EU commission want in return as well as repricocalness?

JohnR wrote: ↑22 Nov 2023, 5:26pm

PH wrote: ↑22 Nov 2023, 12:42pm

mjr wrote: ↑21 Nov 2023, 10:50pm How would you see it was on without stopping?

I've never felt any need to do so, but having two lights makes the chance of complete failure too unlikely to be bothered about.

If using two lights then it is prudent to have at least one flashing to reduce the likelihood of a driver mistaking two lights on a near bicycle as being two lights on a distant vehicle (and if both lights are flashing then they should be on different sequences so they aren't interpreted as distant hazard lights).

If the 2 or more lamps are vertically separated rather than horizontally that should not be a problem?

I think one (or none ) flashing lamp is enough?

Brucey wrote: ↑22 Nov 2023, 3:14pm

SA_SA_SA wrote: ↑4 Nov 2023, 8:35pm.......compared to the Bromptons common garden asymmetrical dp brake the pads should wear evenly....

surely if there is a 'linkage' of any kind involved in the operation of one arm and not the other, uneven wear is inevitable?

The two arms of an asymmetrical dp trace different arcs, and on my bromptons rear such fp (bronze alhonga) it seemed very obvious the pads wore differently due to that (dp side wore slanted
lywith reference to its backing) and required replacement sooner thus wasting the other pad. I changed back to a single pivot (ok at back).

Why would symmetrical dps need a linkage: the above u brake with slant cable entry doesn't?

As Brompton are now big enough to brakes customised for them (last two Alhonga ones and current black(still alhonga according to BrilliantBikes)) ones, so if someone could persuade them that suitably longer reach symmetrical dp brakes (SLR-EV style) were a worthwhile upgrade, then they could commission some...

Edit to add brilliantbikes

Carlton green wrote: ↑20 Nov 2023, 2:15pm

SA_SA_SA wrote: ↑20 Nov 2023, 12:16pm

Carlton green wrote: ↑19 Nov 2023, 5:28pm.... 1 With that experience in mind I’d have thought the NOS AXA with plastic roller would be fine - in general I can’t recall ever having issues with slipping bottle dynamos, but perhaps I’ve been lucky.

2 At £12 inc delivery Amazon do indeed seem very reasonable for a new 8201. ... but I wonder about the rivets going loose and vibration on small wheeled bikes.

1) Thanks, good to know (mine is actually just labelled axa hr so the traction must be marketing speak for rubber ring.

2) Paradoxically does that mean all in one plastic ones loke the duo or trio might be better?

I wouldn’t like to say what was best but IIRC CJ did report for the CTC on bottle dynamo performance(s) - some data is out there. As far as I know the AXA traction is about as good as it gets in bottle dynamos; I’ve found that some of the also rans are - at least - good enough for my purposes and unlike the AXA are available to me for not much money.

To clarify, my phrase "all in one plastic ones like the duo or trio might be better《than the 8201 I should have added》?" was just referring to the slim 8201 and its similarly slim plastic brethren rather than the dearer and less svelte hr.

Carlton green wrote: ↑19 Nov 2023, 5:28pm.... 1 With that experience in mind I’d have thought the NOS AXA with plastic roller would be fine - in general I can’t recall ever having issues with slipping bottle dynamos, but perhaps I’ve been lucky.

2 At £12 inc delivery Amazon do indeed seem very reasonable for a new 8201. ... but I wonder about the rivets going loose and vibration on small wheeled bikes.

1) Thanks, good to know (mine is actually just labelled axa hr so the traction must be marketing speak for rubber ring.

2) Paradoxically does that mean all in one plastic ones like the [similarly] slim duo or trio might be better [EDIT than their slim 8201 sibling]

Brucey wrote: ↑20 Nov 2023, 11:58am then again .it could be the magnet materials or the design....

Interestingly, the very 1st axa HR was more 8201 sized, maybe its design was more conventionalhttps://www.flickr.com/photos/lovely_bi ... 165812540/

Carlton green wrote: ↑18 Nov 2023, 9:18am I briefly had an AXA Traction dynamo but, unfortunately, it turned out to be a non-bargain off of eBay (damaged beyond repair). You win some and you loose some. Would I buy another? Probably not; the drive tyres aren’t cheap and a bit of a fiddle to source, and I’m not convinced that for my limited use the advanced design is a significant gain. Instead of the Traction I’d investigate the 8201. ....

I have the (NOS I think) previous traction with a plastic knurled knob, not yet used in action:
Hopefully ok for driving leds in the wet. The current traction HRs'spare drive tyres are indeed curiously expensive....I did have a RH 8201 which I liked, although on my folder its rivets eventually loosened ..
Amazon looks like the best value online uk source for 8201s?

Brucey wrote: ↑19 Nov 2023, 1:37pm

gat wrote: ↑5 Nov 2023, 9:27pm
Any others?

nice try, but
no cigar....

Is it patentable?

I found a blog where someone dismantled one (the 2nd photo down from top of page):

It just seems everything is scaled up compared to its slimmer brethren....
https://fokkosbikeblog-de.translate.goo ... r_pto=wapp

Why were/are the penultimate and current versions of the axa traction dynamo (as sold in Bromptons in the past) so wide, given that bottle dynamos moved to being slimmer once manufacturers realised that by doing that they could use less wire, thus saving weight, by placing the coils within the rotating magnets rather than outside like earlier dynamos?

Cyclothesist wrote: ↑5 Nov 2023, 4:56pm It's certainly generating some interest! Can you be induced to tell us more Brucey?

I have a suspicion of what it might very very possibly be
But I wonder if Brucey was wondering if it was patentable?

drossall wrote: ↑4 Nov 2023, 8:25pm Is there an advantage - mechanical or other - to the Black Ops product?

I thought it (or it's Brompton variant) would/could have the same advantages as a symmetrical dp (eg the short arm only Shimano EV), but with a simpler mechanism that suits the Bromptons cable entry from below. Also, compared to the Bromptons common garden asymmetrical dp brake the pads should wear evenly.

No cigar

For a Brompton front brake (cable entry from below), the following tweeked u brake, the Black Ops The Clamp Brake, looks a good alternative to long reach symmetrical dps(simpler design too)....but seems to be no longer made..

But Brompton seem to be able to have their own brake design made for them.... (eg the yoke for the pivots to centre brake bolt, needed to convert the above to a sidepull)

https://duckduckgo.com/?q=Black+Ops+The ... _13034.jpg