Cycling dead ends.

For discussions about bikes and equipment.
ratherbeintobago
Posts: 303
Joined: 5 Dec 2010, 6:31pm

Re: Cycling dead ends.

Postby ratherbeintobago » 8 Aug 2019, 7:10pm

SRAM are the masters of the half-developed dead end, some of which are quite interesting ideas.

#1: Hammerschmidt
#2: Automatix hub

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Sweep
Posts: 5362
Joined: 20 Oct 2011, 4:57pm
Location: London

Re: Cycling dead ends.

Postby Sweep » 8 Aug 2019, 7:31pm

Talking of sram am i correct in thinking that the dualdrive is history?
If so, why?
I have one - quite like it.
Sweep

reohn2
Posts: 35254
Joined: 26 Jun 2009, 8:21pm

Re: Cycling dead ends.

Postby reohn2 » 8 Aug 2019, 7:33pm

gazza_d wrote:
pwa wrote:Though I love the way it looks, Moulton's space frame. Too complex to manufacture economically for a bike concept that, with small wheels, was supposed to be more practical. Complex and practical rarely coincide.

The space frame concept was always intended to be a niche high end. The collaboration with pashley took the concept down a notch but it's still fairly niche.

It's a shame the F frame design went to Raleigh who then ruined it before killing it off as that was where the mass market for Moultons existed.

I still think that if that design was relaunched as a mass market bike it would sell lots. That's basically what Brompton are doing.

I disagree a mass market F frame Moulton would sell in any great numbers.Brompton's appeal is in the fold not in the ride.
I large wheel rides better especially on crapmac or gravelly roads,on billiard table smooth tarmac it's a different matter.
Last edited by reohn2 on 8 Aug 2019, 7:42pm, edited 1 time in total.
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I cycle therefore I am.

reohn2
Posts: 35254
Joined: 26 Jun 2009, 8:21pm

Re: Cycling dead ends.

Postby reohn2 » 8 Aug 2019, 7:39pm

jimlews wrote:
......Straight forks. Especially on touring bikes. Uncomfortable fashion driven pile drivers.......

Nope not necessarily so and a touring bike that takes a front load needs a stiff fork anyway.
I have three bikes with straingth forks and all three are comfortable to ride.
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I cycle therefore I am.

Bsteel
Posts: 112
Joined: 31 Jul 2014, 8:41pm

Re: Cycling dead ends.

Postby Bsteel » 8 Aug 2019, 7:54pm

jimlews wrote:Straight forks. Especially on touring bikes. Uncomfortable fashion driven pile drivers.


I've always been curious about this as I've seen different views being given, if the rake and tubing stays the same is there much difference in the flex between a straight or curved blade ?

Brucey
Posts: 34805
Joined: 4 Jan 2012, 6:25pm

Re: Cycling dead ends.

Postby Brucey » 8 Aug 2019, 7:55pm

reohn2 wrote:
jimlews wrote:
......Straight forks. Especially on touring bikes. Uncomfortable fashion driven pile drivers.......

Nope not necessarily so and a touring bike that takes a front load needs a stiff fork anyway.
I have three bikes with straingth forks and all three are comfortable to ride.


but only because you have fat tyres....?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

reohn2
Posts: 35254
Joined: 26 Jun 2009, 8:21pm

Re: Cycling dead ends.

Postby reohn2 » 8 Aug 2019, 8:16pm

Brucey wrote:
reohn2 wrote:
jimlews wrote:
......Straight forks. Especially on touring bikes. Uncomfortable fashion driven pile drivers.......

Nope not necessarily so and a touring bike that takes a front load needs a stiff fork anyway.
I have three bikes with straingth forks and all three are comfortable to ride.


but only because you have fat tyres....?

cheers


And very comfortable they are too :)
Who wants to tour loaded on narrow HP tyres especially on crapmac?
Also as I posted,a touring bike capable of carrying a front load needs a stiff fork anyway
Are curved/radiused forks with discs anymore springy than straight bladed disc forks?
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I cycle therefore I am.

pwa
Posts: 9855
Joined: 2 Oct 2011, 8:55pm

Re: Cycling dead ends.

Postby pwa » 8 Aug 2019, 8:21pm

Brucey wrote:
reohn2 wrote:
jimlews wrote:
......Straight forks. Especially on touring bikes. Uncomfortable fashion driven pile drivers.......

Nope not necessarily so and a touring bike that takes a front load needs a stiff fork anyway.
I have three bikes with straingth forks and all three are comfortable to ride.


but only because you have fat tyres....?

cheers

The springiest forks I ever had were straight, tapered and slender and the tyres were about 23mm. Lovely ride. I reckon the performance has little if anything to do with the bend. My 531 forks on my tourer have a bend but feel less compliant. Even on fatter tyres.

Brucey
Posts: 34805
Joined: 4 Jan 2012, 6:25pm

Re: Cycling dead ends.

Postby Brucey » 8 Aug 2019, 8:29pm

Sweep wrote:Talking of sram am i correct in thinking that the dualdrive is history?
If so, why?
I have one - quite like it.


It is because, after over 100 years of happily making hub gears which mostly worked, SRAM decided to close their european factory, moving production elsewhere. They also redesigned their products so they were no good at all any more, after a wobbly decade or so in which they had taken IGHs which were fundamentally sound/fairly simple and turned them into things that were less reliable than they should have been, mainly by nailing lots of crappy plastic parts onto them which were meant to help them shift gear but didn't.

The dual drive design was quite nice to use but was inherently flawed. The automatix hub was based on a design from the 1960s (which worked) but in its modern guise was bedevilled with QA problems and it still lacked any simple means of adjusting the shift point. The I-9 was discontinued, the five speed and seven speed hubs were pensioned off to make way for the G-8 and G-9 hubs which were announced, listed for a year or so and then also disappeared.

The 'I-brake' didn't catch on so much as squeal intolerably at every opportunity. Because it had a unique hub fitting, it was I-brake or no brake. After a couple of years of getting returns because of squealing, manufacturers refused to fit I-brakes any more and they were discontinued.

The torpedo 3s became the I-3 hub and had both QA problems (which resulted in hubs that smashed themselves to pieces in short order) and fundamental design problems, such as the (mostly reliable) toggle chain was replaced with a (mostly unreliable) cable which bent through an angle instead. This revised means of shifting just wears out and instead of a five minute job to replace the part (assuming the internals have survived that is) the repair takes half an hour because you can't get the remains of the broken cable out of the hub without dismantling it.

This technical weakness was compounded by intense competition; Shimano was manufacturing Nexus 3s hubs in low cost countries, as well as Nexus 7 and 8 s hubs in Japan and SunRace was producing SA designs at keen prices in Taiwan. The result was that manufacturers could spec a SA 3s hub as an upgrade for about ten quid; 'I wouldn't like to make that lot for ten quid' one LBS proprietor said to me, and he was right; there was no margin there for any competitor who hadn't got a super product and/or at the right price. The SRAM IGH products were neither of these things.

So SRAM decided to stop making everything but the 2s and 3s hubs, and after about a year or so (during which time they seemed to be trying to buy market share and succeeding in doing so to some extent, but also succeeded in shipping thousands of hubs which just broke) they announced that they were giving up the whole business as a bad idea.

RIP SRAM IGHs. For years and years they (Fichtel und Sachs, then Sachs and then SRAM) made a million or more hubs a year. In the final year of production (and at a time when cycle production was on the up) they made only about a tenth of that.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

alexnharvey
Posts: 722
Joined: 10 Jan 2014, 8:39am

Re: Cycling dead ends.

Postby alexnharvey » 8 Aug 2019, 9:18pm

iandriver wrote:Suspension handlebar stems. Solid plastic saddles.


Aren't solid plastic saddles (with carbon fibre reinforcement) currently fashionable with weight weenies and posers?

ratherbeintobago
Posts: 303
Joined: 5 Dec 2010, 6:31pm

Re: Cycling dead ends.

Postby ratherbeintobago » 8 Aug 2019, 9:20pm

Brucey wrote:The automatix hub was based on a design from the 1960s (which worked) but in its modern guise was bedevilled with QA problems and it still lacked any simple means of adjusting the shift point.


Wasn't there a lengthy thread on here about adjusting it, involving disassembly +/- custom springs?

Brucey
Posts: 34805
Joined: 4 Jan 2012, 6:25pm

Re: Cycling dead ends.

Postby Brucey » 8 Aug 2019, 9:23pm

ratherbeintobago wrote:
Brucey wrote:The automatix hub was based on a design from the 1960s (which worked) but in its modern guise was bedevilled with QA problems and it still lacked any simple means of adjusting the shift point.


Wasn't there a lengthy thread on here about adjusting it, involving disassembly +/- custom springs?


yes indeed; not that simple.

A better design might have had an adjusting screw accessible from the outside somehow.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

slowster
Posts: 813
Joined: 7 Jul 2017, 10:37am

Re: Cycling dead ends.

Postby slowster » 8 Aug 2019, 10:35pm

1. The 'Deal Drive' - a chainset on which the chainring expanded or contracted in diameter to provide variable transmission. Instead of a continuous round row of teeth, there were several segments with teeth, with gaps in between which allowed the segments to contract towards the axle. I think springs controlled the amount of contraction and expansion, and the chainring was supposed to react to being pedaled uphill by contracting (resulting in a lower gear), and conversely expand when it 'sensed' the rider was spinning out (i.e. in too low a gear). They were very briefly offered as an option on the Holdsworth Mistral tourer in the mid 1980s.

2. Shimano Dyna Drive pedals and cranks, with an enlarged pedal thread and corresponding crank to allow the single pedal bearing to be in the same plane as the crank. A set of those cranks and pedals sat in the window display of my local bike shop for years long after Shimano had discontinued them.

mig
Posts: 2015
Joined: 19 Oct 2011, 9:39pm

Re: Cycling dead ends.

Postby mig » 8 Aug 2019, 10:42pm

pwa wrote:
Brucey wrote:
reohn2 wrote:Nope not necessarily so and a touring bike that takes a front load needs a stiff fork anyway.
I have three bikes with straingth forks and all three are comfortable to ride.


but only because you have fat tyres....?

cheers

The springiest forks I ever had were straight, tapered and slender and the tyres were about 23mm. Lovely ride. I reckon the performance has little if anything to do with the bend. My 531 forks on my tourer have a bend but feel less compliant. Even on fatter tyres.


i find exactly the same on a 631 frame with straight forks using 23c ultremo tyres from relatively yesteryear (no luggage.)

really is the most comfy and best steering bike i use. it is, however, made to measure.

David9694
Posts: 312
Joined: 10 Feb 2018, 8:42am

Re: Cycling dead ends.

Postby David9694 » 9 Aug 2019, 6:08am

The early Shimano 5 speed indexed gears on my BSA Courier - used a solid cable as I recall, but never worked properly. wretched thing.

What was that frame building system that used epoxy - there were Raleigh bikes in the 80s and 90s

SP30 press-fit b/b