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PostPosted: Sun Nov 23, 2008 10:25 am 
Old School Grand Master
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Joined: Wed Feb 20, 2008 12:21 pm
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Location: Lost in Translation
Thanks for that.

GeoffApps wrote:
Does anyone remember the Deore drop-pedal?

The DynaDrive (DD)?

http://www.sheldonbrown.com/shimano1982/pages/27.html


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PostPosted: Sun Nov 23, 2008 10:59 am 
Old School Grand Master
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Location: No brakes? Way to commit soldier.
Fantastic to have you here Geoff. It is truly refreshing to read your comments. Definately thought provoking for those that have blindly followed the 'accepted wisdom' (should that be marketing bull?) that seems to rule our sport.


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 Post subject: 1979 and all that . . .
PostPosted: Sun Nov 23, 2008 7:29 pm 
MacRetro rider
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Hello One Eye Jim ~

Yes, the Dyna Drive. I was V pissed off when it was discontinued so soon after becoming available. Duncan Bedford said the reason they were withdrawn was lack of take-up in the primary market ... the roadie market, which was, of course, rigidly traditional at that time.

Oh how I remember that phrase; I heard it over and over again, when someone couldn't say I was wrong, but didn't want to agree with me
"I'm a traditionalist", which in reality meant he (or she, there were a few) was not going to try anything new, and part with the minimum money for anything he (or she, there were a few) did buy.

Unfortunately, and I'm sure this didn't help sales, you had to buy the crankset as well ~ typical Shimano incompatibility.

My design will fit to a conventional pedal. I've just got to find a friendly engineer who is prepared to take a bit of a gamble; he (or she, there are a few) may not get paid, well not quickly, anyway. Ha! Blasted money.

Yes, that was the HighPath Cross-Frame design I referred to, thanks.

Hello Russel ~

Thanks for your kind words. Wait till I get round to steering geometry and centre of gravity.


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PostPosted: Sun Nov 23, 2008 9:20 pm 
Old School Grand Master
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Location: Lost in Translation
GeoffApps wrote:
Wait till I get round to steering geometry and centre of gravity.

Can't wait.

One more question while I'm at it. I spotted the "trials mod" chainring bolted straight to the primary bolt circle of the TA cranks. At 50mm bcd or so, that should get you down into the sub twenty tooth range. I presume you were having these made by a third party - I don't remember anything smaller than 24t from TA. What gears were you using typically? I recall 34t plus freewheels from Suntour, perhaps even a 38t.


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 Post subject: 1979 and all that . . .
PostPosted: Sun Nov 23, 2008 10:43 pm 
MacRetro rider
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Hello One-eye Jim ~

That trials chainring was as I remember about 20 teeth 50% eggring.
The minor axis took it to equivalent of about 9 teeth and the major axis about 28. Tree-climbing stuff. The TA crank was specially modified with part of the inner ring mounts removed and mounting holes drilled, where they could ~ there was not much room!

It was all done by that estimable cycle transmission guru Chris Bell.

You may find some more information on http://www.highpath.net

Chris Bell teamed up with DWS when they both moved to Wales, but I don't think they are working togther as much these days.

I can't remember all the details of the gearings typically fitted to the production bikes. I do remember that the TAs were 28/44/&50something with the teeth milled off.

Rear clusters were really difficult to get because the hubs had french threading ~ it was this small difficulty that could be said to have caused the operation to close. Want to know the whole story?

I was knocking up prototypes using a variety of gearing combinations, but now I have what I wanted all along; The Shimano Inter8 fits the bill nicely combined with a couple of EggRings with digital shifting, donchano.


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PostPosted: Sun Nov 23, 2008 11:13 pm 
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GeoffApps wrote:
Rear clusters were really difficult to get because the hubs had french threading ~ it was this small difficulty that could be said to have caused the operation to close. Want to know the whole story?

Of course!

Quote:
digital shifting

You mean you use your fingers?


Last edited by one-eyed_jim on Sun Nov 23, 2008 11:48 pm, edited 1 time in total.

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PostPosted: Sun Nov 23, 2008 11:37 pm 
Pumpy's Bear
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Geoff, I may have missed something along the way (late, red wine) but that looks lie an upside down Mavic rear mech. I somehow expect the answer may be "doh" obvious, but what is going on there, simple chain tensioner for the hub gear?


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PostPosted: Mon Nov 24, 2008 12:29 am 
retrobike rider
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Quote:
digital shifting.....You mean you use your fingers?


According to Chris Bell of EggRing fame, you require a chain tensioner for chainrings above 10% ovality. But I'm sure it also plays a crucial role when :idea: "digital shifting". :idea:


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 Post subject:
PostPosted: Mon Nov 24, 2008 12:55 am 
King of the Skip Monkeys
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this thread just gets better and better... (big bertha says Hi BTW)


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PostPosted: Mon Nov 24, 2008 8:18 am 
Dirt Disciple

Joined: Mon Nov 17, 2008 5:54 pm
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Location: Hyde, Cheshire
Phew -last time I looked this thread was on page2!

Fascinating stuff about this pedal powered Montessa-Cota Geoff, keep it rolling 8)


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