Bicycle Mechanics - Is there a quick release gear cable for SRAM T3 (Sachs Torpdeo) 3 speed hub?
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08-21-11, 02:18 AM
I should have explored this more when I was recently changing my trigger shift on a 1990s(?) Batavus Barcelona with a Sachs Torpedo (now known as SRAM T3) 3 speed hub*. It didn't occur to me to explore while the cable was disconnected, and in any case without some prior research I wouldn't have wanted to pull a crucial but unfamiliar mechanism about simply to see what happened. It's all adjusted perfectly now and I don't want to fiddle about with it purely out of curiosity.
So my question is... is there a quick release mechanism anywhere for the cable? Without it, when refitting the rear wheel I'd have to feed a cable through a tiny little hole and then reset the gear adjustment. Possible, but fiddly and time consuming.
There's a photo of my hub and cable assembly here: https://picasaweb.google.com/110055669501444994025/SRAM3SpeedQuickRelease#5642666276575785266
In the picture, the ball-end of my 2.5mm hex key is pointing to the part I suspect is the quick release. Am I right? And what's in there underneath the black plastic? How do I actually get the quick release apart and back together again? Also, just visible behind the hex key is something small that looks like an L-shaped metal catch. What's it for?
Thanks in anticipation... I have tried Googling for the answer but nothing specific is coming up.
* [ See my recent thread http://www.bikeforums.net/showthread.php/759602-Sachs-(SRAM)-3-speed-hub-shifter-springs-from-1st-to-3rd ]
Your pics aren't coming up, so I can't be sure If I understand correctly what you've got.
Is it like this one? (http://activesport.co.uk/shop/article_H7215/SRAM-Locating-Sleeve-T3-(Cable-to-Chain)-(1-pc).html?sessid=YhICiBUyqLBR07zAxH2itEcaKcunmr4yp8zPsCRywsoKfDNyqCNWYHZTRG4UMT32&shop_param=cid%3D2467%26aid%3DH7215%26)
There should be a section of threaded rod as the interface between cable and hub assembly. The rod is inserted from the left in the sleeve in the pic. On that threaded rod there should be a "locknut" that sets the correct cable tension (for that wheel position...).
To unhook the cable, depress the small metal hoop on the top left and the threaded rod should slide right out, maybe with a tiny bit of coaxing. If you manage to get the wheel back in exactly the same position, just slide the threaded rod back in until the locknut fetches up against the black plastic and you're all set.
08-22-11, 12:49 PM
whooops, I thought I'd set the link for public viewing. It's done now so everyone can see.
Yes, dabac, the part you posted the link to is very similar in principle to my one (a slightly different shape but all the important bits are still there and in corresponding positions). Your description tallies too.
It's actually very useful to know what it's called and where I could get another Locating Sleeve if I ever needed one. It is a confidence booster to know how it comes apart and what to expect, and to know that at worst I can get hold of a replacement without undue expense or difficulty.:) Thanks for this.
08-22-11, 01:41 PM
these go on the end of the cable, grip the indicator chain where a threaded fitting would,
but do come right off by pressing a spring clamp release
in parts , bottom center of the group,
seen here: http://www.sjscycles.co.uk/sram-t3-3-speed-hub-36-hole-prod13058/
but that looks like what you have .. in #1, and what Dabac showed
The ones SA uses are a screw barrel and a lock ring-nut.
the location of the ring nut, on the indicator chain gives you a good idea about where the adjustment was.
Just add a nut on the indicator chain shaft?? or a piece of Tape?
You might be able to adapt the Rohloff Bayonet connectors for their internal shifters.
But that requires more space , than shown, in above scene you shot.
08-22-11, 02:40 PM
:) I've just tried it for myself and it works :)
08-23-11, 01:45 AM
I had a Eureka moment last night and now it's daylight I've tried something out... and it works even better.
I realised that threaded rod is more than just a quick release -- it is the adjustment mechanism itself! Previously I'd been doing it with the cable and pliers, but the rod gives me much more precise increments. The rod had been all the way into the locating sleeve, thus giving me no means to tighten up without pulling the cable. So in 3rd gear I detached the rod, loosened the 2.5mm hex nut, loosened the cable and re-tightened it further along (also took the opportunity to rotate the sleeve so that the hex key nut doesn't face upwards and become a water collector). This meant I could use the rod as an adjuster.
Then I inserted the rod till much of the slack was taken up. If there's too much slack it's too loose, I can get it into 1st it's still loose enough, if I can't get it into 1st it's too tight. Click by click, I put it in until I got the adjustment I wanted. No tools required for this part.
Road tested briefly and seems OK. My homeward commute involves 2 miles uphill, when I will often be in 1st. If it's all still OK then some white insulating tape wrapped round the rod will mark The Place.
I had a Eureka moment .. that threaded rod is more than just a quick release -- it is the adjustment mechanism itself!
Congratulations, and apologies for not mentioning it myself. While not Nobel prize complexity I guess it's not immediately self-evident either.
Keep in mind that shifter cable tension is dependent on rear wheel position, so on a bike with horizontal dropouts it pays to have a working knowledge of how to adjust shifting "from scratch". And while it's sometimes tempting to set an adjuster up at one end position (cables rarely shrink...) it's good practise to leave oneself some leeway in both directions.
Any roadside tweak where you have to bring a tool out will take 2-3 times as long when compared to something that can be done with fingers only.
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