Originally Posted by
cudak888
Now that's a work of art, Bob - especially the dual-cable MTB levers.
Curiously, how is that singlespeed jockey wheel kept under tension? I can't seem to see any spring device on it. Looks sharp nevertheless.
-Kurt
There is no spring. Originally there was a jockey like wheel which slid up and down in the bracket you see this attached to. The bracket is well positioned for a right side timing chain. Moving to the left side created the challenge of tensioning the timing chain. This unit works very nice and is simply bolted on. I added the spacers to assist with proper positioning. The red wheel can move left to right on its bearing several mm. The mounting arm is tighten down with that nut and a heavy lock washer. Seems to do the job nicely. I'll see after a 15-30 mile ride.
You have done a lot of nice work. Is the rear crankset a tandem set up or did you modify a single crankset? If it is modified, how did you add the left side timing ring?
If you look at the pictures at the beginning of the thread you can see how the Twinn was set up when I bought it. Both the timing chain and drive chain were on the right side. The rear crank was a triple and the granny gear acted as the timing gear. The captain's crank was a Sugino triple (110 & 74 BCD).
I needed a triple on the rear for my mountain climbs.
First I tried moving the timing chain outboard and you can see pictures of this earlier in this thread. It did not work due to the stoker pedal hitting the timing chain as I cranked.
Then I picked up tandem timing cranks (left side only) as a bargain on ebay. While I found two captains right arms, neither worked because they had different "Q Factors" from the right hand side. Eventually, I cut a swagged on chainring off of a "dump find" crankset and created my own right hand Captain's crank arm.
Now the other challenge was the BB. The Twinn Sport comes with Astubula style BB shells. Therefore I had to convert these with euro adapters, and then find the correct sized cartridge BBs. The front uses a 115mm Tange, and the rear uses a 118mm Shimano.
Originally Posted by
riva
Neato brake setup! Is that ss pulley sprung?? On our tandem we had an RD setup to tension the sync chain at one point but now its back to rigid. I'm wanting to put a sprung tensioner back on as they do a much better job imo...
See above reply to Kurt. There is no spring tension and I don't believe any will be needed.
Originally Posted by
King of Kadence
Looks great Pastor. The Brake levers look trick. The setup sounds interesting too. It reminds me off the linked brakes that I had on an old Moto Guzzi.
Does the lever offer more cable pull in the lower housing?
The brakes were an interesting adventure. Originally there was a sidepull caliper on the front original steel rim, and the Atom hub brake in the rear. Stopping was horrible. I swapped the front for a centerpull and added a centerpul on the rear steel original rim. I only had a little improvement. I knew that if I wanted to see improvement I had to swap the rims for aluminum ones. I figured while I was doing this I might as well add a drum to the front, thus the quad brakes.
When I first tried them, I had both front brakes hooked to one lever and the same with the rear. Pulling two different types of brakes did not work well and there was a great deal of friction in the line. When I reworked them to have the right lever pull both centerpulls and the the left lever to pull both drums, the friction went away and it was significantly easier to to adjust and sync the two brakes on one lever. I don't believe there is more pull in the lower or upper cable attachment.
Last night on my solo ride I got the bike up to about 20-25 mph and tried an emergency stop. I was very impressed and satisfied.
Here's the catalog page for the 1980 Twinns from the Findley collection.
http://www.trfindley.com/flschwinn_1...0/1980_42.html