I saw this unusual tandem bicycle in Santa Cruz last week. I’m trying to figure out some of the weird features of this tandem.
For example,
- How does that big ring inside the timing chain stay in place?
- What is that extra set of cranks under the stokers bars for? Russ suggests these might be hand cranks, but I think they might allow a very short rider to pedal recumbent style.
- What about that handle that appears to stick out obliquely from the stoker’s saddle? Another hint that this might be for a short rider?
Your thoughts?
16 Comments
With enough tension, the chain can hold the big ring in place by itself. He's probably using the ring as a DIY chain tensioner. doesn't seem particularly stable, though – either an impact or a jam at either end of the chain would be enough to dislodge it.
With enough tension, the chain can hold the big ring in place by itself. He's probably using the ring as a DIY chain tensioner. doesn't seem particularly stable, though – either an impact or a jam at either end of the chain would be enough to dislodge it.
+1 for chain tensioner. Without it, the chain was probably 1/2 a link too long.I also think the second crankset is for the recumbent position and the handle at the rear is for the same.
+1 for chain tensioner. Without it, the chain was probably 1/2 a link too long.
I also think the second crankset is for the recumbent position and the handle at the rear is for the same.
is that a motor in the rear hub and possibly batteries in the bag?
is that a motor in the rear hub and possibly batteries in the bag?
I think the post from the stokers seat and the cranks under the bars are for a child, the child seat clips to the bar from under the stoker and the Kid gets to peddle, to.
I think the post from the stokers seat and the cranks under the bars are for a child, the child seat clips to the bar from under the stoker and the Kid gets to peddle, to.
Jasper, that looks almost like a hub motor but that's an Arai drum brake.Cliff — Aha! I thought of that bar as a handle for the child but your idea makes better sense.
Jasper, that looks almost like a hub motor but that's an Arai drum brake.
Cliff — Aha! I thought of that bar as a handle for the child but your idea makes better sense.
Bet that free-floating tensioner pops out all the time when you hit an inconvenient bump. Either that, or he's just messing with us.
Bet that free-floating tensioner pops out all the time when you hit an inconvenient bump. Either that, or he's just messing with us.
Apparently it's called a "ghost" or "phantom" chainring.http://www.mtbr.com/ssfaqcrx.aspx#ssCompTensioners
Apparently it's called a "ghost" or "phantom" chainring.
http://www.mtbr.com/ssfaqcrx.aspx#ssCompTensioners
That's really interesting and I've nver seen that before!
That's really interesting and I've nver seen that before!