1. They are twice as strong- not that the single ones usually break.
2. Because they are twice as strong they last more than twice as long before they stretch and rattle.
3. If you have enough $$ you can buy decent duplex chain (Iwis , made in Germany) that is way tighter when new than the usual noname `chain' they sell now. It lasts heaps longer, many racers will use nothing else.
Was around $60 last time I looked.
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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
