frkl
Retro Guru
Honest question because i have luckily never had a derailleur spring fail--if a high normal derailleur spring fails, which way does it shift? On the one hand, the derailleur cage would be pulled down, so in the low direction, but the chain would want to fall down too, in the high direction. I guess the chain is under load, but i could see this pulling it low or high depending on the chain line. The cage of course exerts a tension...Actually it does make some sense as it keeps the bar end shifters out of the way in lower gears, when you are more likely to be out of the saddle. It saves banging your knees on them.
I tried it years ago, but the rapid rise idea is fundamentally flawed in my view - once the spring (which is all that holds it in a lower gear) weakens, it tends to upshift under load.
I guess the big diff is that if the chain tends to fall high (as strange as it sounds), the cable could pull the derailleur low. But this is only an advantage if the chain reliably falls high.