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| Shimano shifter with cable head (yellow arrow) |
Kaltmann, sometimes known as John Kulhman, has been here before; also talking (through his hat) about bicycles. This time, it's readily apparent that Kaltmann is well outside his comfort zone, even though he opens with what is arguably factual material:
"Although Shimano manufactures multiple shifting systems (Dura-Ace, DXR, Deore DX and Ultegra), they all share a common adjustment method. Adjusting the shifting on a bike means that the tension in the cable connecting the shifting mechanism to the rear derailleur must be tightened or loosened."
Yeah, Jack, that's how you adjust any shifters; also including Shimano's Acera, Tiagra, 105... or SRAM, for that matter. Where you stuck your foot in it is the next sentence:
"Cable tension is altered near the shifting lever that is integrated into the handlebar brakes on road bikes or on the grip of mountain bike handles."
No, Jack, that's not where you adjust cable tension. You adjust it at barrel adjusters on the rear derailleur or at one end or the other of the shift cable housing. What you say next (about integrated shifters) is just plain wrong. No way should a wannabe bike mechanic,
Kaltmann goes on to likewise misinform about grip shifters as well:
"Pull back the rubber housing on the the brake hood to expose the pivot point on the brake handle where the shifting cable is inserted. Loosen the cable barrel adjustment nut, which is located between the brake hood and the rear derailleur. Pull the end of the cable at the brake hood until the cable is snug."This ignorant freelancer clearly has no idea that the end of a shift cable is fixed in an integrated shifter (see cable "head" above) – no matter what groupset – and any tension adjustment must take place at the other end of the cable. That's not to mention that only in the most dire circumstances do you loosen the cable bolt: all adjustment takes place with the high-low screws on a derailleur or the barrel adjusters on the cable. Idiot.
Kaltmann goes on to likewise misinform about grip shifters as well:
"Remove the cover on the grip handle to expose the end of the shifter cable. Remove the small set screw, using a hex or Allen wrench, that holds the cable in place. The cable should now move freely. Loosen the cable barrel adjuster and pull the cable end out of the housing to remove any slack. Tighten the barrel adjuster, re-attach the set screw and tighten."
If anyone's interested, that's part of the instructions for replacing a shift cable in SRAM grip shifters... but has nothing to do with Shimano.
Kaltmann clearly had no idea what he was talking about, which may be why managed to conflate installing a new shift cable with "adjusting a shifter" when what the Dumbass of the Day should have said was, "You don't adjust shifters, you adjust derailleurs."
DD - BICYCLES
Kaltmann clearly had no idea what he was talking about, which may be why managed to conflate installing a new shift cable with "adjusting a shifter" when what the Dumbass of the Day should have said was, "You don't adjust shifters, you adjust derailleurs."
copyright © 2019-2022 scmrak
DD - BICYCLES
2 comments:
Thank you for this! I came back home from my bike-repair training with a close-up picture of the insides of a Shimano road-bike shifter/braking system and your article showed up in my search. I was exposed to the process you describe by my trainer, so trainee-m3 understand very well what you're saying.
My big question, but not part of the training, was what was wrong with the original shifter. We replaced it with a working one that another instructor found at the shop. It was exactly the same, luckily.
The broken one wouldn't pull the cable. It just got stuck after a couple of shiftings.
My eternal question with anything broken, can those shifters be fixed?
Thanks again. I hope you're still around.
As far as I know, Shimano (and probably SRAM, et al.) does not offer replacement parts for shifters. I've only taken apart a non-functional shifter (an integrated version for a road bike) one time, and that one trashed itself as soon as I opened the casing when a spring released. Maybe a very well-equipped, experienced bike mechanic would have the necessary tools and knowhow, but I suspect the solution for most broken shifters is complete replacement.
Mechanical shifters work on a ratcheting/pawl system that holds the cable taut, shortening the effective length of cable when you upshift and lengthening it when you downshift. Everything is spring-loaded. If a tooth on one of those gears breaks, if the spring breaks or comes loose, or the pawl breaks; all that's left is a cable that "flops around." To diagnose, you'd probably have to disassemble the shifter and locate the broken part, find and install a replacement part, then reassemble; all while holding the system taut with the spring(s). Labor costs are high enough that it's more cost-efficient just to install a new shifter; which is probably why you can't get those little fiddly parts from the manufacturer.
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