In another thread about a Sora/Tiagra shifting roughly, Bikeboy said "don't shift under load"

Around here, we have some hills that are not constant grades. There is one set of hills I ride called the humps that varies considerably. Exactly then how do you shift going uphill when your cadence starts to fall off? Or conversely, shift hte other way when the grade flattens and your cadence increases?

I was trying to shift while going uphill last night, which could explain some of the rear derailleur "harshness".

Edumacate me.

In another thread about a Sora/Tiagra shifting roughly, Bikeboy said "don't shift under load"

Around here, we have some hills that are not constant grades. There is one set of hills I ride called the humps that varies considerably. Exactly then how do you shift going uphill when your cadence starts to fall off? Or conversely, shift hte other way when the grade flattens and your cadence increases?

I was trying to shift while going uphill last night, which could explain some of the rear derailleur "harshness".

Edumacate me.

Shifting under load is almost always bad. Some drivelines will do it, at least most of the time, but it's hard on chains and generally not necessary.
The standard advice is to shift before you need to, but in the conditions you've described, that can have you spinning like a hamster in the dip before the climb, so you lose momentum. One solution is to start up the hill a gear or two higher than you can carry all the way up, but then shift a few feet before you bog down, by pedaling HARD for a stroke or two to get some mo, then soft-pedal for a revolution or two during the shift itself. As soon as the chain clicks into place, go back to normal pedaling.

pedaling HARD for a stroke or two to get some mo, then soft-pedal for a revolution or two during the shift itself.

That is exactly what you need to do.

I have never had any problem shifting when pedaling too fast. It is the pressure on the drivetrain that is the issue, and when you are not climbing the pressures are not there. Well, unless you are hammering a huge sprint, but I have never generated that kind of power. So give it a hard go for a few and then let up and shift at the same time and it will work fine.

The reason for the problem is pressure on the chain. You are trying to lift the chain and shove it sideways at the same time. Too much pressure, and that movement gets resisted really hard. In extreme cases you can break the chain (though that is more common when shifting under pressure on MTBs).

I haven't broken it, but I threw it off the chainring once or twice. OK. I'll try this tonight (If I ever leave work).

Tried the "pedal hard, pedal soft, shift, pedal hard" techinique last night and it seemed to work. Also, now that I have the 32T granny on the bike, I found the hills much easier. Only had enough time/daylight for 30 minutes or so, but had fun going up and down the big hill near my house practicing.

Tried the "pedal hard, pedal soft, shift, pedal hard" techinique last night and it seemed to work.

Good! That "Klonk-PING" sound of shifting under pressure always puts my teeth on edge. Never so much as when I do it on the rare occasion!

ever drive a manual trani car?

same gig

ease off the gas, shift, let out the clutch as you give it some gas...

you'll get used to when it is engageing and the whole process will become second nature.

Great analogy. And, the whole thing started working more smoothly after I lubed up the whole tranny, too.

ever drive a manual trani car?

same gig

ease off the gas, shift, let out the clutch as you give it some gas...

you'll get used to when it is engageing and the whole process will become second nature.



I'll go ahead and nominate this for the 'tips Sticky' if it's not already there.