Is shifting under load bad?

jojoma

I just started shifting while out of the saddle, which really helps when taking off from stop lights. But I make sure to ease up on the load to complete the shift. I was wondering if it's okay to shift while hammering away. I have done it accidentally and it doesn't sound like my drivetrain likes it so much. I have 105 from year 2006, so I might need a better group to be able to shift under load.

Thanks

alienator

I just started shifting while out of the saddle, which really helps when taking off from stop lights. But I make sure to ease up on the load to complete the shift. I was wondering if it's okay to shift while hammering away. I have done it accidentally and it doesn't sound like my drivetrain likes it so much. I have 105 from year 2006, so I might need a better group to be able to shift under load.

Thanks

Not really. Depending on your drivetrain geometry, some shifts may be more difficult to complete under a load. Over time, shifting under heavy load will accelerate wear a bit, but the fact is that the amount of shifting done under large loads is likely very small.

bobt1970

Alienator is right, it will wear the gears a little faster but it is made to be able to shift under load especially while climbing a hill, otherwise if you ease up to shift - you would lose momentum.

sogood

Fortunately with modern drive train designs, the choice is up to the individual. Yes, wear would increase somewhat if you do it all the time but I am not sure the predominant wear would be chain stretch or some other parameter we don't regularly measure. Yet, losing momentum on a climb can be just as painful.

alfeng

I just started shifting while out of the saddle, which really helps when taking off from stop lights. But I make sure to ease up on the load to complete the shift. I was wondering if it's okay to shift while hammering away. I have done it accidentally and it doesn't sound like my drivetrain likes it so much. I have 105 from year 2006, so I might need a better group to be able to shift under load. I've said this innumerable times -- Campagnolo shifters CAN shift under load with NO PROBLEMS ... downshifting with Shimano's shifters clearly remains problematic, even with the current generation (I presume you have 10-speed, 105 5600 shifters ... which are now considered to be almost-as-good-as-if-not-equal-to the Ultegra 6600 shifters, BTW).

FWIW. After several years of off-and-on-again fiddling with Shimano's STI shifters (alternating the bike's configuration with downtube shifters), I finally/(accidentally?!?) discerned (many years ago) that I could downshift smoothly when the drivetrain was under load (going UPhill) with Campagnolo ERGO shifters regardless of the incline ... I was sold because it meant that I no longer needed to downshift BEFORE the incline to whichever larger cog I wanted to end up with at the end of the particular slope -- the ONLY limitation I have found is not having another gear to downshift to!

bobt1970

I've never had problems shifting under load with shimano either upshifting for sprints or downshifting for climbs. I do club rides and sometimes try to break from the group on steep up hills with 100% efforts with serveral shifts no problems. It always goes into the gear that I want, and it does it fairly quickly. I never downshift before the incline.

The only thing I'm concern about is breaking a tooth on the cog while shifting. I did break a tooth once on my old campagnolo victory equiped bike, and it wasn't even under 100% effort because I had to take may hand off the handlebar to shift from the tube.

RelevantAaron

On my Shimano Ultegra group I don't go out of the way to shift under load, but I agree with the posts above that it is not a problem. However, when I climbing hard I do find that just a slight ease off when shifting down gets it into gear quicker. Not enough to lose momentum, but enough to get t to slot in fast.