Shift front and back at the same time on 3x7 ?

woody33

Is it considered bad to shift both derailleurs at the same time? How about jumping several cogs at once on the same group? I would ease up a bit on the pedals. If you see what i mean. It's a modest spec 3x7 MTB. Thanks for any words of wisdom.

magicbastarder

i do it quite often, road bike shifters can shift more than one ring at a time on the back.

most common when you reach the point that a further change would result in cross-chaining. i.e. you shift down to the small ring on the front while shifting to a smaller ring on the back, simultaneously.

07Lapierre

I would say it's bad practice to change both front and rear at the same time. You run the risk of the chain jamming between the frame and chainrings etc. It's an even bigger risks if you do it without easing off peadalling.

The real question is why do you want to change both at the same time? I suspect it's because you have a triple chainset and you always feel your in the wrong gear?

Type 17

You should alway ease off the pressure on the pedals for any shift, but multiple sprockets and both derailleurs is fine - Di2 in Synchronised Shift mode shifts both derailleurs and the rear by up to 3 sprockets simultaneously.

If your chain drops because of this, you need to adjust limits, etc.

07Lapierre

Type 17 wrote: »

You should alway ease off the pressure on the pedals for any shift, but multiple sprockets and both derailleurs is fine - Di2 in Synchronised Shift mode shifts both derailleurs and the rear by up to 3 sprockets simultaneously.

If your chain drops because of this, you need to adjust limits, etc.

OP has a 3x7 drivetrain? Moving a few sprockets on the rear while changing from the smallest chainring to the largest chainring on the front is a big ask for any drivetrain.

Type 17

07Lapierre wrote: »

OP has a 3x7 drivetrain? Moving a few sprockets on the rear while changing from the smallest chainring to the largest chainring on the front is a big ask for any drivetrain.

I've owned a few 3x7's myself (still own one). Perhaps if shifting two rings at the front, I'd leave the rear alone for a sec, but I do shift from the middle ring -> top, and shift the rear down 2 or 3 sprockets to compensate, and don't have issues.

woody33

Type 17 wrote: »

I've owned a few 3x7's myself (still own one). Perhaps if shifting two rings at the front, I'd leave the rear alone for a sec, but I do shift from the middle ring -> top, and shift the rear down 2 or 3 sprockets to compensate, and don't have issues.

Yep, that's the sort of thing, or the other direction maybe. A previous bike had a non-functioning middle sprocket on the front, I'm still getting used to the luxury of three working cogs!

magicbastarder

it'd be a very rare occurence that you'd need to shift two rings at the front, that'd be a massive change in gearing.