When changing gears in some gears they skip

[DamiBa01]

I have this bike with a front and rear derailleur Shimano 105 and with a pedalier SRAM red

And when going from 2nd to 3rd instead of changing to 3rd it skips it and changes to 4 it also happens with 6th and 9th any ideas why?

[ReapThaWhirlwind]

SRAM and Shimano have different pull ratios for 9 speed and beyond. I do believe they were once interchangeable with 7 and 8 speed.

You will need a 9 speed Shimano shifter to use the 9 speed Shimano rear derailleur properly.

You will specifically need a 9 speed one, because Shimano 9 speed spacing is proprietary to the group class.

5~8 speed spacing is the same, and thus you can use an 8 speed derailleur for a 7 speed cassette. 10 and 11 speed the same (since spacing is the same between them as well).

Not 9 speed though. It's unique unto itself, and the only components you can mix are crank chainrings.

And you can use higher speed chains on a 9 speed setup, if say you want to run a 10 speed cassette with a 9 speed crank. In this case, you'll need a 10 speed chain, shifter, and derailleur to navigate the cassette properly. And the 10 speed chain will be fine on the 9 speed crank, so long as the front derailleur also matches the chain (so it doesn't rub on the cage).

You cannot run lower speed chains on higher speed cranks or setups, because they are too thick and will disrupt the precision elements.

If you get skips like this any other time, it will generally mean there is too much tension on the cable. You need to dial in the barrel adjuster and/or re-fix the cable to the rear derailleur with less pre-tension in it.

[Jesper]

(08-03-2021, 09:03 PM)DamiBa01 Wrote:  I have this bike with a front and rear derailleur Shimano 105 and with a pedalier SRAM red

And when going from 2nd to 3rd instead of changing to 3rd it skips it and changes to 4 it also happens with 6th and 9th any ideas why?

You didn't mention what type of shifters you have. The previous post is correct about mixing and matching shifters given different speed cassettes. The SRAM Red crankset should not affect it as far as I know. It is possible that your indexing system is not set up properly, or as previously stated is not compatible with the shifters themselves.