Shifting question
 

My bike has a Suntour RDER and Suntour power shifters on the down tube. I have to move the lever 30-45 degrees to shift from one cog to another. This happens with both a V-GT and a 1st gen Cyclone GT, whether I'm up- or down-shifting.

A couple of days ago, I rode a bike with Shimano 600 Arabesque shifters and RDER. The seller said the bike used friction not SIS. The shifts required much less lever movement than my bike needs. I think shifting through all 6 cogs required less than 90 degrees of movement.

Is something wrong with my RDERs or shifter?

Thanks in advance.

Those derailleur should be compatible with the power shifters and shift across a 5-6 range in just over 90 degrees of lever throw. Based on your description, you should only be able to shift across 2-3 cogs.

1.Cable slack: Excessive cable slack will increase lever throw, but only for the first shift.

2. Long housing: Running long lengths of improperly anchored housing can cause longer lever throws, due to compression and flexing of the housing, though typically not to the extent you describe.

3. Anchor bolt/nut: If insufficiently tightened or stripped, the cable will can slip between the nut/washer and derailleur body, causing longer throws. But this typically happens for only one cycle and then you're back to #1.

4. Routing the cable on the wrong side of the anchor bolt can affect the pull ratio but again,typically not this much.

What you're describing would typically only happen consistently only if the lever barrel is too small for the cable pull ratio of the derailleur, but this should not be the case based on your component descriptions. Please provide photos of the actual components and cable routing.

Is there any sort of leverage-altering device along the cable's path? It sounds like a Demultiplicator or Travel Agent accessory may have been added.