Shimano Revoshift twist grip unusably tight Shimano twist grip shifter on Apollo Neo 6 girls bike. I bought this bike 6 months ago for my 7 year old.



After getting it serviced at 99 Bikes the shifter was so stiff my daughter couldn’t change from the 2nd gear into the first.  Took it back &amp; the mechanic checked it &amp; said it was normal.  I insisted on him replacing the gear cable but… no change.  I flooded the handlebar twist grip with lube but no change.  Went back to the shop and the same guy said nothing wrong and that’s how those shifters work.  I demonstrated that my daughter couldn’t access the first gear.  Seriously, it requires a very firm grip and a firm twist even for an adult.  Now I’m quoted $100 to replace the shifter with a thumb shifter.  My daughter is normal strong for a kid.  Is this a design fault or a mechanic needing replacement?
As per AndyP’s comment, I have also heard anecdotally that these styles of shifters can be stiff for children’s hands, but then again some thumb push trigger shifters can feel quite stiff to my adult thumbs. 

As you mention it is most difficult for your daughter to access first gear, I would investigate or have the shop check the Lower Limit screw on the derailleur. If this is set a fraction too tight then the shifter is trying to pull tension against this limit. If this screw is set too tight then the shop should adjust it to the correct position as part of the labour you’ve already paid for. It’s probably only a fraction of a turn. 

Otherwise, changing to a trigger shifter unit needn’t be very expensive, but I would try models out and find which suits your daughter’s hand strength the best. if you’re quoting AUD price then maybe it includes the part cost and a minimum labour charge and that’s how much it costs to have work done on bikes where you are. 

It has been suggested by an anonymous edit, from a person who had a similar problem, to double check the cable placement at the derailleur fixing bolt. For example this extract from the Shimano Tourney Dealer's manual