Front shifter, integral tension adjuster

[miniman]

My wife did a 100 mile ride yesterday, which made Saturday rather fraught when her front shifter stopped shifting from large to middle chainring (jumping over middle ring). We diagnosed it at the local bike shop as a worn-out ratchet in the shifter and swapped it out for a fortuitously-available Shimano 105 spare. Ride was completed successfully but I now need to give back the borrowed shifter.

Oddly the original shifter, pictured, has an integral tension adjuster.



The Shimano doesn't, and we didn't get it perfectly tensioned. Looking at other bikes, most seem to have adjuster barrels in the cable guides at the top of the downtube. This bike doesn't, and doesn't look like it would accept them (the guides are slotted with no screw thread.

I can't find any shifter, including the brand currently fitted (Microshift - cheap Shimano-compatible as far as I can see).

Any thoughts? I will probably replace the bike and give the current one to one of the kids when they are big enough, so want to fix it without massive cost (bike was only £300).

TIA

[matt-ITR]

Use an inline barrel adjuster.

[miniman]

matt-ITR said:

Use an inline barrel adjuster.