My gear shifters (c. 2000 Shimano XT) will not shift to the bigger cogs (higher cable tension). Pushing the shift lever doesn't move the indicator past about half way so I can't reach the big cog on the front, or the lower gears at the back, it just doesn't click up into the next gear.
The bike is about 16 years old, so I'm guessing something in the shifters has worn out, but I thought I'd ask here in case there's something I missed and they're repairable!