I hope somebody is kind enough and patient enough to read this lengthy explanation and perhaps offer me the benefit of their advice / wisdom/ mechanical expertise. I am having a nightmare with the front mech / chainring on my 5 year old Sirrus Pro. I posted this a few months ago, but the problem persists https://www.cyclechat.net/threads/problem-with-front-derailleur-gear-shifter.226433/ The main problem now is that the chain will not shift to the large front chainring. 2 separate mechanics, working for different places have taken it for repair (one about 3 or 4 times), told me they have repaired it and made sure the shifters work, but each time I take it back, the chain moves to the big ring the first couple of times I have tried it, but then stops doing so. It seems to work okay when in a stand but as soon as I ride it, under load, it stops operating properly. The latest attempt involved fitting a better quality chainring, but the same thing happened. I am beginning to think it might be time to give up on the bike, but it is only 5 years old and I would have thought it would have much more life left in it yet. Perhaps before doing that, it might be worth systematically changing each component, or just the whole lot, but that could end up with money wasted. I also wondered if it could have something to do with my weight, which at 15 stones, isn’t inconsiderable. Any advice gratefully considered.