Replacing Chainset due to thread problems

[Guy23]

Hi,

I'm new to this forum and bike DIY generally so apologies in advance if this has been covered elsewhere etc.

I have a 2006 Giant OCR3 with a TruVativ Touro, 30/42/52T chainset. Last year I replaced the existing pedals which was fine on the one side, however, it turned out that the thread on the second one had essentially fused with the crank arm. With lots of effort and two pedal wrenches later I managed to get it off with half of the thread left. I managed to make do with this position over the winter, however, now the pedal has come away and basically the crank need replacing.

I am happy to do this replacement however, I am now entering the world of chainset ratios, BB cartridges etc. etc. and I am finding "too much" information on the internet which is in places contradictory. I could replace the chainset with another one of the same size, or even the same model, however, I noticed that this ratio seems to be associated with beginner models and that 30/39/50 seems more common in the next level up. If I were to replace with a different ratio such as this what would be the implications in terms of knock on jobs - ie. would I have to replace derailers, adjust the chain and so on? Also, the original specification just says I have a BB cartridge attached to the chainset, would this also need to be replaced when I do the work? There is no particular noise etc. from the bike, it was running perfectly (aside from only having one pedal attached!) so maybe these would not need to be replaced at this time.....

If I stay with the same 30/42/52 ratio I will probably go with the Shimano 2303 but if adjusting to the 30/39/50 is not going to cause too much further work then I would probably go with the Shimano Tiagra 4500 range 30/39/50. I mainly ride on roads in the UK so no major hills etc. and I use the bike for Triathlons.

Any advice and thoughts would be gratefully received. I am looking to do all of this work for below £100 but if I can marginally improve performance of the bike at the same time then I would rather do this.

Thanks in advance