Chainset replacement question.

[BlackPanther]

As my Allez (16 speed) has now done a few thousand miles, I'm about to order a new cassette and chainrings. The cassette I was looking at buying is the Shimano Sora HG50 8 speed 13-26 at £22.95.

My confusion though is with the chainrings. It came with 52/39 rings and I'm perfectly happy with this gearing for commuting, but the 39 tooth rings I've seen are listed as '10 speed', and the only set I can find is 52/42. I can't see why the 39 wouldn't be suitable for an 8 speed, but if that were the case, why do they list it as '10 speed'?

Finally, any advice on what would be the best all round set to buy as there are so many variants from Shimano alone. I do around 4-5,000 miles a year, so don't mind forking out a bit more for longevity, but I'm not too bothered about paying loads just to save a few grammes. It's the 1st time I'll have replaced the cogs, at last I'll be able to use those funny looking tools that came with my Halfords bike tool kit! Any potential cock ups that I need to look out for?

 

[gaz]

Do you really need to change the chain rings after a few thousand miles?
Did you run your chain for too long?

 

[gds58]

Don't worry too much as any chainring that is listed as '10 speed' will be suitable for 8 and 9 speed as well. Unless they are listed as being 1/8th size which is for single speed and track use then they should all be OK with 7, 8, 9, 10 speed set ups. I can't vouch for the newer 11 speed as they may use a slightly narrower chain (I honestly don't know)

I think they are listed this way as you would get the reverse happening where people would then be asking "is it suitable for 10 speed?"

Hope this helps, Graham