new bits advice for Trek7300fx (circa 2006)

[Steveo100]

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[Steveo100]

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[ElCani]

Those chainring teeth do look pretty far gone. If it was me I'd probably just replace like-for-like with another triple chainset, assuming the bottom bracket is ok. Moving to a 1x system would ideally mean using a narrow-wide chainring (to stop the chain falling off over bumps etc) and will generally cost more time and effort to end up with a less-flexible set-up.

[peetee]

Steveo. If you want to do anything with the information we have provided you need to answer the question both myself and 531colin have asked, namely which cassette cogs do you predominantly use, large or small?

[531colin]

Middle and big chainring teeth are worn quite badly, so the chainset will need replacing. (caused by running a badly worn chain!)
So, as Peetee says, the question is, which gears do you use, and which can you do without.
Just as a bit of a guess, you generally seem to use the middle chainring, but also the big one, so 38T, 48T
If you want a single chainring, go somewhere in the middle, say 42T. with a similar cassette as now.
Theres one here for £25 https://spacycles.co.uk/m8b0s109p2188/STRONGLIGHT-ST55-Single-Chainset
Much better quality one for £55 https://spacycles.co.uk/m8b0s109p1699/STRONGLIGHT-Impact-S-chainset-with-double-chain-guard ...not only can you replace the chainring if it wears out, but it has chainguards both sides to keep the chain on.
For either you will almost certainly need a new bottom bracket bearing unit of the correct length.....it might be worth looking at your existing one to make sure you can get it out, ie it isn't rusted in....the tooling won't be too expensive, provided the old and new units use the same tools!

[Brucey]

FWIW those chainring teeth are a bit knackered.... but is that the best bit or the worst bit? Normally the chainrings are least worn inline with cranks and most worn at about 90 degrees away from this.

In any event the acid test is to see if the worn chainrings make any difference or not when you fit a new chain and cassette. Same as the worn jockey pulleys really; if there is any doubt I'd try them and act accordingly in the event of problems.

FWIW I'd expect the transmission to be a little rough/noisy for a while with those chainrings but it may just settle down after a while. By contrast the cassette is definitely bin-fodder; there is much less leeway with cassette sprockets.

cheers

[Steveo100]

Steveo. If you want to do anything with the information we have provided you need to answer the question both myself and 531colin have asked, namely which cassette cogs do you predominantly use, large or small?

I did mention that I mainly use the middle ring and 4 or 5 of the cogs running up the cassette. It's been a while since riding the bike so didn't take to much notice.

[peetee]

Steveo. If you want to do anything with the information we have provided you need to answer the question both myself and 531colin have asked, namely which cassette cogs do you predominantly use, large or small?

I did mention that I mainly use the middle ring and 4 or 5 of the cogs running up the cassette. It's been a while since riding the bike so didn't take to much notice.

Yes, but all the cogs “run up the cassette”. Do you use the largest or smallest 4 or 5?

[Steveo100]

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[ElCani]

My girlfriend had a 2007 (I think) Trek 7.3 FX and assuming the rest of the bike is basically sound (and you've already said you like it) I can't see how you're going to end up with something better for £300-500. I'd fix and keep, better for the environment and you end up with something you know works for you!

[Jamesh]

A chainset, cassette and chain can be had for £50 and it's an easy fix.

If you have a bike library near you they will do the work for very little money.

Cheers James

Ps at least donate it to a bike library for renovation for someone to enjoy.

[Steveo100]

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[Steveo100]

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[Steveo100]

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