As the title says, I have to replace both some gears in the back and chain wheels in the front (probably two of each) due to a worn chain I used for too long (I have a replacement for that not pictured). My local bike shop sold me these large parts that replace the entire set of gears and all the chain wheels plus the pedal arm as larger pieces. My dad, who knows a bit about bike repair but his knowledge is a little out of date, found this unusual and thought it should be individual gears and wheels replacing the worn ones while the less worn ones would stay behind. Is there a superior option in terms of parts? Should I return these and get individual pieces online or just use the ones I've already bought? The return window closes in a couple days, so any answers will be appreciated.
by Da_Beast
4 Comments
on low end components, replacing the crank is cheaper, if not as expensive. cassettes are only sold as one set, so you cannot replace certain gears. the first 3 on some, yes. but mostly you replace the whole cassette, except for ebikes who only drive in the smallest sprocket….
to you dad with the idividual approach: cool but who in the right mind wants to track all their gears and their wear, which is barely really noticeable? maybe some, but thats not how 99% of the cyclist do it. Cassette and chainwheel wear is hard to gauge visually, if not overworn to shark tooth.
This is hard, could you back out a step and show us the bike and current condition of your rings and cassette? You are presenting part of the problem and one solution – more info would probably lend to better advice.
If you have a less expensive bike the chainrings (front gears) will be permanently attached to the crank arms as it’s cheaper to manufacture. You’d need to replace the entire crankset which is what you have there.
If you have a crankset with replaceable chainrings then the bike shop has done you wrong although this crankset is probably cheaper than new chainrings.
For the back gears it’s normal to replace them all.
So you have an older MTB or hybrid. The components they gave you are correct for this older style of bike. The CS-GH50-8 is a great cassette (I have about 5000 miles on my current one) and gear #7 is typically (for me) replacing at about 2x the rest of the cassette, it is replaceable at about $6 vs the cost of the cassette at ~$24. The choice of 11-34T vs 11-28T depends on you and your conditions and how much you want each gear to move you away from your ideal pedal RPM.
The front set is the cheaper chain ring set (with cranks) from Shimano. Its fine, I don’t prefer it as it wears quickly for steel. Since the rings are riveted to the spider you need to purchase it with the cranks. You can easily switch this out to a 104/64BCD in the future if you have cranks you care about and want to save. For my riding I find 48-38-28T on the front to be FAR too steep as it prevents the use of the smallest 3 gears on the cassette except when you’re barreling downhill. I’m personally running a 44-32-22T front set by Samox PN 304ASS. The Samox is wearing evenly between the outer most ring and the middle. I don’t really need the low range so W/E.
The FC-TY501 will wear out quickly, but at ~$22 its fairly priced, so it doesn’t really matter if you’ve not gotten 160mm or shorter cranks. By comparison the Samox quoted are ~$25.
There is an argument for getting a crank with a replaceable spider just to reduce waste in the future. The environmental cost of casting those cranks is way beyond almost anything else you’d replace on the bike.
Added Edit:
I just took a look at a new old stock Shimano SG-X chainring set I have on the shelf, and I think I see why the 304 Aluminum is wearing more slowly. The SG-X rings are mostly heavily tapered on the forward drive of the teeth, whereas the Samox are only front tapered for 2 teeth at about 1/3rd the spacing around the outer chain ring. This probably makes it shift slightly worse, but last much longer.