I'm about to install a new wheel/freehub and 8-speed cassette on my hybrid (find links to parts below). There isn't any difference that I can see between the new parts and the old, except for this. The (very) old cassette is a Shimano CS-HG40 11-34, and the new one is a Shimano CS-HG41 11-34. I wanted everything to stay the same, but when I searched for the HG40, all I could find was HG41. I'm pretty sure the new parts are compatible with each other, so my first question is probably moot: The cassettes look to be identical, so what's different about them? Compatible with RD?

But here's the real question: My current chain has only a little over 200 street miles on it. Should I replace it anyway?


Shimano Wheel Rear 700 x 35 Silver, QR, Altus RM30 8Sp Hub, 14g UCP Spokes, 36H

Shimano CS-HG41 8-Speed Cassette, 11-34T

Difference appears to be on teh 40 the first 2 sprockets come off. A 41 would be a direct replacement for a 40.
I wouldn't replace a chain with 200 miles on it. Heck I have 200 miles this year on a chain I plan on replacing once we get some rain to wash some of the salt and grit off the roads from winter.

file:///home/chronos/u-71c0988f1649b1a49d367c58f9d512f2c860aba7/Downloads/EV-CS-HG41-8-3236A.pdf

file:///home/chronos/u-71c0988f1649b1a49d367c58f9d512f2c860aba7/Downloads/EV-CS-HG40-8I-2550A.pdf

Shimano tends to up the second number of of a part series when they upgrade. i.e. 105 generations are 5400, 5500, 5600, 5700 as they updated/upgraded.

You'll be just fine with that cassette and your 200-mile chain...shouldn't even need to adjust the derailer... Slap 'er on and ride!

Thanks to both of you. That numbering information is enlightening.

I didn't think that replacing a chain with 200 easy miles on it would be necessary, but I just kept seeing recommendations to always install a new chain with a new cassette.



This has been a bit like starting out to paint one room, and ending up remodeling the whole house.

This all started because the cheap tires I put on my bike would not mount without a bulge or two somewhere. (They were from the original wheels [7 speed freewheel] on this bike, which were replaced so I could upgrade to an 8 speed freehub [from an older bike]). So I got new tires to put on it. They mounted very evenly, but that just made the slight low spot in the rim more noticeable. (Too many truing jobs, I guess. It had been wrecked and pretty severely bent a couple of times.) Maybe a little OCD at play here, but getting it so close to perfect just made this little flaw really bother me. So I start to order new rims (the exact ones I wanted happened to be on sale), and I just happened to notice the cassette on the same site, at a really nice price. And I figured it might be a good idea to avoid putting an old (>10,000 mi) cassette on a new freehub anyway. (Any excuse for new gear, right?) But now I'm wondering, what's next? Where will this all end?

N+1; when you have more than a dozen bikes.