I expect I would need a compatible bottom bracket too, like the one that this Claris crankset is frequently bought together with, here. The front derailleur is already a Claris, a few months old.

This is on a Jamis Aurora 2000 that I have been riding since 2003. Between my aging and the bigger hills here in San Francisco, where the bike and I moved two years ago, the gearing on the Sora, at 52/42/30, feels a bit too tall anyway. The Claris at 50/39/30 might suit better.

Would this be worth doing? The bike fits me well, I'm fond of it. The stock wheels are aging and the cantilever brakes are squealing, but it's still a fun ride. I'd have this done by the bike shop, I'm no mechanic myself.

  • 2
    I would also consider changing just the cassette rather than the crank. Yours is probably an 8 spd with the smallest cog having 12 teeth and the largest 25. If you switched to 13-26, you would get lower gear ratios with your existing crank. Shimano makes an HG50 cassette with that range that is available many places for ~$25-30.
    – Andrew
    May 28, 2019 at 11:21
  • The original cassette was indeed a Sora 12-25. But as of a year or so ago, it's a SRAM 12-26. The difference that extra tooth is making is imperceptible to me. Maybe 50 vs. 52 in front would be just as small an effect.
    – Gabi
    May 28, 2019 at 22:11

1 Answer 1


Well, one consideration is that this particular Claris crankset (2403) mates to an Octalink bottom bracket. The particular model of Octalink BB required is popular and as a result costs about twice what many others cost.

Additionally, if you don't change your cassette (& it's always a good idea to pair it with a new chain), you're really not getting any easier gearing on the low end as tooth count on the small ring remains 30. The cost of improving your ride is becoming significant and the value of the new crankset alone is near-equivalent to the Jamis' value (looking at numbers from Bicycle Blue Book).

A new road bike with a Claris groupset can be bought for around $500. They have compact and sub-compact options for cranksets and paired with a cassette with a tooth count range of (for instance) 11-32, there's plenty of low gear for the hills. Good bike shops will have staff that will help you with a good fit. Take lots of test rides too. That's the best way to discover the bike for you.

  • You're right about the smallest ring, and that settles it. I'm not sure that 50 would be that much more pleasant than 52 on the smallest cogs. Thank you for giving it thought. As to trading up, the Jamis fits and it aged well. It looks just about worn enough that it's neither thief bait nor do I look like a slob riding it. I'd agonize too much over a new bike that would be a worthy replacement.
    – Gabi
    May 28, 2019 at 22:16
  • @Gabi Believe me, I'm all for improving the ride I love and am used to. Perhaps a new cassette with wider gearing would be your best bet. A cassette with a tooth count 12-28 or even 11-32 would help tame the hills.
    – Jeff
    May 29, 2019 at 2:13
  • An 8-cog, 11-32 cassette would help, but that's MTB gear, so I'd need a new rear derailleur as well. I've considered it. I'm just confused about the choices. In road gear the Shimano hierarchy seems clean and simple. MTB, not so.
    – Gabi
    May 31, 2019 at 0:29
  • 1
    I have a newer Claris GS cage (R2000), total capacity is 43 and can handle a 34 tooth large sprocket. I have a triple front 52-42-30 and a SRAM 11-32t cassette and all works great. Here's the Shimano Rear Derailleur specs page. These are the road derailleurs. The R2000 runs $25-35 depending on where you go. A 7, 8, or 9 speed mountain derailleur (long cage, SGS, w/ triple fronts) will also be compatible with your shifters. At these speeds "road" &"mountain" are marketing terms only.
    – Jeff
    May 31, 2019 at 4:10
  • Thank you! I had no idea what chain capacity was, googled it. Now all of these specs make perfect sense.
    – Gabi
    Jun 1, 2019 at 4:39

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