Specs:Number two in my “I had to replace everything” series.
This is a review for the Shimano FC – M582 LX crankset. This crankset features forged aluminum cranks, aluminum outer & middle chainrings and a steel inner chainring, in a standard 44, 32, 22 ratio. It is supposedly compatible only with narrow, 9-speed chains, but I’ve heard that 8-speed chains work just fine.
This also utilizes Hollowtech II bottom bracket technology, with an external bearing BB. More on that a bit later.
Why I Bought It:Well, this bike is my trusted friend and I didn’t want to give it up. That said, there was much that needed replacing. First, my cassette was starting to wear and grind, my brake lever had lost its spring-back, my front derailleur was failing, my brake arms were flexing. Finally, I had everything done that I could do myself and brought the bike into the LBS for them to replace the BB and small & middle chainrings. Well, it was my lucky day, because the middle chainring was irreplaceable (that’s right, it’s PRICELESS!). Instead of the now-standard, every chainring gets bolted to the crank, my small chainring was bolted to the middle chainring via tabs (see pic). So, I had to spring for a whole new crankset, which is good and bad.
Conclusion:What's good ...
1: I can actually feel the improvement in power transfer with this crank. Keep in mind that I am moving from the classic tapered BB, so that’s most likely where the improvement is coming from. Other suspects are: the new chain (least likely); the increase in crankarm length (probably does affect it some); the fact that this BB is not worn out and does not sound like it’s filled with tiny, saucer-shaped ball bearings (most likely, and also an apt description).
2: The shifting is crisp, but again, this could either be the new chainrings or the new derailleur, but most likely a combination.
3: Also, it’s kinda cool you can see right through the BB.
So now we get to …
What's bad ...
1: First of all, there’s the lifespan issue. This is not something I have yet experienced, but others certainly have (see this thread). As Andy says, why take something that has worked so well for so long, e.g. sealed internal bearings, and move them to the outside? It don’t make no sense.
2: Maintenance! Maintenance! Maintenance! I guess it’s because of the design change, but rather than the old, “pound ‘em in and they're on for life” approach with tapered BBs, cranks are now held on with these bolts. And, as bolts will do, they loosen. It’s not a huge complaint, but every bit counts.