In Vt., we do lots of hills, my commute for example has two separate mile plus climbs and descents with 7-10% grades - in each direction. So I get plenty of opportunity to launch myself along in a 48/12. Smaller cogs like a 12 will hit each tooth much more often than the larger cogs. When I'm running the 48/12 I will be turning it over 4 time per pedal revolution whereas when I'm in a 34/24 it's only 1.4 times, and there are twice as many teeth to hit on each evolution. At least that's why I believe I always wear out the smaller cogs first. I wish it weren't so.
I think of chains and cables as general wear items and like to start each season with new brake cables and a new or at least newish chain. Michael On Jun 9, 10:50 am, Steve Palincsar <palin...@his.com> wrote: > On Wed, 2010-06-09 at 07:34 -0700, MichaelH wrote: > > I clean the chain every couple of hundred miles, or sooner if I've > > gone through wet & mud. I ride 10 miles of dirt roads almost every > > day, so even with fenders, my chains get dirty. I use the Park tool > > on my chains and find that I got about 1500 miles out of Shimano > > chains, so I consider 2500 - 3000 miles pretty good. Most mechanics, > > and all mfg. recommend chains be replaced at about 1500 miles. I don't > > often ride with a bike computer and don't keep any mileage log, but I > > know that I do about 3500 miles commuting each season, and have never > > pushed a chain longer than that. A worn chain will wear out the cogs > > much faster, and I find that if I push a chain too far, it will damage > > the 12 tooth cog enough to cause skipping. I also use two sets of > > wheels, so am using multiple cassettes and that might make a > > difference too. > > I think the dirt roads are the key here. I'm amazed that you wear out a > 12T sprocket. I find 12s to be nearly useless except on tandems and if > you have a 44T big ring -- and even there, you're in the top gear so > infrequently a 12 tooth sprocket could be transferred from cassette to > cassette a half dozen times or more without showing significant wear. > For me, it's the ones in the middle of the block that get the wear. > > Recommending a chain replacement at 1500 miles irrespective of wear > might be fine if you are in the business of selling chains, but unless > that chain is actually worn it's just wasteful. If it is worn, of > course replacement is in order. Chains are much less expensive than > cassettes. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bu...@googlegroups.com. To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
