Originally Posted by carlton
George--If the cassette and chain are in good shape run them. If they show signs of excessive wear replace them. Look at the gears on the cassette that you use the most often. Then compare it to the gears you use the least often. Does the drive side of the teeth show a cup like or dished out wear pattern? Are the teeth pointed on the ends instead of blunt? If these conditions exist the gears are worn out and should be replaced. I usually measure the chain length for wear and then bend it a bit from side to side to check for side plate wear. If it looks good, clean it up, and lube it and run it some more. My LX front XT rear equipped bike has between 7 and 10 thousand miles on it and shows only minor wear on the original cassette and chainring. I recently installed the 3rd chain.
If you have put a 3rd chain on a cassette and still have it work, you should consider yourself lucky. I've seldom been able to run even a second chain on a cassette without it popping like crazy. Most everything I've read...and my personal experience...says that chain and cassette should be changed at the same time. I do think you are changing your chain at too high a frequency however. Seven to 10 thousand miles and 3 chains seems excessive.
Originally Posted by carlton
Pretty flat over there in Katy. Cant imagine you needing a lower gear unless you go visiting in the Hill Country.
If you decide to go lower in the rear (11/34) you will probably have to replace the derailleur also. If your front derailleur is a clamp on it should work with mountain bike chainrings after being lowered to the proper height and then adjusted for proper side to side movement. You should be geared plenty low enough with mountain bike chainrings and your current cassette.
This is a Trek 7300 that is already running a long cage derailer. If it can shift a 30 tooth cog, it can handle a 32 or 34 just fine. No need to change the rear derailer. A Deore rear derailer should handle a wide range cassette without problem.
Originally Posted by carlton
I have pretty much the same terrain and high headwind here in corpus christi as you do in katy and I almost never go lower than about 34 gear inches or higher than 100.
Gearing is always a personal thing. What works for one person might not work for others. Maybe George is going to go ride in Colorado or do RAGBRAI or do the TransAmerica Trail. He know what his needs are. I seldom ride much less than a 53 gear inch combination on my commute to and from work in our hilly city but I occasionally run across something that requires much lower gears. I'd rather have it and not need it, then need it and not have it. On a touring bike, with a 60 lb load, a 16" gear is very welcome and, even at 3 mph, is far easier than pushing up a hill on foot.
Originally Posted by carlton
Absolutely. Use the gear calculator to try out new combinations before you go spending money. Use your current gears as a guide and work from there.
George,
Don't make this more complicated than it needs to be. Get the cassette you want, put it on the wheel and see if it works. Since you are only going up a few of teeth in the back, you might not even need a longer chain. If the derailer won't shift to the lowest cog (not that I think it will have problems
), look into another rear derailer. Do your calculations and see if a smaller front is what you want too.
Good luck