Chain ring advice
06-04-15, 06:10 PM
#1
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Chain ring advice
Our 2005 Trek T2000 has Shimano 6500 triple chain rings, 30/42/53. We tend to wear out the 42 the fastest, every 5-6000 miles. Can't seem to find a Shimano 130 BCD 42 Tooth middle anymore. Should I stick with Shimano and use a 39 tooth middle, or switch to another brand of chain ring, or...?
06-04-15, 06:19 PM
#2
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Our 2005 Trek T2000 has Shimano 6500 triple chain rings, 30/42/53. We tend to wear out the 42 the fastest, every 5-6000 miles. Can't seem to find a Shimano 130 BCD 42 Tooth middle anymore. Should I stick with Shimano and use a 39 tooth middle, or switch to another brand of chain ring, or...?
06-04-15, 06:38 PM
#3
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Premature chainring wear is typically caused by a stretched chain. Are you measureing chain stretch and replacing when needed?
06-04-15, 07:05 PM
#4
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Replacing chain religiously at 0.5%. But we also climb 100' per mile...
06-04-15, 08:59 PM
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06-04-15, 09:23 PM
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We climb a fair bit too, and prefer the 39T anyway. We've gone to a SS 26T granny because we wore the grannies too and then would get chainsuck on the burrs. Our 26T aren't made anymore. Peter White says TA Zelito has a 24T SS 74 BCD inner ring. Might shift to the 39T fine. I'd always rather go with a smaller granny ring and a closer ratio cassette.
06-04-15, 11:52 PM
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Those FSAs look the most promising if you want the 42T over the now more common 39T. Rotating the old ring one or two bolt positions might be something to consider before throwing it away, as you'd be able to use a fresher part of the chainring -- you'd probably want to rotate the big ring with it to keep the shifting aids in sync.
06-05-15, 10:05 AM
#8
Clipless in Coeur d'Alene
Only 5-6000 miles? Holy Toledo you are tough on your middle ring!
A gear ratio issue in moving to a 39t, is that your normal cruising a the top end speed in your middle ring may come too early and require more shifting to the big ring. If you currently typically do not cruise using the 42t and the 2nd smallest rear cog (never use the smallest other than with the big ring), then there should be additional ratio available for the 39t with shifting up, and no ratio "issue". The other "gotcha" is ramp & pin alignment...
While other brand 42t triple middle rings can be found, the problem is that each mfr has their own alignment of ramps and pins, and even each set of rings are oriented in a specific spacing to allow the chain links to mesh from one ring to another while engaged. If you mix ramped & pinned rings, typically the shifting will not be as good as when using a complete set.
A gear ratio issue in moving to a 39t, is that your normal cruising a the top end speed in your middle ring may come too early and require more shifting to the big ring. If you currently typically do not cruise using the 42t and the 2nd smallest rear cog (never use the smallest other than with the big ring), then there should be additional ratio available for the 39t with shifting up, and no ratio "issue". The other "gotcha" is ramp & pin alignment...
While other brand 42t triple middle rings can be found, the problem is that each mfr has their own alignment of ramps and pins, and even each set of rings are oriented in a specific spacing to allow the chain links to mesh from one ring to another while engaged. If you mix ramped & pinned rings, typically the shifting will not be as good as when using a complete set.
06-05-15, 11:47 AM
#9
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Thanks for the help. I'll give the 39T a try. Hopefully it will still shift okay into the 53 outer.
not sure why we've been so hard on the middle rings. The other rings and the cassette seem to last better, and I'm pretty good about chain wear, cleanliness and lube. Must be the local hills and our tendency to do a lot of climbing out of the saddles in the middle ring. Plus I'm sure we put more miles on that ring than the others.
not sure why we've been so hard on the middle rings. The other rings and the cassette seem to last better, and I'm pretty good about chain wear, cleanliness and lube. Must be the local hills and our tendency to do a lot of climbing out of the saddles in the middle ring. Plus I'm sure we put more miles on that ring than the others.
06-05-15, 12:04 PM
#10
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We mostly ride in the big ring. Less chain tension, more teeth, less wear. We don't use the 2 largest cogs with the big ring. Works fine. The middle and inner rings are for climbing. The 39-53 shift (actually isn't yours a 52?) will work fine. Either 52 or 53 works fine. I don't have to call that upshift.
