Altus ST and triple crankset
02-24-21, 04:50 AM
#1
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Altus ST and triple crankset
Hi all
is it possible to use Altus ST with triple crankset?
is it possible to use Altus ST with triple crankset?
02-24-21, 05:52 AM
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RD cage looks awfully short for it. Without looking anything up I'm saying no.
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02-24-21, 06:02 AM
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Max cog is 28 teeth but no idea what the capacity is, VeloBase.com - Component: Shimano RD-AT12, ALTUS LT
Yes you can get even a short cage RD to work with a triple but that is a somewhat compromised triple with the chain rings close together in size and a smaller freewheel. That may have been an acceptable compromise BITD when you only had 5 in the back as that could help you eke out different gear ratios (so does half step gearing). But why go to that trouble when you can run a wider gaps in your triple and a larger freewheel to gain some useful gears for climbing steep hills and mountains plus have useful in between gears so you can find a proper cadence?
Yes you can get even a short cage RD to work with a triple but that is a somewhat compromised triple with the chain rings close together in size and a smaller freewheel. That may have been an acceptable compromise BITD when you only had 5 in the back as that could help you eke out different gear ratios (so does half step gearing). But why go to that trouble when you can run a wider gaps in your triple and a larger freewheel to gain some useful gears for climbing steep hills and mountains plus have useful in between gears so you can find a proper cadence?
02-24-21, 08:57 AM
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It would have to be a very narrow range triple set-up. The front derailleur only has a capacity of 14T. Even then, the throw might be insufficient. The specs for the rear derailleur are strange as it states a maximum 28T large cog but 30T if used with Shimano products. I don't know what difference a Shimano freewheel would make over another brand! Regardless, with Frank Berto tested the Altus ST for Bicycling magazine, he found that it would handle a 30T large cog and 28T of chain wrap. Overall, he rated the shifting performance VG (Very Good).
02-24-21, 12:24 PM
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I run an SIS 600 rear derailer with 13-28t freewheel and 34-42-52t chainset and it's totally fine, even though the chain is sagging if on the smallest two cogs while in the small ring.
Most old front derailers seem to handle triple gearing if the front range is modest. Again though, things are better if the smallest cogs aren't used with the small chainring.
Most old front derailers seem to handle triple gearing if the front range is modest. Again though, things are better if the smallest cogs aren't used with the small chainring.
