shimano 11-28 chain sizing
In the shimano tech docs they outline a different method for measuring a chain on an 11-28 cassette on a SS RD compared to all other combinations. They suggest the chain around both big rings and add 2 links. Does anyone know why this combination is different? And also what do Shimano mean by 2 links. Is it one outer with an inner. Or is it two sets, I.e outer-inner-outer-inner ?
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They are probably recommending the chain should be fractionally longer as the short cage rear mech is approaching the limits of its design on a 28 tooth sprocket. Add 2 links means 1 x inner+ 1 x outer link.0
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Just use this to calculate the ideal chain length. Have used it numerous times and it works on cassettes up to 30 tooth with compact 50 chainring.
http://www.epicidiot.com/sports/chain_l ... ulator.htm
BTW I would interpret Shimano's 2 link as 1 outer plus 1 inner link0 -
It is accepted in chain terminology that one link comprises one inner and one outer link, so two of each would be what Shimano are recommending.
I often use that same method when fitting a new chain. Big ring, largest sprocket, not through the rear mech, then add 2 links. Easy to do cos there's no tension in the chain. Just remember to thread the chain through the rear mech once you've cut it0 -
Although if you buy a Shimano chain it has, for example, 116 links. That's 116 individual links, not 116 pairs., so I would read the instructions as just adding one pair (one inner plus one outer link).
For me, both methods ended up with the chain the same length on an 11-28.0 -
BUGGER BUGGER and BUGGER..
Fitted my new 11-28 cassette and resized the chain *EXACTLY* by shimanos instructions. Checked and double checked. It's too short! In the big ring at the front it won't change into the big at the back. If I give the RD pulley a little push forward it will change up but you can feel it's pulled to the limits and you can feel resistance when you turn the crank by hand. One more link would probably have been perfect...
It's not the end of the world. I'll just avoid using that gear combination (which you shouldn't use anyway). Probably buy another chain in a month or so when the weather improves and size it one link longer. Little pissed that Shimanos instructions didn't work for me (unless I did something silly wrong)0 -
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So did you add two links or two half links as others were suggesting?0
