Thorn Cycles Forum
Private Classified => Bike Bits / Accessories For Sale => Topic started by: Teaboy on July 02, 2016, 05:12:14 pm
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https://www.sjscycles.co.uk/cranks/150-thorn-10464-pcd-triple-crankset-mk2-black/
Thorn part No. 31813L165
fitted with Black Thorn 3/32" 46T reversible ring (Thorn part No. 11054S46)
plus
Black Thorn 3/32" 46T 34T reversible ring (Thorn part No 11054S34)
All new Oct 2015. 800 miles on road use.
£40.00 plus postage.
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Hi, sorry for my ignorance but would these work, alignment wise with rhollof equipped Bike?
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there are some clues on the SJS description: "110mm bracket required to get a 54mm chainline on middle ring, 107mm can be used if only using a single ring in the outer position."
I think 54 mm is the old Rohloff chainline, with the threaded sprockets. The new sprockets bump it up to 57mm, as I recall. I think a 1mm increase in chainline needs a 2 mm increase in bracket, because the bracket is measured full width while the chainline is measured half-width, i.e. center to edge.
I have never actually worked with this stuff so I hope those with real experience will chip in and correct me!
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If you put the ring in the outer position instead of the middle you 'gain' 3mm, so it would work with the new sprockets.
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Thanks for this helpful advice but it seems that I would need new bottom bracket to accommodate these cranks it seems to make sense to dive out and stay with existing. So thanks all again!