Converting SRAM Rival to Shimano 105
10-05-23, 02:12 AM
#27
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I think in your position I'd either go with an 11-speed throughout or find some way to mount the battery for Di2. Or, if you're having to replace the rear wheel anyway, go with SRAM AXS 12-speed, where the batteries are mounted on the derailleurs.
10-05-23, 06:34 AM
#28
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10-05-23, 11:22 AM
#30
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Yes, we are discussing the lack of 12 speed bar end shifters, and I stated why there aren't any at the moment for Shimano.
The problem of trying to shift 11 speed with friction shifters is that the amount of cable pull is very small. If you use a small diameter shifter it takes more degrees per shift, which makes it more controllable - but you end up needing to move the shifter 180 degrees. If you make the cable drum diameter larger, you can do the whole range in closer to 90 degrees of lever throw, but that's 11 or 12 locations in 90 degrees, which is 50% more of a sensible 8 speeds in the same lever throw distance. Then you have backlash, the tendency of the friction shifter to settle to a position slightly less than where it was shifted to, making it that much harder to get to the right point.
Part of the reason the old Simplex retrofriction shifters are so beloved is that the mechanism has very little backlash and has a small diameter, separating cog positions by more rotation degrees per shift. They are noticeably more accurate than the really nice Suntour ratchet shifters.
Anyway, the simple solution is probably using 11 speed index bar end shifters, because they are compatible with 12 speed derailleurs. But I doubt you'll get to the 12th cog.
The problem of trying to shift 11 speed with friction shifters is that the amount of cable pull is very small. If you use a small diameter shifter it takes more degrees per shift, which makes it more controllable - but you end up needing to move the shifter 180 degrees. If you make the cable drum diameter larger, you can do the whole range in closer to 90 degrees of lever throw, but that's 11 or 12 locations in 90 degrees, which is 50% more of a sensible 8 speeds in the same lever throw distance. Then you have backlash, the tendency of the friction shifter to settle to a position slightly less than where it was shifted to, making it that much harder to get to the right point.
Part of the reason the old Simplex retrofriction shifters are so beloved is that the mechanism has very little backlash and has a small diameter, separating cog positions by more rotation degrees per shift. They are noticeably more accurate than the really nice Suntour ratchet shifters.
Anyway, the simple solution is probably using 11 speed index bar end shifters, because they are compatible with 12 speed derailleurs. But I doubt you'll get to the 12th cog.
Thanks, I took out the bearings last night from the BB, and the diameter is 41mm with a 68mm width (just 2 6806 bearings with retainer rings), so I will have to replace the bearings and use the step adapters to convert to the 24mm spindle. I think I may go with the 105 and the 11 speed bar end index shifters and then when the 12 speed index shifters are released can swap them out (maybe I'll leave the new derailleur cable ends a little long for that 12th cog later?), I did look at the SRAM Force AXS wireless system, and while I did like the fact you get the power hub and that it would be easy, the set comes to over $1700....I guess I just thought of this also, could I install the Shimano 105 crankset and 12 speed derailleurs with the Shimano11 speed index bar end shifter and just use an 11 speed cassette until the 12 speed bar end shifters are available?? Cassettes are pretty cheap and I would just then have to swap cassette and bar end shifters later??
10-05-23, 11:36 AM
#31
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Thanks, I took out the bearings last night from the BB, and the diameter is 41mm with a 68mm width (just 2 6806 bearings with retainer rings), so I will have to replace the bearings and use the step adapters to convert to the 24mm spindle. I think I may go with the 105 and the 11 speed bar end index shifters and then when the 12 speed index shifters are released can swap them out (maybe I'll leave the new derailleur cable ends a little long for that 12th cog later?), I did look at the SRAM Force AXS wireless system, and while I did like the fact you get the power hub and that it would be easy, the set comes to over $1700....I guess I just thought of this also, could I install the Shimano 105 crankset and 12 speed derailleurs with the Shimano11 speed index bar end shifter and just use an 11 speed cassette until the 12 speed bar end shifters are available?? Cassettes are pretty cheap and I would just then have to swap cassette and bar end shifters later??
10-06-23, 06:52 PM
#32
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Thanks, I took out the bearings last night from the BB, and the diameter is 41mm with a 68mm width (just 2 6806 bearings with retainer rings), so I will have to replace the bearings and use the step adapters to convert to the 24mm spindle. I think I may go with the 105 and the 11 speed bar end index shifters and then when the 12 speed index shifters are released can swap them out (maybe I'll leave the new derailleur cable ends a little long for that 12th cog later?), I did look at the SRAM Force AXS wireless system, and while I did like the fact you get the power hub and that it would be easy, the set comes to over $1700....I guess I just thought of this also, could I install the Shimano 105 crankset and 12 speed derailleurs with the Shimano11 speed index bar end shifter and just use an 11 speed cassette until the 12 speed bar end shifters are available?? Cassettes are pretty cheap and I would just then have to swap cassette and bar end shifters later??
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10-09-23, 08:20 AM
#33
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I would not assume there will be 12 speed bar ends from Shimano. The only 12 speed mechanical group is 105 and it does not have bar end shifters. https://bike.shimano.com/en-EU/produ...anical_lp.html
10-11-23, 11:22 AM
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Thanks for all the help, I ended up ordering the Wheels BB/PF30 Universal Adapter for 24mm Spindle Cranks that tap into some new 6806 bearings, and the Shimano 105 12 speed mechanical 52/36 crankset and derailleurs with the Shimano 12 speed 11-36 cassette and 12 speed chain, new shifter cables and the Shimano Dura Ace 11 speed indexed bar end shifters. Also got a set of Vision 30mm wheels with the Shimano HG hub to complete the set. Hopefully Shimano or Microshift will come out with the 12 speed bar end shifter soon so I can access that last cog.....all told about $900 for the new driveline and wheels, not to bad....... 
