Author Topic: Using Shimano triple chainset and hollowtech II bottom bracket  (Read 152 times)

lestat_12345

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Using Shimano triple chainset and hollowtech II bottom bracket
« on: November 06, 2018, 09:53:29 AM »
Hi All,

Does anyone use a Shimano triple chainset and hollowtech II bottom bracket with a Thorn Nomad? I was thinking of using this combo with the gold coloured eccentric shell and a Thorn 3/32 inch chainring on the outer position with a splined sprocket. My main concern is getting the correct chainline but the Rohloff manual suggest that a chainring on the outer position should still give 54 mm. I know the chainline with a splined sprocket should be 57 mm but I think the three mm is negligible. If the only thing it amounts to is increased component wear then so be it.

I currently use a square taper Thorn chainset/bottom bracket combo but hate the fact that it is so difficult to remove the bottom bracket. The last time I tried I gave up and just installed a new eccentric shell and bottom bracket. My previous experience with hollowtech II is that the bottom bracket doesn't last as long but they are way simpler to loosen. A sacrifice I am willing to make.

Thanks,

Richard.

mickeg

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Re: Using Shimano triple chainset and hollowtech II bottom bracket
« Reply #1 on: November 06, 2018, 10:34:25 AM »
I have been running a chainline on my Nomad that is about 5mm off without any noticeable adverse affects. 

In my case, I wanted to run a double crank with a chain guard (or bash guard) in the outer position, the chainring in the inner position.  I use a square taper setup, thus it is easy to adjust chainline by buying different spindle lengths.  If I had bought the ideal spindle length for an optimum chainline, my Q factor (width between pedals) on my Nomad would be about 10mm wider than on my other derailleur bikes.  I did not want a wider Q factor, so I intentionally bought a spindle 10mm shorter, thus the 5mm chainline error.

I have never run a hollowtech crank, can't comment on that.  I have no problems with the UN55 bottom bracket I am running on my Nomad, I have a fairly long half inch drive ratchet and also a long arm torque wrench, both give me plenty of leverage when tightening or loosening anything that uses a half inch drive wrench, such as the tool for fitting a UN55 bottom bracket. 

The only difficulty I have had with my crank or bottom bracket removal has been that I fitted self extracting bolts on my crankarms on my Nomad.  And the self extracting part that was threaded into the crank arm loosened up and was lost.  Since I have to remove both crank arms to fit my Nomad in an S&S case, when I went to pack up my bike at the end of a bike tour, I had to move my self extractor from one crank  arm to the other crank arm and I did not have the proper tools to do that.  Thus, I went back to plain crank arm bolts and will carry a proper crank arm removal tool on future bike tours with my Nomad.

Good luck with your plans.  If you run a triple or a double crank but with only one chainring, you would need the spacers that take up the space because your chainring bolts are sized for two chainrings, not one.  Do you have those?  When I bought my Rohloff hub in 2013, those spacers were included with the hub.  A good bike shop should have spacers if you need them, although they might not be the exact same thickness as the Rohloff ones.


lestat_12345

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Re: Using Shimano triple chainset and hollowtech II bottom bracket
« Reply #2 on: November 06, 2018, 02:00:00 PM »
Thanks for your reply mickeg. I already have the spacers so no issue there.

Dave Whittle Thorn Workshop

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Re: Using Shimano triple chainset and hollowtech II bottom bracket
« Reply #3 on: November 07, 2018, 09:10:23 AM »
We do this all the time, 1 x 2.5mm spacer on the drive side under the hollowtech cup, none on the other side, SLIM Rohloff Splined carrier and Thorn Chainring in the outer position.

lestat_12345

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Re: Using Shimano triple chainset and hollowtech II bottom bracket
« Reply #4 on: November 07, 2018, 10:17:55 AM »
Thanks for the confirmation Dave :)