highroad 2
Member
- Local time
- 12:07 AM
- Joined
- Jul 22, 2020
- Messages
- 69
I would like to mid drive my Giant Yukon fat tire bike with a BBSHD for sand dune riding.
FWIW online I have learned that it is hard to get good chain lines (CL) with a BBSHD.
The Yukons current CL is 16 mm outboard of the bottom bracket (BB) shell.
The BBSHD is 34 mm from where it would make contact with the BB shell to where the chain ring bolts on (assuming the chainstay will allow the BBSHD to slide all the way in).
The Luna Eclipse 42T has a 25 mm inboard offset, which brings the CL to 9 mm outboard of the BB shell. ( 34-25=9 mm)
If i used a Luna Mini 30t which has a 8 mm inboard offset, which brings the chain line to 26 mm outboard of the BB shell. (34-8=26)
The stock CL is 16, the 42t moves this inboard to 9 and the 30t moves it outboard to 26.
if I use the 42t then the CL is not ideal for the smaller chain rings on the cassette and if I use the 30t then the CL is not ideal for the larger inboard chain rings on the cassette.
Questions
1 I have read online where BBSHD users rave about using the luna mini 30t versus the 42t because it makes the motor much more responsive accelerating and climbing with only a few mph loss in top speed.
2 A Luna 36t has the same 8 mm offset as the 30t so exactly the same CL but a more in between gearing?
3 I have a hard time making SramNX 1 x 12 chain last on my Haibike. What chain should I use with the more powerful BBSHD?
4 Am I over thinking this project?
Thanks
Highroad 2
FWIW online I have learned that it is hard to get good chain lines (CL) with a BBSHD.
The Yukons current CL is 16 mm outboard of the bottom bracket (BB) shell.
The BBSHD is 34 mm from where it would make contact with the BB shell to where the chain ring bolts on (assuming the chainstay will allow the BBSHD to slide all the way in).
The Luna Eclipse 42T has a 25 mm inboard offset, which brings the CL to 9 mm outboard of the BB shell. ( 34-25=9 mm)
If i used a Luna Mini 30t which has a 8 mm inboard offset, which brings the chain line to 26 mm outboard of the BB shell. (34-8=26)
The stock CL is 16, the 42t moves this inboard to 9 and the 30t moves it outboard to 26.
if I use the 42t then the CL is not ideal for the smaller chain rings on the cassette and if I use the 30t then the CL is not ideal for the larger inboard chain rings on the cassette.
Questions
1 I have read online where BBSHD users rave about using the luna mini 30t versus the 42t because it makes the motor much more responsive accelerating and climbing with only a few mph loss in top speed.
2 A Luna 36t has the same 8 mm offset as the 30t so exactly the same CL but a more in between gearing?
3 I have a hard time making SramNX 1 x 12 chain last on my Haibike. What chain should I use with the more powerful BBSHD?
4 Am I over thinking this project?
Thanks
Highroad 2