Crankset advice please
I bought one of theses as a complete novice 3 years ago, but it was the tiagra triple version
http://www.trekbikes.com/uk/en/bikes/2013/archive/trek/domane_2_0_compact/#/uk/en/archive-model/details?url=uk/en/bikes/2013/archive/trek/domane_2_0_compact
Now i consider myself half decent i am thinking of replacing the gears with a 50/34 crank. At the time i bought the bike, my mate also bought the compact 105 version for a little extra. Seeing as theyre essentially the same bike with different hardware, surely i can just buy the different parts and swap them around? Obviously i may need to adjust the front deraileur to accomodate the new chainrings.
One sticking point is i read I may need to change the BB (which I need to do anyway but cant find which one to buy) and also Im unsure what model will fit, eg do i stick with tiagra or can I stick a 105 on? All the "6800, 5700" numbers etc dont make much sense to me.
http://www.trekbikes.com/uk/en/bikes/2013/archive/trek/domane_2_0_compact/#/uk/en/archive-model/details?url=uk/en/bikes/2013/archive/trek/domane_2_0_compact
Now i consider myself half decent i am thinking of replacing the gears with a 50/34 crank. At the time i bought the bike, my mate also bought the compact 105 version for a little extra. Seeing as theyre essentially the same bike with different hardware, surely i can just buy the different parts and swap them around? Obviously i may need to adjust the front deraileur to accomodate the new chainrings.
One sticking point is i read I may need to change the BB (which I need to do anyway but cant find which one to buy) and also Im unsure what model will fit, eg do i stick with tiagra or can I stick a 105 on? All the "6800, 5700" numbers etc dont make much sense to me.
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Comments
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If your bike has a threaded BB then you can use any of the external Shimano HT II BB e.g. Tiagra SM-BB4600, 105 SM-BB5700, Ultegra SM-BB6700. There is also the SM-BBR60 which is specified for the 6800, 5800, crankset and SM-BB9000 Dura-Ace and BB-RS500 for the Tiagra 4700.
http://productinfo.shimano.com/#/lc/2.4/ultegra/2x11?tocst=520 -
I bought one of theses as a complete novice 3 years ago, but it was the tiagra triple version
http://www.trekbikes.com/uk/en/bikes/2013/archive/trek/domane_2_0_compact/#/uk/en/archive-model/details?url=uk/en/bikes/2013/archive/trek/domane_2_0_compact
Now i consider myself half decent i am thinking of replacing the gears with a 50/34 crank. At the time i bought the bike, my mate also bought the compact 105 version for a little extra. Seeing as theyre essentially the same bike with different hardware, surely i can just buy the different parts and swap them around? Obviously i may need to adjust the front deraileur to accomodate the new chainrings.
One sticking point is i read I may need to change the BB (which I need to do anyway but cant find which one to buy) and also Im unsure what model will fit, eg do i stick with tiagra or can I stick a 105 on? All the "6800, 5700" numbers etc dont make much sense to me.
You can fit a compact (50/34) if you wish but you need to be aware that your LH shifter is designed to operate with a triple chainset. I'm sure it's possible to adjust the set-up so that a triple shifter will operate a double (compact) chainset OK but if not you will have to buy a new LH shifter.
Regarding the bottom brackets - All Shimano Hollowtech BB's can be used with any your new compact chainset. The key parameter is the spindle diameter and that is constant throughout the range.
The only issue is that your Trek will be fitted with a pressfit bottom bracket which has a wider diameter than the normal Shimano chainset spindle. It is almost certain therefore that there will be adaptors fitted to enable the Shimano triple to work.
If your bike needs a new BB you will have to identify which pressfit BB you need (might be BB86 but not exactly sure) - thereafter the Shimano Hollowtech adaptors will be standard items0
