Giant SCR2.0 bottom bracket. Help please

spadger

Hi,

I have removed the old BB as it has fallen apart, most of the writing on the original BB has worn off so have struggled with make/size I know its a 113mm. I have fitted a new Shimano Bottom Bracket UN54 Bottom Bracket Square Taper 68-113mm.

For some reason it does not feel correct, I am unable to tighten both sides fully and if I back pedal when in the top gear on the front mech and a large cog on the rear it will try to jump gears on the rear (as if the front chainring is sticking out a bit to far) I have looked all over the internet for some answers with no luck.

Any help or advice would really be appreciated.

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sungod

try removing the bb, then give the threads in the bike a really good clean and grease, you may need to chase out the groove with a sharp point to get all the gunk out

i had the same problem changing a bb, but it was just due to the threads being clogged with the various crud that can build up whe rain gets inside the frame, it even seemed to have paint itn it from when the frame was made, after cleaning it was fine

after cleaning/greasing, when fitting the new bb, give it some welly, they do take a lot of oomph

spadger

Thanks for that, i will have another go at it tonight as I am sure its the correct BB, if not its off to the local bike shop but they will take ages.