Noob needs help: Bottom Bracket on Roscoe 7

Forums Mountain Bike Forum Noob needs help: Bottom Bracket on Roscoe 7

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    • #602560

      Hi everyone, biking beginner here for about 4 months. I have a 2021 Roscoe 7 Medium size with a SRAM SX 12 speed. I had a little accident while my bike was strapped to my bike rack behind my car while driving down on a very steep hill. My bike front tire hit the ground and my bike lifted upwards and pulled from the strap that I had tied down to the left crank so the bike doesn’t sway while driving. Now when I pedal my bike I hear some creaking noises I believe to be coming from the bottom bracket. I have the tool to remove the cranks and I’m waiting on the tool to remove the bottom bracket to inspect it.

      I have been doing some research online and this is the crank I have according to the Trek website: “Truvativ Powerspline, 73mm, threaded cartridge, 118mm spindle”

      I was thinking about replacing with the same one, but having a hard time finding it online. I found one on Amazon but I’m confused about the sizing since it says 63×118 size..

      I was also thinking about upgrading the BB but I am very confused on the different ones out there since they look different and my best guess is I’ll have to get new cranks as well as they don’t look like they’ll work with my current ones.

      If it turns out the bottom bracket is damaged, what do you guys recommend I do? I don’t plan on upgrading anything else at the moment. If I upgrade the bottom bracket what cranks will work with it? If you have any suggestions or links that will help point me in the right direction I will appreciate it.


    • #603626

      Sorry to hear about your mishap!

      My first thought is do you see damage to BB, like a dent?  Hard for me to believe your frame bent knowing how much car bike racks move around, meaning if your bike was strapped so tight and unmovable, I’m certain your front wheel would have been damaged, even taco’d, for enough force to mess up your frame.

      I would have the noise checked out by a pro before spending money on parts, could be something a little bent on the drivetrain making that noise.  Hard to believe BB is the issue, so let us know!

      Good luck!

    • #603747

      Gerardo, you need the bike inspected carefully by a shop that actually has a frame table. The weight of a car and lack of it for the bicycle can do unseen damage without you taking notice that something bad may have happened.

      Spend some coin as needed after the bike receives a clean bill of health.

      Hope your bike is just needing some care and everything is good.


    • #603748

      I looked up your Truvativ Powerspline, 73mm, threaded cartridge, 118mm spindle, and it looks to be a threaded in cartridge bottom bracket.  I also notice it is a splined mate to the cranks.  Once you get the proper tools use a torque wrench to tighten the bottom bracket nuts.  Also use a torque wrench on the bolt that holds the crank arms on the splined shaft.  Torque specs can be found on the bottom bracket manufacturers and possibly on Treks website.  I would also check the frame for cracks everywhere.  Noisy bottom bracket/crank arms can be very irritating.  I’ve always found that a quiet bottom bracket/crank arms that started making noise was loose somewhere.  I use a little non permanent thread locker on my bottom bracket nuts to help keep them from loosening.  Good luck with your problem.

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