Noob cycle question - please help!

jpod · 11 Jul 2020 at 16:17

Will these fit my bike?
Shimano EXTERNAL Road Bike Bottom Bracket BB-RS500
SHIMANO Crank Chainset Tiagra 4700 50/34 170mm

I picked up a Boardman Hybrid Competition Pro Carbon Fork Road Bike on ebay and the pedals were poorly fitted in the past and damaged the threads on the cranks - I need to change the bottom bracket too
cos it creaks.

Current set up is:

20 gears
front derailleur suntour f90
rear derailleur s-ram x9
chainset Truvativ Touro compact 50x36T
cassette Shimano CS-5600 12-27T
bottom bracket Truvativ GXP
cassette (rear cogs) Shimano CS-5600 12-27T
chain Shimano CN-5600

The other parts listed above are in good condition.

I guess I need a BB spanner to remove the current one and fit the next, greass.
What do I torque the crank bolt up to 40nm?

Many thanks pod

Bear · 11 Jul 2020 at 19:30

The RS500 bottom bracket is threadfit, you need to see if your GXP bottom bracket on your bike is threaded or pressfit. If it is threaded you need to find out which thread type. If it’s a pressfit you need a pressfit replacement bottom bracket. You also need to find out which standard it is as there’s a boat load like BB86 etc. Once you determine which bottom bracket you need, then you can use the Tiagra Chainset you listed above

jpod · 11 Jul 2020 at 21:02

Bear said:
The RS500 bottom bracket is threadfit...................... you listed above

Thanks for sharing your expertise Bear - I will have a research and figure that out. Many thanks.

The_Arbiter · 11 Jul 2020 at 21:21

Not entirely sure on many crank angles, bb lengths etc vs compatibility, i will say you can just switch out the bearings on your current bb. Creaking can be from a crack, but also from lack of grease. You could also get your cranks helicoiled if wanting to save cash again. But if they're on there straight, just chasing them might be okay. Or you could araldite those puppies in

If cash saving is not an issue, you may as well switch out your entire drive chain, or the front sprockets as you've mentioned and chain at least.

Torque ratings should be on the manufacturer's website, and/or in the product box.

jpod · 11 Jul 2020 at 22:59

The_Arbiter said:
Not entirely sure on many crank angles, bb lengths etc vs compatibility....................and/or in the product box.

Thanks for posting, having difficultly identifying the BB and shimano equivalent - the search continues!

The_Arbiter · 12 Jul 2020 at 10:05

The old or new one?

Jonny ///M · 12 Jul 2020 at 12:11

Take a photo of the left hand side of the bottom bracket. I'm sure they have a black GXP threaded bottom bracket so the one you linked will work fine and use the same tool to remove and install each bb.

jpod · 12 Jul 2020 at 20:15

The_Arbiter said:
The old or new one?

The old one. Jonny M may have answered the q there.

jpod · 12 Jul 2020 at 20:15

Jonny ///M said:
Take a photo of the left hand side of the bottom bracket. I'm sure they have a black GXP threaded bottom bracket so the one you linked will work fine and use the same tool to remove and install each bb.

Fingers crossed (no pun intended) - thanks for posting.