You are here:

Bicycle Repair/Replacing crankset and bottom bracket.


Hi James, I'm just wondering if you would please be able to provide me with some advice. Basically the bolt that holds together the crankset to the bottom bracket has worn on my bike and stripped the threads on the bottom bracket and damaged the crankset. I've taken all of this off of my bike and identified a similar square tapered bottom bracket that will fit and a crankset which is the same size. However with me replacing this would I also need to replace the derailleurs or the rear cassette? While I am doing this I will also likely replace the existing chain.
Kind Regards, Max.

There are a few factors to consider in replacing your crankset. Firstly, if the replacement crank/chain ring set is identical to the old one (in terms of chain ring tooth count), then your existing derailers should be compatible. Secondly, depending on how worn your existing chain has become, it might be necessary to replace the cassette, as well; as the drive chain wears, it effectively lengthens, thus causing the other drivetrain parts, especially your "favourite" gears to become  worn to this pattern. Installing a new chain on overly worn drivetrain parts invariably causes problems such as "skipping" under load and/or chain "suck" while shifting, so it might be a good plan to replace that old cassette and chain.  

Bicycle Repair

All Answers

Answers by Expert:

Ask Experts


James Novak


I can answer most inquiries with respect to bicycle assembly, repair, tuning and maintenance. I am less than inclined to speak on such questions as "What kind of bike should I buy?", &/or "What is this bike worth?", etc. Any answers to these types of questions may correlate poorly to an acceptable "fact/sarcasm" ratio.


7 seasons of "Professional" bicycle service/repair, etc. 4 seasons as Instructor, Professional Bicycle Mechanic training college. n-1 seasons of riding, cracking, crushing, mutilating and breaking bikes of any & all varieties, and thus requiring intense and at-hand skills development, etc.

Certified Professional Bicycle Mechanic; Winterborne Bicycle Institute/Conestoga College

Past/Present Clients
The Hub Bicycle Shop, Hespeler Winterborne Bicycle Institute

©2017 All rights reserved.

[an error occurred while processing this directive]