Square taper BB upgrade advice
1964johnr
Posts: 179
I would like to convert my circa 2007 Shimano Tiagra square taper triple crankset to a compact double and upgrade to a hollowtech 2 BB and crankset. I have always worked on my own bikes and have never had to resort to paying the LBS to do work for me so far. I've never tackled this before and would appreciate anyone who has, letting me know which tools I need to purchase, along with any tips which might help me. I have aquired a lot of tools over the years, but don't have a square taper BB removal tool or the tools to install the new Hollowtech BB. I guess I will also need to take some measurements of my existing BB housing to enable me to obtain the correct size BB, but not sure which measurements to take. Any help would be appreciated.
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My twopennyworth - get the LBS to remove the old one (and make sure they give it to you) because it'll have the necessary dimensions on it to buy the correct new one...
The tools should only be max of 10 pounds for the remover and new h/2 tools.
Allen keys
Cable snips
Bb square remove
Copperslip
Crank remover
New mech cable inner and outer and ferrules/end cap
Penetrating fluid
New bb
New bb installation tool
new cranks
Maybe a chain tool
Screwdrivers
Maybe a long bar dedependant on what typ of bb removal tool and how stuck the old bb is
Pedal removal tool or suitable long Allen key for the back of the pedal if it has Allen key recess
That's it offhand as I'm eating my breakfast - I may be back later to add to it.
Remove pedals while the cranks are still on the bike - just makes it easier
Soak the bb area in penetrating over a number of days - you can also soak it from the inside by removing the cable guide from underneath and flooding it from there. You may be able to get away with just taking the screw out, leaving everything in place and slipping your lubed straw in through the hole.
Once out it will have the dimensions on it but as above it'll just depend on English or Italian thread
Really good clean of the threads then loads of copperslip and install new bb
Reset front mech height for new cranks - this is why you may need the new cable and outer
Adjust mech
If you are going from triple normal to double compact remember to set limits so that the extra click on your shifter doesn't Jeff you up.
Scrub pedal threads clean, loads of copperslip and do up
Remember to smash all the old bits up with a hammer and set fire to them before throwing them into next door's garden.
As an aside......
Why do you want to get rid of the square taper? Nowt wrong with it and you can get loads of triple chainring cranks for them.
De Sisti wrote:
This is one of the silliest threads I've come across.
Recognition at last Matthew, well done!, a justified honour
It cost me 1x crank extractor from wiggle at £4 and a bracket tool square/octalink for a £5
make sure you do your home work and know what way to turn the bracket tool AND what side to start with .. an old BB can easily disintegrate when you put force on with the BB tool leaving you with an issue of how the get the cartridge out ... start on the wrong side and turn the wrong way and you'll be in trouble
For square taper BB has to match crank.
Why? Or should we be busy invading Alderney?
De Sisti wrote:
This is one of the silliest threads I've come across.
Recognition at last Matthew, well done!, a justified honour
He's swapping a BB - not rebuilding a Napier Sabre..
rear mech will be perfect - nothing tge front does affects the back. you may as well throw on a new cable while you are there.
De Sisti wrote:
This is one of the silliest threads I've come across.
Recognition at last Matthew, well done!, a justified honour