Square taper BB upgrade advice

1964johnr

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.

Man Of Lard

You need the BB removal tool for the old one, the BB removal (and fitting) tool for the new one - depending on which HT2 BB you buy, then the tools are not necessarily standard one-size-fits-all

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...

Sportiveman

If the op is going for a hollow tech 2 he will only need to know if it’s a bsa or Italian thread should be bsa , then a B.B. tool for fitting then the round torque tool for the crank . And you can get a square taper bottom bracket tool off eBay for under five pounds which should also double up as a crank puller . Keep note of the measurements of the old one in case u ever want to go back to square taper.

The tools should only be max of 10 pounds for the remover and new h/2 tools.

Matthewfalle

Pliers
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.

Moonbiker

:shock: Don't listen to ^

fat daddy

read up on it ... look at you tube

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

Moonbiker

All hollowtech BB are the same size i think?

For square taper BB has to match crank.

Matthewfalle

Moonbiker wrote:

:shock: Don't listen to ^

Why? Or should we be busy invading Alderney?

imposter2.0

Matthewfalle wrote:

Pliers
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.

He's swapping a BB - not rebuilding a Napier Sabre..

1964johnr

Thanks for the replies. I think I will be able to tackle it now, although I do take the point that swapping my square taper cranks for a aquare taper compact double would be an easier option and less expensive and may give me just as good a ride as the hollowtech. I did see a compact double from SJS cycles for £25. My existing bottom bracket seems to be fine so it is an option. I wouldn't have to buy any tools either because I have a pedal remover and a crank removal tool. If I did this will I need to adjust the front mech and buy new inner and outer cables. Will the existing rear Tiagra mech be okay?

arthur_scrimshaw

It's recommended to get the bb shell faced to ensure it's square. This is a shop job unless you want to spend a few hundred quid on the tool. That said I took a chance on not doing this on my charge plug when I went to HT and it's been fine.

cycleclinic

hollowtech II is not an upgrade. Square taper rules OK. it is a better BB type. The good one's last 50,000 to 100,000km. I have various bikes and the square taper BB out last there modern comterparts by quite some margin. The exception seems to be the Campagnolo ultra troque BB with cult bearings but this is quite pricey.

Matthewfalle

1964johnr wrote:

Thanks for the replies. I think I will be able to tackle it now, although I do take the point that swapping my square taper cranks for a aquare taper compact double would be an easier option and less expensive and may give me just as good a ride as the hollowtech. I did see a compact double from SJS cycles for £25. My existing bottom bracket seems to be fine so it is an option. I wouldn't have to buy any tools either because I have a pedal remover and a crank removal tool. If I did this will I need to adjust the front mech and buy new inner and outer cables. Will the existing rear Tiagra mech be okay?

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.