BB advice

[Tripster]

Swopped the TH Industries BB for a Shimano. Both same dimensions 68 x 118.
The original had a shoulder that was butted up to the frame on the drive side, the non drive side had no shoulder and just ended with threads. (Pics below)
The new Shimano has a shoulder on both sides.
I installed the drive side and up flush with shoulder to frame as before and to keep the chain line of the SS.
That leaves a 0.025” gap on the non drive side. I am assuming it does not matter as it’s not like it’s a sealing face and had no shoulder previously but would like to check with those having much more knowledge of BB’s and square taper ones.

Last two show the old TH Industries BB with no shoulder on left side/non drive side. It just ended inside the frame

 

[Moodyman]

Makes no difference. The key is the BB spindle length, which you confirmed is the same.

Enjoy, Shimano Square Taper BBs are pretty robust.

Edit: Might be worth carrying the Hex key with you for the first few rides. They tend to loosen every so slightly when new BB is added to old crankarm. If they loosen too much and you keep on riding, the square in the crankarm will develop play rendering it useless.

After the first few tightenings, they find a happy place and don't move again. They need a lot of torque so don't be afraid of giving it some welly.

 

[Pale Rider]

Did you - or did you not - grease the square tapers?

Plenty of opinion both ways.

Last one I did I compromised on a tiny smear, which is probably the worst of both worlds.

 

[Tripster]

Makes no difference. The key is the BB spindle length, which you confirmed is the same.

Enjoy, Shimano Square Taper BBs are pretty robust.

Edit: Might be worth carrying the Hex key with you for the first few rides. They tend to loosen every so slightly when new BB is added to old crankarm. If they loosen too much and you keep on riding, the square in the crankarm will develop play rendering it useless.

After the first few tightenings, they find a happy place and don't move again. They need a lot of torque so don't be afraid of giving it some welly.

Hex key for crank arm bolt ?
Torqued them to 40Nm

Did you - or did you not - grease the square tapers?

Plenty of opinion both ways.

Last one I did I compromised on a tiny smear, which is probably the worst of both worlds.

I smeared a small slither on each flat

 

[Moodyman]

Yes, hex for bolt and yes, 40nm is about right.

 

[Moodyman]

On the grease front, I understand Campagnolo say No, and Shimano say Yes.

Most technical folk say a slight smear of oil is a good half-way.

 

[Tripster]

On the grease front, I understand Campagnolo say No, and Shimano say Yes.

Most technical folk say a slight smear of oil is a good half-way.

Metal to metal and driving something on I would prefer a smear of grease, anti seize, but that’s just my thought. Thanks for the help and advice @Moodyman. Appreciated

 

[Ajax Bay]

Edit: Might be worth carrying the Hex key with you for the first few rides. They tend to loosen every so slightly when new BB is added to old crankarm. If they loosen too much and you keep on riding, the square in the crankarm will develop play rendering it useless.
After the first few tightenings, they find a happy place and don't move again. They need a lot of torque so don't be afraid of giving it some welly.

Screwing up the crank bolts will 'pull' the crank further and firmly onto the spindle. As you advise "give it some welly". The design and the forces a square taper interface deals with actually means that, when ridden/turned with moment, the crank creeps up the spindle's tapered facets very slightly (the basis of the design) and the crank bolts loosen a bit. This does not matter, and I'd certainly not carry this heavy allen key nor check/tighten a crank bolt mid-ride. Take care not to keep tightening the crank bolt(s).
More here: https://www.sheldonbrown.com/brandt/installing-cranks.html