Road Cycling

Bottom brackets....I'm looking to change my chainset and I have BB questions.

I want this BB and this chainset to replace a;
  • CRANKSET: FSA Vero Compact 50/34
  • BOTTOM BRACKET: Sealed Cartridge
How do I know what BB my bike currently has and what it can take? I asked where I got the bike from and they said they couldn't help and I can't easily see anything on the bike to give it away. The bike if it helps

Some pointers would be great.


Cheers!
 
Last edited:
l
Bottom brackets....I'm looking to change my chainset and I have BB questions.

I want this BB and this chainset to replace a;
  • CRANKSET: FSA Vero Compact 50/34
  • BOTTOM BRACKET: Sealed Cartridge
How do I know what BB my bike currently has and what it can take? I asked where I got the bike from and they said they couldn't help and I can't easily see anything on the bike to give it away. The bike if it helps

Some pointers would be great.


Cheers!


Looks like a standard BSA (English) threaded bottom bracket, which is what you've picked out from wiggle.
 
That's great, thanks a lot again. Are most bikes like that? And it's more how the BB interfaces with the chainset that differs in all the different BB standards?
 
That's great, thanks a lot again. Are most bikes like that? And it's more how the BB interfaces with the chainset that differs in all the different BB standards?

Some frames have BBs that screw in like yours, others have press in ones.

there are also several different crank/axle systems.

Your current system appears to be a square taper one (the axle of the bottom bracket is a tapered square one that the crank pushes onto). The axle is part of the BB in this system

the tiagra crank is shimano hollowtech 2 where an axle is permanently bonded to one crank, this goes through an "open" bottom bracket (the bearings are sealed but you can see through to the other side) and the other crank clamps to this axle. The axle is part of the crank in this system


both systems can be run in a standard English threaded BB shell
 
That's great, thanks a lot again. Are most bikes like that? And it's more how the BB interfaces with the chainset that differs in all the different BB standards?
Not exactly... The BB interface determines the size of the BB which you can fit in the frame, the width and the 'fitment' type - the size/type of screw (standard BSA) or the size of the press fit cups. Once you have that in place then you need to match the size/type of cranks to fit, in your case which size crank arms to fit on your 'square taper', in pressfit's case the width and size of the axle (usually attached to crankarms). Once you have the BB and cranks in place then the chainset kinda fits to that. In most cases the cranks in use will determine the 'chainset' (chainrings) you can use.

So frame determines BB, BB determines cranks, cranks determine chainset.

There's a handful (at least) of each type so there are probably close to a hundred various different combinations depending on age, brand and even what country it was produced and by whom.

The vast majority these days are pressfit as the main manufacturers consider it a modern technique (it makes their life easier), but you'll still find many small frame builders and people wanting frames with threaded BB's to avoid much of the stigma and 'creaking' issues some have seen with pressfit. You'll even find adaptors to use threaded BB's in pressfit frames.

Man has skills :D

And a deathwish! At least he's made his peace. Can't hear the audio but think those club guys appreciated the skill involved! Dread to think how many replacement hats he gets through...

-10 for not being able to read a simple diagram
OK.
 
Last edited:
Hope you cycled in wearing winter gear, I didn't (just waterproofs) and it's been bitter here since mid morning!

Brace yourselves, winter is coming again.jpg
 
Ok take +5 back I feel that I took too many from you :D
Thanks. I'll take them but can I redeem against the headwinds today?

17.2mph avg home (gusty headwind) / 21.7mph back to work (cross tailwinds). Admittedly more uphill home and downhill back...

Brace yourselves, winter is coming again.jpg
Fully layered this morning! :D

Base, arm & leg warmers, jersey & shorts, thermal tights, windproof warm jersey & windproof gilet. Bear in mind my short <10 min commute and the fact I overdress layers so I can tailor them for my 7:45am ride in, 1pm & 2pm lunch rides & 5:30pm ride home. Lunchtime was just Base, shorts, thermal tights, jersey & gilet.
 
Some frames have BBs that screw in like yours, others have press in ones.

there are also several different crank/axle systems.

Your current system appears to be a square taper one (the axle of the bottom bracket is a tapered square one that the crank pushes onto). The axle is part of the BB in this system

the tiagra crank is shimano hollowtech 2 where an axle is permanently bonded to one crank, this goes through an "open" bottom bracket (the bearings are sealed but you can see through to the other side) and the other crank clamps to this axle. The axle is part of the crank in this system


both systems can be run in a standard English threaded BB shell

That's some good info Saytan, thanks a lot for your time.
 
Not exactly... The BB interface determines the size of the BB which you can fit in the frame, the width and the 'fitment' type - the size/type of screw (standard BSA) or the size of the press fit cups. Once you have that in place then you need to match the size/type of cranks to fit, in your case which size crank arms to fit on your 'square taper', in pressfit's case the width and size of the axle (usually attached to crankarms). Once you have the BB and cranks in place then the chainset kinda fits to that. In most cases the cranks in use will determine the 'chainset' (chainrings) you can use.

So frame determines BB, BB determines cranks, cranks determine chainset.

There's a handful (at least) of each type so there are probably close to a hundred various different combinations depending on age, brand and even what country it was produced and by whom.

The vast majority these days are pressfit as the main manufacturers consider it a modern technique (it makes their life easier), but you'll still find many small frame builders and people wanting frames with threaded BB's to avoid much of the stigma and 'creaking' issues some have seen with pressfit. You'll even find adaptors to use threaded BB's in pressfit frames.

It's quite a large topic, still i'll know a bit more after my first swap out. Cheers for your help.
 
Pretty sure I said before, but 35mm is quite a big air volume! Can't remember if you where already running 32's, if you're running smaller I'd say step up to 32's first before going as large as 35. At least for road riding!
I'm already on 35mm Schwalbe CX comps on the winter machine but I got 2 punctures in around 60 miles so they are heading for the bin! They also have quite chunky side lugs for deep mud which I don't really like as I'm conscious of them when I corner, not that they've ever caused an issue.

UTmaniac - thanks for the heads up on the Grips but I thought they may be a bit more orientated for deep mud which I don't tend to ride in.

Gone for the G-one allrounds so I'll see how I get on with them. They only had 38mm in stock but what's another 3mm ;) Got stacks of clearance so that isn't an issue.
 
Back
Top Bottom