Press fit bottom bracket concern

[3beers]

Hey, need some advice on this one please.

Getting around to building up a new frame (first time) and not overly happy how loose the pressfit bottom bracket is.

Purchased a wheels mfg bb92 thread together bottom bracket for sram gxp cranks to try and avoid pressfit problems like this:
http://wheelsmfg.com/bottom-bracket...contact-bb-for-24-22mm-sram-cranks-black.html

Problem is the drive side cup just presses in by hand 100% of the way with not a huge amount of force, the non drive side goes in about 50% of the way by hand.

Is this a bad thing?
What do I do - buy a different standard sram bb92 bottom bracket to try? use a retaining compound? suck it and see? Or PANIC? :fear:

Thanks

 

[moorey]

Can't really help you, other than chide you for buying a PF frame. I've passed up many a bargain just to avoid it. Its a NEW new frame? doesn't sound right that it would be that loose.....but I proudly know nothing about PF.

 

[3beers]

Can't really help you, other than chide you for buying a PF frame. I've passed up many a bargain just to avoid it. Its a NEW new frame? doesn't sound right that it would be that loose.....but I proudly know nothing about PF.

But.. but... but... it was a bargain......:laugh: and I'm only mostly going broke building this thing... Anyway yeah it's a new frame and chide away :noidea: when the headset is harder to press on than the bottom bracket I'm thinking something is wrong unless the wheels BB is meant to be looser cause of threads together?

 

[link1896]

Hey, need some advice on this one please.

Getting around to building up a new frame (first time) and not overly happy how loose the pressfit bottom bracket is.

Purchased a wheels mfg bb92 thread together bottom bracket for sram gxp cranks to try and avoid pressfit problems like this:
http://wheelsmfg.com/bottom-bracket...contact-bb-for-24-22mm-sram-cranks-black.html

Problem is the drive side cup just presses in by hand 100% of the way with not a huge amount of force, the non drive side goes in about 50% of the way by hand.

Is this a bad thing?
What do I do - buy a different standard sram bb92 bottom bracket to try? use a retaining compound? suck it and see? Or PANIC? :fear:

Thanks

if you turn around the bb, does the looseness on the drive side remain?

What frame?

 

[moorey]

Not sure about the Wheels one. I have a praxis one, yet to fit, on the one press fit frame I have...but will deny owning...but it was a bargain :behindsofa:

 

[pharmaboy]

Just licktite it - there's a recommended particular one - search up "the angry Asian" and bottom bracket, he had a good article about problematic BBs a few years ago - and love s wheels manufacturing from memory too.

 

[teK--]

Loctite 609

 

[3beers]

Ok more testing, can actually hand press either cup in on either side of the frame, so either it is meant to be like that or something, something....

Will track down that thread and maybe some Loctite - thanks

 

[pink poodle]

4 million years ago I had press fit bb on bmx...I was able to hand press the cups in. Of course I was a teenager, so my forearms were much bigger and stronger than they are these days.

Why is it that mtb press fit is a problem but bmx press fit is bullet proof?

 

[Boom King]

Ok more testing, can actually hand press either cup in on either side of the frame, so either it is meant to be like that or something, something....

Will track down that thread and maybe some Loctite - thanks

It's the new "Tool free" press fit standard. Easy to remove and throw though your window when you get jack of the creaking.

 

[Boom King]

Get some cranks to match...

 

[3beers]

4 million years ago I had press fit bb on bmx...I was able to hand press the cups in. Of course I was a teenager, so my forearms were much bigger and stronger than they are these days.

Why is it that mtb press fit is a problem but bmx press fit is bullet proof?

Are you saying pressing in by hand isn't a crisis? Or just wanting to mention awesome feats of teenage strength? :nod:

 

[Binaural]

Can't really help you, other than chide you for buying a PF frame. I've passed up many a bargain just to avoid it. Its a NEW new frame? doesn't sound right that it would be that loose.....but I proudly know nothing about PF.

Count me amongst the teeming masses who have had leisure to regret buying a frame with a pressfit BB. The benefits of this standard basically are exclusively felt by the manufacturers, with the trade-off being far inferior bearing life and more squeaking than a mouse threesome.

Regarding your ability to hand press, this is part of the reason for the standard - the shells can be installed far faster with less risk of wrecking threads and less risks from loose frame tolerances. Both of the pressfit bikes I've had could be pressed in by hands with some force, with maybe a gentle tap of a rubber hammer to flatten them against the shell. There are press fit tools available, but these are generally a waste of money.

 

[The Duckmeister]

If it's a screw-together arrangement it needs to be a little bit loose to allow you to screw the two parts together. When tightened it will not move. Regular press-fit needs to be effing tight, as it's solely reliant on interference fit to stay in place and be relatively noiseless.

 

[pink poodle]

If it's a screw-together arrangement it needs to be a little bit loose to allow you to screw the two parts together. When tightened it will not move. Regular press-fit needs to be effing tight, as it's solely reliant on interference fit to stay in place and be relatively noiseless.

Do you get as much or any press fit hate from bmx riders?

 

[pink poodle]

Are you saying pressing in by hand isn't a crisis? Or just wanting to mention awesome feats of teenage strength? :nod:

I've no experience with mtb press fit, only flogged old 80s/90s bmx...and building up strength in one arm.

 

[3beers]

If it's a screw-together arrangement it needs to be a little bit loose to allow you to screw the two parts together. When tightened it will not move. Regular press-fit needs to be effing tight, as it's solely reliant on interference fit to stay in place and be relatively noiseless.

Thanks Duckmeister, would you worry about the Loctite or just screw it together and see how it goes?

 

[99_FGT]

Thanks Duckmeister, would you worry about the Loctite or just screw it together and see how it goes?

Chances are you will need to tighten it again in a few rides - my praxis settled in after a few rides, shop tightened it again and was good 2000km later when I sold that roadie.
Also note that the instructions specifically mention that locking compounds will void warranty (as will dirt and mud, so :sad

 

[bear the bear]

Thanks Duckmeister, would you worry about the Loctite or just screw it together and see how it goes?

If it is the screw-type PF BB from wheels there is no need for loctite. It relies on the friction on the shoulders so as not to move.
I've used it to cure a creak before.

 

[Binaural]

If it is the screw-type PF BB from wheels there is no need for loctite. It relies on the friction on the shoulders so as not to move.
I've used it to cure a creak before.

Shit, I didn't know these were available. I ordered a replacement for my current creaking nightmare from bikebug.com.au that is basically just an aluminium shell version of the inadequate plastic cup basic design. Fuggheditabout!