beemaa

Morning fellow bike wizards,

Need some quick advice, currently working on a systemsix (2020 ish model) with press fit bearings, one of them is shot so going to replace both 6806RS.

Now, I’ve never removed press fits from a cannondale, I’ve got the tools etc, not an issue.

The question I have is, the removal tool doesn’t seem to sit against the back of the bearing so I can’t hit the tool against the back of the bearing directly, this is because there seems to be another metal or so ring directly behind the bearing that has a small 2mm gap or so between this metal ring (it’s not a cclip).

Should I assume the other ring behind the bearing is the cup that the bearing is housed inside and the tool should be hitting the back of the cup rather than the bearing itself?

Kontact

Dunno exactly what you have, but this manual says that it is a PF30, which is bearings glued into nylon cups. With those you remove and replace the cups/bearings as a unit, not just the bearings.

https://www.cannondale.com/-/media/f...0318_en_eu.pdf

beemaa

Yes that’s the ones I have, just not sure how these are removed, if the bearings are glued inside the cups, the bit I’m banging the tool against is the nylon cup then and not bearing which make sense

choddo

My cube was the same (shimano pressfit). You could feel the tool ping twice in quick succession as you drew it back through the bearing. There’s nothing else inside the shell of a SuperSix there so I reckon you’re right.

Barry2 

beemaa ,
If you do a lot of miles, consider replacing the two cup type BB with a one piece BB.
They do cost more, but bearing alignment & life are improved.
Plus, if you get the correct type, bearings can be replaced quickly without removing the shell/cups.

As an example, I use Hambini BBs, but there are others.

Barry

choddo

Seen that BB in his video. I assume it's two halves that thread together? Is there a small gap between the bearing race and the cup that allows you to punch the bearings out?

Barry2 

The Hambini PF30 (link may be incorrect version for your particular bike) is a single piece and does not thread together.
Single piece BB's (not just Hambini) are able to hold the two bearings in better alignment.
I really like being able to leave the one piece BB shell in the bike and being able to extract just the bearings for replacement.
I'm unsure if all one piece BB's offer this method of bearing replacement.

I use a threaded bearing extractor and pull them out. No banging required 8-)

Barry

SpedFast

I use a threaded also and grind washers to size as needed for varying bearing requirements. So much nicer than hammering. Then use the same threaded tool to pull the new bearings in.

Barry2 

Be sure not to put pressure on the inner race when putting the new bearing in.
Bearings don't like that one little bit.

Barry

choddo

Ah ok so it pushes in from the non-drive side? For some reason I always thought it had that little overlap on both sides.

What braces your threaded tool so it can push the bearing out? I hate getting the hammer out.

Barry2 

I've installed on two Cervelo R3's and I have an R5 that will get one when it needs the original BB replaced..
Both BB shells have pushed in to the Drive Side (DS) of the frame.
They are flush with the frame on the Non-Drive Side (NDS).

I use a bearing press and the Hambini BB installation tool (IIRC, it comes with the BB's)

Barry

SpedFast

I use a 3/4" drive socket that has the right diameter to fit on the OD of the BB housing and run my threaded puller thru the ctr of it. To fit a washer inside I use the right dia. washer and grind it oblong so it runs in at an angle and then pulls up flush to the surface that you want to extract. When pulling a worn out bearing it doesn't matter if you pull against the inner race so long as it slides out complete. Don't push or pull against the inner race when inserting a new bearing. Like Barry2 stated, they don't like that. Good luck and don't overthink it, it's not very complicated.

Barry2 

A bearing extractor braces against the outside of the shell and pulls the bearing out of the shell.

Barry

beemaa

Thanks for all for help and suggestions.

I may look at replacing the two push fit bearings to a one piece as well. Just a messy system the way cannondale have designed this, it’s the second systemsix I’ve seen in the last 2 months with same bb issues not aligning, causing excessive wear on the parts.

can anyone recommend a good one piece?

Barry2 

beemaa
post #7 has a clickable link to an awesome BB.
Like I said, expensive, but designed so bearings are replaceable.
(those colored underlined items are links)

Barry

WARNING…. YOUR BIKE MIGHT BE PF30A & NOT PF30
Do be sure to purchase the correct BB for your particular bike

BTW
If BB bearings die of old age, fair enough.
If BB bearings die in early life, it may be misalignment due to the frame.
The “racing” version of Hambini’s BBs are stiffer and can better resist such a frame issue.
I’ve only used the “racing” version on my bikes.

beemaa

Barry2 thanks for that, and yes i suspect the reason why these particular bikes seem to have bb fails is due to frame flex. I’ve noticed the bottom bracket region tends to flex more so than say my sworks, could just be me seeing things but it does seem more soft which would make sense as to why these bearings don’t seem to last very long or become misaligned over time from movement.

Barry2 

Flip the bike upside down and use a caliper to measure the width of the frame at the BB.
You should measure either 68mm or 73mm.

Barry

Kontact

Misread

Kontact

Carbon bikes can't use a tool like this. There is generally no lip to put it on and you'll destroy the paint.

The correct extractor uses a hammer from the back or a slide hammer from the front.

Barry2 

Thanks for the warning, but my puller has an ID of 44.7mm the BB has an OD of 46mm, it's not resting on the paint.

YMMV

Barry

Kontact

So you want to leave the cups in the frame? Why?

Barry2 

It's not Cups.
It is a single piece of aluminum alloy that pushes in from the DS and goes all the way through to the NDS.
It is designed so that bearings can be serviced (removed/replaced) without removal of this one piece BB shell.

All of my posts in this thread have been recommending and dealing with this type of BB and it's advantages.

Barry

choddo

In Hambini’s video of one of these, where his BB had been installed but the bearing was being crushed, the alignment was bang on but one side of the shell was undersized.

Kontact

The carbon BB shell crushed the bearing through 2mm of nylon?

Barry2 

We are still not discussing nylon cups.

Barry