Kogel PF30 Issue

Discuss light weight issues concerning road bikes & parts.
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Posts: 367
Joined: Tue Jun 30, 2009 7:40 pm
Location: CA

by billspreston

I picked up a Kogel PF30-386 bottom bracket to replace a Chris King PF30. I like this Kogel PF30-386 design as it would allow me to run a wide-axle Quarq spindle without large spindle spacers. I pulled the CK unit and cannot for the life of me get this Kogel unit to press in straight using my Enduro PF30 press. The BB is going into a Parlee Z Zero and the BB shell calipers to 45.95mm. The CK BB calipers to 45.95mm while the Kogel calipers to 46.05mm so it appears the Kogel is technically oversized for a 46mm (+0 / -0.05mm) shell. Perhaps this oversized fit is Kogel's solution for creaks? In any event, the CK unit goes in smooth and straight using the same Enduro press so I'm assuming this 0.10mm difference in diameters between the BBs is enough to cause an issue.

Now, I've obviously seen Kogel BBs installed on many frames so I'm at a bit of a loss as to why this thing will not press in properly. The only thing I can think of is that my Enduro press is not strong enough to overcome this very tight press fit. Perhaps using a beefier press like a Park HHP-2 would get it done, but I don't own this press and cringe a bit at the thought of pressing an oversized 46.05mm piece of alloy into a 45.95mm carbon fiber shell. I've put the CK unit back in and admitted defeat for now.



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Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

What about greasing it up and heating the shell a bit with a hairdryer. I'd also put the cup in the freezer first. It might slip in easy this way.

The only problem with crushing a larger diameter in is that you will effectively enlarge the shell so if you ever need to put back a 45.9mm cup again you might need to use retaining compound of some sort to avoid creaking. Depends on if you are a strong/big guy or not.

Nice slippers!

Last edited by alcatraz on Tue May 08, 2018 1:53 pm, edited 2 times in total.

Posts: 131
Joined: Tue Nov 15, 2016 8:13 am

by hambini

mmm... This is a bit ropey because the measurement does not look right.

If you can get hold of a micrometer, I would do that rather than go off a vernier to establish sizes.

If you go here https://www.hambini.com/technical-suppo ... re=default and download the shell drawing for PF30, it's supposed to be 45.96 as the bottom end of the tolerance. The Chris King BB looks (if your measurements are accurate) to be too slack for the hole - it is size for size.

Having said that, the Kogel BB looks like way too much of an interference fit for the PF30 standard but I don't know what materials they use. I certainly don't make bottom brackets with a 80um interference fit! I would be worried about snapping.


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