Published by Tristan on 30 May 2009 at 10:07 am
My bearing press
Almost all modern hubs use sealed cartridge bearings – only Shimano and the higher end Campy hubs use loose ball bearings.
Despite these hubs being common-place the tools required to correctly remove and replace the bearings are not. To correctly install the new bearings they need to be gently pressed into place by their outside race – this prevents the force required to install the bearing from being transmitted though the balls and cages and damaging the new bearing before they’re even fitted. Most bike shops try to accomplish this by using a socket which ‘closely’ matches the outer bearing race – I’ve seen a lot of high end hubs damaged by botched installations (and I have to confess to damaging a hub myself in my younger days!)
This tool is something I built to make sure cartridge bearings are installed correctly every time without any damage to the hub. I machine special press adaptors to suit each type of bearing on a lathe, and the center pin guides these adaptors and keeps them (and the bearings) square to the hub shell. After applying a thin coat of Loctite 641 to help lubricate the bearing while installing I use a soft-faced hammer to gently tap the bearings into place. Because the adaptors and bearings are held square to the hub there is no risk of damage to the new bearings or the hub.
I have bearing adapters to fit most of the common hubs I work on and if I encounter something a bit strange then I machine a new adapter to suit.
Some pics showing a Tune Mag180 rear hub. The plastic box in the background keeps all the bearing adapters organized.
pics
The press tool's base clamped in the vise |
The lower bearing adapter on the base |
The freehub body resting on the lower adapter |
The new bearing (coated in Loctite 641) and upper adapter in place |
The driver fitted on top. The top of the driver is gently tapped with a soft-faced hammer |
The bearing fitted |
The hub sitting on the lower adapter |
A different upper adapter fitted for the larger bearing on the driveside of the hub |
The driveside bearing fitted |
All done! |
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Athos on 04 Feb 2010 at 7:28 am #
Hi Tristan, that is beautiful! How do you get the bearing out? Maybe something like this Cyclus tool?: http://www.bike-components.de/images/product_images/popup_images/11899_1_cyclus_nabenschalena.jpg
Tristan on 04 Feb 2010 at 7:46 am #
Hi Athos
It depends on the bearing but most bearings have a visible shoulder and can be knocked out with a drift. The slide-hammer you linked to is useful on blind bearings where you cannot access the opposite side of the bearing, however on bikes these are quite rare.