Wheel Bearings and Axles

Desmo_Demon · Post by **Desmo_Demon** » Wed Jan 24, 2007 4:05 pm

I'm getting ready to change the wheel bearings on my Paso, and I noticed something that caught me offguard. The bearings for both wheels are the same (20mm id x 42mm od x 16mm width - I believe it is an SKF #63004-2RS1), but the issue that I see is that the front axle is 17mm and the rear is 20 mm. :umm:

Looking at the front wheel, I noticed a bushing that takes up this 3mm difference for the smaller axle. According to the Parts Manual, it shows the "distance piece" between the two bearings to have a shoulder for the bearing to fit over. If this is the case, how do I knock out the front wheel bearings? It doesn't look like I can knock them out like I did the rear wheel bearings (which were completely worn out). If the "distance piece" is two pieces, I assume I just knock out an inner sleeve and then proceed to remove the bearings and spacer as I did with the rear wheel.

Anyone have any insight?

Note: The original 20mm x 42mm x 16mm bearings are fairly uncommon and cost between $30 and $45 USD EACH. I noticed, though, that a much more common, and cheaper 20 x 42 x 12 bearing is available (4mm thinner - and has the same loading and rpm specs of the 16mm wide bearing). I'm going to see if I can use this thinner bearing by making some 4mm spacers to make up the difference in width (one on each side of the wheel). It'll be the difference in $80-$100 USD if I can use the 12mm wide bearings. I'll update at a later time.

Desmo_Demon · Post by **Desmo_Demon** » Wed Jan 31, 2007 2:37 pm

No one has changed out their front wheel bearings?.....I guess I'll look into pulling them out in the next few days and report my findings.

Christian · Post by **Christian** » Fri Feb 02, 2007 7:40 pm

Hi,

I had changed front wheel bearings, but with originals bearings.
You will change one or two times during the Paso life. Evaluate the time to build spacers ? I suggest you to buy original bearings without problem !

persempre907 · Post by **persempre907** » Fri Feb 02, 2007 8:05 pm

I also would use the original spare parts even if they are more expensive.
I can't say anything about the safety of the bike but, no matter, I would spend $. 80-100 more.
Ciao

ducapaso · Post by **ducapaso** » Sun Feb 04, 2007 8:39 am

A wider bearing means an higher load to bear...

actually I don't think that there's such a load to bear in the front axle, but switching to std bearings will require a complete set of machine made spacers (they have to be absolutely exact, tolerance 0.05 mm) and I think that a good mechanical can make those spacers, but this might cost you a lot more than special bearings!

Desmo_Demon · Post by **Desmo_Demon** » Mon Feb 05, 2007 2:43 pm

If you look on the SKF website.....

http://www.skf.com/skf/productcatalogue ... tartnum=12

You will see that the dynamic loading is actually lower with the 16mm wide bearing compared to the 12mm wide bearing (25x42x12 vs 25x42x16). The static load, fatigue load limit, and limiting speeds are either the same or higher for the thinner bearing. Naturally, these are only for SKF bearings, so if using a diufferent brand, you may have to compare the specifications of that brand with the SKF, which I think the original bearings are SKF.

As for making the spacers, I have a buddy who will make all the spacers I need for a 12-pack of beer. He's also the guy who does aluminum castings and has a plasma cutter. He made this bracket for my wife's electric shifter for *free*.

I was able to get two pair of bearings for free, so I'll see if I can get them to work. If they don't, it won't be anything for me to go buy the OEM bearings and replace them in a couple of hours.

I almost forgot. It looks like a stepped drift is needed to knock out the front wheel bearings. The stepped-drift will limit any chance of damage to the spacer in the hub, as this spacer appears to be stepped for the inner race of the wheel bearings and to make up the difference between the 20mm ID of the bearings and the 17mm front axle. The spacer will have to be driven out with one of the bearings, and a stepped drift will prevent damage to the spacer's edge. My buddy is going to turn down some bar-stock and make a drift on his lathe.

Desmo_Demon · Post by **Desmo_Demon** » Thu Feb 08, 2007 8:49 pm

Update - To remove the front wheel bearings a stepped drift is the best way to remove them without damaging the spacer between the two bearings in the hub. The spacer has a step to it where the bearing inner race fits over it.

To use the 12mm wide replacement bearings, we are thinking about installing 4mm wide spacers on this stepped spacer to bring the bearings back outward in the hub to their original locations. This will eliminate any necessary fumbling with addition external spacers and having to be concerned with fitting one between the bearing and the speedometer drive housing on the left side.