Bearing spacer questions

[tdm34]

Morning all, I have a nicely modified 1TX, it's fitted with a '87 FZR1000 front wheel, but unfortunately i've hit a pothole and knocked it out of true, so I looked at getting it straightened and was staggered to find that i'd be charged $355 for the job!

So plan B look for another '87 FZR wheel, no chance, none anywhere, there's plenty of 89-92 wheels about at reasonable cost but they use a 17mm spindle as opposed to the 15mm one the '87 FZR/FJ wheel uses.

I understand that I can change the bearings for 6203-2RS/15's so it'll fit, but can I still use the original bearing spacer with the 15mm spindle?
as I understand it's just there to keep the bearing centers in the right place, or will I have to alter the original spacer from the '87 FZR wheel.

[fj1289]

IF (and this is a BIG if) the bearings are the same distance apart on the new rim, then yes you can use the old 15mm ID spacer.   

The spacer does "just" keep the bearing centers in the right place - - but what that does is to keep from side loading the bearings which will lead to their quick failure.   Think of a complete bearing failed at highway speeds in traffic or on a busy, windy 2 lane road with oncoming traffic.   

Easiest way to check would be to compare the two internal spacers and see if they are the same length.  If so - good to go!  If not, thanks the next thing to solve!

[ajacstern]

I have heard that it is better to drill the fork legs out to fit a 17mm axle rather than bearing down to a 15mm axle, but honestly I think you would be just fine. My guess is that the 15mm bearing spacer will fit just fine in a later model wheel with appropriate 15mm wheel bearings. The way you might be able to check that they have the same length is to compare the width of the wheel bearings for the 87 and the later model wheels wheels, if they are the same then it is likely that the internal spacer has the same length as well. In the case the spacer didn't fit it could probably be modified pretty easily or a new spacer could be cut by a machinist, it is just a simple cylinder.

[Pat Conlon]

The thought of a 1mm thick axle bushing supporting the loads of my front end, gives me the willies...
...but that's just me. What could possibly go wrong?

[fj1289]

Pat,  that's the reason for using the 6203-2RS/15's  - they are a "special" bearing - normally a 6203 bearing has an ID of 17 mm - these are specially made hid an inner race that is simply a non-standard 15mm - no 1mm spacers/shims/gun bins required!  Luckily we have Whisler Bearings in Denver.  Had to order them, but was able to pick them up in person and measure them to be sure!

[Pat Conlon]

Hey Chris, yes, that's cool....a wheel bearing that will fit the OD of the '89-93 FZR rim and step down to the 15mm ID needed for the FJ axle...very good.

On this special bearing, the last I recall was that the width was slightly different (narrower?) than the oem FJ/FZR bearing, is this the case?  If so, are spacer adjustments needed?

My comment above was for the folks who wanted to run the stock 17mm ID  FZR bearings and with a 1mm thick bushing to shim down for the 15mm axle. I don't like that idea one bit.

Still, I don't understand the resistance on drilling out the FJ fork legs for a FZR 17mm axle and thus keeping the stock FZR bearings. All of today's modern bikes (Bandit, FJR, XJR, etc) that are still using the conventional RU forks, have 43mm dia. stanchion tubes and 17mm dia. axles.

[fj1289]

I have a feeling the "resistance" is not wanting to go at it themselves with a hand held drill - or even the average home bench top drill press - and not wanting to try to find a trust worthy and competent machine shop (took me nearly 6 years to find one around Denver!).  The bearing swap makes the "hardest" part of this swap easier.  Yes, there will probably be a couple spacers needed.  I don't know if a simple washer on each side will do the trick or not (sort of an inside out version of the GSXR rear swap)?   I'm lucky enough to have a small bench top lathe so custom sized bushings are routine for me - but a challenge for those that that don't have a good machine shop they are familiar with.

[jannickz]

You're right, the original roller bearing spacer won't work with the 17mm spindle as the spacer is designed for the 15mm spindle and there will be a 2mm difference in width.

Since the bearing spacer keeps the bearing centers in the right place, you'll need to alter the original spacer to accommodate the wider spindle. You can machine 1mm off each side of the spacer to make it fit the new wheel.