Help request - Rockster front axle measurement

[sweatmark]

Fellow Rockster riders, need your help. If time allows, would you measure the length of front axle that protrudes outside of the right-hand fork bottom? It's the short section of hollow front axle containing two holes. I need the length along the axle's primary axis, from where the axle exits from the fork, to its stub end.

Here's why:

I'm sure I'm not the only one to have noticed that the front fender has less clearance over the tire on RHS than the gap evident on LHS. If you check the rearward black plastic portion of that fender, you might find the same type of clearance dissimilarity. I've wondered whether the carbon fiber/fibre (showing the love for the UK folks) might be skewed, or possibly some slight twist in either fork tube. After removing the fender and measuring its symmetry, I'm convinced the problem is not the fender.

Also, my Rockster (Edition 80, mfr date 03/03) has never had front wheel free spinning... there has always been brake drag evident, enough to halt an aggressive hand spin within 1/2 rotation. I asked my dealer to check this during the 6k service, and then again at 12k, but the response was "we can't figure it out". The brake drag wasn't sufficient to impede performance or cause wacky pad wear, so the nuisance was ignored... until now.

"I have a theory, which is mine, which is my theory" (bonus points if you can name that Monty Python sketch), namely that the same BozoMW engineer who effed up the R1150 transmission input shaft splined length - yes the bloke who is no longer on my Christmas card list - said engineer was given a second assignment: design the fitment of the Rockster front wheel assembly borrowed from the R1100S. Somewhere in the transfer of the earlier bike's front end, one or more critical dimensions was screwed up, possibly because two versions of ABS timing ring were used on the R1100S. Regardless, the LHS spacer "pipe" length was spec'd incorrectly, resulting in off-center front wheel, and consequently the uneven fender gap and my bike's constant brake pad/rotor drag.

Working on a solution now. The axle stub end measurements will provide reference.

Thanks in advance.

[brico]

I measured mine at 10.4mm. My front wheel is free spinning and only slight brake drag after i squeeze the brake once hard after which it spins but not as free as before applying and releasing the brake.

[Laserr Boy]

Mine measures 10.0 mm. There is no brake drag, if I give the wheel a hard spin it will rotate at least 4 full revolutions. All of the fasteners are torqued to factory specs. Prior to changing my brake pads the left side used to hang up and the wheel would not rotate freely.

[kirby]

1745

[sweatmark]

Gents, thanks a bunch for your responses.

Did some measuring tonight, and confirmed that my axle "overhang" is 11 mm, similar to what you have documented. I spec'd two different front wheels and came up with similar geometry, which was good news (was concerned my 2nd wheelset was mismatch).



Link for the wheel specs I used as reference:

http://www.largiader.com/parts/wheels.html

As far as the front wheel alignment is concerned, I'm still thinking that the wheel/tire is biased right of centerline. After determining the rotor mount post offsets to hub edge on each side of the wheel (which are quite different), I realized that I'd need a special jig in order to measure the distance from each brake disc/rotor's to the wheel centerline, via outer edge of rim. There's a BMW alignment tool that would make this easy:



So, until rotor face to centerline measurement gets done, the wheels are going back on, tires touch tarmac, and I'm heading out to the desert.

Thanks again for your help.

[riceburner]

I find that the wheel alignment issue can be mitigated by tightening up all the various bolts in the correct order.

IIRC it's spindle bolt FIRST, THEN the pinch bolts, THEN the brakes.