Alloy Wheels & ABS

[Cook1e]

Hi All,
I am aware that this topic has been discussed many times and I have searched the forums (fora?) for the distilled wisdom of expert & experienced folks, but with no real definitive answer.

I have fitted 17" alloys, plus speedo drive and pressed steel ABS rings, from an RS. Mechanically, everything is fine and I am very pleased with the result - it makes the bike handle better on-road. I may fit knobblies to the original wire wheels so I can learn to ride off-road, but that will be a different thread for the future.

Here's my problem (in common with several other tossers, apparently):
On riding off, the ABS unit "clunks" as normal and both ABS warning lights go out. So far, so good. But, as I increase speed, I hear the ABS servo whining more than normal. The whining seems to occur in response to speed changes - acceleration, closing throttle and changing gear. The brakes work normally (although I haven't tested the ABS function) at up to legal speeds apart from the whining servo.

When I ride above about 80mph, the ABS lights start flashing alternately and remain flashing until I stop & switch off. On riding away again, the above symptoms recur.

The ABS rings are those that came with the RS wheels (pressed not cast) and I have checked, adjusted and re-checked the ABS sensor gaps to 0.5mm. When initially assembled, the rear gap was too small (<0.2mm) and the front gap too wide (about 1mm). Adjusting each gap in turn, then test-riding, made no difference at all.

In searching previous threads on the subject, I learn that some tossers who have done the mod have had the exact same symptoms/problem, but others have noticed no problems at all. No-one seems to have a solution, although there is much speculation of the cause. Favourite theory is that the ABS "brain" is programmed specifically for the standard 19"/17" wheel combination and 17"/17" confuses it.

So, anyone have facts (not guesses) and/or a solution (not experiments)? How about swapping the ABS controller for one from an RS? Can I temporarily disable the ABS without making the light flash, e.g. by pulling the fuse? Surely not everyone is "living with it"? Even if I put up with the flashing lights, or stuck to below 80mph chuck), I would be concerned that the servo is overworking and would be prone to failure.

Or is the definitive answer "can't be fixed"?

Thanks in advance for sharing wisdom.

Cheers,

Ian

 

[roddy]

just a point of clarity did you have pressed or cast ABS rings on your original wheels ?

 

[Cook1e]

Hi Roddy,
I had the cast ABS rings on the wire wheels - sorry, I thought they were all like that. I should have also said the bike is a 2001 1150.

Thanks,

Ian

 

[petkostas]

A local rider transformed a GS 1150 to a mix of R and GS 1150 with cast wheels and everything, he had problems with the ABS on the R wheels but he managed to fix it, I will try to find what he changed and get back... (our Greek bmwbikers forum is down for the moment till 15th March for upgrade reasons, I know the guy but don't have his phone, will try to find it tomorrow).

 

[Cook1e]

Thanks Petkostas, I hope you can find some info. I will be away on business Tuesday-Thursday, so no rush.

 

[Steptoe]

Here's my problem (in common with several other tossers, apparently):
On riding off, the ABS unit "clunks" as normal and both ABS warning lights go out. So far, so good. But, as I increase speed, I hear the ABS servo whining more than normal. The whining seems to occur in response to speed changes - acceleration, closing throttle and changing gear. The brakes work normally (although I haven't tested the ABS function) at up to legal speeds apart from the whining servo.

When I ride above about 80mph, the ABS lights start flashing alternately and remain flashing until I stop & switch off. On riding away again, the above symptoms recur.

Yep, as you say, it's a very common problem when using different wheels and or ABS rings.

Let us know how you cure it.

 

[Cook1e]

Hi again all,
No answers - do I assume it's not possible?

 

[roddy]

So, anyone have facts (not guesses) and/or a solution (not experiments)?

This probably hasn't helped

as a suggestion have you tried the cast ABS rings on the cast wheels ?

 

[Cook1e]

Thanks Roddy - good idea, except they don't fit (unless I missed something).

Next time I get into the garage, I may take some photos - but I just started a new job and it's all a bit fraught at the moment, so don't hold your breath!

Cheers,

Ian

 

[Cook1e]

It Healed Itself!!!

No kidding - I took it out before my last post and it did exactly what I described in the first post.

On Monday, having sussed out where to park the bike and hang the leathers at my new workplace, I rode to work and back "the pretty way". Over 90mph, no problems, even tested the ABS (on purpose!) and I heard no unusual whining from the ABS pump.

I wonder if the ABS "brain" has belatedly reprogrammed itself?

Thoughts?

Thanks for input all who responded, I'll update again if owt changes.