Re: Tire Changing questions

["Clive Liddell" <cliddell@xxxxxxxxxx>]

Jack,
Just to say I also thought the wheels "looked" nice and light - until I hung
them from a scale.  I don't have any off right now but here are some
figures:

An unused BT54 (neglecting the black bag it's in):  6 kg = 13.2 lbs
My rim doesn't have rotor attached and per ETK:   6.73 kg = 14.8 lbs

Not quite a negligable total weight to have out of balance (IMO).

Yes I agree, if you take the trouble to balance, then at least do it as well
as you can...

Regards
Clive Liddell
Pietermaritzburg, South Africa.
'96 R850R   72k.km
'01 R1100RT 45k.km

- ----- Original Message -----
From: Jack Bunce <jackbunce@xxxxxxx>
To: <oilheads@xxxxxxxxx>
Cc: <cliddell@xxxxxxxxxx>; <PLPKLT@xxxxxxx>
Sent: Wednesday, June 23, 2004 4:11 AM
Subject: Re: Tire Changing questions


> What does a rear wheel, tire, brake disk, and other miscellaneous parts
> weigh?
>
> If the answer is at least 10 lbs that is equivalent to about 4,536
> grams. If that was off center by 0.001 inch that would be equivalent to
> exerting a torque of 4.5 gram/inches which out at the inside of the rim
> might be (4.5/15) or 0.3 grams out of balance at the rim.  Don't think
> you would notice that?
>
> But that said, I agree that every effort must be made to fit the wheel
> properly to the balancing device. Allowing any slop would be self
> defeating!
>
> For the BMW content: When I put my R1100SA on the centerstand and spin
> the rear wheel under power the bike feels unbalanced and shakes. Yet, I
> do not feel this imbalance on the road. Should I have the rear wheel
> pulled and balanced or is it normal for an R100SA to act that way on
> the centerstand with the rear wheel under power? [This came up because
> I had the bike on the dyno and the tester mentioned the rear wheel hop
> to me.  So I tried it at home.]
>
>
> On Jun 22, 2004, at 4:47 AM, oilheads-digest wrote:
>
> > Date: Mon, 21 Jun 2004 21:29:08 -0400
> > From: PLPKLT@xxxxxxx
> > Subject: Re: Tire Changing questions
> >
> > In a message dated 6/21/2004 10:24:51 AM Eastern Daylight Time,
> > cliddell@xxxxxxxxxx writes:
> >
> >> If you are a only a couple of thou's out then the whole
> >> weight of the wheel acting at that tiny distance can easily equate to
> >> around
> >> 10 or 20 g - and, of course, you are only un-balancing the
> >> wheel :(
> >
> >
> > I'd like to see you provide some calculations on that!   1/1000 of an
> > inch times 1 gram  = 10 or 20 G ( does this stand of Gravity or
> > something else....
> >
> > Jess with such obvious dangerious physics just waiting to jump on our
> > poor unbalanced wheels , it is a wonder were not all laying somewhere
> > in a ditch....
> >
> >
> > Paige

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