Gidday,
I hope someone can shed some light on this problem. I have purchased a set of Morris rims and are having difficulty fitting the rear rim. It seems the rim is offset, that is, it sits off centre when fitted, to the left of the bike approx 20mm. The disc rotor also won't line up with the Brembo caliper either, it's as if the rim needs to sit further over to the right.(which it would maybe sit central then?). Must mention the bike I am trying to fit the rim on is a 1980 R100S with a disc on the rear and snowflake rims.
When the Morris rim is sitting on it all aligns with the drive flange correctly and has about 3mm clearance to the largest web on the diff housing (the biggest web is on the inner-lower housing) so it's sitting where it needs to be on the diff side.
It's got me stuffed what's going on, I must be overlooking something?. Has anyone got any experience with Morris wheels? Did they make different offset rear rims? These rims supposedly came off an R90 with a rear disc conversion.
Cheers Dazza.
Morris Rims
Re: Morris Rims
If memory serves me,
Morris offered a rim one size wider than the OEM rim
in order to allow fitment of 'wider than stock spec tires'.
The extra rim width is needed to properly fit the tire,
and the offset is necessary for the tire to clear the driveshaft housing.
The width of your particular wheel is not mentioned.
Assuming that the cast wheel is intended to fit your mc ...
Having experimented with rear tire widths and offsets on airheads,
I can assure you that a bit of head-scratching,
garage-engineering, and fabricating will be in order.
Since the rotor is fixed to the wheel
and the caliper bracket "floats" on the axle ...
The only modification that should be necessary
will be the placement / position of the brake-stay.
Morris offered a rim one size wider than the OEM rim
in order to allow fitment of 'wider than stock spec tires'.
The extra rim width is needed to properly fit the tire,
and the offset is necessary for the tire to clear the driveshaft housing.
The width of your particular wheel is not mentioned.
Assuming that the cast wheel is intended to fit your mc ...
Having experimented with rear tire widths and offsets on airheads,
I can assure you that a bit of head-scratching,
garage-engineering, and fabricating will be in order.
Since the rotor is fixed to the wheel
and the caliper bracket "floats" on the axle ...
The only modification that should be necessary
will be the placement / position of the brake-stay.
Re: Morris Rims
Disconnect the brake-stay at the caliper hanger and the swing-arm.
Remove it.
You should now find that the caliper will align with the rotor.
Then, decipher what spacers, repositioning, or adjustmentswill be needed
to reattach the stay without introducing torque or tension
into the caliper hanger / bracket.
Hope that helps ...
Remove it.
You should now find that the caliper will align with the rotor.
Then, decipher what spacers, repositioning, or adjustmentswill be needed
to reattach the stay without introducing torque or tension
into the caliper hanger / bracket.
Hope that helps ...
Re: Morris Rims
Gidday,
A bit of an update, I've done a bit of measuring tonight and found that the rear disc rotor left face is 25mm closer to the left inner swingarm face when compared to the original snowflake rim. Also the centre of the hub spacing on the Morris is 23mm lower from the outer disc face and the snowflake has 0 spacing (that is, it's flush with the disc).
All that causes a bit of a problem with the caliper swinging mount as it just simply doesn't fit. So a new caliper mount is needed or a different disc rotor mount that has bugger all offset.
Is there such a thing available?
I can,t find the rim width stamped on it anywhere but it's the same width as my 7 month 1977 R100S rear wire spoked rim, which is 2.15 x 18.
Also the rim clearance to swing arm drive shaft side is increased from approx 7.5mm to 25mm with the Morris rim. So that's why when standing at the rear of the bike the centre of the rim is about 20mm offset to the left.
Regards,
Dazza
A bit of an update, I've done a bit of measuring tonight and found that the rear disc rotor left face is 25mm closer to the left inner swingarm face when compared to the original snowflake rim. Also the centre of the hub spacing on the Morris is 23mm lower from the outer disc face and the snowflake has 0 spacing (that is, it's flush with the disc).
All that causes a bit of a problem with the caliper swinging mount as it just simply doesn't fit. So a new caliper mount is needed or a different disc rotor mount that has bugger all offset.
Is there such a thing available?
I can,t find the rim width stamped on it anywhere but it's the same width as my 7 month 1977 R100S rear wire spoked rim, which is 2.15 x 18.
Also the rim clearance to swing arm drive shaft side is increased from approx 7.5mm to 25mm with the Morris rim. So that's why when standing at the rear of the bike the centre of the rim is about 20mm offset to the left.
Regards,
Dazza
Re: Morris Rims
Hi, I just saw this. I haven't used the Morris wheels I bought but I may be able to help just a little.
It is my understanding that the use of Morris Mags on BMWs is pretty much not based on any stock configuration at all. In other words, any brake set-up will have to be engineered by the end user. You may or may not have a head start by already having a disc brake BMW. With my wheels, there was a box of very weathered looking parts that looked very "home engineered", even more that way than what I tend to make. They were brackets and, I think, a Lockheed disc brake caliper.
If I've been able to help at all it will be mostly the idea that you won't want to go at it thinking it is based on any existing brake set-up. Custom baby! Not for the weak willed, evidently.
Chuey
It is my understanding that the use of Morris Mags on BMWs is pretty much not based on any stock configuration at all. In other words, any brake set-up will have to be engineered by the end user. You may or may not have a head start by already having a disc brake BMW. With my wheels, there was a box of very weathered looking parts that looked very "home engineered", even more that way than what I tend to make. They were brackets and, I think, a Lockheed disc brake caliper.
If I've been able to help at all it will be mostly the idea that you won't want to go at it thinking it is based on any existing brake set-up. Custom baby! Not for the weak willed, evidently.
Chuey
Re: Morris Rims
Thanks for the information, I will have a better look at all of it over the weekend and see if I have a brainwave and an easy solution. Anyone know of a brake supplier that retails disc rotor centres? (Need one with very little offset) As I can't seem to find any.
Will look into disc rotor centre modification first as that's the easiest solution (I think?).
Cheers Dazza.
Will look into disc rotor centre modification first as that's the easiest solution (I think?).
Cheers Dazza.
Last edited by Dazza62 on Thu May 16, 2013 3:38 am, edited 1 time in total.
Re: Morris Rims
Um, the easiest solution would be to find and run stock wheels. We now know at least some of what's not so good about Morris wheels; what makes them so compelling?
Re: Morris Rims
I would also be concerned about the (measured) 23mm offset.
I seem to remember that stock track offset
only approached 7.5mm on the 80s era wide rim RS models.
0 is the ideal -
23mm is certainly excessive.
Chuey's assessment is valid.
Morris, Lester, etal. only marketed cast wheels for the BMW mc
until about that time when BMW introduced the Flake.
And this timing would coincide with BMWs fitment of a stock rear disc.
It is quite likely, then, that these manufacturers
did not plan to accommodate the stock brake hardware.
The handling advantage of a cast wheel vs a spoked wheel is lateral stiffness.
The disadvantage, at least in the early years, increased unsprung weight.
The Morris (& esp the magnesium version) weighed less than
either the Lester or the BMW Flake.
I seem to remember that stock track offset
only approached 7.5mm on the 80s era wide rim RS models.
0 is the ideal -
23mm is certainly excessive.
Chuey's assessment is valid.
Morris, Lester, etal. only marketed cast wheels for the BMW mc
until about that time when BMW introduced the Flake.
And this timing would coincide with BMWs fitment of a stock rear disc.
It is quite likely, then, that these manufacturers
did not plan to accommodate the stock brake hardware.
The handling advantage of a cast wheel vs a spoked wheel is lateral stiffness.
The disadvantage, at least in the early years, increased unsprung weight.
The Morris (& esp the magnesium version) weighed less than
either the Lester or the BMW Flake.
Re: Morris Rims
When BMW issued a service bulletin on the introduction of the optional wider top hat spacer to improve tire clearance they also specified that offset be adjusted to a max. of 4mm. Seems a tight tolerance but I've just looked at the North American and European bulletins and they both say the same.
barry
Cheshire
England
Cheshire
England