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Rim swap - 75/7 to an R100T
Posted: Sat May 24, 2014 10:17 am
by oldRNineTguy
I recently purchased an '82 R100T that the previous owner painted the rims a flat grey, which is not to my liking (they show ALL road dirt and brake pad dust). I've priced out getting the rims off, tires and bearings removed, and the rims blasted and powder coated. The back tire is well past its best before date and the front is getting on as well. I've found a set of never used spoke rims from a '77 R75/7 The R100 has Brembo dual discs, the R75 has a single disc. Are the old rims compatible with the new(er) bike? Has anyone here done this swap before? Is this the dumbest question I've ever asked?
Re: Rim swap - 75/7 to an R100T
Posted: Sat May 24, 2014 12:57 pm
by Bamboo812
The brake discs are the same, can you measure the width of the hub?
Re: Rim swap - 75/7 to an R100T
Posted: Sat May 24, 2014 3:27 pm
by oldRNineTguy
good question. I can measure the hub width on my R90/6,(should be the same as a /7) and can probably swag the width disc-to-disc by guessing since my R90 has only one disc; but I'd like to double check, since being out by a few mm is the same as being out by a few inches. Can anyone tell me the distance from the outside of one disc to the outside of the other on a twin disc /6 or /7? I can compare the disc thickness and dia on my own 2 bikes. Anyone know if there is an axle dia. difference? The only stumbling block is the current owner of the spoke rims; he wants to sell them along with the bike that originally came with the spokes, and is now sporting a pair of aftermarket alloys.
Re: Rim swap - 75/7 to an R100T
Posted: Sun May 25, 2014 6:22 am
by PAS
Do some serious research before spending any money. The Brembos are a problem. The 81 R100CS came out with spoked wheels but I believe they were recalled due to stability issues.
Re: Rim swap - 75/7 to an R100T
Posted: Sun May 25, 2014 7:03 pm
by Bamboo812
PAS wrote:Do some serious research before spending any money. The Brembos are a problem. The 81 R100CS came out with spoked wheels but I believe they were recalled due to stability issues.
Are you sure you don't mean the cast snowflake wheels? I can't find any mention of a spoke wheel recall:
Re: Rim swap - 75/7 to an R100T
Posted: Sun May 25, 2014 11:11 pm
by Major Softie
Actually, a recall of the 81-82 CS front spoke wheel IS all over the web, but, as certain as all of them are about it, I've never seen anything official.
Re: Rim swap - 75/7 to an R100T
Posted: Mon May 26, 2014 12:16 am
by SteveD
Major Softie wrote:Actually, a recall of the 81-82 CS front spoke wheel IS all over the web, but, as certain as all of them are about it, I've never seen anything official.
Scroll right down to note 25 ala Snowbum. Still not official though. http://bmwmotorcycletech.info/catch.htm.
Re: Rim swap - 75/7 to an R100T
Posted: Mon May 26, 2014 12:45 am
by Bamboo812
OK, Snowbum says," ALL of the 1981 R100S polished (spokes) wheel models were recalled, during the time of shipment from Germany. This was NOT a federally mandated recall..." So, with this, and the "stability issues" mentioned in another post, what was actually wrong with them? Did they narrow the hub too much and compromise wheel strength? How could better brakes be a problem? Just curious...
Re: Rim swap - 75/7 to an R100T
Posted: Mon May 26, 2014 1:06 am
by Sibbo
No ST's on that list .
Re: Rim swap - 75/7 to an R100T
Posted: Mon May 26, 2014 1:31 am
by SteveD
Max Headroom @ Advrider wrote:...both Andy Schweitzer and Ian Falloon mention it in their books.They refer to the factory's concerns about the stability of the wire wheels with the narrow hub, citing that the spoke angle was too steep. It doesn't make sense to me, considering that the angles would be even worse with the G/S 21" wheel, and especially in light of the fact that the UK Police had the same wire wheels and they weren't using their bikes for Sunday afternoon pootles in the countryside.
A contemporary article I recently read reckoned that the factory stopped fitting wire wheels because it was the only R100 model not to have snowflakes and therefore the cost was too high. That explanation makes more sense,
I've never been able to find any specific detail about the CS hubs. Have you got one, or seen one? I'd love to know exactly how wide they actually are, compared to the ATE model.