The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: pastafasool on December 15, 2012, 09:52:40 PM
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I have a '79 R65 with single front rotor and ATE caliper. Having a very hard time finding a replacement rotor. Bike came without it, it was a parts bike. Even EBC couldn't give a positive answer, saying their listing starts with the '81 model. Has anyone found the right aftermarket rotor for this year ?
thanks
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Motobins claim their Grimeca disc Part No.20300G fits R45/65 78-84.
I'd get them to confirm the offset is correct. I tried to measure mine for you and although it's not easy to get an accurate figure with the disc on the bike I make it approx. 40mm.
(http://)
http://www.motobins.co.uk/bmw-parts.php
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Hello !
I've seen bikes where only the disk has been changed. The rivets have been replaced by screws never seen before (Allen head but spherical shaped heads, and not protruding a bit on the other side they looked like a hot rivet of the 19th century but with an Allen imprint). the disk where cast iron so rusty after a rain.
Maybe something to investigate ? (the support part is specific to the R65 I think so keeping them is a good thing )
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Barry-thanks for trying to measure the offset. EBC has 2 possibilities,
identical except for offset & thickness. One is 35.8 mm and the other 47.8 mm. I also have a local shop, Beemer Barn in Johnson Creek, NY, looking.
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I've had very good experience with Spiegler Performance - they know BMW's!
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I just measured the rotor on my '81 R65 and a rotor off of an LS .
The snowflake wheel rotor is 48 mm from the outer surface to the surface that contacts the wheel .
The LS has a dimension of 37 mm .
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Barry-thanks for trying to measure the offset. EBC has 2 possibilities, identical except for offset & thickness. One is 35.8 mm and the other 47.8 mm. I also have a local shop, Beemer Barn in Johnson Creek, NY, looking.
I measured 40mm from the wheel hub to the inner surface of the disc so measuring as Bob did to the outer surface would make it match with 47.8mm.
I believe the LS discs have a smaller offset due to a wider rim width.
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The LS disk is the same as all the 'normal' bigger beemers. The snowflake R65 disc is also used on the R80G/S 1981-86 and the R80ST. That ought to make it a little easier to find.
I've also heard of using the shallower disc and machining up a spacer disc with longer mounting bolts.
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I have an ebc disc on the front of my 1979. So you should not have an issue. Just take the 1981 ebc disc.
I have also updated my 1979 to take Brembo brake as well, so that is also an option.
I have not had a good experience Grimeca - I had a pair and did not get 10,000 miles out of them before they both warped to the point that they would not pass an MOT.
having said that, I have not yet covered that sort of mileage with the single EBC.
Rev. Light
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'Braking' an Italian company make brake rotors that bolt to the original carriers, they supply all the screws, washers and nylock nuts required.
It was an easy job to grind the end off the original rivets and punch them out before bolting up the semi-floating rotors.
They even supply 2 sets of 5mm bolts in different lengths to suit the brake carriers of the LS and the other BM models that the rotor can fit.
If you look them up on the web you will see that they have a new range of rotors that look less like the factory ones, I think they were slotted or maybe a wave pattern as opposed to being drilled in a similar patttern to the OEM ones.
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I just looked up a disk on the website that Bruce mentioned. Seems like a good price although this is the fixed version. The floating disc is another 50 Euros.
http://www.braking.com/catalogue/dettaglio_prodotto.php?codice_articolo=BW01FI
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Another bad experience here with Grimeca.
http://www.bmbikes.org.uk/Forum/viewtopic.php?f=15&t=16756&p=104395&sid=125c1f09062c0b09eef6ba573d8d7702#p104395
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Bob and Barry- your info was correct. Our non-LS 1979 R65 took the EBC # MD606LS (larger offset) . After receiving the MD602LS (smaller offset) we finally received the right one and it's perfect. EBC's "LS" has nothing to do with BMW's "LS", in case anyone is confused by that. Thanks again for the help.
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So, 79 model takes the regular disc and LS take the narrow disc. Did I get it correct?
What about dual discs?
My bike has two ATE units, but always wondered which disc fits by EBC.
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The rotors are the same for the OEM 'snowflake' wheels of all the years of R65's .
The wheel, not the caliper is the determining factor .
The ATE and Brembo calipers can be used on any R65 .
The LS model and the monoshock bikes take the shallow discs .
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Hello Bob.
The ATE and Brembo calipers can be used on any R65 .
I was under the impression the mono R65's has 285mm diameter discs and 38mm diameter calipers. I think the same as R80/R100's.
Whereas the 79 has 260mm discs and 36mm calipers. Will the calipers fit a 79 R65?
If so the search for twin front brakes may be over.
Cheers for any insight.
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I should have said 'twin shock ' R65's, I don't know about the mono shock bikes, not many members here have these bikes, so I have no idea if the rotors and calipers are the same as the twin shock bikes .
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If I have read Snowbums Brake article correctly,
http://bmwmotorcycletech.info/brakes.htm
most Airhead Forks and Brembo calipers have 108mm mounting hole centers. My 79R65 has 108 centers.
He also states that performing a dual disc conversion does improve braking but at the cost of handling.
Whereas the installation of a single 4 spot caliper from a classic K bike or oilhead offers much improved braking with no handling sacrifice or installation trouble other than milling the mounting surface of the caliper up to 4 mill.
Happy days.
I wasn't looking forward to dishing out $400+.
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My 1986 R65 mono shock, with single front disc brake, has a 285 mm disc with a piston dia. of 48 mm.
With a twin front disc setup, the piston dia. is 38 mm.
The caliper dia. you've mentioned is for the twin disc. setup, not the single. This data is from my owner's manual.
Dave
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Thanks Dave,
I'd be interested to find out what the mounting hole centres are on your bike. A 36mm to 48mm increase would surely improve braking power. The more options the merrier.