Need advise on R90 /6 brakes or lack of

Discussion in 'Airheads' started by David_S, Mar 24, 2008.

  1. Max Headroom

    Max Headroom lost in the '70s

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    The reason that BMW kept the same design lies in the contemporary magazine articles of the era. Compared to other bikes of the time, the ATE caliper setup was regarded as "different" but very capable and highly regarded. ATE had considerable experience in automotive brakes, and the design principle was sound.

    The single disc had its limitations, but the double disc didn't. The first year criticism of wet weather braking performance was largely overcome with the drilled discs fitted for the 1975, so with the 40mm calipers fitted for 1976 onwards the double discs were considered among the best brakes then available on a production bike, with impressive stopping distances "in the day".

    Consider that this was a "pioneering" phase for disc brake technology on bikes, and remember the nasty cable operated calipers on some cheaper bikes and the fully enclosed setup on early '80s Hondas and it becomes quickly apparent that the technology was still finding its feet.
    #41
  2. kixtand

    kixtand Long timer

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    Exactly my point.

    BMW was using the best stuff available at the time, not worrying about a lawsuit over owners that "launched themselves over the bars".
    #42
  3. gplane

    gplane Putty Conjugator

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    I have a speigler floating disc and EBC pads on a 75 R90/6, and although it is not as esthetically appealing as the original, it will lock em up.
    #43
  4. Dolly Sod

    Dolly Sod I want to do right, but not right now

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    After about a year of ownership, I went with the dual disc upgrade on my R90.

    I wouldn't say the upgrade was probitively expensive. I did end up buying a new under tank master. This was about 10 years ago, and the price was around 300$. I found a wrecked R90S locally, and used its right side slider and disc.

    Probably spent 500-600$ on the whole thing, including stainless lines. I did good on the wrecked bike as I sold the motor, trans, final drive and frame, so I came out about even.

    I've recently gone to the floating disc's available from Bob's, as one of my original discs developed a hard spot causing the brakes to pulse. The floaters make a nice difference as well.
    #44
  5. mrc.engr

    mrc.engr n00b

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    [QUOTE ... because its impossible to ride an Old School /6 safely in todays environment. [/QUOTE]

    Horses arse. Been riding /6 for three decades and lovin it. Sure.... I did some brake work to make things better. Got rid of that stupid cable operated m/c under the gas tank. What re re thought that one up. "Lets give them a disc brake and then take 50% of it back with cable operation".

    Got rid of the stainless rotors because they're so soft they don't last worth a damn especially if you try some real brake pads (H or HH) on it, so what the hey..... might as well drop on some cast iron rotors and fit some Ferrodo kick ass pads on it. VIOLA !!! Damn thing stops.

    No..... not as good as 4 pot Brembos w/320mm rotors.....but it's a hell of an improvement. So much so I throughly enjoy running with all the squids that come out of the DC area and want to play in West By God on the weekends.

    Never ceases to amaze me that they need almost 120 hp pushing 450 lbs down the road to stay up with 68hp, 575 lb 38 yr old Airhead BMW (R90S). All to many times I've had one say they still need more hp.:shog

    Now you and I both know that's a crock and I tell 'em just start taking some track days and learn how to ride that thing instead of just pointing it down the road and get all puckered up when a corner comes up.

    Like Code says..... "just tell the bike what you want it to do and relax..... it'll do it all on it's own.

    Somebody here said it..... ride an old bike accordingly, but this dosen't mean you have to ride like a pussy just because it's old. :nod
    #45
  6. chasbmw

    chasbmw Long timer

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    Standard R90/6 Dual discs with a 13mm handlebar M/C will work quite well, the brakes then have both power and feel. Use the later R100 M/C for twin pull throttle cables and it's a very easy upgrade, even the 75 on electrical switches mount up correctly. Available from Motobins, but make sure that you specify 13mm.

    The brakes are not as good as the Brembos on my 82, but they are nearly as good.

    P.S. the single front disc on my 1972 Norton was almost as bad as the BMWs single disc, I do think that with the not that great tyres available back them manufactures were all wary of riders locking up these new dangled disc brakes
    #46