The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: jcsaintp on December 18, 2013, 06:53:15 AM
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Have '84R65 with single disc, Brembo caliper. Current set-up functioning correctly with new fluid, ss line, good pads and rotor... properly bled.
Would like to increase stopping capability. Investigating finding components to add second caliper and rotor. OEM available but pricey! Any other suggestions?
Thanks,
Jeremy
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While you are at this, I would suggest replacing the rubber brakelines with braided stainless lines .
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Already has a SS line as noted in original post.
Suggest starting a search online for good used components. May not be easy or quick. Best chance would be to source a complete R65LS front end.
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If he installs the second disc, he'll need three lines, one from the master cylinder to the splitter, then two from the splitter to each of the calipers .
Sounds like he has one line now from the master cylinder to the left caliper .
Another possible way to go, is to get a longer banjo bolt for the left caliper, then get a line made up to go over the fender to the right caliper .
Probably would need 90 degree banjo fittings on the ends of the new line .
If you were not aware of this, you most likely will need to replace the master cylinder as well, the 13 mm master cylinder used in the single disc, seems to be a bit on the weak side for dual discs .
Probably need to get a 15 mm master cylinder .
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I can smell the burning credit card from here! ;D
You did mention "good pads". How did you make this determination? What brand are they? Have you checked them for remaining pad thickness against the Bremo caliper's specifications?
EBC brake pads are very popular replacements.
Properly set up, single disc R65 front brakes can actually skid the front tire as I well know.
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If you can get the bike to lock up the front tire there isn't any need for going beyond that... unless perhaps you are racing and need additional power to compensate for some fade caused by heat.
But if you wanna burn some cheese or time, you could try a couple things.
-find pads with the best friction rating you can, though keep in mind that some materials work better when hot and are really best for racing.
-if you put new pads on, do a thorough job cleaning your rotors, including in the drilled out holes. No point in contaminating new pads with old grunge.
-cast iron rotor (will rust but should provide more bite than the stock stainless steel).
The smaller the MC bore, the more mechanical advantage you have on the caliper pistons. The smaller bore will only become a problem if your brake lever is bottoming out on the handlebar, so it might be possible to go to a smaller bore for a single disc.
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It has been my experience that often you trade power for progression. I like progression. But I do like enough power to pull her up quickly, when necessary. Master cylinder sizes are matched for caliper/s for that very reason.
I am the very odd person that dropped his second disc for a single disc setup. Its lighter and cheaper, and although I have ultimately lost a bit of power, its fine for a road bike. And it has only improved with time.
But the point about pad material is a good one. Some improvement might be gained here. EBC make good pads as well. But it will be difficult to measure any improvement and there will be a 'bedding in' period to muddy the water - so it is something that will take time.
If you are running a standard disc, as mentioned above, there are plenty of after market discs that should offer an improvement. Again its down to materials used.
Has anyone considered mounting a bigger disc - in diameter? You will have to mount an adapter plate for the caliper - to move it out. But it should be achievable in theory.
Of course, if you have just jumped of some modern tackle, with a pair of 4/6 pot calipers on a discs the size of the whole wheel then you are going to be disappointed. And I mean forever!
Cheers
Rev. Light
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Has anyone considered mounting a bigger disc - in diameter?You will have to mount an adapter plate for the caliper - to move it out.But it should be achievable in theory.
I have seen it, and I think on this forum (could be mistaken).
But then, it also was using a fork (and probably wheel) from another bike.
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I replaced the OEM rotors on my '81 R65 6 years ago .
I now have EBC semi-floating steel rotors and EBC graphite pads .
Have I seen any noticeable improvement in braking, no .
The only improvement, is wet braking, which is greatly improved .
Which is a real benefit, seeing as I live in a desert !!!!! ;D ;D ;D
So, what I am trying to say, is that you can put a lot of money and effort into this, but the end result won't be much of an improvement over what you have now .
The one thing I do recommend, is replacing the OEM rubber lines with braided stainless aftermarket lines and aftermarket brake pads .
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Lots of good comments. Thank you!
Bought the bike from RePsycle BMW end March 2013. Pads reportidly new. Had a stainless line installed at that time. Have since put about 3,000 miles on the bike. Have been fortunate to find an excellent R and K bike mechanic locally who advised brakes working 'fine'. Had a wife who used to say she was 'fine'... but I digress.
I crashed about a month ago. In the process of repairing the bike, one of the folks I'm working with suggested I consider adding a second rotor given I'm 'party size' (i.e. weigh 225 pounds). Crash result of operator error, not insufficient brakes but situation could be different next time so looking into options.
Will keep on the prowl for needed components while working with local mechanic to make sure sure what I'm currently running in top form.
Component between my ears probably where greatest opportunity for improvemnt lay! David Hough's latest book, particularly section on aging riders (of which I'm one) has provided ample food for thought.
Thanks again,
Jeremy
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Jeremy, I've done business with RePsycle in the past and always found them to be good guys. Their statement that the disc pads were "fine" is their opinion as far as selling a motorcycle. The pads may even be OEMs, contaminated with brake fluid, or terribly glazed over. The term "caviet (sp?) emptor" comes to mind...
Try a pair of fresh EBC pads. Break them in as per the instructions and you'll be pleasently surprised. Plus, you'll save a ton of money. Keeping in mind that the duel disc setup adds a substantial amount of weight to the front end which will effect front suspension ande handling.
Last thought. Try tying back the front break lever and leaving it for a day or two. This is an old trick used to force up n' out remaining air bubbles.
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My rotor was warped beyond use a couple years ago. Had the rotor rebuilt by spiegler, top notch. Would highly recommend it if your rotor is out of spec.
Another thing that can be overlooked in the in the "stopping and going" department is tires. Different manufacturers or even tire lines have different compounds.. more sticky = stops better, but also more sticky = wears faster. Worn / old tires do not grip as well as new tires. (Ask me how I know!)
I'm of the opinion that the best investment for better stopping, as the OP mentioned, is some education and practice. (once the system is sorted, at any rate) Take the basic MSF class if you haven't already, or take it again, or see if you can get into the advanced course. Find some out of the way parking lot or road and practice controlled stops from different speed levels, in some different but common road conditions.
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"caviet (sp?) emptor"
Well finally my Latin background is useful! it's Caveat (and for more than you wanted, a 3rd person singular present active subjunctive)
Monte, does EBC make both sintered and organic pads? I briefly had a set of BraKing sintered metallic pads on my bike and they had more bite than the current EBC organics. The BraKings did not have the right backing plate, and I wasn't happy with the way grinding them down turned out, which is why I went to the EBCs.
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I rock the EBC organic disc pads on both my R65s. They play nicely with the OEM brake discs and offer outstanding braking performance... IMO.
Luca, I could have looked up the correct Latin spelling but right now I'm down on the Texas Coastal Bend, Port Aransas, enjoying a condo on the Gulf of Mexico, excellent fresh seafood, 75 plus degrees and sunny. Plus multiple cold cervesas.
Off to Austin, Texas, tomorrow to hook up with the grandkids.
Screwing with this PC I found in the condo. I miss my Mac.
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The bike is old, and it's braking performance will NEVER be on par with the current market. This is something to keep in mind while riding!
That said - the R65's had GREATLY improved brakes and front ends over the Type 247.
They do need regular maintenance, which I was never a fan of, apparently. As you would see in the picture below, of when I rebuilt my brake system.
In other words, you may want to consider opening your caliper and see what it looks like.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F75975722%2Fmedium.jpg&hash=59ee6bea3d8234792428b1ab11d8a7e386a78988)
http://www.pbase.com/tomfarr/r65_brakes
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Sorry Monte, didn't mean to nit-pick... I just get excited when I get to use a bit of Latin. Hope you're enjoying vacation... it's nice to get a brake once in a while
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Nit pickin' and puns. Oh, my... :D
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Sorry for coming in late to this one, but I've got a few things to say.
Sintered pads tend to wear the discs, so go with organics.
I know my opinion is counter to a lot of others who feel stainless brake lines are mandatory for good braking. The rubber lines swell a little, but not enough to make much of a difference in normal street riding. Some of my bikes have old rubber lines, others, stainless, and yes, the stainless feel a bit more solid, but they both stop fine for me.
BMW didn't get it right for a long time on matching master cylinders to discs. The 13mm master works very well with the dual discs. This isn't conjecture or speculation. Both my R65s have had 13s and I run 14s on my larger beemers that originally came with 17s. The smaller master makes for far superior braking.
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I still have rubber lines and have tested them by measuring the diameter at different points with a digital caliper while squeezing the brake lever far harder than I have ever done while braking. There was no measurable expansion, not even half a thou.
Rubber is only the outer covering. The actual brake line is a small bore nylon or some thing similar and probably little different to the internals of braided lines.
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There are no inner liners on OEM BMW brake lines, just the rubber and it's not even reinforced with fabric .
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Rubber is only the outer covering. The actual brake line is a small bore nylon or some thing similar and probably little different to the internals of braided lines.
When I did my rebuild I replaced mine for the stainless steel ones, there was a section of the old one (79er) which the outer rubber had split off revealing what looked like a fabric mesh as reinforcement. That said the Euro 79 version is a twin disc and probably a different spec to the US one
Lou
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There are no inner liners on OEM BMW brake lines, just the rubber and it's not even reinforced with fabric .
I confess I've never cut up a BMW OEM brake line but the ones I have were a multi layer construction with reinforcement. If the BMW ones are just solid rubber they must be very good quality not to expand. I just did another quick test to make sure I wasn't mistaken and again I measured no expansion. Perhaps there is some internal expansion of the line that doesn't show on the surface. That could only be if there was some reinforcement in the construction.
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BMW didn't get it right for a long time on matching master cylinders to discs. The 13mm master works very well with the dual discs. This isn't conjecture or speculation. Both my R65s have had 13s and I run 14s on my larger beemers that originally came with 17s. The smaller master makes for far superior braking.
Now I'm intrigued. My '82 LS has rather unimpressive but sufficient dual discs. I have ridden single disk R65s that seemed to have much better front braking. I never compared the master on these to my 15mm. Now that I have a bad master I'm wondering about swapping it for a 13. Does the pull distance on the handle increase a lot?
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The few members that have had 13 mm master cylinders, when they added the second disc, commented that the brake lever was almost up against the grip with the second disc added for whatever that's worth .
My concern with old OEM brake lines, is brake line failure .
My '81 R65 had a line fail in '91, the line from the master cylinder to the splitter behind the headlight, broke at the swaged fitting that threads into the splitter .
My '02 oilhead had a front brake line failure in April, line broke at a swaged fitting again .
I've replaced all of the brake lines on my 4 wheel vehicles with braided stainless lines in the last 6 years .
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I bet that the dry Arizona heat is helping those old brake hoses fail more quickly than if they were in a temperate climate.
I'm not exactly proud of it, but my LS is still sporting the factory brake hose from MC to splitter.
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Both my single-disc R65s have rubber brake hoses running from the MC to the OEM hard line junction. Both bike's hoses have semi-flexible, hard 'nylon' interior tubing. I know this as I had the lines made locally and viewed the hose material prior to the construction. The end fittings used are the same as used on many Mercedes-Benz autos and match the OEM metal bits.
I use speed bleeders and take plenty of time insuring the lines are totally free of air. I can still skid the front tire if I really try to do so; which I avoid doing.
My R100S has an OEM rubber hose from the handlebar to the under-tank MC. Stainless braided from the MC to the twin ATE calipers.
Good front braking on all three Airheads. Just not as powerful as the more modern triple disc set-up on the Triumph.
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I didn't mean factory brake hose as in BMW rubber, I meant it as in 31 year old BMW rubber :-[
For the curious, the hose ends that attach to the short steel brake lines Monte speaks of are metric ISO (bubble) flare fittings. Every now and then they will also creep up on some non-European vehicles.
Bubble flares are a single step flare that mushroom the end of the steel line. Can't recall the metric size, but when I made lines for the R65 and the old MB I used to own, 3/16" line worked just fine.
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I lived in Chicago until '93, the '81 R65 line failed 2 years before I got here .
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The brake lever with the 13mm mastercylinder doesn't have excessive travel - as a matter of fact I mostly leave two fingers on the throttle with one or two on the lever. There's plenty of room for my hand.
If the lever has more travel than that - something's wrong. My first guess would be air in the system.
Not sure how much difference it makes, but the bike does have stainless lines, and I believe the previous one did as well. My first such conversion was to a 76 R90 I added a second disc. Not knowing anything about different sizes of master cylinders, I had the 14mm (under tank style) drilled for a second line. That bike has rubber lines and doesn't have excessive lever travel either.
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Glad to read this, just ordered the EBC organics for my R65.
I rock the EBC organic disc pads on both my R65s. They play nicely with the OEM brake discs and offer outstanding braking performance... IMO.