Are rear brakes on the RT purposely weak?

General discussion of the BMW R1200RT/R1250RT
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jackronner
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Are rear brakes on the RT purposely weak?

Post by jackronner »

I'm on my second RT, and both have rear brakes that seem very ineffective, at least when you use the foot pedal only.  Both seem identical in their lack of function so I assumed it was designed that way;  nothing obvious was wrong with the brakes/pads/rotors.  Tho'it's capable of keeping the bike still on a steep hill,  pretty hard to get much effect even when stomping on the pedal.  I'm thinkning that it's a function of the ABS and the dual brake function of the front brake lever.  Personally, before ABS I left my brake pedal loose, since the rear end would tend to skid to the side in panic stops, etc.  You guys find the same story on your bikes?

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Re: Are rear brakes on the RT purposely weak?

Post by Nick Evans »

If I press hard on the back brake only I can get the ABS to kick in, meaning I have lost adhesion, meaning the tyre is doing all it can and the braking effort has exceeded the friction between the tyre and the road. The only way to increase effectiveness is to either increase the value of µ (by using stickier tyres) or by increasing R, by applying more weight to the back wheel (Friction, F=µR)
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David.
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Re: Are rear brakes on the RT purposely weak?

Post by David. »

In the UK, a rolling road MOT test will confirm whether or not the rear brake is effective enough.

Are MOT's or similar required in the US.
jackronner
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Re: Are rear brakes on the RT purposely weak?

Post by jackronner »

David,  50 states means 50 laws.  In New York, inspections stickers were mandatory (don't remember if they were yearly).  The only thing in California is emissions verification on purchase of a car.  Stupid.  But it's the only state where you can filter (they actually went from perennially ignoring it - there was no law against it - to actually codifying it's legality!  I'm never leaving.
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Re: Are rear brakes on the RT purposely weak?

Post by simbo »

Have you tried different brake pads? I use EBC HH sintered pads and find they're better than the oem ones.
The GS 'is' the better bike :-)
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David.
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Re: Are rear brakes on the RT purposely weak?

Post by David. »

Having looked at this video, perhaps, "rear brakes are purposely weak", https://www.youtube.com/watch?v=C27Hp3GpVTM
Little-Brit
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Re: Are rear brakes on the RT purposely weak?

Post by Little-Brit »

An interesting little video there David.


Of course all recent RT's (since they dropped the powered brakes on the early 1200s I believe) have a neat, intelligent semi-linked brakes.  Using the front brake applies the rear brake too but the rear only applies the rear. 


Normal braking, with just the front brake lever used, applies both brakes up to the point where traction at the back gets close to the ABS limit at which point all of the braking effort goes up front.  Perfect, maximum braking effort at both ends all of the time.   


I only use the rear brake now to improve manoeuvrability during low speed manoeuvres, although old habits kick in in emergency situations and everything gets jumped on, but all that does is bring the rear ABS in to play instantly.


Having ridden with a pillion for more years than I care to admit I have always valued a good rear brake because the extra "load" at the back keeps the rear wheel well pinned to the ground allowing much more effective braking from that quarter.  There is nothing that gives me cause for concern regarding the effectiveness of the rear brake on my 1250RT!
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Re: Are rear brakes on the RT purposely weak?

Post by Casbar »

Haven't noticed any indications of the rear brakes on my 1250 or the 1200 before it being poor. I don't actually use the rear all that much, just for slow riding. In my Harley days, the rear was a much needed accessory though :)
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