Are you out on yours tonight, fancy checking how hot the rear caliper gets??

Pottsie

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Hi

I placed a post at the weekend hoping to get info to sort out the problem I appear to have with the rear brake, it seems to get extremely hot. The advice offered was great but everything checks out. The planned holiday (hotel last night, ferry this morning and hotels for the next 10 days in France through to Italy all now cancelled and no money back) and so I have dropped the bike into local dealer who supplied it.

Anyway they have run it on a test ride and the caliper gets to 54 degrees (you can't keep your hand on the caliper, you can't touch the disc) and on the same route they have then put a matching caliper on my bike and run it on the same test route and when measured it also runs at 54 degrees on the caliper.

At this point the wheel spins freely but if you push the floating caliper in you can increase this to no resistance at all.

So, is there anyone out there who is on a bit of a ride tonight on a GS or GSA 1200 air, (mines 2012) who can just put there hand on or near the rear caliper (without getting burned!) to tell me if theirs also runs hot (ie. you couldn't place your hand on the caliper and leave it there).

The front calipers at the same point are cold.

Also, can anyone confirm if they are linked brakes, the back wheel on the stand seems to stop when you operate front brake but apparently it doesn't happen on the rolling road.

It may be its expected to get that hot, I just can't understand why the front ones don't and in fact I can remember it being like that before.

Cheers
 
Last year I convinced myself that rear brake was binding, as it was running hot ( 1200 GSLC) I experimented by only using the front brake, rear still hot.
I even took it into a BMW dealer in Germany who confirmed brakes were fine. Interestingly they recommended changing rear pads every 2500KMS !

Concluded “they all do that”,

Brakes are linked ( on the LC at least ) operating the hand (front) brake also operates the rear
 
I saw your last post so I did a bit of feeling round my brakes (2010 model GS). After 18 miles of country lanes, single-carriageway A-roads and the last 2 miles in 30 mph limits my front callipers were barely luke-warm on a hot day with a reported air temperature of 30 degrees. The rear calliper was hot but not so hot I couldn't put my hand on it. I didn't try feeling the disc.
The are linked if you have ABS. Using the foot pedal applies the rear brake. Using the hand lever applies the rear brake then adds in as much front as is needed. It's why they tend to eat rear pads and barely wear the fronts.
 
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I have been out on my 2011 TC today and completed around 150 (spirited) miles. I replaced my pads all round last weekend so have been reading your post with great interest.
When I got back today I checked my front discs and they were warm. I was able to touch and hold them with no real problem.
The rear however was hotter. I was able to tap it with my fingers but could not hold at all. Wheel spinning freely and piston nice and free as normal.
I do believe it was hotter than the fronts but not as hot as what you have described earlier. Not hot enough for me to be in the slightest concerned.
I hope this helps.
 
Brakes linked front to rear, so applying front also applies some rear. Opposite is not true
 
As per my post on other thread, if you ride the bike without touching brakes and rear is hot, then you likely have warping or binding caliper.

If you ride without using brakes and rear cold, then it is likely foot dragging on pedal (others have recently posted about doing this from what I recall) or just your use of brakes and it's normal.

Fwiw i have a laser thermometer and it's not hugely accurate. (also fwiw 54C isn't that hot. Brake fluid boiling point >200C generally. See here: http://www.ate-brakes.com/media/3339/ate_td007_dot4-sl6.pdf)
 
Just came home from work tonight,

7 miles mixed traffic

Fronts disc& caliper cold to the touch

rear caliper warm, and could hold it, disc cold

i dont have linked brakes btw
 
11 mile ride to work this morning.
Rear brake pedal un touched. Linked brakes.
Brake disc a littlewarm.
Rear caliper cold to the touch.
I fitted brake pads just a few weeks ago all round.
 
Thanks for all of this. The result so far is that after some tooing and froing the dealer has changed the caliper to one from a newer bike. I did a 20 mile run yesterday and found rear disc very warm and caliper a little warm (technical terms!) compared to how it was when the rear disc after 20 miles created steam off a damp cloth and you couldn't touch the caliper either. I will do a longer test this morning, unfortunately holiday was cancelled with little being refunded so if the bike is right we are looking maybe just to cross the channel for a few days to say we've been away.

Thanks for taking the time to check.

The measured 54 degrees sounds fine to me, its just that to the touch it burned your fingers so I had little faith in their measuring tool!
 
my rear brake runs at melting point always did... (I only use the rear if really pressing on round town, on the open road I never bother wasting my time touching the rear brake.... the wheel is usually in the air)

with the bike cold, put on the centre stand and see if the rear wheel spins freely, now stand on the rear brake, and re check if the wheel spins freely, if it does its just the linked bakes and your enthusiastic riding

they only do sporty compound on the fronts.... seems very dim of Brembo considering my rear runs more than twice as hot as the fronts

The front discs run pretty cool but the last useless EBC pads melted all over the discs. The Brembo SC ones I put on the front recently seem to have cleaned up that mess nicely and do stop it a bit better (they had some weird bedding in compound that worked a treat), the rear Brembo SP ones are taking a while to bed in as the rear disc is way more worn than the fronts.

Not that surprising the disc is too small and there's only one of them and it does a hell of a lot of work. When getting the MOT I'm always shocked at the weight distribution you can see when they do the brake test. From memory its something like 85kg front and 255kg rear
 
Another useful bit of info Botus. I've just come in from 50 miles, the first 25 on the motorway, minimal braking and 80 plus all the way. Stopped just of the deceleration and back caliper cold and even the disc was comfortably touchable. Rode back on A roads with a bit of town work and in the last half a mile a couple or three real hard brakes (rear only and to the point of abs kicking in) and then felt disc and caliper. Disc was touchable without burned skin and the caliper hot but hand could be just about held on. I guess that's correct all round then compared to how it was before they replaced the caliper which was untouchable all round and steam if made wet.

In all my years riding I've never touched a caliper or even disc after braking (as far as I can remember) so may be a lot of them are the same.

Anyway thanks - my superior half now looking for somewhere for a few days in France as we lost the places we had booked in Italy. Onward . . . . !
 
I remembered another bit....

with the rear running at melting point all the time and wearing out the disc, it made me think running non sintered pads on the rear caliper would be a good idea and hopefully redistribute some of the work to the front. So a couple of years back I gave it a go. Its not a good idea, it was a disaster, for first time in many years I had wet weather issues with no brakes and even in the dry the feel at the front dropped and the braking power went down 35%
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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