rear brake power (non-ABS)

RRDallas · Post by **RRDallas** » Sun Aug 12, 2007 6:40 pm

Greetings: I am a new member, and I just purchased my first R1150R -- a 2003 non-ABS model. I have had it less than a week, and I am still getting used to everything. It is a very big change (and step up) from my 1972 Yamaha 650 XS2.

I am very impressed after just a few quick trips.

I always use both brakes to slow or stop but I noticed that the rear brakes don't do a whole lot on their own, even when I push down firmly with my foot. They slow the bike somewhat gradually but I feel like they are lacking. Is this an indication that I need new brake pads or brake fluid? I understand that the rear brakes typically only supply about 30% of the braking power but these brakes feel especially weak.

The bike is due for an 18,000-mile service so I was planning to have this checked out. But I have really enjoyed listening to the input and analysis of members on this site. So I thought I would ask.

Many thanks in advance for your guidance.

Post by **DJ Downunder** » Sun Aug 12, 2007 8:01 pm

G'day and welcome...Congrats on the bike..

Personally I don't expect much from a rear brake anyway..and rarely even use it.

But on my bike (it's an 02 non abs) I found it all too easy to lock and skid the rear wheel because the rear brake works so good.

I would have then check it out during your next service.

DJ

Post by **Lobo1625** » Sun Aug 12, 2007 8:52 pm

That is a bit of a shock, since I use my rear brake more than the fronts. Mine seems to work very well, but in a pinch the front will most certainly drag the bike to a stop. My bike doesn't have ABS either. You may want to make sure that you have good movement when you hit the brakes, and that the system has new fluid and no trapped air bubbles.

Oilhead · Post by **Oilhead** » Sun Aug 12, 2007 8:55 pm

DJ Downunder wrote:
But on my bike (it's an 02 non abs) I found it all too easy to lock and skid the rear wheel because the rear brake works so good.

DJ

Same here. I have never had a bike where the rear locks up so easily. I use the rear to slow down but as far as quick stops are concerned, not only is it useless, it's dangerous. I only use the front if I have to stop very quickly.

RRDallas · Post by **RRDallas** » Sun Aug 12, 2007 10:12 pm

Thanks for the quick responses everyone. I will bring it up at the next service and see if there is something unusual going on.

Arbee · Post by **Arbee** » Mon Aug 13, 2007 6:41 am

Most of your dynamic braking should be undertaken with the front brakes
because the weight shifts forward making the rear brake less effective locking up & skidding easier.

Rear brakes should be used mainly under 60kmh, wet roads, dirt roads
or tricky situations like fuel stations.

If you compare the diameter of the rear brake disc & the diameter of the
twin front brake disc the front brake, must have more omnipotence
(argument based on physics alone)

If you want real rear brake action try using the heel of your boot &
compare the difference, it may be just too much travel has entered the
equation and may require an adjustment only

Ves · Post by **Ves** » Mon Aug 13, 2007 7:23 am

DJ Downunder wrote:G'day and welcome...Congrats on the bike..

Personally I don't expect much from a rear brake anyway..and rarely even use it.

But on my bike (it's an 02 non abs) I found it all too easy to lock and skid the rear wheel because the rear brake works so good.

I would have then check it out during your next service.

DJ

I'm with DJ on this one. Hardly use the rear brake on any bike I've owned. If you're counting on the rear brake to stop you in an emergency situations, you're going to be in a world of hurt. Learn to use the front one to it's max potential.

That being said. The BMW front end doesn't dive like other bikes. So, you can get a little more out of the rear brake than you typically can on a bike with normal telescopic forks that dive.

Also, cruisers tend to carry more of their weight over the rear tire, so in that case a lot of you stopping power is in the rear.

Anyway. Adjust and bleed.

Badger · Post by **Badger** » Tue Aug 14, 2007 4:20 pm

I have a 2004 r1150r with abs....the brakes are linked front to back, but not back to front......the front brake on my bike is very grabby at low speeds and makes it easy to drop the machine, a negative feature of the power assist....

I believe non-abs bikes also have the front to back link.....so when you hit the front brake you are also hitting the back....

I use back only in parking lots, on steep slow hills......places where the front is just too damn grabby....otherwise I always hit the front and forget the back.

Post by **DJ Downunder** » Tue Aug 14, 2007 6:20 pm

I believe non-abs bikes also have the front to back link.....so when you hit the front brake you are also hitting the back....

I may be wrong but I don't think so....Mine is non-abs and there's no link between the front and rear.

DJ

Post by **OU812** » Tue Aug 14, 2007 6:39 pm

DJ Downunder wrote:
I believe non-abs bikes also have the front to back link.....so when you hit the front brake you are also hitting the back....
I may be wrong but I don't think so....Mine is non-abs and there's no link between the front and rear.

DJ

No link. That is for sure. And yes, my rear will lock-up very easily!

telliott · Post by **telliott** » Tue Aug 14, 2007 9:58 pm

Lobo1625 wrote:That is a bit of a shock, since I use my rear brake more than the fronts. Mine seems to work very well, but in a pinch the front will most certainly drag the bike to a stop.

I hope you were kidding

or said "rear" instead of "front". 80% + of braking is up front! You will never make an emergency stop with the rear only!

Good advice on checking the rear brake. There's got to be something wrong. I've never had a bike lock up the rear so easily!

Post by **Lobo1625** » Tue Aug 14, 2007 10:04 pm

No joke, I do use the rear most of the time, but that's not saying i'm not ready to use the fronts. The compression braking of the bike, helps alot as well. It seems to me that the brakes on this bike work exceptionally well. I've only locked the back up once, and that was under a panic stop (yeah I was using the fronts too).

Post by **OU812** » Tue Aug 14, 2007 10:14 pm

Lobo1625 wrote:No joke, I do use the rear most of the time, but that's not saying i'm not ready to use the fronts. The compression braking of the bike, helps alot as well. It seems to me that the brakes on this bike work exceptionally well. I've only locked the back up once, and that was under a panic stop (yeah I was using the fronts too).

I locked up the rear in a panic, with the front on as hard I felt I could safely. Deer jumped out in front of me. I smelled burnt rubber.

riceburner · Post by **riceburner** » Wed Aug 15, 2007 4:42 am

Pretty much what DJ said.

I'm in the situation where, due to an accident, I have a weak right knee, and on my previous bike (ZXR400) if I had the ball of my right foot on the peg I couldn't actually reach the rear brake pedal very quickly, (the knee wasn't strong enough to move the foot forwards). Therefore I very quickly developed my front braking skills to 100% useage and have been very happy with that.

Now that my leg is stronger I do use the back brake a bit - and on my Rockster it's more than strong enough (using OE pads) to slide the rear in the dry.

Mind you, the fronts are plenty strong enough to lift the back of the bike up off the ground so in an emergency I still don't need the rear!

(if anything you want the rear to keep spinning if it comes off the ground to keep a bit of balance in the bike)

Post by **OU812** » Wed Aug 15, 2007 6:24 am

I must agree with all on the issue of 80 percent of braking comes from the front, 20 rear.

You can use it anyway you like!

Ves · Post by **Ves** » Wed Aug 15, 2007 6:50 am

riceburner wrote:Pretty much what DJ said.

...
Mind you, the fronts are plenty strong enough to lift the back of the bike up off the ground so in an emergency I still don't need the rear!

(if anything you want the rear to keep spinning if it comes off the ground to keep a bit of balance in the bike)

Good points.

I will say that whether or not you can lift the rear wheel off the ground or not depends on how good your tires are (rubber is not as sticky when it gets older and sport tires have more grip than touring).

The only way you'll know for sure is braking drills. Keep braking harder and harder until you either lock the front or lift the rear off the ground. Just realize that locking the front can be an "exciting" experience.

Post by **Boxer** » Wed Aug 15, 2007 6:53 am

The rear just FEELS weak. They are adequate and feel so much weaker because the front ones by comparison are so effective. If you don't believe it, just hit the rear brakes in a little sand and see what happens.

Remember, the brakes stop the wheel...NOT the bike.

Post by **towerworker** » Wed Aug 15, 2007 7:11 am

With any vehicle (2 or 4 wheels) the rear brake does little compared to the front. As soon as you hit any brake front or rear much of your weight is shifted forward and off of the rear tire. No weight on the rear tire = little braking action.

Mine is an 03 (non-abs) with 37000 miles--I replaced my brakes (F&R) at 16000. Replaced rear again at 32000

Wayne

riceburner · Post by **riceburner** » Wed Aug 15, 2007 7:12 am

Ves wrote:
riceburner wrote:Pretty much what DJ said.

...
Mind you, the fronts are plenty strong enough to lift the back of the bike up off the ground so in an emergency I still don't need the rear!

(if anything you want the rear to keep spinning if it comes off the ground to keep a bit of balance in the bike)
Good points.

I will say that whether or not you can lift the rear wheel off the ground or not depends on how good your tires are (rubber is not as sticky when it gets older and sport tires have more grip than touring).

The only way you'll know for sure is braking drills. Keep braking harder and harder until you either lock the front or lift the rear off the ground. Just realize that locking the front can be an "exciting" experience.

I use Pirelli Diablo Stradas. They're grippy enough to lift the rear with a controlled use of the front. (it should be pointed out that just "grabbing" the front is mroe likely to lock it up than a controlled application).

RRDallas · Post by **RRDallas** » Sat Aug 18, 2007 10:01 am

I think I might have discovered the root of the problem in the Oilhead Maintenance Manual. I think the brake lines need bleeding (which should be done once a year anyway):

"If you feel air in the brake lines (spongy brakes), you MUST bleed the brakes until all of the air is expelled!!! If air is allowed to remain in the line, it will compress when the brakes are actuated and will not give you firm and steady pressure on the pistons and pads. This will result in uneven and dangerous braking. Soft or spongy brakes feel as though they are not working because they are not working. The best procedure is to work so that no air enters the system. If it does get into the system, you must expel all air from the system."