Locked up rear tire TWICE in last two weeks...

[mjensen2k]

The first one, I was already slowing, down shifting, etc. and the car in front of me was braking a bit harder than I expected. Before I recognized what had happened, the backend started to slide out, I recovered it, the car was cleared and I went right ahead. All this was at like <25mph.

I wholly admit to not giving enough room and/or under estimating the stopping of the car ahead of me or gapping out or whatever. But I was shocked that the backend locked and started to slide. I also was shocked how easily the Beast stayed steady and I easily just rode away.

Now, last night, I'm riding about 40mph and the light turns yellow right in that 'should I go or should I stop' zone. So I stop. I think I'm just braking/downshifting a bit more than usual and again my back brake locks up the back wheel and it starts to slide on me. I recognize it and let off on it before my conscious self even knows what happened...

But I wonder. The brakes were all just redone when I bought the bike a couple months ago. Could they be over sensitive in the rear?

Or, to take the responsibility on myself, I've been using the rear brake more as I've been doing more mountain road riding and if I stick with engine and rear braking, I (think) the bike behaves better in the switch backs and parking lots... When I use the front brake, then the handling goes away, etc.

Am I relying on the rear brakes too much and causing myself these lockups/slides?

Should the brakes be setup such that I can even accidentally lock them up without a real panic moment?

Thoughts?

By no means am I trying to shed blame on my own mistakes. I'm just trying to understand so I don't make ones that actually cost me something important.

Thankfully, so far, just two quick rear end slides and no issues.

 

[Evil Mitch]

I locked my rear wheel a couple of times when i first purchased the beast but i was just grabbing a little too much rear and not enough front but im in touch with the big girl now.
when im riding in the twisties i use probably more engine than brakes but i use my rear through the corners also . Ive found the torque of the rocket slowes her up quick but i always just tap the rear so the bikes behind me know im slowing down other wise they end up almost running up me butt when the big girl slows with no warning. But definatly in traffic if i need to stop in a hurry its mostly front and just a little rear after all 70% of our stopping power is at the front.
regards Mitch

 

[TriumPhil]

These bikes, which are so unique amongst the galaxy of available motorcycles, have a huge, high quality, strong (taken as a whole, excessive) Brembo rear brake setup, so those riders who have developed the bad habit of using more rear brake than they really should, will get bitten on the ass for the error of their ways on this particular machine. Your front to rear braking effort ratio should be about 70/30. To overcome or bypass any problems in this regard, you simply need to become familiar with this motorcycle's performance envelope and practice, practice, practice until proper and safe handling of the beast becomes second nature. Oh, and the inline three cylinder mill is really not very amenable to nor will it deliver much useful gear braking as is the case with most V-twins.

Undoubtedly, you will hear from folks that advocate using a car tire on the rear in order to eliminate what generally is referred to as the "skittish" quality of the stock Metzeler rear tire and/or the "over aggressiveness" of the OEM brake setup on our Rockets. I'll simply say that, IMO and based on my experience, there is absolutely nothing wrong with either the tire or the brakes on The triumph Rocket III. The problems that folks have in these regards are nearly always user/driver error. Substituting a car tire for the motorcycle tire simply swaps out one set of benefits and disadvantages for another. I rode on the Darkside for 7,000 miles on this bike and returned to the motorcycle tire predominantly for safety reasons, but there is a discernable difference in handing and the amount of effort required to move the bike around. My opinion on the square tire thing is that it ain't for me on the Rocket, although I had a very good experience with them on other bikes I have had. Bottom line it is a matter of choice very much like what type of helmet you choose to use, if you must use one at all.

 

[TOMCAT]

Same here, locked the rear up a couple of times when i was new to the Rocket. Mitch right just a matter of getting used to it. I use front brakes and just bad at the back in the twisty stuff ( Which i'm enjoying the **** outa after five years up in Darwin)

 

[JAGROCKET]

I have worked with the Triumph demo team here in the northeast and been riding Rockets since introduction. If it is a matter of becoming accustomed to the bike both Evil Mitch and TriumphPhil are right on. A suggestion would be that when in situations where braking is more likely keep your right middle finger extended in the ready position for the front brake, your right foot on the peg away from the rear brake and keep your rpm up between 3000 to 3500. Be aware that when downshifting to first from high rpm a fast clutch release can slip the rear tire. With that said four years ago I had the rear wheel chirp on me several times just before I blew the rear drive. It happened to be on a 2006 Rocket at the time. Pucker factor 10!

 

[atomsplitter]

Here's the physics behind your problem. Your bike's weight bias shifts under braking. It doesn't matter which brake you use, the shift occurs. Stomping down on the rear alone the front end dives under the weight shift forward. This shift reduces the coefficient of traction (multiplier of friction force) on the rear tire, but INCREASES it on the front. The stopping power up front is 85% of the total available with the brakes (hence the double disks in front). As this coeffiecent reduces the bike's tendency to stop the rear wheel rotation increases. If the front brake is being applied at all the bike will go sideways when the lockup occurss because friction is much less on the rear than the front, so the back tries to 'pass' the front because it's going faster (momentum is maintained).

The 'cure' is pretty simple. Use the rear brake as a speed trim only. If you are going to stop, use the front brakes as your primary and the rear applied only near the point of stopping.

If you are towing a trailer with your bike, under NO circumstances use the rear brake to slow, or stop. Just remove the pedal it will get you into a heap of trouble faster than you can crap your khakis. (I have some knowledge of what can go wrong).

 

[TOMCAT]

Ok brainiacs .. can anyone work out what the headers ( 2 posts down) cost?? I promise if there is such a thing as reincarnation i will pay attention in math classes next time around... maybe ... as long as theres no pretty girls !!

 

[tdragger]

You have discovered the safety hazard made up of the Metzler-Rocket Rear Brake combination. Many of us mere mortals have also discovered it. Several not as fortunate as you to recover. G-man (RIP), T Frazier and others have had serious offs due to the bike sliding out and/or the resulting highside launch that follows. You're very fortunate.

 

[Ugarte]

I have always considered the rear brake as the assistant brake, existing only to lend a little bit of help to the front brakes. Have never had a problem locking the Rocket rear. I have, however, locked up the front tire, in rain on the paint, and that was plenty scary and I was very lucky I didn't go down. Good judgment for the riding conditions is paramount, and there are exceptions to every rule.

 

[Binnsy]

Roadster .... ABS

still can chirp the rear if I try really hard.