Bonneville America Forums Forums Technical Forums General Tech Front Brake Rotor out of spec 6K

I just took my 07 America in for its 6000 mile check up. Had the bike 11 months. Felt a pulsation/lurching sensation in front when braking at slow speeds to a stop, or slow downhill stop. Tech told me it's out of spec .005 Lateral Runout and .020 Radial Runout and that he'd have to get the OK from some off-site tech guy to authorize repair or replacement as the bike is still under original warranty. I'm kinda befuddled-angry as it may not yet be a bonafide safety issue but it sure isn't "right" like it used to be. Anyone had this happen? If the upper-mgmnt guys do not OK repair I will be VERY unsatisfied - this bike has been absolutely perfect until now . . .

Please reply ASAP as the yet-unnamed management guy is considering the OK at this time.

I'm at 8200 ish and my third one is waiting to be fitted. Apparently Dayffdd fitted a floating rotor to his and that's warped too. (He thought it would cure the problem...)
I'm still waiting for someone to say it's how I ride the bike......the other one (my 03) never had this problem.
It's part of the reason I'm changing the front wheel and caliper next week. That and the warranty's nearly out....so the TBS wheel is finally going on.

Keep on at them till they do change it. It IS a safety issue. They should though. They just have to get the goahead from Triumph as they pay for it.

i had about 10-15k out of my americas stock rotor with hard riding and no problems. i put the ebc floater on anyways and am happy i did. braking is much improved and it looks better which is always a plus. i suggest just getting the floating rotor and be done with brake problems

Frank

Some times during break in of new pads and/or new rotors only gentle breaking is suggested. Reason is pads and rotors have not been seated w/ each other yet. If you agressively used the brakes during the break in period it can cause excessive heat build up and warp the rotor.

Good luck w/ that. Scott

I've never had the problem on my '03 America, but warped front rotors have been an issue for years now. They even changed the design of the rotor - they used to have a raised portion around the circumference, now they are flat/the same thickness across the entire surface.
If it's under warranty, they should replace it no questions asked. I would also ask them to check out the caliper and make sure neither of the pistons are sticking.

I posted the following info a long time ago but it bears repeating...

These brakes on our bikes are primitive - nothing exotic about them. Apply the brake - fluid under pressure goes down the hose - 2 pistons push the pad against the rotor.
When the bikes are crated and shipped, they are sprayed down with an anti-corrosion substance. Cosmolene comes to mind, but I doubt it's that... the dealers clean it off as part of the prep.
Anyway, when my bike was new, after some miles my front brake began to make some noises once in a while. A chirp or a grunt now and then. I pulled the front caliper off and found it was loaded with this sticky protective stuff and it had brake dust, road dirt, and even half of a stinging insect glommed in there. The stinging half, I might add. I took the pads out and douched everything out with Braklean and cleaned it up real good. Put it back together with a slight coating of grease on the moving parts and lived happily ever after. Found the same/did the same on the rear caliper as well. Since then, I do the same everytime I change pads, only now I use my dry lube chain lube on the slidey parts - it doesn't hold the dirt and brake dust like the grease does.

Just my experience. Your results may vary...

I knew that....

seems to me that the warped rotors are a symptom of a warped hub face. Has anyone had their actual hub surface examined for flatness? The part the rotor bolts to?

I am already ducking for cover on this one.

That could be a possibility. But if the mounting surface wasn't true, you should feel something from day one, I would think. There isn't a lot of clearance involved. For that matter, it could be the caliper mounting bosses or the caliper itself. Even a slightly twisted fork.. But again, I'd think you would notice it from day uno.
Heat warps rotors. Scissors cut paper. Rock breaks scissors. Smegma in the caliper sticks pistons...
I was hinting more towards a stuck piston in the caliper combined with the high-quality Chinese rotor material.

"you should feel something from day one, I would think." Agreed. to a point.

would the rotor instantly warp when mated to an off plane hub? Being as it bolts towards the center, perhaps the outer edges stay rigid/in plane until the rotor adjusts as it undergoes heat cycles repeatedly over time. Thus not upon installation but only with the passage of time will the minuscule hub imperfections warp the rotor. Deflection increase with distance, distance from the center which may not be too far out to start with. Just guessing is all. as this has not been brought up, and a hub's mating surface has not been examined for flatness and a cause for the rash of warped rotors has yet to be sorted out.

Point taken.

You would think Triumph would have this one sorted by now.