UUC BBK Defect? .

[firemanory]

Hey Guys. Just looking for some validation about an issue I am pretty sure I have pinpointed as the rotor hub center diameter being too large, as well as the lug holes in the rotor hat being drilled off of center from where the lugs should line up. This causes the thread of the bolt to be against the hat instead of being center to it. I made a short video showing the out of roundness that all of this has created. My question is this; do you think this can create a Significant shake at various speeds?

https://www.youtube.com/watch?v=QIPH3CZs4CE&feature=youtube_gdata_player

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[SkiFree]

Well what did UUC say when you emailed them? (I'm sure you did this prior to bringing it to our attention)

First if all, is the vibration only under braking?

Have you had the run out on the rotors tested? Looks to me that's potentially your issue. Anything over .006" or so will give you the vibration under braking. If it's not much, it shouldn't be a problem for a brake shop to resurface them properly.

[firemanory]

The main issue is that the rotor assembly sits slightly off center, creating a hop so to speak in it's rotation. Rob said to have it tested for runout, but that is a non-issue because the rotor doesnt sit right on the hub, which creates the hop and can't be machined out.

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[firemanory]

Sorry, forgot to say that yes there is some vibration under braking, but it is not very bad compared to when at higher speeds...

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[SkiFree]

I see, what I'm saying is that your hypothesis is extremely unlikely (but certainly within the realm of possibility). If you still have your stock brakes around, I'd swap them out to confirm your hunch the vibration is due to the brakes in the first place.

And a word to the wise. When dealing with an issue like this avoid phrases like "too large" and start taking down measurements (and even better if you had a stock rotor to compare them to).

[firemanory]

Ok, further disclosure. I'm at work and kinda zonked so my aplogogies for the lack of data. I have full caliper measurements at home of the differences between the stock rotors and the BBK rotors, and the difference is 66.34mm in diameter whereas the OEM rotor opening is 65.91mm. Rob measured a new batch of rotor hats and the hub measures 65.94mm. I dont have measurements for my spacing of the lug openings, but I will find a picture that should make it very clear the issues of hole alignment.

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[firemanory]

Ok, further disclosure. I'm at work and kinda zonked so my aplogogies for the lack of data. I have full caliper measurements at home of the differences between the stock rotors and the BBK rotors, and the difference is 66.34mm in diameter whereas the OEM rotor opening is 65.91mm. Rob measured a new batch of rotor hats and the hub opening measures 65.94mm. I dont have measurements for my spacing of the lug openings, but I will find a picture that should make it very clear the issues of hole alignment.

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[firemanory]

Anyone else have input?

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[GThomas]

Anyone else have input?

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Are the bolts all torqued correctly on the rotor?

[firemanory]

Yes they are, I double checked both left and right corners.

[markseven]

Well what did UUC say when you emailed them? (I'm sure you did this prior to bringing it to our attention)

Not sure why this is relevant. One could wait indefinitely for a vendor to reply.

[SkiFree]

Not sure why this is relevant. One could wait indefinitely for a vendor to reply.

Really? I thought that it would be common sense to go back to the guys you bought the kit from to see if they can help. Nowhere in his original post did he say if he even bothered touching base with them. The manufacturer tends to know their parts better than the peanut gallery of a message board. They are the most likely to be able to help fix the issue (either with the customers improper installation or with replacement/refund a defective product).

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firemanory - the difference in the hub diameter is irrelevant if were only talking .4-.5mm. The brake rotor cannot be truly hub-centric, as the manufacturing tolerance of the chamfer around the hub makes it impossible (unless you manufacture them as a matched set which is obviously not reasonable).

You will find a surprising amount of rotors out of round (I've seen brembo, zimmerman, meyle, and OEM) but not due to bolt pattern offset. These were simply balanced with cuts/grooves done in a similar fashion to balancing a crankshaft.

I'm guessing that it would not be unreasonable to ask for a new set of hats to try out, only after you swapped out the brakes back to stock verifying the problem was isolated to the brakes (and not a wheel weight coming off as you removed your wheels in eager anticipation of putting on your new brakes).

[markseven]

Really? I thought that it would be common sense to go back to the guys you bought the kit from to see if they can help. Nowhere in his original post did he say if he even bothered touching base with them. The manufacturer tends to know their parts better than the peanut gallery of a message board. They are the most likely to be able to help fix the issue (either with the customers improper installation or with replacement/refund a defective product).

Yeah, that is common sense. I didn't say he shouldn't.

Maybe I misunderstood your post.

[firemanory]

Really? I thought that it would be common sense to go back to the guys you bought the kit from to see if they can help. Nowhere in his original post did he say if he even bothered touching base with them. The manufacturer tends to know their parts better than the peanut gallery of a message board. They are the most likely to be able to help fix the issue (either with the customers improper installation or with replacement/refund a defective product).

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firemanory - the difference in the hub diameter is irrelevant if were only talking .4-.5mm. The brake rotor cannot be truly hub-centric, as the manufacturing tolerance of the chamfer around the hub makes it impossible (unless you manufacture them as a matched set which is obviously not reasonable).

You will find a surprising amount of rotors out of round (I've seen brembo, zimmerman, meyle, and OEM) but not due to bolt pattern offset. These were simply balanced with cuts/grooves done in a similar fashion to balancing a crankshaft.

I'm guessing that it would not be unreasonable to ask for a new set of hats to try out, only after you swapped out the brakes back to stock verifying the problem was isolated to the brakes (and not a wheel weight coming off as you removed your wheels in eager anticipation of putting on your new brakes).

I need to get this other pic up as it will show what I am talking about in terms of the bolt drilling spacing. It is to the point where one of the lugs has to be pressed rather firmly against the hat to start the threads into the hub assy. When I take the bolt out, you can see that the threads have started to cut into the hat and make a slightly threaded section on the inside of the rotor hat. In my humble opinion, this causes the rotor to not have any flexibility in movement and cannot center itself properly. I agree that the hub center diameter is not the issue here, but the drilling locations for the lug bolts. I will find or take another picture of what I am talking about and post up for review.

[matthugie]

FWIW I haven't had any trouble with my rotors with the UUC kit. I'm interesting in seeing the pics of your issues though.