NofakeJake

Look at the weight on the rotor of that ZR1...



NO WAIT! Scroll down.........





It's a Ferrari 458 Italia rotor, with TWO WEIGHTS

So all you guys that have been whining about paying GM $100K for wheel shimmy, don't feel so bad!

Looks like Ferrari charges $300K for their wheel shimmy ! My guess is Ferrari owners aren't telling the world about it either



This rotor was sans weights





Sorry about the misleading title, but I thought no one would look at another wheel shimmy thread without trickery.

I caught this 458 on a dyno and wanted to share that Corvette and Aston Martin owners might not be the only cars with these rotor issues. Why else would they now have these on Ferrari rotors?

3LZZ06

Very interesting and enlightening find, thanks for sharing...

Gary '09 C6

so, does that suggest that the same supplier has Q/C issues with their manufacturing process ? all made by Brembo, correct ?

NofakeJake

All I know is I love my car. The Corvette ZR1 is the best super car, pound for pound, dollar for dollar.

If people want to drop GM over this rotor issue, let them. They can go buy a Ferrari

NofakeJake

That's the way I read it.

Gary '09 C6

all true, IMO...

3LZZ06

^^^

I imagine brembo was tired of throwing away rotors when all that's needed is balancing. Pretty good thinking by their engineers for a very simple fix.

Gary '09 C6

I saw a an episode of "How It's Made" once about carbon-ceramic brake discs. Doesn't look like a simple process at all.
Not surprising that irregular manufacturing defects show-up. If the proper-placed weights truly solve the problem,
then I suppose that should be a very acceptable solution.

NofakeJake

Looks like the weights on the Ferrari rotors are ceramic (white).

The weights on the new ZR1's look like they are metal nuts....

It's all about value proposition. OK by me...

whatcop?

Uhm I noticed my 2011 has a weight on the drivers front.

ufaj26

I would have no problem with this type of fix. But it would be better if GM did it at the plant before the cars ever hit the highway.

mirage2991

does yours shimmy at all?

that also means nothing, if they are using two weights this mean their balancing tolerance is much tighter theirs may not ever shimmy...and why in the world would GM not do that from the get go? what year is this 458?

narush

GOLD72

The manufacturing process inherently leads to a certain amount of non-homogenity which can't simply be machined out like a ferrous metal rotor. Still no excuse for brembo to ship out of balance rotors to GM that could have been balanced with weight attachment.

mirage2991

google search ferrari 458 rotors....I can find many with those weights, no hits on shimmy or vibration...so I'd say it's safe to say it's not an issue on those cars...which leads me to believe perhaps our issue is not related...but then what could it be?

jvp

I sorta wonder how much of this out-of-balance is due to the actual carbon ceramic disk versus the aluminum hub?

Two-piece steel rotors can get out-of-balance as soon as the Al hub is bolted on. To balance those rotors, they'll sometimes shave whole chunks of the steel off (look at the edge of the disk and note that some sections are almost flat vs round: that's balancing).

So back to my original question: I wonder if this could be remedied by somehow balancing the rotor, once it's assembled, by carefully lathing some of the Al off. Hm...

It's certainly easier to bolt weights onto the hub assuming the threaded holes are there. But it'll throw off the total mass of the rotor, specially as the rotor evaporates over miles of use. Remember that each rotor has its own minimum mass stamped onto the hub. That mass is all-inclusive of the hub and carbon ceramic disk. Does it also include the balancing weight?

Another thing that makes you go, "Hmm..."

jas

ZR1Cat

Neat photo. Thanks for sharing. Perhaps these rotor weights are as common as wheel weights to balance tires and wheels. I did a quick check of my late build 2012 and did not see any such weights (I have as yet never experienced the infamous shimmy)

NofakeJake

It leads me to believe it WAS the issue and that IS the fix.

Maybe you could find a picture a 2009 458 rotor and show us the rotor design/ weights on it... ??

mirage2991

it appear the older 458 had our old type of rotors without the extra drilled ant tap holes in them.

The best way to fix this imo is to have an on car wheel balancing machine...

DanY

I just checked my 2011 Z06 Carbon Edition. No shimmy yet (fingers
crossed).

The front rotors have the extra holes drilled where the weights
can me mounted, none installed now, while the rear rotors do not
have the extra drilled holes.

Maybe they only worry about the front since steering wheel
shimmy is noticable to the driver and the rear imbalance would
not be.