wobble, vibration, grooves and cross drilling

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PhilHunt
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Re: wobble, vibration, grooves and cross drilling

Post by PhilHunt » Thu Apr 21, 2011 12:40 am

Any nearer to an update on the D3 disks Chris?


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Re: wobble, vibration, grooves and cross drilling

Post by moose » Thu Apr 21, 2011 10:00 pm

I will chase :thumbright:


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Re: wobble, vibration, grooves and cross drilling

Post by moose » Thu Apr 28, 2011 4:47 pm

No news of the discs yet however I have had this reply today from my original questions, a little late but a good answer - no guessing where this came from.

As performance brake systems are consumable items, and are also particularly subjective in terms of performance/feel, etc, it is a difficult area to give advice, but I will try and answer your questions below.

Generally speaking with brake discs and pads, you get what you pay for, and you will find that you will not get the same level of performance and longevity from the cheaper end of the market. Brembo invest large amounts of money in the development, design and manufacture of OEM, Aftermarket, High Performance and Racing products, which are in many instances copied by companies who do not invest anything in development.

Of course Brembo believe they manufacture the very best in terms of quality and performance, and stand alone in terms of the number of OEM customers they have, but also manufacture more brake discs in general than any other manufacturer. They develop, design, test and manufacture all these products in house, and as far as I am aware they are the only manufacturer to do so, turning over around 1Billion Euro in the process.

Disc warp - In our experience, and we deal only in the high performance and Motorsport markets, warped brake discs are very uncommon. With cheaper manufactured discs, the problem of thickness variation can create vibration, once this starts the problem gets worse due to the uneven heating of the disc surface, thus making the problem worse. The next common problem with pad deposit transfer on the surface, due mainly to poor bedding in, or the pads running above the recommended operating temperature. It is fair to say that the installation of the disc is also widely overlooked, and the preparation of the hub face, etc, are not correctly checked for run out also during the installation process. Very often a fractional run-out of the wheel hub can translate to a larger degree of run-out when you get to the edge of the disc, so when the disc has been installed, run-out should always be checked prior to the vehicle being driven.

? Recomended maximum run-out is 0.10mm
? Drillings and Cross Drilling serve several purposes, but most of the benifits are only seen during more extreme use. Drillings in particular increase initial bite between the disc and pad, allow the escape of hot gases, allow the pad surface to be refreshed at high temperatures, allow water to be dispersed in wet conditions. Downsides are a slight increase in pad wear and a little more noise. Slots offer mostly the same advantages, but to varying degrees, but are a little noisier than drilled and offer better resistance against thermal shocking at high temperatures, so are better for track use.
? Brembo offer many different friction materials, but manufacture none of them. Pretty much all OEM applications use a specifically developed friction material, Brembo now offer an aftermarket pad which will perform similar to the OEM pad but not specifically designed for the specific vehicle. Brembo Sport pads offer increased friction levels, better heat tolerance and better life than and OEM pad, these are also the same type of friction material found in Brembo Gran Turismo Brake Up-Grade Kits. Then Brembo Race Pads, which are specifically for Race and Rally use.
? Friction materials are now very advanced in comparison to older counterparts, so the compressibility of the pad does not always mean that soft is stronger bite, hard is longer lasting. A so called harder pad will not be the answer to all drivers braking needs, an OEM quality pad will be enough for some, where as some will require a full race pad in some circumstances, really depends on how the vehicle is driven and the duty level the brakes are put under. A good compromise is the Brembo Sport Pad, in general the stopping power will be stronger, the heat range will be higher and in the same circumstances will last longer. The downsides can be slightly higher disc wear and more potential to create low duty squeal.
? For the Sport / GT and Racing Ranges, Brembo use the highest specification high carbon cast iron alloy, discs are founded in Brembo foundries in Italy, then machined and individually dimentionally checked in house before packing and distribution. The quality systems in place are second to none.


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I may not have gone where I intended to go, but I think I have ended up where I needed to be. :moose:

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PhilHunt
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Re: wobble, vibration, grooves and cross drilling

Post by PhilHunt » Thu Apr 28, 2011 7:52 pm

Thanks Chris. Did you say that there was a prize for guessing who the reply was from? :thumbright:


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Re: wobble, vibration, grooves and cross drilling

Post by Discovery 4.4 » Sun Sep 24, 2017 3:44 pm

Great read many thanks for posting you have answered a coup elf queries I have about my rear brake wobble.

Tim



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