glenahan at vfemail.net
Thu Jan 11 20:48:03 EST 2007
I guess I have been judged to be a maniac driver :-)
..and didnt even know it.
On Jan 11, 2007, at 10:07 AM, LL - NY wrote:
> FWIW, my Mom's 2001.5 Passat (Bosch 5.1) also wore it's rears
> faster than it's fronts. Mom mostly drives like a little old lady.
> As Taka noted, the harder you drive, the more the fronts wear.
> In the most recent Road & Track (Feb '07) Dennis Simantis,
> explains in the Technical Correspondence column brake bias
> and pad wear, and his conclusion is that the real cause of
> un-balanced brake pad wear is brake bias rather than where
> the work is being done. In a system like Bosch 5.X, where the
> system decides what bias it's doing based upon situations, if
> most of your braking is less than threshold, then it's possible
> for the rears to do a majority of the work if that's how the system
> was programmed (to reduce dive by moving the pitch point further
> back). If you threshold brake more often, the wear will move further
> forward b/c the need for more front brake force will be required.
> LL - NY
> On 1/10/07, Taka Mizutani <t44tqtro at gmail.com> wrote:
>> I know that you're doing more like 80-90% of the braking in the front.
>> the initial brake drag on the rears is a characteristic of most
>> VW/Audi cars
>> Bosch 5.1 and newer, exactly how I described.
>> If you "drive it like you stole it" all the time, then you would not
>> this phenomenon,
>> but I don't know too many people that do that.
>> When you mention your S4 and S6, both of those cars have the
>> 2-piston caliper setup. I don't know how that factors in, all of the
>> cars I
>> was talking about
>> are single-piston setups. Maybe the cars with the big brakes act a
>> The brake proportioning is conducted via the ABS system, all the
>> time- at
>> least that is
>> my understanding of the system, although I could very well be wrong.
>> I did not see anything like this on my 5ktq or 200q, both pre-5.1
>> systems. I
>> have only noticed
>> the high rear brake pad wear on VW/Audi cars with 5.1 or 5.3 ABS.
>> I will have to see what comes of the V70R which also has a Bosch brake
>> system, I think-
>> I haven't really been under the hood of that car very much. I know
>> that the
>> front pads in
>> the V70R were fairly worn in 19k miles, the rears look fine. Maybe
>> does not spec
>> a calibration like VW. All 4 wheels dust an insane amount on the
>> though, so the rears
>> are definitely doing something even in everyday driving. Either that,
>> having 4 piston brakes
>> all around with huge rotors and pads simply makes a ton of dust.
>> On 1/10/07, Grant Lenahan <glenahan at vfemail.net> wrote:
>> > Not my experience, although the explanation sounds a little
>> plausible -
>> > but only up to a point. Read on.
>> > However, on more serious braking, ABS cannot do what you say and
>> > have the car brake effectively. braking grip is proportinal to
>> > Weight in an Audi, on deceleration, will probably be 70% of more to
>> > front. QED.
>> > Grant
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>> quattro at audifans.com
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