More Brake Dust on Front Wheels than Rear Wheels?

[M3ac]

Hi guys,Just an observation:1)Realized even though our UDM's are rear wheel drive cars, yet, the Front Wheels tend to be laden with heavy brake dust. Why?2)The rear wheels has less brake dust. Why?3)My OBC shows that my rear brake pads wears off faster than my front, yet, my rear wheels/rims are not covered with as much brake dust as the front. Why?4)My rear bumper (the horizontal plane, where the boot meets the bumper - (M Sports E90) tends to collect a lot of dust and brake dust in general......Perhaps, I guess, its the airflow and the design of the car which gives better downforce..... I thought only Front Wheel Drive cars faces this issue, but, our Rear Wheel Drive UDM also? Hmmmm....Appreciate your thoughts.Thanks.

 

[SilverBullet]

just my 2 cents opinion:

- When we brake, where does most of the force shifted due to the inertia? Forward (if u notice when u see a car brakes last minute when approaching a bump, the front part normally goes downwards and the rear tends to go upwards - "tercongek"), hence more braking force required on the front wheels (which explains why the front brake calipers & discs are much larger than the rear ones)
- Where is the engine located? In front (for most both FWD and RWD cars). Hence, more weight at the front side, more load to the front wheels, more stopping power required.

 

[Eggie86]

If you noticed, the rear wheels of almost every car hardly get any brake dust or get as dirty as the front wheels. Always noticed that on my car when I do my weekly rims cleaning.

Most likely due to the factors as mentioned by Silverbullet above.

 

[haywire]

I ride motorcycle only to work, and if I only used the rear brakes I would have hit the rear end of cars long time ago.

Front brakes are more efficent in braking than the rears.

 

[fabianyee]

The brake bias for most, if not all cars are front biased.. whether it's front wheel drive or rear wheel drive... It means the front will have more brake dust becos it works harder to slow down the car..
Technically, the front brakes will tend to wear out faster than the rear....

And if more brake bias to the rear brakes, the rear end will feel light under braking and will probably oversteer braking into corners.... This would be reversed for competition driving and customised to the driver's preference...

 

[aidilj]

All of the answers above are correct. This is simple physics where it is best to brake with the front wheels, when braking weight would shift to the front thus giving more traction on the front wheel. So better (bigger) brakes is put in front and would wear faster than the rear. Remember the olden days where cars would have drum brakes at the rear but disc at the front..

The opposite applies to when accelerating where weight would shift backwards, more traction at the rear wheels. That is why higher performance vehicle are rear wheel drive and have wider back wheels - to put all the power down properly.

Cheers

 

[fabianyee]

Ironically, physics & common sense are getting lost as the society seemingly advances.... All these gadgets and internet are making some of us lazy to make use of our brain to process all things that is going on around us.. Almost everything around us are related to physics which is explainable with simple logical common sense, if we give a second to actually think about it.

also, jobs that made money are no longer technical jobs, but marketing fields which requires a lot of goreng-ing and bullshitting which are devoid of common sense.. So common sense doesn't pay anymore... twisted logic pays more....

 

[loafer]

What fabian says is so true especially now in the 21st century.

So many things around us can be understood so easily if a little bit of common sense is applied together with some logic. Even if that fails there is always google but I still see so many people failing at it....some people are wayyyyyyy too lazy to be alive.

 

[jarance]

1. Front braking is designed to take 70% of the braking load.
2. Front brake got air duct to force cool the disc. Rear have?
3. Force air from front duct is blowing the brake dust toward the rims. Rear got meh?
4. You normally change 2 times the front pads before you need to change the rear pads.

 

[aidilj]

[video=youtube;pZITRDLQrAM]http://www.youtube.com/watch?v=pZITRDLQrAM[/video]

 

[M3ac]

Thanks guys for all your thoughts and logical sharing. The thing that irks me a little is that my OBC indicates that my rear brakes need to be replaced in 46000kms whereas the front in 50000kms, which means the rear brakes are wearing off at a faster rate than the front.

Jarance/Eggie, thanks for your input as well, that explains the brake dust around the front wheel arch area below the indicator/repeater light, below the side mirrors (below the A pillar).

Unless the OBC is wrong or it's still too new to ascertain the wear and tear as the car OBC is adopting conditioned based programming logic, no?

 

[M3ac]

Thanks guys for all your thoughts and logical sharing. The thing that irks me a little is that my OBC indicates that my rear brakes need to be replaced in 46000kms whereas the front in 50000kms, which means the rear brakes are wearing off at a faster rate than the front.

Jarance/Eggie, thanks for your input as well, that explains the brake dust around the front wheel arch area below the indicator/repeater light, below the side mirrors (below the A pillar).

Unless the OBC is wrong or it's still too new to ascertain the wear and tear as the car OBC is adapting/analyzing using the conditioned based programming logic, no?

 

[fabianyee]

We never got to answer your question on the rear brake cos I, for one, don't know the service history to give comment... we were all posting based on the common scenario.

If indeed this is still the first set of brake pads for front and rear, then something is not right if u need to replace the rear set.. u might need to check whether the rear calipers pistons are not retracting as much as it shud, hence wearing the pads down quicker than usual...

 

[jarance]

chances is the rear brake cylinder is siezed up. check that first.

 

[M3ac]

Thanks Fabian and Jarance. Yes, they r the first set of brake pads. Few things came to mind if the rear did seized up then:
1)I would expect unusual sound/screech at the rear wheels, instead, nothing unusual.
2)Maybe more brake dust since more friction with the brake disc, instead, less brake dust than front.
3)After each drive, would expect the rear to be hotter, instead, it's always the front wheels that emits more heat.

But thanks again guys, I will get the SC to check when I send in for my next oil change.

 

[Eggie86]

Thanks Fabian and Jarance. Yes, they r the first set of brake pads. Few things came to mind if the rear did seized up then:
1)I would expect unusual sound/screech at the rear wheels, instead, nothing unusual.
2)Maybe more brake dust since more friction with the brake disc, instead, less brake dust than front.
3)After each drive, would expect the rear to be hotter, instead, it's always the front wheels that emits more heat.

But thanks again guys, I will get the SC to check when I send in for my next oil change.

Almost always the front will heat up more, due to the reasons covered earlier by the others. Like the distribution of weight shifted to the front under braking...

 

[M3ac]

Yup got it, thanks Eggie. Appreciate it

 

[aidilj]

Hi, just pouring my thoughts into your rear braking concern.

AFAIK, E90 uses computer estimation on the brake pad wear rate basing on how much, often, hard etc you use the brake. So there could be a miscalculation in the wear rate.

Or, the numbers are correct, and brake pad installed at the rear are thin so that they wear out the same or faster than front pads. To make quick bucks maybe, rear pads are cheaper than front most of the time..

But in the end, nothing beats visual inspection of them pads.. Happy learning

 

[aidilj]

Or probably the driving routine would involve more braking while going in reverse..?

I say this assuming your E90 software does not miscalculate.

 

[Jules]

My 2 cents....

front more brake dust is NORMAL as well explained by others.

rear pads has shorter lifespan......NOT NORMAL especially if both changed same time, and ur front more brake dusts. ( contradict )


HOWEVER, brake dust aside - if REAR finished first......then ur front is not working hard enough, rear overworking to slow car down ( not good ) and means u better check ur front brakes also. Possibility - siezed calipers, but at FRONT.

Have fun and be logical, you be fine.