Can anyone tell me the pad thickness on new, OEM, BMW front pads for my
97 328? I'm trying to estimate how many miles on the remaining pads (~7mm) before I have to change them. Planning a 4000 mile trip this summer and don't want to run too low, but changing now seems like a bit of a waste.
Pad wear depends upon how you use the brakes, so no one can tell you how long your pads are likely to last. If you're worried, buy a set now, stick them in the boot along with a 7mm hex key, and change when necessary. Mike.
11mm, IIRC. 1.5mm is reckoned to be the change point so they're less than half worn. I reckon on about 20k miles out of front pads but it totally depends on how you drive.
I think he's asking so he can gauge the remainder of the pad vs. the present wear rate from the time they were new. The assumption being that the wear will continue at the present rate, which should be a pretty good one (assumption).
That would have been my 'guess' for a reasonable starting point. However, during my 'free' maintenance period the dealer told me my front brakes were
50% worn at 15K miles (Inspection I) so at Inspection II (35K) I just had them 'automatically' replace the pads - they'd be fully worn, right?.
Took the old pads home and measured them, and front pads had 10mm left. (This is how I learned my lesson about BMW dealer service - now use independents) I do about 80/20 highway/city driving, but don't think I drove
35K miles on just 1mm of pad, so that is the origin of my question. A thicker original pad would make the wear rate much faster - throwing off my estimate of remaining pad life.
I now have about 92K miles on the second set of pads that have ~7mm left. But driving habits have changed, somewhat, so I wanted to see if I could calculate an estimate of remaining pad life with say, a 25% safety margin.
...well, obviously, keep those 10mm pads and toss them back in there when the current ones wear out. That ought to last you the rest of your life based on the way yo (don't) wear brake pads out. ;-)
Indeed, that has been the plan. Although, I keep thinking it might be nice to throw them out and get something with less dust - my wheels are relatively easy to clean, but the novelty has somewhat worn off. Also, rotors are near minimum, so thinking I should just go ahead and put in all new pads and rotors.
It's not just BMW dealers. We had a Nissan that two separate garages said needed new pads so I went and bought some without looking myself. Went to fit them and the old ones had 5mm compared to 8mm on the new set so I left them. A couple of years later my mother had the car and asked me to fit new pads because the MOT test man said they needed changing. They still had
3mm, which was a bit low so I changed them (using the set I'd bought before) but they were not worn out. Don't trust anyone.
But I don't measure new brake pads and then guess how long it will be until I need to next look at them. Brake pads are one of those things that you inspect periodically and replace as needed. I'd say you should start out inspecting them every 6 or 12 months and plan on replacing them 'soon' when there's about 1mm or so of meat left on them. Or, you could just rely on the brake pad wear warning light thingy, if you like. There's prolly no harm in doing that either.
I happen to have a set of new pads for a 318is. They measure 11mm pad thickness. My Chiltons manual says they should be replaced when they are
3mm thick. This means that at 7mm thickness that you are half way through the life of yours. It should be a couple of years before you need to replace them.
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