How much life left in my discs?

pjs · 08-03-2010, 01:50 PM

According to I-Drive my front pads have 4000 miles left so booked in at the end of the month for these and a microfilter.

From memory, I always seem to have got skanked/persuaded to get discs at the same time (except my last 330d which had magic brakes and seemed to go on for ever).

Just had a 'feel' and there is only a slight 'lip' on the edge of the discs. Previous owner did discs and pads at 23k, car now done 45k. Advice please.

E92Fan · 08-03-2010, 02:12 PM

Quote:

Originally Posted by pjs

According to I-Drive my front pads have 4000 miles left so booked in at the end of the month for these and a microfilter.

From memory, I always seem to have got skanked/persuaded to get discs at the same time (except my last 330d which had magic brakes and seemed to go on for ever).

Just had a 'feel' and there is only a slight 'lip' on the edge of the discs. Previous owner did discs and pads at 23k, car now done 45k. Advice please.

Discs will last till the next pad change most probably! If there's only a slight lip you have nothing to worry about. The discs doesn't visually show signs of being beyond repair? No cracks or major score marks along the surface?

You'll be fine - they have only done 22k miles and you'll get at least 30-35k out of them, especially if a lot of your miles have been motorway based.

pjs · 08-03-2010, 02:14 PM

Quote:

Originally Posted by E92Fan

Discs will last till the next pad change most probably! If there's only a slight lip you have nothing to worry about. The discs doesn't visually show signs of being beyond repair? No cracks or major score marks along the surface?

You'll be fine - they have only done 22k miles and you'll get at least 30-35k out of them, especially if a lot of your miles have been motorway based.

Thanks Tony, no signs of any marks/cracks and yes, plenty gentle motorway miles

F31-340i · 08-03-2010, 02:16 PM

Thje discs show what their min thickness on them usually - unless its so rusty you can no longer see.

BMW TIS tells you the thicknesses for each model, but I can't access mine anymore as I have a fast but pants 64bit laptop.

Measure with a vernier caliper (digital ones cheap on ebay, can also use their depth gauge to measure tyres & also pads without removing wheel). Use 2 coins against the flat bit of the disc to ensure you're not measuring the lip thickness (measure coins alone between caliper and zero it before measuring coins & disc, if that makes sense).

m1bjr · 08-03-2010, 04:08 PM

FYI, fronts on the 335i
New=24mm
Min=22mm

I just replaced all mine with my usual supplier, Brakes International.
Had these on a few cars and always worked them hard on track with no issues.
Why pay more?

I bought a couple of cheap micrometers (Stanley) from eBay and they were decent quality for cheap parts and ideal for things like this too.

08-03-2010, 01:50 PM	#1
pjs Colonel 284 Rep 2,774 Posts Drives: i8 Join Date: Oct 2008 Location: NORTH iTrader: (1)	How much life left in my discs? According to I-Drive my front pads have 4000 miles left so booked in at the end of the month for these and a microfilter. From memory, I always seem to have got skanked/persuaded to get discs at the same time (except my last 330d which had magic brakes and seemed to go on for ever). Just had a 'feel' and there is only a slight 'lip' on the edge of the discs. Previous owner did discs and pads at 23k, car now done 45k. Advice please.
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08-03-2010, 02:16 PM	#4
F31-340i Colonel 161 Rep 2,475 Posts Drives: BMW 340i Touring Join Date: Apr 2007 Location: ... iTrader: (1)	Thje discs show what their min thickness on them usually - unless its so rusty you can no longer see. BMW TIS tells you the thicknesses for each model, but I can't access mine anymore as I have a fast but pants 64bit laptop. Measure with a vernier caliper (digital ones cheap on ebay, can also use their depth gauge to measure tyres & also pads without removing wheel). Use 2 coins against the flat bit of the disc to ensure you're not measuring the lip thickness (measure coins alone between caliper and zero it before measuring coins & disc, if that makes sense).
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08-03-2010, 04:08 PM	#5
m1bjr LSD - No, you're not seeing things 73 Rep 3,302 Posts Drives: Baby F36 Gran Coupe Join Date: Mar 2010 Location: Plymouth UK iTrader: (4)	FYI, fronts on the 335i New=24mm Min=22mm I just replaced all mine with my usual supplier, Brakes International. Had these on a few cars and always worked them hard on track with no issues. Why pay more? I bought a couple of cheap micrometers (Stanley) from eBay and they were decent quality for cheap parts and ideal for things like this too.
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