Brake pads needed

[Timberflake]

Hi guys, cars gone in for a service and mot today, just received the video on the visual health inspection and it says front brake pads are 70% worn and need replacing soon, looks like they'll charge £125!

Anyone know where i can buy them online more reasonably and i'll get them fitted by a local garage

Sent from my SM-G935F using Tapatalk

[Shauna_H]

CarParts4Less I got mine from, got discs and pads for £61

[DaveB]

If they're only 70% worn there's plenty of life left in them!

[Czar]

If they're only 70% worn there's plenty of life left in them!

How can you even think that 70% wear of a brake pad lining would still provide adequate stopping efficiency !!

The brake pad has lost 70% of its material, therefore a 70% reduction in thermal braking efficiency, the remaining brake pad material can not absorb and dissipate the generated heat effectively, you now have a situation where your braking efficiency will very rapidly become brake fade, just when you need them at the critical time !!

[DaveB]

If I were designing a system to dissipate thermal energy I wouldn't use a material with poor thermal conductivity, such as a phenolic resin. I'd use . . . now let me see. . . a big lump of cast iron, maybe?

Show me empirical proof that pad thickness has any measurable effect on fade characteristics.

[BenS]

If I were designing a system to dissipate thermal energy I wouldn't use a material with poor thermal conductivity, such as a phenolic resin. I'd use . . . now let me see. . . a big lump of cast iron, maybe?

Show me empirical proof that pad thickness has any measurable effect on fade characteristics.

I wouldn't argue with Czar, he knows exactly what he is talking about.

[cyclone]

It's not arguing it's disagreeing and then comes discussing the issue presenting reasons and proof. No matter who brings a piece of information up one should never be timid or afraid to ask WHY. Neither should one take offense at being asked why.

[BenS]

See your point Cyclone, but I saw the post as being more confrontational than discussive.

My interpretation of this is that, while brake pads are not the best material that exists to dissipate heat, they are chosen to generate enough friction with minimal wear and damage to the discs. A lump of iron versus a disc brake might get hot enough to friction weld the two together in the right situation, royally buggering the car.

So if there's a big lump of material trying to dissipate some heat, versus a 70% smaller lump of the same material trying to dissipate the same amount of heat, the former will do it much better than the latter.

[Czar]

If I were designing a system to dissipate thermal energy I wouldn't use a material with poor thermal conductivity, such as a phenolic resin. I'd use . . . now let me see. . . a big lump of cast iron, maybe?

Show me empirical proof that pad thickness has any measurable effect on fade characteristics.

Good afternoon DaveB, thankfully you do not design or have not designed a brake system, before I write my answer which will include the thermal proof you are asking, how about taking the time, as I will to write my answer, you supply the forum with your knowledge on this very subject, I look forward to reading your answer.

It's not arguing it's disagreeing and then comes discussing the issue presenting reasons and proof. No matter who brings a piece of information up one should never be timid or afraid to ask WHY. Neither should one take offense at being asked why.

^^^ spot on cyclone.

[DaveB]

Oh dear, looks like I've been a naughty boy! OK, I was a little bit (well, more than a little bit) facetious, but I didn't expect such a torrent of abuse!

Just to clarify, the comparison between phenolic resin & cast iron was between the pad & the disc, in the context of losing heat energy. Brake pads have very low thermal conductivity - the base material is a thermosetting phenolic resin, a low-conductivity material, & the fibre fillers are materials chosen primarily for their heat-resistance but which are also commonly used in thermal insulation applications - used to be asbestos, now a variety of materials, such as Kevlar, glass fibre, rockwool, etc. On the other hand, cast iron has high conductivity & the large surface of the disc allows for efficient heat loss.

The key word in my post was "empirical". The fact that manufacturers are happy to specify minimum pad thicknesses as low as 1,5mm would seem to suggest that they are maybe not too concerned about deteriorating brake performance with severely worn pads.

I stand by my original, apparently controversial, statement that pads which are 70% worn have plenty of life left in them.

[AJD88]

(Grabs popcorn)

[Funky]

This is going to be interesting

[pmk]

Better than any crap currently on TV lol, hope it stays civil hehe

[DaveB]

Don't worry, I won't be posting any more in this thread.

[Funky]

Dave, please don't think we meant it in any other way than what it was, which is us waiting to hear both you and Czars opinions and clear technical knowledge on this subject matter. This forum is open to all to freely express views, opinions and knowledge, which makes it such a good place for these types of discussions and I, for one, would like you to continue with what you know, as it's making interesting reading.