So what is the consensus on MMC brakes?

So what is the consensus on MMC brakes?

Author
Discussion

AVES

Original Poster:

65 posts

245 months

Wednesday 31st August 2005
quotequote all
If one is looking at buying an early car with low miles do you avoid cars with MMC brakes or not? OK you're going to have to replace with steel in due course but is that any more costly or problematic than standard replacement?
I've been told that wet weather performance isn't great - That bad?

Ju.

163 posts

230 months

Wednesday 31st August 2005
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I have not had a problem with mine yet at all and i am happy to keep them for quite a while longer

Mr_C

2,441 posts

230 months

Wednesday 31st August 2005
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I quite like MMCs. They do squeal a bit, and aren't that great when they have a film of water on them, but in the dry they're brilliant, and last aaaaages!!

scuffham

20,887 posts

275 months

Wednesday 31st August 2005
quotequote all
AVES said:
If one is looking at buying an early car with low miles do you avoid cars with MMC brakes or not? OK you're going to have to replace with steel in due course but is that any more costly or problematic than standard replacement?
I've been told that wet weather performance isn't great - That bad?


why do you think you are going to have to change them for steel?

Pads are avaliable for MMC's no problem, and the disks will not wear out as such...

StuartB

339 posts

236 months

Wednesday 31st August 2005
quotequote all
AVES said:
If one is looking at buying an early car with low miles do you avoid cars with MMC brakes or not? OK you're going to have to replace with steel in due course but is that any more costly or problematic than standard replacement?
I've been told that wet weather performance isn't great - That bad?


How is it likely to be any more or less problematic in replacing the MMC disks over a normal steel set ?

In any case. MMC's are great, you don't have to clean the wheels, you do not have to buy pads, you do though need to dab the pedal occaisionally when its wet

Mark B

1,621 posts

266 months

Thursday 1st September 2005
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Speak to Tindall Matt...... that's all I'll say....

Mr_C

2,441 posts

230 months

Thursday 1st September 2005
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what will he say about them?

Mark B

1,621 posts

266 months

Thursday 1st September 2005
quotequote all
Mr_C said:
what will he say about them?


A mutual friend had MMC on his Elise for 60k miles, loved them in the dry thought they down right scary in the wet. As indicated above, he didn't rush out to get them changed but did advise me to avoid a car with them when using the car everyday, only as they add that element of concern especially when being used in the winter months.....

I know AVES and know he is planning a purchase for everyday use, which let's face it is what an Elise should be used for

AVES

Original Poster:

65 posts

245 months

Thursday 1st September 2005
quotequote all
Thanks - as Mr B says I have this strange idea of buying an Elise & using it everyday all year round on the road. No trackdays etc so I'm looking at unmolested S1's which do appear to still have MMC's sometimes. My trip to work is only 5 miles in traffic so brakes are not going to get up to temperature on that trip.
Just had one possible ruled out by the missus on the basis that it has a "Pimp" colour scheme - aubergine & cream leather. Pushing for a budget increase to get me into type 49 territory but as she's selling her MX5 to part fund & letting us keep the Impreza & Caterham I can't push too hard.............

paulwakinshaw

436 posts

241 months

Thursday 1st September 2005
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MMC's

Pro's: Light, last for ages (upto 100K miles for discs and 40K for pads) and give excellent feel and bite

Con's: Crap when wet (bit the new pads eliseparts sell are supposed to be much better) can squeel like mad at times but copperslip on the backs of the pads helps, when combined with more power and sticky tyres they could be overcooked and finished.

Paul

Buster44

487 posts

248 months

Thursday 1st September 2005
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I like MMC's, but will have to change mine shortly for trackdays etc as they are prone to failure on track.

If looking at a very early MMC car check whether disc shields have been fitted as this improved wet weather braking no end.

cuzza

2,042 posts

254 months

Thursday 1st September 2005
quotequote all
Buster44 said:
I like MMC's, but will have to change mine shortly for trackdays etc as they are prone to failure on track.


Hardly "prone" to failure. If you were to give them very serious abuse i.e. racing or extended track sessions you might see problems but for trackdays they'll be fine.

If you really want rid of them, Lotus are doing a swap out deal via dealers - details are on their website somewhere.

I drove an MMC'd car recently and found they had less bite than the steelies on mine and a different feel but they seemed to ultimately stop the car every bit as well.

Esprit

6,370 posts

284 months

Friday 2nd September 2005
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I love my MMCs.... seem to have more feel than any other car I've driven (although I've not driven a cast-iron-braked Elise S1 for comparison)

I think that their only drawback is the wet-weather use and the fact that you can't replace them that easily with more MMC ones (I've heard that new MMC discs are around but cost an arm and a leg to get)

I am keeping MMCs on my car for as long as I can. According to my investigations, my car was THE LAST car ever to come from the factory wearing them

tony charente

23 posts

237 months

Sunday 11th September 2005
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The only PROPER Elises are those with MMC brakes - a fundamental part of the Elise design ethic...... Unless really and truly abused, the MMC brakes seem to last (and still look brand new) for ever. Cast iron brakes not only go rusty over night, but they add weight (and unsprung weight at that) and also add to the inertia of rolling masses, both on braking but also on acceleration - like having 4 extra fly-wheels. The change to cast iron was certainly not of Lotus' choosing, but it was the first step towards heavier and heavier Elises (with air-con and cup-holders....) that need more and more power just to get back to where they started. (PS: Can you guess which model I have?)

Esprit

6,370 posts

284 months

Monday 12th September 2005
quotequote all
tony charente said:
The only PROPER Elises are those with MMC brakes - a fundamental part of the Elise design ethic......


I tend to agree... MMCs are part of the original design ethos of the Elise and are really pivotal to achieving that.... Ditching MMCs was the first in a line of modification that made the Elise heavier and less of a driver's car than the original (not saying the later ones are bad, just that if you read the interviews with the designers, the move away from MMCs was universally acknowledged as taking the car away from its ethos).

I feel in years to come, the MMC cars are the ones that will make the money. Just as with the Jaguar E-Type, the 3.8L cars with the moss box and the flat floors (the least uder friendly, but the most "true to form" became the icons, I feel in time the Early S1s will be the same.

As I said above... mine's supposed to be the very last ever made with MMCs, so I'm a very happy man

I will have a cast-iron-braked car, but it's going to be an Exige... and yes, I'm hanging on to my MMC car for a long while yet

Buster44

487 posts

248 months

Monday 12th September 2005
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cuzza said:

Hardly "prone" to failure. If you were to give them very serious abuse i.e. racing or extended track sessions you might see problems but for trackdays they'll be fine.


Certainly not the impression I've been given from reading the archives on British Cars.

Several reports of complete cracking of the disc away from the hub when used on trackdays.

Might not happen to every MMC equiped Elise, but it's enough of an issue to be worth changing for peace of mind imho.

melvinolotus

23 posts

230 months

Wednesday 14th September 2005
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Best thing about MMC's is no brake dust- my Elise has done 40,000 and wheels are as new.

Esprit

6,370 posts

284 months

Wednesday 14th September 2005
quotequote all
Buster44 said:

Certainly not the impression I've been given from reading the archives on British Cars.

Several reports of complete cracking of the disc away from the hub when used on trackdays.

Might not happen to every MMC equiped Elise, but it's enough of an issue to be worth changing for peace of mind imho.


Given that all the owners I've spoken to over here and from my own personal experience, MMCs hold up very well on trackdays. I know one Elise with 250+ bhp from a Honda engine and even then the MMCs are fine... sure with that sort of punishment the brakes are now almost the weakest link, but they seem to have soaked up most of the punishment thrown at them without batting an eyelid

Buster44

487 posts

248 months

Wednesday 14th September 2005
quotequote all
Esprit said:

Buster44 said:

Certainly not the impression I've been given from reading the archives on British Cars.

Several reports of complete cracking of the disc away from the hub when used on trackdays.

Might not happen to every MMC equiped Elise, but it's enough of an issue to be worth changing for peace of mind imho.



Given that all the owners I've spoken to over here and from my own personal experience, MMCs hold up very well on trackdays. I know one Elise with 250+ bhp from a Honda engine and even then the MMCs are fine... sure with that sort of punishment the brakes are now almost the weakest link, but they seem to have soaked up most of the punishment thrown at them without batting an eyelid


I don't doubt what you're saying - there are also posts from several other people using MMC's on track without problems (yet?).

However, there seems to be no notice of the impending disc failure and they also don't seem to be isolated to high powered/sticky tyre equipped Elises.

There were enough reports of complete disc failures to make me think twice. I doubt fancy pranging my car (or worse!!) when out on track. Seeing it was a documented problem I thought it worthwhile to change the type of disc - don't want to, but is it worth the risk????

Have a search on the Elise section of British cars yourself. If you're not already registered I can highly recommend it as a valuable source of info.

Buster44

487 posts

248 months

Wednesday 14th September 2005
quotequote all
One of the posts taken from British Cars:


''The disks are made from an alloy carrier with ceramic partically 'suspended' in the ali.

The ceramic provides the 'running' surface of the disk, the ali just holds it together.

Basic proble is that ali, although it conducts heat well, does not rediate heat well (nothing like as good as steel) so they have a problem sheding heat.

This means that with persistant use, they got hot, and somewhere arround 350-400C the ali becomes soft enough for the pads to 'drag' the ceramic bits around the disk.

now, assuming they are not that bad hand you have the money to pay for the tooling, they can be skimmed, however, the tooling cost more than a set of disks is worth! (this is one of the reasons they are not still made as the machining costs are riddiculus).

Second problem with MMC's (and the Lotus Steel ones) is that they are designed badly in that they are almost flat (ie no offset), to get some offset they turned the vent round, thus they don't cool well.

this creates great stress in the centre of the disk at high temp, and eventually, they crack. I have seen quite a few MMC's that have litteraly come appart with the outer part of the diks seperating from the centre. (steel ones just crack on the running face).

Considering the cost of MMC's and your with to go on track days, change to steel.

Simon (S)



Posted 09 December 2002 at 10:33:54 UK time
B Pitch, Reading, ben.pitch@veritas.com
I have a friend at work with an old set of MMC disks for sale... drop me an E direct if your interested and I can hook you guys up!

Cheers

Ben


Posted 14 December 2002 at 14:58:14 UK time
I Macauley, Cheshire, United Kingdom, iainmac@macauleys.fsnet.co.uk
OK, Liz Doctor says it's one rear disc, the result of a slightly sticking pad heating things up. Do I change it (and the other rear), or can I expect an exploding disc?

Comments?


Posted 14 December 2002 at 15:14:28 UK time
Simon Scuffham, Leicestershire, United Kingdom
Considering the cost of MMC's and your with to go on track days, change to steel.

Simon (S)



Posted 15 December 2002 at 11:39:23 UK time
Ian Haverly, Buckinghamshire, United Kingdom
I thought that there was only a problem with MMC's melting if you don't use the standard tyres, that was what was quoted on the Lotus website site.


Posted 15 December 2002 at 11:41:10 UK time
Simon Scuffham, Leicestershire, United Kingdom
Ian,

I know of 3 people so far that were running std tyres that have had them failed!

It basically comes down to the cct, the driver and time.

Simon (S)



Posted 16 December 2002 at 12:52:30 UK time
JJ Bill, Cheshire, United Kingdom
Ian

I've managed to wreck 2 MMC's while running on road tyres (Yoko A520's). Both failures were the same with the disc cracking around the bell and allowing it to separate from the rotor - entertaining when you're trying to brake from 110+!

FWIW, I had some discs and bells made up by Performance Braking and I run Pagid RS4-2's on the front and RS14's on the back. The level of feel isn't quite as good as I had with the MMC's but the stopping power is tremendous!

BTW - I guess I'm one of the people that Simon knows about as he was in the passenger seat when I lost a disc at Rockingham!

JJ