Drilled brake rotors for IS250/220d/250C

Linas.P · May 1, 2016

Just wanted to share one subtle "enhancement" I have recently installed on my IS250. This is purely cosmetic and really depends on personal taste. Some might like it, others hate it...

So my front rotors were up for changing - probably still more than 25mm, but dealer would mark them as amber (or even red) due to the pronounced lip. The decent update would have been getting IS350/GS350 brake calipers and rotors (which I still planning to do in my dreams), but for time being I wanted to upgrade that dull and rusty part with something more suitable looking.

I wanted for brakes to look more "performance" oriented so I was considering "drilled" design. Never liked Slotted/Dimpled brakes too much (again personal taste). The only rotors I have found for reasonable price were MTEC made p/n: MTEC1576 Front 296mm and MTEC1621 Rear 291mm (check if you rear ones are vented or not as vented ones are 310mm - p/n: MTEC1614). Additionally, I added protective coating "gold edition" ... anyway that comes to the taste... I knew that the face going to wear out when quickly, so it is really just nice detail around it... essentially replacing rust with some "gold" coating (other options were silver/grey and black).

Parts:

I throw some brembo low dust OE-equivalent pads on front and some Mintex cheap stuff on rear (in fact Mintex front pads were more expensive than Brembo).

The end result (as expected) is very minimal difference and in my opinion subtle.... I know I know ... I need to refurb my rims before taking any more pictures .. they are really poor right now.

Generally, I am happy with this tweak, but I would not recommend MTEC coatings. This is because I expected the coating to be more like "metal plating" - essentially some hard wearing coating which protects from rust, but does allow heat dissipation etc. In reality is some kind of heat resistant paint, which can be easily damaged when installing, secondly only outside of the discs is covered i.e. face and the back, but not inside vents. I do understand that covering vents in this coating would prevent rotors from cooling and therefore they are left naked, BUT the surface which rusts the most is exactly the inside of the vents... so protection vise this is not great design.

P.S. Dealer was not impressed with this and gave amber. In fact they might have been missed them but the re**rd who installed them threw away anti-squeal shims. I have noticed that some time after I have left the garage, but it was little too late. Next time when installing the pads I will make sure these are not missing. So lesson learnt - don't allow id**ts near your car or watch them carefully. I must admit I had no space to upgrade myself and I was foolish enough to allow the mechanic to fiddle with my car unsupervised. The replacement part is: 04945-30140 and it is £30-70. The relief ... so far there are at least no squeal.

P.P.S. Obviously, I wanted to spray calipers and dust shield (on the rear) matching colour. But I only have 2 options: either pay fortune to do them properly ~£150 per caliper (removed, prepared and professionally sprayed with heat resistant caliper paint) or do them for reasonable price ~£20 by same person who lost my anti-squeal shims (using spray can... which will bubble-up and burn after 100 miles). The third option - doing myself properly, unfortunately unavailable for now.

jackcramerr · May 1, 2016

Question: how can I tell if I need new rotors ?

Linas.P · May 1, 2016

By measuring minimum thickness. The front rotors are 28mm new and minimum thickness before replacement are 25mm. Meaning you have 3mm of steel to wear before replacement. Usually, you can tell by the "lip" if the rotor is near minimum thickness. I believe the rotors can be actually used longer, but you won't pass MOT with the rotors below minimum thickness .. even if they are still perfectly safe to use.

jackcramerr · May 1, 2016

Every rotor has a lip.... How can you tell by lip? Is lip bad ? I can see lip on your new rotor... or where is the lip if thats not a lip...This has always confused me.

Linas.P · May 1, 2016

Well, it is actually pretty simple - if the new rotor is 28mm thickness and can be worn by 3mm, that means 1,5mm on each face, so the lip can bet at most 1,5mm high.

So yes - you are right even after 2k miles you rotor going to have a lip... maybe 0.15mm which means your rotor is 10% worn. When saying "new" .. it would be great to mention how many miles are already covered (pictures taken after ~700 miles) and as well consider the fact, that on IS250AT rotors are actually poorly designed. They are undersized for car weight and power, that is especially noticeable on AT, less on MT. That said rotor wear is excessive to almost everyone's expectation - some rotors were replaced only after ~20k miles. Low dust brake pads make it even worse, as reported by some users, sometimes the pads can outlast the rotors.

As for the lip on my new rotors... well theoretically there is already some kind of "lip" - I would expect it to be no more than ~0.00375mm or 2.5%. IF that is correct the rotors would last 28k or about average with "low-dust" pads. I believe the coating itself looks a bit like a "lip" as it is fairly thick, probably like ~0.3mm. So that is why my new rotors looks like having a "lip".

I must admit my disks lasted fair mileage ~45k, but that's on OE Confort pads which generate extensive dust. If you zoom into the picture below, the lip is quite noticeable and I would say just over ~1mm.

As mentioned previously, I believe the disks were still "legal" though probably worn over 70%. Additionally, it is clear that they are excessively rusted inside the vents, hence I think new disk coating is bit pointless as it would not provide any improvement in such rust prevention. Another fair point - majority of those layers are probably rusted brake dust and dirt rather than actual metal from rotor.

rayaans · May 2, 2016

Hmm not sure you made a wise choice regarding the rotors though.

Had these on the Merc and I had to dispose them early as they developed little cracks. Little did I know back then that it's a big issue with drilled brakes.

I guess Lexus also found out, the IS-F came with drilled rotors but the RC-F comes with slotted ones

Also I guess it's purely cosmetic. They won't really stop the car ant faster, only tires and bigger brakes will do that

Linas.P · May 2, 2016

Well.. we will see - I would like to upgrade to IS350 calipers and rotor in the future anyway - so this is more of filler in the mean time. I am not expecting them to outlast OE.. and considering low-dust pads even match them.

As mentioned, I don't like slotted "looks". As for cracks .. I was aware there are risk of these warping and cracking - only time can tell if that will materialise. The car is not used for anything else except daily traffic queues - so I guess they would wear below minimum thickness before developing any other fault.

toffee_pie · May 2, 2016

Yellow stuff pads will stop the car a heck of a lot faster. Ain't cheap however.

is200 Newbie · May 2, 2016

In changing the discs from stock would this be a notification to the insurance company?

rayaans · May 2, 2016

45 minutes ago, is200 Newbie said:

In changing the discs from stock would this be a notification to the insurance company?

Pretty much everything thats not standard should be declared to the insurance company. Too much hassle if you dont and they find out when/if you have an accident

jackcramerr · May 2, 2016

So do they charge more the insurance company?

I am also thinking now that i changed the brake pads but not the rotors.... if I needed to change the rotors.

If I have to, the mintex looks good visually... drilled and dimpled/grove. Will make it look like Merc Amg.

toffee_pie · May 2, 2016

I notified my insurance for changing discs and pads. They are not OEM

jackcramerr · May 2, 2016

Do we also tell them when we burp while driving ? :)

What about working on the car ourself? surely that will be far more worrisome, sunday mechanic monday racer boy.

Linas.P · May 2, 2016

I would only notify insurance if parts are non-OE compatible e.g. bigger or changes the way car, same stopping power. Holes in the discs and protective coating is "style" thing, not performance. If I would need to declare that to insurance, I would need to declare Lexus owners club sticker on the boot lid too...

Same goes for the rims for example - I would only notify if the rims are something completely different from car specs e.g. IS250 came with R16/R17/R18 as standard. R19 can be fitted wth tires which keeps the wheel size the same... so that is kind of on the edge.. I would probably notify insurance for R19s.. and would definitely do for R20s. However, if I just pick up R17s with different style from OE.. I don't consider that modification.

Anyway.. the disks will not be reported.. but that is my opinion and risk, by no way take it as a legal advice. I reckon it is possible to call insurance and as if they consider something modification or not..

toffee_pie · May 2, 2016

yellow stuff pads are quite different from OEM, Good luck in having an accident and getting an assessor see them!

Linas.P · May 2, 2016

I don't know how would assessor would consider "Yellow stuff" pads.. and how he would see them either without taking calipers apart. One way or another I don't use Yellow-Stuff pads, my pads are brembo OE equivalent low-dust and Mintex standard OE on the back. As far as disks themselves - they are as well direct fit and at least MTEC themselves market them as OE.

If that would satisfy assessor it is another story, but at least for now I am not planning to have any accident

jackcramerr · May 4, 2016

Someone told me if I told inaurance an improvement made to brakes of the car so it works better will reduce the insurance ...

Linas.P · May 4, 2016

That is not true. Any modification will increase your insurance... Improving brakes if you lucky wont increase the insurance premium. However, "Improving" is not really that straight forward and what somebody regards as improvement, might not be treated as such by Insurance provider e.g. IS350 brakes (or even "big brakes" kit) for IS250 is definitely an improvement - better wear, better stopping power etc... but insurance in such case would consider that as simple modification.

As mentioned already - I do not consider my new brakes as improvement, nor as modification, because all specifications are equal to OEM. For this reason I don't see any reason to report them to Insurance company.

I heard that upgraded security system e.g. gps tracker or Dash cam can potentially reduce your premium, but it is likely on case-by-case basis..

Yorkie740 · November 6, 2016

I had the mtec black coating discs on my celica for two years no cracking and the coating was fine over two years very good product and I will be buying again