35i / 35iS brake upgrade (without costing the earth)

S

stuartinzg

Active member
I have been looking around for an upgrade (OEM+) equivalent without big bucks on a BBK as I think the calipers themselves, although cheap, seem to be able to apply more than enough pressure to kill my pads.

I remember a few other members also asking questions about brake updates... :driving:

I was browsing German forums yesterday and stumbled across Tarox who surprisingly offer upgraded discs for the 35i/35is at the right 348mm size (most are smaller, which is illegal in Germany- you are not allowed to fit smaller discs than OEM).

They are quite pricy, but significantly better than stock,

http://en.tarox.com/products/brake-disc-f2000.html

http://www.brake-point.de/BREMSENTECHNIK/Bremsscheiben/TAROX-Brakes/Vorderachse/BMW/Z4/Z4-E89/sDrive-35is/TAROX-F2000-Sportbremsscheiben-BMW-Z4-E89-sDrive-35is-09-2010::87510.html

tarox-f2000.jpg

Coupled with what some consider to be the best pads for fast road use, the Hawk HPS 5.0 pads

Good review here: http://www.e90post.com/forums/showthread.php?t=1042276

http://www.ebay.com/itm/BMW-Z4-Sdrive-35i-35iS-Front-Fast-Road-Hawk-HPS-5-0-Brake-Pads-/171752842689

All in around £350 (less German VAT) plus shipping.
May go braided hoses (+£100) / Tarox RoadRace Brake fluid (DOT4, but 300c+ boiling point)

Probably looking at around £650/£700 with all expenses - a lot less than £2700 + fitting for the Brembo !

They also offer rear set up, but no point until those discs are dead.
 
I'm partial to Maxtorq group N discs. They're a no compromises cast iron budget racing/rally disc. They look boring, they will rust if it's raining in the same continent, wear quickly & will eat brake pads. However, they're cheap, nearly impossible to warp or crack (they're designed to get plunged into the local river when cherry red) & have a friction co-eficent to die for when cold and improve with heat.

There is a a drilled & grooved version but I bought Grp N & a them machined with 3 groves per face which proved a more reliable solution for fast road/track use.
 
Is the brake upgrade for track day use? I have a few criticisms of the 35is but I have never found the OEM brakes wanting on the road - even when employing the most spirited driving!
 
Garvin said:
Is the brake upgrade for track day use? I have a few criticisms of the 35is but I have never found the OEM brakes wanting on the road - even when employing the most spirited driving!
Click to expand...

On the autobahn, yes... total brake fade after braking from 140+ mph, do it once, next time 50% brake power
 
techathy said:
I'm partial to Maxtorq group N discs. They're a no compromises cast iron budget racing/rally disc. They look boring, they will rust if it's raining in the same continent, wear quickly & will eat brake pads. However, they're cheap, nearly impossible to warp or crack (they're designed to get plunged into the local river when cherry red) & have a friction co-eficent to die for when cold and improve with heat.

There is a a drilled & grooved version but I bought Grp N & a them machined with 3 groves per face which proved a more reliable solution for fast road/track use.
Click to expand...

Very interesting left field choice, thanks for the info :thumbsup:
 
stuartinzg said:
Garvin said:
Is the brake upgrade for track day use? I have a few criticisms of the 35is but I have never found the OEM brakes wanting on the road - even when employing the most spirited driving!
Click to expand...

On the autobahn, yes... total brake fade after braking from 140+ mph, do it once, next time 50% brake power
Click to expand...

Not much call for 140mph in good old Blighty, not enough clear spaces and even if there were the licence wouldn't last long. You'd think a German car would have that scenario covered, although thinking about it the worst car I had for brake fade was, in fact, a Mk1 Audi TT 225!
 
Garvin said:
stuartinzg said:
Garvin said:
Is the brake upgrade for track day use? I have a few criticisms of the 35is but I have never found the OEM brakes wanting on the road - even when employing the most spirited driving!
Click to expand...

On the autobahn, yes... total brake fade after braking from 140+ mph, do it once, next time 50% brake power
Click to expand...

Not much call for 140mph in good old Blighty, not enough clear spaces and even if there were the licence wouldn't last long. You'd think a German car would have that scenario covered, although thinking about it the worst car I had for brake fade was, in fact, a Mk1 Audi TT 225!
Click to expand...

Yes, although I used to seriously warm up the brakes on a 944 S2 going between roundabouts on the A27 toward Portsmouth from Brighton! They were 4 pot Brembo's all round...wish I could transfer them over.
 
First thing I would do is go for 4 or 6 pot radial callipers with some decent fast road pads on OE discs. From there I'd then move to increasing disc sizes using 2 pcs disc/bell (this is made much easer by first moving to a radial calliper)
 
So why is this tarox disc an upgrade?
Its exactly the same size and thickness as the OEM disc.
BMW makes it's own discs and they are pretty good at it. Usually the only way a bbk offers an upgrade is because they have bigger or thicker discs (more heat dissipation), 2 piece floating discs (lighter than all steel due to aluminium inner core and better protected against heat warping etc), bigger pads (more friction potential, more heat resistance per set amount of energy) and bigger but lighter calipers (aluminium calipers, less unsprung mass or the same mass with the benefit of bigger pads).
That tarox disc is just another all steel disc (if that picture on their website is accurate), with some grooves. In fact I believe that the OEM discs are even 2 piece with an aluminium core, so lighter (=better)

I see nothing here of that. I only see an 'upgraded' pad, and even upgraded pads are very debateble. I mean the stock OEM bmw pads are not rubbish. You might get more fading the second time, but an OEM street pad is designed to brake the first time very strongly. A track pad is terrible at that. That brakes the 2nd time better ;).


Imho if you have fading the second time on the autobahn, you have a heat dissipation problem. Get bigger discs and larger pads. also called BBK. Maybe make some brake ducting.
Or lighten your car. A heavy car has more kinetic energy to dissipate so it requires bigger brakes.
 
GuidoK said:
So why is this tarox disc an upgrade?
Its exactly the same size and thickness as the OEM disc.
BMW makes it's own discs and they are pretty good at it. Usually the only way a bbk offers an upgrade is because they have bigger or thicker discs (more heat dissipation), 2 piece floating discs (lighter than all steel due to aluminium inner core and better protected against heat warping etc), bigger pads (more friction potential, more heat resistance per set amount of energy) and bigger but lighter calipers (aluminium calipers, less unsprung mass or the same mass with the benefit of bigger pads).
That tarox disc is just another all steel disc (if that picture on their website is accurate), with some grooves. In fact I believe that the OEM discs are even 2 piece with an aluminium core, so lighter (=better)

I see nothing here of that. I only see an 'upgraded' pad, and even upgraded pads are very debateble. I mean the stock OEM bmw pads are not rubbish. You might get more fading the second time, but an OEM street pad is designed to brake the first time very strongly. A track pad is terrible at that. That brakes the 2nd time better ;).

Imho if you have fading the second time on the autobahn, you have a heat dissipation problem. Get bigger discs and larger pads. also called BBK. Maybe make some brake ducting.
Or lighten your car. A heavy car has more kinetic energy to dissipate so it requires bigger brakes.
Click to expand...

All good input, thanks. The Hawk pads will probably make the most difference. I ran EBC pads on my E92 and it was a huge improvement over OEM for fade reduction, but terrible dust. Apparently the grooves in the disc help with heat dissipation (one of your points) - they are also german TUV approved for the 35iS which adds confidence.

If their blurb is anything to go by:-
"Tarox Brakes are recognised all over the world as the very best performance discs available on the market. Tarox are based in Osnago in Italy and have been established since 1976. Tarox have been heavily involved in many forms of motorsport including Formula 1." Lots of positive reviews online.

Probably the more expensive ones posted above would be the ultimate upgrade without going BBK as they look to be 2 piece / lighter than OEM.

557249_x800.jpg
Aluminum hats, 2-Piece construction
Rotor weighs only 19.8lbs compared to a stock 335i rotor (24.3lbs).
 
No the grooves are there to guide away gasses that can occur when the pads heat up (just as drilled is), and the grooves are said to help with skimming off glazing off the pads, although I doubt that to a certain point, because that would result in huge pad wear.
It doesnt help with heat.

Also that ecs comparison is to a 335i disc. according to bmw's parts catalog, that disc is heavier (maybe all steel, different part as the 35is). And I personally think the displayed weight is shipping weight, so including box (I never really checked that though, but for a parts system shipping weight is much more important :wink: ).
I think the ecs disc is not significantly lighter than the stock 35is disc, because I think that already has an aluminium inner hat. But if you have a 35is, that is really easy to check I imagine :roll:
 
When we're talking about fade what do you actually mean. Is it reduction in braking efficiency or getting to the point where attritional brake pressure does not increase braking power? I consider the latter to be fade & have not experienced it on my car. I have experienced a progressive reduction in braking efficiency but I've always been able to compensate with increased brake pressure.

If you're experiencing what I consider fade then your only solution is to increase disc diameter. But if you're experiencing progressive loss of braking efficiency then fast road pads would be a good first step.

One thing to remember is any surface area removed from drilling/groves reduces the swept braking surface so translates into higher braking temps. This is why I had very minimal proved machined into my Maxtorq discs, just enough to disperse pad gas & nothing more, as I was struggling to get big enough discs under my front rims (I was stuck with 14" rims).
 
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