To Big Brake or not?

[arb]

That is the question… Is there a case for challenging the-bigger-the-better paradigm here?

The pro’s of big brakes are known. So are the con’s, among them cost and legal (insurance) issues (weight might also be added, a single ready big brake assembly, as listed below, weighting 23.5kg). As already indicated on this forum, it is quite an extensive (read expensive) job to fit 312mm disc brakes on a ZF (280mm) front brake system.

For reference purpose, here are the main required part numbers, which are widely available from the VAG stable of car brands (Germany, by the way, being a very good new or used part source on the continent, representing the single largest car market in Europe):

Wheel bearing housing 1K0407255AA    Left

(Achsschenkel)                1K0407256AA    Right

Wheel bearing set          1T0498621         

(Radlager/Stützlager)                  

Brake Caliper carrier      1K0615125C      

(Bremssattelhalter)                      

Brake Caliper housing    1K0615123E        Left

(Bremssattel)                   1K0615124E        Right

Brake Disc                         1K0615301AA   

(Bremsscheibe)                              

Brake Pad                          3C0698151C      

(Bremsbelag)   

[Note: to be checked whether front suspension struts are 55mm (PR-L56) rather than common 50mm].

I did source a “Bremse Umbau kit” (new OEM preassembled big brake set) in Germany but did not mount them at this stage (having not cracked the insurance nut yet).

Consequently, I keep wondering: actually, the BMW 325iX touring has 260x22 vented front and 258x18 vented rear disc brakes, or an overall braking power about comparable to the CR110 Yeti. And, personally, I never had issues with the BMW brakes.

So, I would really appreciate getting feedback from those hardy folks who actually chipped their engine but kept their 280mm front disc brakes, along with their eventual recommendations for brake discs and brake pads.

Best,

ARB

[muddyboots]

Before the Yeti, I upgraded the 288mm front brakes to 312mm on 3 different cars (Seat Ibiza and two Passat estates), all remapped TDIs - although I was lucky on those cars that they just required a carrier change.

Each time it made a massive improvement. Gives you so much more confidence in the car.

It's hard to explain the difference - people (as I used to) will think "If the standard brakes are capable of locking the wheels, what's the point of anything bigger?".

Trust me though, it does make a big difference - gives you so much more control and confidence.

Just swapping to OE 312mm discs and pads gives a big improvement; if that's not enough then I thoroughly recommend EBC Yellow pads; perfect from cold, no squeal and a big improvement over standard pads.

Although I've just fitted some slotted discs I wouldn't say uprating the discs is necessary, the standard ones will work just fine with uprated pads.

Use some good fluid, I use Castrol React Performance DOT4.

I've used standard 312mm discs, EBC Yellow pads and Castrol React DOT4 fluid on a track in my Yeti and never had any fade.

If the BMW you refer to is a fairly old - and 2wd - model (sorry, no expert on BMWs!) then I'm guessing it'll be a fair bit lighter than the Yeti, so would probably suffice with smaller brakes.

[Urrell]

If the BMW you refer to is a fairly old - and 2wd - model (sorry, no expert on BMWs!) then I'm guessing it'll be a fair bit lighter than the Yeti, so would probably suffice with smaller brakes.

 

The 1986 BMW 325iX touring is 1370kg, 105kg lighter than a new 110 4x4 Yeti.

[arb]

Thanks,

The BMW 325iX was the first generation all-wheel drive car produced by BMW (permanent viscous coupling transferring 37% of the engine power to the front wheels, 63% to the rear). Compared to its contemporary, the Audi Quattro, it enjoyed an almost perfect weight repartition and was definitvely more fun to drive. The 1991 325iX touring (4325mm long 1645mm wide estate body) had a 170hp DIN in-line 6 engine and weighted 1 350kg.

ARB