Brake Question

[BigFas]

Hopefully over the coming weeks I'm going to do a front brake conversion with calipers / discs from a 330. These are bigger than the ones I'm running now, but I have a question about brake bias.

As the brake bias is at the front, will larger brakes at the front upset the braking feel of the whole car? Bearing in mind I'm keeping the rears stock (for now)? Or will it just feel like normal?

[peppernick]

Brake bias will inevitably be altered by putting on larger front brake discs. They grip more. However, more front bite is not as deleterious as increasing braking force at the back. When you brake hard, the weight of the car will be transferred to the front and you have very little weight at the rear; hence the front dips and the rear rise. Increased braking force up front will accentuate this effect more but because the rear brakes only work at 20% of what the fronts do, more front bite is not going to screw up your brake balance to a point where they will make your car dangerous to drive. I doubt there will be any significant increase in braking feel with the 330 brakes.

It's just like upgrading your front brakes to BBKs and keeping the stock rears. A lot of people do it and it's safe.

What you MUST NOT do is to put on more powerful rear brakes whilst keeping the stock fronts. This will invariably lock up the rear wheels and cause the rear end to loose traction, spinning your car.

[Tin]

yep, i concur with nick's diagnosis :D.

Just want to add, what are the specs of the std rear brakes on a 330? are they the same as the rest of the e46 bar the m3?

some folks, simply upgrade the rear pads when going for a front BBK, adding stainless steel brake lines allround and opting for a high dot 5.1 brake fluid.

Something like ATE supeblue (dot4) should be sufficient for your setup fas. [read

[Ali_]

Fas been wait a while for you to have a go at this mate cant wait to hear your results. [ok

[peppernick]

what are the specs of the std rear brakes on a 330? are they the same as the rest of the e46 bar the m3?
No they are not the same across the range. 318 one size, 320/323/328/325 another size, 330 one size. Can't remember the dimensions though.

[Tin]

No they are not the same across the range. 318 one size, 320/323/328/325 another size, 330 one size. Can't remember the dimensions though.

ah rite, on alittle searching at RealOEM.com (http://www.realoem.com) educated guesses..

selected e46 318is convertible 07/02 build car.

rear brakes : 276x19 (looking at the supplement field)
clicky for pics (http://www.realoem.com/bmw/showparts.do?model=BP72&mospid=47600&btnr=34_1014&hg=34&fg=10)

compared with e46 330is convertible 07/02 build car.

rear brakes : 320x22 (again supplement field).
clicky for pics/info (http://www.realoem.com/bmw/showparts.do?model=BS52&mospid=47605&btnr=34_1014&hg=34&fg=10)

seems like a quite a big difference.........

likewise fronts are 286x22 (318) Vs 325x25 (330)....

interestingly, there is a oem drilled disc (http://www.realoem.com/bmw/showparts.do?model=BS52&mospid=47605&btnr=34_1394&hg=34&fg=95) for the 330..
http://www.realoem.com/bmw/diagrams/d/5149.png

probably the same ones you were close to fitting on your old car nick?

would be beneficial to go for the drilled, if going for the upgrade imho.. might aswell make the best out of it, if its going to be done. :D plus will look nice behind ya 19's hamanns. :p

[Ali_]

Tin, Im pretty sure Fas took those drilled discs off Nicks hands for that very reason [ok

[kris d]

You still haven't put these on!
Getting slow inyour old age Fas! :D