BBK (Appropriate), Fit, Brands

[matt]

Changing master cylinders will also change your brake bias in many cases.

More rear bias is usually good.

[Mike325]

Changing master cylinders will also change your brake bias in many cases.

More rear bias is usually good.

Yes, to a point. Too much will cause the rears to lock up and that is not a good thing.

[Jean]

Changing master cylinders will also change your brake bias in many cases.

More rear bias is usually good.

I don't believe brake bias will change in my case, I am installing 325i calipers and rotors upfront, and 325i trailing arms. According to another thread the proportioning valve is the same on the 318i and 325i cars so there are no other differences ..

[matt]

As long as you put in the 325i master cylinder, you should have the same brake bias as a STOCK 325i.

Your car isn't a stock 325i is it?

Your car is lower all around and lighter in front than a stock 325. Both of those factors point to you needing more rear bias.

[Massive Lee]

Changing MC size will NOT affect bias. Both chambers in the MC have the exact same diameter.

[matt]

Changing MC size will NOT affect bias. Both chambers in the MC have the exact same diameter.

Both chambers in the stock master cylinder do not have the same diameter. One is 22mm and one is 17mm. Both chambers in the common 25mm M/Cs are the same diameter. Thus, the bias changes.