Quote:
Originally Posted by Pedro
Had the P4’s on my 1000DS, epic stopping power when combined with a radial master cylinder
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Agreed!
Quote:
Originally Posted by stopintime
...the effect of the "999" four pads calipers over your own "996" two pads calipers is very small.
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Having actually carried out this mod on my S2R, (which shares OE calipers with the S4R), I'd have to disagree with that.
Although you'll have slightly less pad area in contact with the disc with the new calipers i.e. 42.6cm³ (2 x 21.3cm³) per disc vs 39.6cm³ (4 x 9.9cm³) for old and new respectively, the overall stopping power is increased and the feel is quite different.
Because piston size increases from 30mm + 34mm (stock) to 2 x 34mm (P4s), you will get an increased force against the disc for any given effort at the lever. There will be slightly more lever travel but it's not enough to warrant a different master cylinder, (I certainly didn't have any problems running the P34s with the stock m/c on my S2R).
The thing you have to be wary of, especially until you are used to the feel of the new setup, is that, because of the increased initial bite, grabbing a handful of brakes in an emergency is more likely to result in an instant lockup - you need to treat them with respect and build up to maximum braking effort.
Boosting your brakes isn't all about lap times - I think anything that can help you stop quicker in an emergency is a worthwhile upgrade. You may only ever use the additional stopping power once but, if those calipers give you the extra metre you need to avoid that myopically driven SUV that pulls out on you during the school run, then that's money well spent in my book!