No worries, my wife’s blonde so I speak the lingo fluently
Not a dumb question Carly, but there's quite a few technical things you need to look at ; unless someone else has already done this and can provide practical experience, here's what needs to be considered :
• Distance between centres of the mounting points on the calipers – will it bolt straight up to your forks, or would it need an adaptor bracket
• O/D of the disc - is the disc a larger diameter on the later model
• Width of swept area of the disc – measure from the outside of the disc to the inside of the swept area (area that is touched by the pads) ; chances are it’s narrower on the 6p disc, I don’t think this would affect you as long as the pad width is no more than the swept width
• Disc offset : place a 6p caliper over the disc, and see where the mounting lugs are relative to the holes in the caliper – it’ll be obvious straight away whether a) the holes line up, b) you need to have spacers made and get longer high-quality bolts, or c) you’d need adaptors made
• The 6p caliper will have a different bore area to the old 4p (that is, if you take the radius of each individual piston and calculate the area using Pi R squared, the 6p almost certainly will be more than the 4p). This will change your hydraulic ratio, and if the new calipers have more area, your brake lever will have a lighter pull with more travel, it will have more power, but it will also have less feel (not necessarily good under heavy braking). I once swapped a ZXR 5/8” master cylinder for an R1 14mm unit, and the difference was astounding. The easy solution here would be to get a matching master cylinder for the calipers.
I can’t think of any thing else, maybe someone else will point out something I’ve missed.
All the best,
Brian