Disc Brake Post mount, IS mount, adapters, 140/160/185????

I've had disc brakes in the past but they've either come already set up on a bike or have been a complete set I've bought with all the correct bits & pieces included.

Now however I have a Pace RC38 fork, an Avid Juicy 5 disc brake caliper & lever for the front, a 160mm Avid disc rotor, and a (presumably post-mount adapter) 185mm spacer/mount thing for it.

I've tried the caliper on for size and it seems to fit the Pace RC38 forks, do I need such an adapter for these forks? what sort is it I should be using? a Post-Mount or IS one? as using the adapter which came with the brake and says "Avid 185mm" on it seems to put the caliper in the right position-ish :?

However, when using this adapter the 160mm disc rotor will not fit the caliper correctly :roll: so whats the easiest way around this? do I get a different caliper adapter to space the caliper to suit a 160mm disc and then also get a 160mm disc? or do I simply buy a 185mm disc and use the current hardware?

I thought 160mm disc up front would be more than enough for a retro XC bike, does a 185mm disc really give that much more bite?
And why are there so few 185mm disc rotor sabout? 180mm seems to be the more common size?

:? :?

to save weight :? I replaced the front 185 mm discs by 160 and they stop me fine. (pretty sure 185 is the more common diameter)

on my lightest hardtail, I have 160/140 KCNC razor discs that stop me too but not quite so well but enough (check them discs out, more air than metal).

I am 95 kg +/- a couple.

I'd be inclined to run the 185 up front, the added weight isn't really too much of an issue as the diameter does make quite a difference is stopping power & cooling.

Pace recommend 165mm dia disc maximum, run a 160mm on my RC39's

http://www.pacecycles.com/PDFs/SpecSheet.pdf

not_fat_matt":33mjndei said:

Pace recommend 165mm dia disc maximum, run a 160mm on my RC39's

http://www.pacecycles.com/PDFs/SpecSheet.pdf

Click to expand...

forkin' 'ell I thought I remember seeing that somewhere :roll:

as I have a 160mm disc then I guess I need to find an adapter to mount the Juicy5 caliper to the fork to suit a 160mm disc.

Anyone help me out? is it a IS to Post-Mount adapter I need? like this one?...
http://www.ebay.co.uk/itm/Avid-Disc...sure_cycling_bikeparts_SR&hash=item27c6576882