Learn me custom brake kits wrt center bore

So I'm looking at upgrading the brakes on my X-Type and I was wondering, if I go with some off the shelf rotors, what issues will I run into with going with a larger center bore opening on the rotors compared to what the car actually has? Center bore on my car is 63.5mm and I found a bunch of rotors I would like to use but the centers are listed at 67. Will this be an issue? Ideally I'd like to use the calipers for that particular rotor. Keeping the bolt pattern the same most of my options would be in the volvo family. I'm currently employing 300mm rotors with a thickness of 24mm. Pad options are limited and the rotors aren't really thick enough to handle the heat at the track. Thanks!

Anybody? My thought is if the bolt patterns match up it shouldn't be a big deal to have it centered and therefor nothing be out of balance.

I would think you'd have to come up with something similar to a spigot ring for wheels in order to center the disk properly. Given that your life will depend on it I wouldn't be too keen to have a somewhat unattached brake disk on the car.

IIRC the X-Type and the Contour SVT share the same brakes, right? If so, there's several well-worked out brake upgrades, such as 300mm Focus SVT front rotors with a spacer for the stock caliper and the 268mm Contour SVT fronts at the rear with similar spacers.

You'll definitely need an adapter ring if the bore doesn't match. The lug holes in rotors tend to be oversize. The rings can be made fairly easily on a lathe, or stick with rotors that share the same bore diameter.

Looking a little more (and re-reading your original post, doh!) it appears that the X-Type already uses 300mm front discs. Have you contacted some of the bigger brake pad manufacturers about pads for your car? Maybe getting custom pads made up? Looks like Porterfield makes an R4-S pad for your car, perhaps you can get them to make up a set in a more track-friendly compound? Seems to me that'd be easier than trying to upsize rotors. How about adding some brake cooling ducting?

I am using the R4-S pads now and I'm cooking them. They don't make anything more aggressive than that for my car. I've thought about going back to Carbotech for some more aggressive pads but I feel the rotor size is a larger hindrance than pad material at this point.

I've also got a set of brake lines in with Pegasus Racing for some stainless steel lines to be made. That will help with the feel but I'm not sure if it will actually help the braking capabilities - unless the stock lines are swelling to the point I AM losing pressure.

The rear rotors are solid and I'm looking at trying Gen I SHO rear rotors to see if that helps. I'm hoping with the SS brake lines and vented rear rotors the brakes will have a much better pedal feel on the track and maybe work better - I'm wondering if I'm overheating because I can't get proper pressure at the pads to work. If these don't work I'll try more aggressive pads but I'm sure I'm still going to need larger rotors, 300mm x 25mm doesn't seem like enough rotor for a 3300lb car...

I have been looking at Focus upgrades but not the SVTF ones. A lot of the European spec Focii have larger brakes, like the Focus RS. Problem is I've been trying to find stuff in the US market that will work with relation to the size I need and applicable bolt pattern but anything larger than what I have has a much larger centerbore.

Thanks for all the posts, looks like I need to find something with a closer centerbore than the options I've been looking at...

If Porterfield makes an R4S, they should be able to provide an R4. And if you have a set of cooked pads, most companies should be able to make you a set of replacements.

Hmmm, good idea. I'll see about the R4's.

I ended up ordering a set of Carbotech XP10's, we'll see how the car likes them.

On another note, I ordered a set of brake lines from Pegasus Racing and installed them the other day. MUCH better pedal feel, I had a feeling a large part of my problem was line flex. That definitely confirmed it.