I have some 11 inch rotors but the suspension is setup for 10 inch...is it reasonable to machine the diameter of the rotors down an inch? These are vented rotors so I'm not sure if that matters. I could move the calipers but that would mean that I would need bigger rims. This is going into a MKVIII IRS on my Merc and I am trying to get rid of the 4.25 inch lug spacing in favor of a more standard 4.5 inch...it's just that rotors that fit the 4.5 hubs are larger than the stock MKVIII rotors.
It'll depend on the caliper. Can the caliper you use move inward 1/2" without contacting the hub/center? Will the pads stick out over the edge of the rotor? There's no reason- physically- you can't cut the rotor down, but if the caliper can't be moved inward to match, it won't do much good. Doc.
Thanks Doc. The caliper is good just where it's at now assuming I can make the rotor smaller to match. There is a guy who makes a spacer for these IRS that will move the caliper out to match the 11 inch rotor but that isn't my first choice. If it's possible to just turn the rotor down an inch then I am good to go...thanks again.
You'll lose a considerable amount of braking power by reducing the diameter of the rotor that much, and your Merc isn't a light car. If it was me, I'd do what's necessary to keep the 11" rotor.
As I understand this- You got a rear end with disc brakes and 10" rotors and a 5 on 4.25 bolt pattern (metric) hubs and axles. You want to keep the calipers where they are and change to a 5 on 4.50 bolt pattern. You got some discs you want to use with the right bolt pattern but they are 11". If I got this right the yes you can chuck 'em up in a lathe and whack off an inch of diameter with no problem. BUT This ain't gonna change the axle flanges to the bolt pattern you want. More parts will be required.
You are right on the money...I have already ordered a set of Ford Cobra hubs that are 4.5 inch pattern, I just haven't been able to find rotors to match that are 10 inch diameter. For as often as I would need to replace rotors I think that the machining would be a small inconvenience compared to going to a very large diameter brake rotor/caliper setup and then having to go to 17 inch or larger rims. As for stopping power I feel relatively confident that the rear brakes off a Lincoln MKVIII will be sufficient to handle the Merc...compared to the stock drums these disks are monsters. Now I just need to find a local machine shop to turn the rotors...damn I wish I had a lathe!
Charlie, They should cut down just fine. I would want to know that my machinist was competent. Probably not a problem in Diego but back here incompetence is the name of the game. If it were mine what I would do if I expected to keep the car is get a second set soon and have them machined for spares. Maybe this is just a quirk of mine but I ran some many oddball pieces over the years that I try to keep spares on hand so if I need them I have them. You will never believe how many times that I have waited in the Greyhound station for pieces that I had left with someone in the event that I had a failure somewhere on the road. I also think that the 10" brakes will stop you just fine. maybe not in a canyon carving or auto cross situation but for driving it should be just fine. I assume that you are running multi piston calipers or at least large single piston calipers?
I hear you on the competancy issue...awhile back I had a set of rear brake caliper mounting brackets re-drilled so that I could use them on a small bearing 9 inch rearend. I made a CAD drawing with all the dimensions and how I wanted the holes modified and they still screwed it up. Needless to say I don't go there anymore. The rear brakes on the MKVIII are fairly stout, I am not concerned at all about the stopping power but the issue of having a spare set on the shelf interests me. I too like having backups whenever possible
I had a mechanical disk from a go cart that I made up for my hawg for awhile. I built it just to have a hill holder. I managed to tear the caliper up trying to go enduro riding (don't even ask), but I had the foresite to make up a seciond setup while I was at it. I left the second caliper with my little brother. I called him from someplace like Pig snarf Colorado and was on my way to Bula (sp?), Montana. He put it on the Greyhound and I picked it up there and changed it out in the parking lot. Whenever you got something oddball you really need two of them.
You must have a lot of negative offset that pushes the wheel out clear of the caliper to be able to run that size rim.
The car is actually a 72 Comet but has the early mustang disc conversion from SSBC..Here is pic, I think the wheel is from a 70/71 Torino...
Yep, from the looks of that rim it is deep on the outside and shallow on the inside. I bet that if you looked on the backside of the wheel you will see the caliper standing clear of the rim and not within the rim. Nice looking Comet by the way!
Well I bought the rotors and hubs that will give me the 4.5 lug spacing that I want but now I find that the rotors have a deeper backspace so now I have to move the calipers. Since I will be moving the calipers back I may as well move them out as well and eliminate the machining and "one-off" parts. If I didn't love it I'd be screaming.
I've been referencing this page for quite awhile, maybe something is there for you too. And yes, the offset is different by about 5mm. Go half way down the page. http://home.comcast.net/~dlfraleigh/Article.html
Yeah havi I have seen that page too...I guess that there is some guy named "Fast Eddie" that makes these conversion brackets but they just look too amateurish for me. I have already done up a drawing for the backet and intend to machine it out of a solid piece of steel or aluminum. At the time I ordered the rotors I wasn't sure if they were the same as the one referenced on this site, now I know that they are. Now I just need to get the hub nuts broken loose so I can fit the new hubs and bearings.
I wanted to follow up on this thread to let everyone know about a really fine product that I found to accomplish the caliper offset that I needed. A fellow on the SCCOA forum makes the exact caliper bracket that I needed...precision CNC machined, anodized, and comes complete with mounting bolts. Here's a link to the post on the SCCOA http://www.sccoa.com/forums/showthread.php?t=120811 I bought the brackets and I am thoroughly impressed with the quality of the work and the precision of the design. Anyone who is considering going from a 10.12 inch rotor to a 11.62 rotor, either by changing hubs or re-drilling the rotor, these brackets are the real deal. Saved me a ton of work and $$$.
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