brake rotor redrill

[Lambo nut]

I have a set of wheels that's dual drilled for 4x114 & 5x114. They look exactly like your diagram. These are wheels from a reputable company who wouldn't do it if they thought it was unsafe.

And this is because as noted in a previous post, once the rotor is clamped between the wheel and hub, the holes in the rotor are doing nothing. Once the rotor is centered on the hub and the wheel properly attached, the rotor is not going to rotate and put any force on the sided of the studs between the wheel and the hub. If it were to move, you've got a big problem, or likely just loose nuts.

Kevin

 

[that-guy]

gave drilling a shot on my lunch break, sat on a 3/16" Cobalt bit on my air drill with no cutting oil for about 5 seconds and went half way through the thickeness of the hat...SUCCESS...now to get it clamped down on the mill and get these things done

 

[logixjock]

I don't see a problem. Don't weld on it, just drill the holes and call it a day.

+1 Back before we had all the armchair builders from the internet to tell us how unsafe everything was, I saw lots of these done. Before the CAD/CAM age, you actually had to modify stock parts a lot of times to get what you wanted Heck, that was half the fun!

 

[Beenman]

my question is, how safe is this to do,

Perfectly safe. Its quite common a modification on rotor hats. Many German cars (BMW, VW etc) have up to 10 or more holes in their rotor hats without much "meat" between them.

Two things to note:

1) Put a decent chamfer (around 2-3mm at 45 degrees) under the new holes where the rotor mounts up against the hub. This is critical to clear the radius around the wheel studs.

2) Never ever weld onto the hat. Even slight distortion due to the heat of the welding process will cause massive runout issues.

Hope this helps.

 

[zkling]

Hm... looks like I was wrong. It will still look kinda rigged to anyone who pulls the wheel off but functionally will be fine.

That is if only the person pulling said wheel off doesn't know WTF they are doing / talking about.

"Hey guys I pulled out this drain plug, WTF is this black sticky oily substance that is coming out, is that normal?"

so its obvious that this conversation has more opinions than facts,

No, it is just another case of some folks know what they are talking about, others don't. Plain and simple.

gave drilling a shot on my lunch break, sat on a 3/16" Cobalt bit on my air drill with no cutting oil for about 5 seconds and went half way through the thickeness of the hat...SUCCESS...now to get it clamped down on the mill and get these things done

Did you just drill a random hole with an air drill just to see if it would work? Please, do it on a mill and indicate off the hub bore. Don't forget to chamfer both sides.

 

[markw365]

Jeep guys do this all the time for upgrades to steering components. XJ knuckles to WJ knuckles with crossover steering. Requires getting a set of WJ rotors and redrilling the pattern from 5 on 5 to a 5 x 4.5 pattern. Not a big deal, as the rotor is hub centric. I've even cut the hat off an old rotor to use it for a template in my drill press. I've seen plenty of dual bolt pattern rotors, heck I've got dual bolt pattern axle shafts in the rear dana 44 in my jeep. Just lay it out so you have plenty of material between the holes. If you have the rotor with the proper pattern and hub center, use it for a guide.

 

[V-10 Killer]

Looks like the 1 hole you are keeping will have to be slightly slotted as well...

Does the 5-lug and the 4-lug pattern share the same distance from the center of the rotor (same radius)?

I was also wondering these things. it might only be a few millimeters but having it offset could really cause balancing issues.

 

[gungatim]

as mentioned, this is done all the time, and used to be quite common back in the day on VW's. My dunbuggy is drilled from 4 lug to 5 lug chevy pattern and has had no issues since 1970 when it was originally built...