I recently purchased a set of 4 OEM rotors that are drilled and slotted. Zimmerman Rotors. Very nice and good Germany quality. I thought so until today when I went to put them on the would not seat correctly. The torx screw that holds the rotor to the hub did not draw the rotor completely on the hub. Concerned I called the company and they said they have sold over 30 sets and have not had one problem. They suggested that I put the tire on and use the lugs as make shift press while tightening the wheel and that should seat the rotor on. Anyone here have these rotors or have any thought on the suggestion the company made with the pressing them on theroy? Will this work or cause problems?

 

Where'd you get 'em? Did that suggestion come from the distributor who sold them to you or did you contact Zimmerman? Whichever it was, I'd probably ask the other. Otherwise, you might try calling a Zimmerman Rotors distributor who knows a lot about MINIs....for example, I bet the folks at Turner Minisport (they sell Zimmerman drilled) would be willing to answer a question or two even if you didn't buy from them.


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'02 IB/IB MC (name=ZIPPY) w/ assorted factory extras + SSR Comps (17&quot w/ B-stone Potenza S-03s + RDR rear swaybar + B&M short shifter + HSport ARCAs + Racing Dynamics strut brace + RSpeed exhaust + PiperCross Viper CAI......etc

 

Nobull60,

i got the slotted ones. i ran into the same problem when i was doing my install.
i took the rotors off and measured them, and they where the same as the factory ones, even the bevel on the center ring.

this was how i did minep:

i first lined up the rotor, then i put two lug nuts back in (be sure not to over tighten).
this is to line up the rotor to the hub. then i tightened down the torox screw. finally, the wheels went back on without too much banging on the freshly aligned rotor.

so far, there seem to be no ill effect except the sqeeking from the ferodos.

bbt4

 

Thanks for the ideas. bbt4 was yours Zimmermans?? And I got mine on eBay.

 

I use the Power Slot rotors which are really the factory rotors that have been slotted and recoated in that trick silver finish. I haven't had issues with them. I have used the Zimmerman rotors on Porsches in the past with absolutely no problems either - but sometimes the finish keeps them from going on dead perfect. I think bbt4's suggestion was a good one. Use the wheel lug studs to center the rotor (with the wheel off the car) and then tighten the torx. On the Porsches, we left out the two small phillips head screws that work the same function as the torx on the MINI to save the unsprung weight (I know, a couple ounces). We never had any problem other than the rotor will sometimes pull off when you pull the wheel off. Once you tighten the lugs down, the rotor will be in place if it was aligend on the hub to begin with, so that's probably where the suggestion came from to just throw the wheel on.

Feel free to call me if you need help during the process.

 

Nobull60,

they are slotted zimmermanns and i did get it from ebay.
but i got my pads and fluid from randy.

btw,
i love these pads.

bbt4

 

Thanks Randy as always and bbt4 for the information. Will try this week to get things together.

 

>>btw,
>>i love these pads.
>>
>>bbt4

<hijack>

I thought the pads were squeaky...but you still love them despite the squeaks?

</hijack>

 

>>I use the Power Slot rotors which are really the factory rotors that have been slotted and recoated in that trick silver finish. I haven't had issues with them. I have used the Zimmerman rotors on Porsches in the past with absolutely no problems either - but sometimes the finish keeps them from going on dead perfect. I think bbt4's suggestion was a good one. Use the wheel lug studs to center the rotor (with the wheel off the car) and then tighten the torx. On the Porsches, we left out the two small phillips head screws that work the same function as the torx on the MINI to save the unsprung weight (I know, a couple ounces). We never had any problem other than the rotor will sometimes pull off when you pull the wheel off. Once you tighten the lugs down, the rotor will be in place if it was aligend on the hub to begin with, so that's probably where the suggestion came from to just throw the wheel on.
>>
>>Feel free to call me if you need help during the process.

Randy-
With Zimmerman rotors once they are finished on the surface can the cross drilled version be redrilled to a slightly larger counter sink for the holes or even bore out a mm or two more to each hole for a more obvious look or would that be bad for the finish and allow more corrosion to form or bad from a structural and performance/stopping angle?

 

>>Randy-
>>With Zimmerman rotors once they are finished on the surface can the cross drilled version be redrilled to a slightly larger counter sink for the holes or even bore out a mm or two more to each hole for a more obvious look or would that be bad for the finish and allow more corrosion to form or bad from a structural and performance/stopping angle?

I didn't hear back from RandyBMC but I did get to discuss this topic with Alex@tirerack.
Bottomline- if you get cross drilled rotors don't mod them in any way- just use as is.
Better to get either:
Powerslot rotors (as RandyBMC recommends for good reason)-slightly higher cost than cross drilled but has good finish, doesn't warp, allows some flow of gas to escape, allows better performance than with stock rotors.

Or larger rotors/brake calipers (set)- The only time you will do as well with a cross drill design is if you increase the diameter of the rotor from stock- this increases the surface area of the rotor to compensate for the loss of surface area due to drilling and or slots. The Calipers are larger so the brakes will do well but the cost is high.
Don't forget about the rear brakes if you do a front brake upgrade.

Cross drilled rotors have potential problems. Same OEM diameter plus drilled holes create more edges to cause friction which helps a little on "bite" to stop but also creates more heat and dust- need good less dusty brake shoes.
The holes remove surface area and doesn't help stopping. The holes might help a little with releasing gases but the danger of warping the rotors is present with street and esp track use so be careful if you have them and allow them to cool down well after a long descent or trailbraking. Never put cold water on hot rotors. So what is good about cross drilled rotors? Low cost and for some -good looking.

Thanks very much to Alex@tirerack for his opinion on this topic.

 

Nobull60,

Can't really add anything new to this thread other than I do indeed have the Zimmerman cross-drilled rotors at all 4 corners of my Mini along with EBC green pads and they have performed flawlessly, have a good friend with the same set-up and excellent performance as well for him.

Kevin

 

>>Nobull60,
>>
>> Can't really add anything new to this thread other than I do indeed have the Zimmerman cross-drilled rotors at all 4 corners of my Mini along with EBC green pads and they have performed flawlessly, have a good friend with the same set-up and excellent performance as well for him.
>>
>>Kevin
Thanks kevin- that is adding. It means that the set up is OK but you just have to be wary of the trade offs of a "stage 1" brake upgrade. I already bought and am installing today my Zimmerman cross drilled rotors (fullset $175+), mintex pads, stainless steel brake lines and Super blue brake fluid. Only the calipers stay stock and I cleaned them, will polish and repaint them.

The net effect is better braking, better pedal feel, good looks- better than OEM and low cost. Still have to worry about heating up the rotors and warping as in OEM so be kind to your MINI.

The downsides I mentioned earlier are minimized by the better than stock brake pads with less dust (EBC green or the Mintex-both OK for street use). The stainless steel lines and better brake fluid always help. Calipers are OK as is,

Not all of us can budget or afford to spend over $1000-2000 on the big brake upgrades no matter how good they work or look. Besides I want to go in my MINI, not stop (unless I have to).

 

Are those the brakes sold by Mini Mania?

 

The real reason I don't use drilled rotors is because they will stress crack from hole to hole. They do also remove surface area.

You may ask, well why does Brembo use drilled rotors? The easy answer is - they don't. The Brembo rotors actually have the holes cast into them during the manufacturing. Even then, we used to have issues with them heat stress cracking on the Porsche race cars.

To answer your question, do not redrill the holes, as that not only removes more surface area, but also would remove the chamfer the holes have that are there to try to combat some of the stress cracking issues.

Hope that helps! Sorry I couldn't answer sooner, we've been out at the track all day, and working on new products in the shop over the first part of the week.

Randy

 

>>The real reason I don't use drilled rotors is because they will stress crack from hole to hole. They do also remove surface area.

Randy-
Thanks for your comments. I know we did talk about cross drilled problems. I guess it really isn't fair to say that stress cracks are guaranteed to happen just because we all may drive differently. Since heat is a major factor, if we know that this risk exists then we can make some adjustments for it to reduce heat at least on the street or with driving school. On the track and in competition obviously the Power slot rotors are the way to go and not have to be as concerned about heat issues. More cost-more performance.

It's just that with the lower cost of the cross drilled you get less performance. I doubt that the stress cracks will show too soon or large but may creep up over time and the heat gets to them and the metal fatigues. I will check them regularly and treat them with care. By the way, all the labor to install or time spent is an investment.

>>You may ask, well why does Brembo use drilled rotors? The easy answer is - they don't. The Brembo rotors actually have the holes cast into them during the manufacturing. Even then, we used to have issues with them heat stress cracking on the Porsche race cars.

I know you mentioned about cast rotors not being drilled to make the holes and this is good. Heat is heat and rotors will succumb if beaten up enough.

>>To answer your question, do not redrill the holes, as that not only removes more surface area, but also would remove the chamfer the holes have that are there to try to combat some of the stress cracking issues.

Besides being for looks the holes displace surface area of the disk and reduce the contact of the pads with the disk- thus lowering stopping area- not so good. But the whole edges create some added friction and cutting against the pad so that helps a little. The new brake linings and better fluid help efficiency of the brake system and help the better quality pads bite more into the rotor (also there is less dust-with good pads). As mentioned before both the slots and to a lesser extent the holes may allow release of gases when braking.

>>Hope that helps! Sorry I couldn't answer sooner, we've been out at the track all day, and working on new products in the shop over the first part of the week.
Thanks- alex@tirerack was also very helpful.

 

>>Are those the brakes sold by Mini Mania?
(not sure on brand) front slotted cross drilled rotors are $180 (not on special)
http://new.minimania.com/web/Item/NMB2002/InvDetail.cfm
Or for other options in rotors
http://new.minimania.com/NewMiniSuspension.cfm

Here is one approach.
Stock brakes are OK. Not great but not bad. For street driving they will work. Lots and lots of brake dust. The least you can do if you don't like brake dust everywhere is to switch out the pads to something less dusty. EBC green front and new rears or Mintex Red. (brake covers may collect heat)

For those on a budget or they just like the looks, the less costly cross drilled or slotted and cross drilled Zimmermans are possible. Do a full upgrade as mentioned above and keeping the calipers will run roughly $500-600 parts and about 4-5 hours labor. (replace brake linings, replace all brake fluid, replace all rotors and pads).
An example of drilled rotors- http://outmotoring.com/cross_drilled_rotors.html for about $195 a set.
About $240 from Turner.

Next up would be if you were going to autocross and drive on the track a fair amount, you have another $400+ in your budget then powerslot rotors and Ferodo DS 2500 pads would be good. Takes the heat better, higher performance. Probably a good practical solution.

Helix has a $375 stage 1 kit (slotted rotors fronts only/linings and pads) http://www.helix13.com/html/products/brakes.htm
RandyBMC has a stage 1 kit as well (Power Slot rotors front and rear, Ferodo DS 2500 pads, brake fluid) $775
http://www.mini-motorsport.com/suspension.php

Then if you really want the big brakes then make the jump up but it will run you alot more. $1700 and up.
http://www.turnermotorsport.com/html...ect_mini.shtml
Major systems- sorta overkill. Need more $$$ for the rear brake setup. ($400)


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ALOHA