Group Buy: Two-Piece Slotted Rotors

[Evil Twin]

Earlier this year, I contracted with Dave Levy of Cedar Ridge Fabrication to put together a two-piece brake-rotor replacement package for my Elise. I shook the setup down at Sears Point a week or so ago, and I’m very happy with the new setup. Having done the work for my setup, Dave’s agreed to open up the package to the EliseTalk community in the form a Group Buy. Details are below.


For those of you who’ve not heard of Dave, check out the safety equipment thread in the Track & Technique sub-forum. Although Dave spends most of his time building high-end custom bicycles under the TiCycles brand name, he also builds lots of car parts, including the vastly superior anti-submarine strap bar I’m using. We’re both instructors in the PacNW. Dave tracks a highly modified NSX and is active on NSX Prime under the screen name TitaniumDave.

A few words of background:

Here’s what I like about the stock brakes. The system is well-balanced. The rotors are appropriately sized for the weight of the car. The calipers are strong and well matched to the rotors. With good fluid and track pads, nothing overheats and the rotors only need replacing when they wear (rather than when they fail/crack; with my last track car, I used to crack the front rotors after 6-9 track days!). So far so good.

Here’s what I *don’t* like about the stock brakes. The OEM rotors (i) aren’t as robust as they could be, particularly when used with an aggressive track pad, (ii) are ridiculously priced from the dealer ($300 per corner retail – bleh!), (iii) have uni-directional vanes, so the vanes point the wrong way on one side of the car thereby degrading cooling (this may not matter, but I find it offensive), and (iv) are much heavier than they could be -- in the worst possible way because the weight is unsprung AND rotating. Moreover, the rear rotors provide more swept area than the pads require, which is sloppy -- and heavy.

Aftermarket options are limited. Given that the stock system is well balanced, I see no need for a “big brake” kit. The car doesn’t need more brakes, it needs lighter/cheaper brakes. So, I went searching for options that can be used as a bolt-on replacement for the stock rotors while using the stock calipers. The Sector111 gold-plated offering a neat product, but for $1600, it doesn’t pass my gag-threshold, and I don’t see any need for floating rotors (which adds weight) as we don’t suffer thermal-related failures. Others have arranged for a Group Buy on DBA 5000 rotors. That’s not a bad solution, but I felt that I could do better by working out a deal with Dave.

Here’s what Dave put together:

Both of the options, described below, are drop-in replacements for the stock rotors (although they provide slightly less than 1mm less wheel clearance, so PM me if you’ve got aftermarket wheels with seriously tight clearances) and satisfy the following criteria: (i) two-piece high-quality cast rotors mounted to aluminum hats, (ii) assembled using *safety-wired* Grade 8 hardware, (iii) sized like the stock rotors (288mm outside diameter, 26mm thick), (iv) vented with side-specific directional vanes so the vanes point in the right direction on all four corners, (iv) slotted with slots that do not reach the radial edges of the rotor to prevent premature cracking, and (v) delivered to the buyer fully assembled and -- this is a neat feature -- balanced and heat-treated for stress relief.

The aluminum hats will be treated with electro-less nickel for corrosion resistance (the photos below show the untreated rotors we did for my car, but there is one photo showing the nickel finish to give you an idea of what they’ll look like) and will be sized differently, front and rear, in order to cut further weight in the rear and to provide a swept area exactly equal to the footprint of the rear pads. Note that these hats *can* be used for a floating setup (switching from fixed to floating would require new, t-nut style, hardware), although Dave did not price this out for me, as I have no interest in it. If this is important to you, PM me, and I’ll raise the issue with Dave. Rotors will be manufactured in the United States to assure the supply of replacement rotors/hardware going forward.

The pricing Dave put together is per set (four rotor-assemblies) and excludes shipping:

• Option 1 (Basic Setup): $998 per set of four. Total weight savings (all four corners): 5lbs. Cost per replacement rotor without new hats: $145. This option is $200 cheaper than replacing all four stock rotors, reduces unsprung/rotating weight by a significant 5lbs, and the replacement rotors are less than half the cost of OEM replacements.

• Option 2 (Lightest Setup): $1158 per set of four. Total weight savings (all four corners): 10lbs (attributable to using a rotor with slightly larger internal venting). Cost per replacement rotor without a new hats: $185. Replacing all four rotors costs about $50 less than stock, but cuts unsprung/rotating weight by twice as much (10lbs!), and the replacement rotors are still less than two-thirds the cost of OEM replacements.

If you have questions: post them here or PM me, and I’ll respond on Dave’s behalf (he’s agreed to honor these prices only if I agree to doing the legwork with the Elise community).

If you want to order.

• PM or email me your address, including your zipcode, so I can figure out your shipping costs.

• Either (i) mail a check to Dave Levy, Cedar Ridge Fabrication, 15707 NW McNamee Road, Portland, Oregon 97231 or (ii) send Dave the money by Paypal using the address titaniumdave@msn.com. Pls. include the address and telephone number for where you'd like the rotors delivered. If you elect to use Paypal, pls. add 3% to the total cost of the order in order to cover the fees for the funds transfer.

Best,
Twin

The photos below show the untreated aluminum used to make my prototype hats. The hats sold through this GB will be treated electro-less nickel.









The picture below shows the electro-less nickel finish that will be used on the production hats:

[Evil Twin]

Below is a photo of the rotor on the car (passenger's side rear wheel):



Below is a photo of the rotor on the car (passenger's side front wheel):

[CountTracula]

Cool. Time to update the signature, ET!!!

[ChrisH]

Is there a downside to option #2 other than the higher cost relative to option #1? For example, would it be more likely to warp, is there less material to wear (hence it wears out faster), etc.

[MyElise]

Nice job Evil. You seem to have covered all of the bases and I totally agree with your assessment of our existing system.

One question. The clearance issue you mentioned is with the hats? Don't think it could be with the calipers as you haven't changed the mounting points.

[Evil Twin]

ChrisH: there's less material in the rotor (the vent between the two faces of the rotor is slightly wider), that's where the weight savings comes from. In a heavier car, sure, I'd worry about using too light a rotor for fear it would start developing cracks in the rotor face and ultimately fail sooner, but in our car I don't believe that's an issue -- with these rotors or the OEM ones. Nobody is cracking their rotors, even guys running Hoosiers and doing lots and lots of track days. FWIW, I've got the "lightest" setup, and I expect to get as much wear from these, if not slightly more, than what I'd get from the OEM ones before replacing them. The good news, is that when I go to replace them, they're two-thirds the cost of the OEM replacements. MyE: the clearance issue relates to the wheels, as the material of the hat face is thinner than the stock rotor-face, but we're talking 1.5mm or so, nothing serious. I only mentioned it in case someone is running aftermarket wheels that just barely clear the calipers (say, with less than 2mm of clearance). For stock wheels, the difference isn't noticable.

[TimMullen]

Are the replacement rotors interchangeable between the hats? In other words, could someone opt for option 1 now, but later get the replacement rotors from option 2? Or the other way around. Might let people choose one version now, and change to the other version as things develop later on...

[Evil Twin]

Tim: The only difference between the two options is the width of the internal vent (i.e., the gap between the two rotor faces), so, yes, the same hats can be used with the lighter rotors (or vice versa). If Dave could source the lighter rotors for the same cost, there would only have been one option, but the lighter rotors are more expensive. I wasn't sure whether the weight savings would be worth the extra cost to some folks, so he priced out the two options. For him, it's only a matter of which rotors he orders. Production of the hats and assembly are identical.

[MyElise]

Originally Posted by Evil Twin

MyE: the clearance issue relates to the wheels, as the material of the hat face is thinner than the stock rotor-face, but we're talking 1.5mm or so, nothing serious. I only mentioned it in case someone is running aftermarket wheels that just barely clear the calipers (say, with less than 2mm of clearance). For stock wheels, the difference isn't noticable.

Ahhh, so you are slightly changing the net offset. I am running CE28's and while I haven't measured it, the caliper offset is less than with the LSS wheels. This could be an issue. But it would be easily resolved with a set of 2-4mm spacers.

[Evil Twin]

Yes, but we're talking (I think) all of 1.5mm of difference in the final design relative to stock (my prototypes are even thinner, which saved a bit more weight). So the difference is pretty small, and, yes, you're right, you can always use a spacer from Blackwatch Racing if you're having clearance issues (my guess is that if your wheels are THAT tight, you're already having to use a spacer!). But the net change in offset is really pretty tiny. Remember that 1.5mm is all of 5/100 of an inch. With the stock wheels, the difference is insignificant.

[powerbookguy]

Originally Posted by Evil Twin

Yes, but we're talking (I think) all of 1.5mm of difference in the final design relative to stock (my prototypes are even thinner, which saved a bit more weight). So the difference is pretty small, and, yes, you're right, you can always use a spacer from Blackwatch Racing if you're having clearance issues (my guess is that if your wheels are THAT tight, you're already having to use a spacer!). But the net change in offset is really pretty tiny. Remember that 1.5mm is all of 5/100 of an inch. With the stock wheels, the difference is insignificant.

is the replacement measurement spec any different from stock with the wider vents?

[MyElise]

Originally Posted by Evil Twin

Yes, but we're talking (I think) all of 1.5mm of difference in the final design relative to stock (my prototypes are even thinner, which saved a bit more weight). So the difference is pretty small, and, yes, you're right, you can always use a spacer from Blackwatch Racing if you're having clearance issues (my guess is that if your wheels are THAT tight, you're already having to use a spacer!). But the net change in offset is really pretty tiny. Remember that 1.5mm is all of 5/100 of an inch. With the stock wheels, the difference is insignificant.

Just measured it. I have 8.4mm minimum.

[Evil Twin]

Originally Posted by powerbookguy

is the replacement measurement spec any different from stock with the wider vents?

These rotors have the same exterior dimensions of the stock rotor (both thickness and diameter), so they fit within the stock calipers exactly as the OEM rotors do and will permit the exact same amount of pad travel.

[spider]

Slotted cuts and vented vanes are running in the same direction. I thought they were usually running in the opposite direction... Just wondering. It may not make a different either way. Thanks.

[Buz]

What is the weight of these rotors? Are they avable in pairs?

[unibrain]

Are the replacement rotors a standard part? If Dave decides he hates cars will we be able to get them from somewhere else?

- Jim

[Evil Twin]

Spider: I can't imagine that it matters, and I've seen them both ways, FWIW. Buz: the lightest setup saves 2lbs per corner in the front and 3lbs per corner in the rear. The light setup saves about 1lb less per corner all around. I'll ask Dave if he's willing to sell just a pair (rather than all four), but for the time being, just assume he will. It's a reasonable request, and it's not logistically any more difficult for him. Jim: yes, replacement rotors are off-the-shelf. If Dave vaporizes, I'll release all the information publically, so you can find another supplier for the rotors and someone to balance/heat-treat them for you -- but bear in mind that he's been doing this a long time and has a pretty sizeable following among the NSX community...

[Tim Taylor]

Twin -

This is a really well thought out offering. "Hats" off to you (sorry, couldn't resist). It almost makes me wish my OEM rotors were shot, but unfortunately, I still have quite a bit more left in them.

Nice job.

[Evil Twin]

Originally Posted by Tim Taylor

Twin - This is a really well thought out offering. "Hats" off to you (sorry, couldn't resist). It almost makes me wish my OEM rotors were shot, but unfortunately, I still have quite a bit more left in them. Nice job.

Thanks for the kind words, Tim. Dave did the prototyping for me as a favor as he'd gone through a very similar exercise putting 997 turbo brakes on his NSX (the calipers still say "Porsche" on them, which makes me laugh). But given that I can't be the only Lotus-owner gagging at the cost of OEM replacements and given the obvious appeal of dropping 10lbs. of unsprung/rotating weight from the suspension, I figured that others might want to go the same route. If there isn't enough interest, that's fine. This was all driven by my lack of success in finding something that works for me.

But go start start actually using your car....

[raggedy1]

I'd be very interested in this setup, but my brakes are nowhere near shot so I can't justify the replacement. Nice job!