I've done it... Yesterday with a lot of help from Jeff of TSW and local club member agranger I converted my 11.7" dia Wilwood rears back to OEM size TSW rear rotors. The occasion was the quarterly MetroplexMINI DIY Day graciously hosted by MINI of Dallas. First, the difference. The Wilwood kit consists of an 11.7" rotor, hat and adapter to move the OEM caliper. I've had this on the car for some 40K miles and many sets of Porterfield R4 pads. The rotor has reached end of life as the slots were about totally gone. It's been said many times the only reason to go with this larger rotor is the bling factor of having the rear rotor more closely match the size the front rotor. Even Todd of TCE will tell you that on the MINI there is no performance gain as the rears do not work that hard even under track conditions. Making this swap even more challenging was the studs. Being I have a very late 06 I'm blessed with the 14mm setup. Back when TSW first introduced the 14mm to 12mm conversion I was one of the very first customers. These held up very well over this time but the only way we'd be able to get the rotor off was to remove the studs. Oy Vey, what a job. TSW had speced the studs to use a 7mm Allen key and that left thin walls at the very end of the stud. After cracking 2 studs and then breaking the 7mm Allen key we had to resort to destroying them with vice grips, even then the buggers were recalcitrant. Quite a bit of human energy was used to extricate. They now reside in a metal recycling bin. The latest version is speced to use a 5mm Allen key to make removal easier. Also Blue Locktite is now used instead of Red. After getting the rotor to a point where it could be removed we moved to the dog bone and caliper frame setup. Once the right tools were in hand that was a lot easier but still proved to be entertaining. I can't imagine how hard this would be in an area that has salted roads. Even without the added corrosion salt would add all this hardware was still a bugger to loosen. To make things even more of a challenge the rear pads were within a whisper of the backing plates. Took a bit of finagling to use the special MINI tool one of the techs lent us. Finally we got it all apart, cleaned and lubed all the bits and reassembled with the TSW rear rotors. I'm not sure what I have for pads right now as I had a box full of assorted rears. They are either R4's or R4S's. I'll be able to quickly tell by the amount of brake dust created. Many thanks to TSW's Jeff, MM.org's agranger and the techs from MINI of Dallas for their help, advice and tools. The next rear rotor change will be nowhere near as difficult! I can't say enough about MINI of Dallas. For about 1.5 years now every quarter MetroplexMINI members invade the shop. MOD allows us to use 8 of the 16 lifts for the day. On top of that they have techs on hand to guide us. Even more fantastic is the techs let us borrow their tools and show us the little tricks they have learned over the years of servicing MINIs.
I wish the local Mini dealers were that supportive of the enthusiasts. Here it's "Got mods? Pay extra or go away!" Mat
I had similar issues getting Pilot Racing studs out of my car, if it's any consolation. it's just impossible to get any torque on a 5mm allen without stripping it. Robogrips are your friend here (as is tapping them inboard with a hammer to break up any corrosion).
I have found the only reasonable way to remove studs (whether you used blue or red loctite) is with a propane torch. If you heat them up they come right out.
I have a couple questions because I have a similar rear setup, 11.75 Wilwoods with 14-12 studs, and hope I am not going to have issues when it is time to replace the rotors. 1. Why didn't you just get replacement Wilwood rotors? I think the replacement Wilwood rotors are a little cheaper than the TSW rotors? Where you experiencing a problem with the wilwoods? Were you going to replace the hats and rotors, so it made it more expensive? If so, why did you need to replace the hats? 2. Why did you need to remove the studs to replace the rotors? Couldn't you just remove the caliper and slide the rotor off the studs. I installed the 11.75" Wilwood rotors with the studs already installed so I hope I can get them off. Did you have some type off unusual problem that made it hard to remove the rotors?
Rotor cost was a wash. After changing the front to the TSW BDM BBK the hats no longer matched. I had also done a bit of horse trading with TSW a while ago and picked up the rear rotors in the trade. I was looking long term here as well, for me, with TSW only a few miles away it made sense. If I lived where either had to be shipped I probably would have not made the swap. I have R56 trailing arms, the bolts that hold the caliper to the dog bone were covered by the trailing arm making it impossible to remove the caliper carrier when the rotor is still in place. To remove the carrier I had to unbolt the entire assembly from the trailing arm but to access the two added nuts the rotor again was in the way. My situation is unique do to the R56 trailing arms. Going forward to replace the rotor I'll still have to remove the caliper and carrier but without the extension in place for the larger rotor I can just remove the 2 13mm bolts holding the carrier to the trailing arm. The OEM type setup does not have nuts on the bolts.
Now I am confused or maybe I am just forgetting something. I have a GP so I also have the R56 aluminum trailing arms. I had the studs already installed when I added the Wilwood rotors. I was able to install the rotor, carrier with dog bone, and caliper with the studs installed. Thus, I believe I should be able to remove the rotor with the studs in place. Maybe I installed mine slightly differently but I can not imagine how. I did have to grind some of the trailing arm to provide clearance for the button head bolts. I will have to unbolt the carrier with dog bone (as a complete assembly) from the arm to get the rotor off but there is no problem getting to those bolts because they are in the same location as stock.
On my application there were two nuts on the front side of the trailing arm that would just spin in place when trying to unbolt the carrier and dog bone assembly. If we could have held the nuts in place the studs would not have to be removed. The bolts are in same location as stock, but those darn nuts on the front side were the problem we ran into. I too had to do bit a grinding on the trailing arms to provide clearance for the button head bolts.
Thanks Nathan. That makes sense. I do not remember having a problem holding the bolt head and torquing the nuts (or holding the nut and torquing the bolt head). Maybe I installed the bolt/nut backwards from you. Maybe I was able to torque without holding the nut but that might not be the case when I want to remove the bolt. Now I am curious and will need to jack the car up next weekend and take a look at my install to see if I will have a similar problem that I should plan for.
I'm guessing there's no loss at all. The Wilwood kit uses stock calipers so should produce the same sort of braking as the stockers. As Nathan said in his first post the only real point of the larger diam rear rotors is to balance the look front to back...particularly when you switch to larger than stock front rotors. If you don't gain (functionally) by switching to the Wilwood kit, you don't lose by switching back.
I added the larger Wilwood rear brakes not to gain braking power but to help reduce the heat and disapate the heat generated by the small pads. Many people have measured very high temps on the rear brakes which can cause fluid to boil.
I'm pretty sure that it's close to none. There's huge weight transfer to the fronts with such a short wheel base and relatively high center of gravity under heavy breaking. Matt
So far I've noticed no difference. I've also only driven about 100 miles if that much since the swap with no track work. However, both Alan and myself used some heat sensing paint on both the fronts and rears. At the time he was using the TSW OEM type rear and I was on the 11.7" Wilwood. Our temps fell in a similar range. I really do not expect and degradation in performance as there was no real gain in moving to the larger rotor. As I've stated, I went with that larger rotor at the time solely for the look.
After adding the TSW BDM I get about double the life of rear pads. In other words the more work the front brakes do, the less you need the rears. Alan
Wilwood rrr: I'm curious to see if anyone has actually measured before and after stopping distances after putting on their BBK.
I did not do before and after braking distance testing but I would not expect the BBK to decrease braking distances (at least until the stock brakes start to fade). I added the BBK to provide better braking capability over sustained high heat braking activities, such as track days. The intent of the BBK is to help dissipate the heat (across larger rotors) to help the brake pads and fluid stay cooler so you do not have brake fade. It is difficult to do a comparison between stock and BBK because most people (including me) use a different pad compound with the BBK. Even the different Mini Models/Options use different pad compounds. For me, I think my braking distances are a little longer with the BBK when the brakes are cold. I use Hawk HPS for the street and Wilwood B for the track. The Hawk HPS do not seem to have much initial bite compared to the stock TRW pads (on my GP) especially when a little cold.
Tires are the limiting factor when braking. The OEM setup has the capability of locking up the wheels so for one or two quick panic stops are more than sufficient for the majority of people. It's when one starts to get a bit more aggressive that the BBK shines over the OEM setup. As stated in a previous post, the ability of a BBK to shed heat better is the factor that for many of us makes the expense worthwhile.
I understand that point very well. But a properly balanced BBK will be able to shed heat better as well as maintain or improve the stock braking distance. Hence the question, has anyone measured their stopping distances from stock to post-BBK and seen an improvement? I understand pads will play a role as well but I'd be curious to see the results for Wilwood and Wilwood-type caliper setups. I knew of two teams at Super Lap Battle that got rid of their Wilwoods because they could see the caliper flex while bleeding their brakes.