When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Install only so far, race review to come later. Here's AP's deliriously light RadiCal kit. The amount of material removed here and there boggles the mind, you can see how much engineering went into designing such a package. For me this is upgrading from the AP's 8350's they designed several years back. While the 8350's are the best brakes I've used on the platform, the discs were just small enough to still require that PITA brake ducting we all love to mess with. As most of you have already commented, going to a bigger disc aka Heat Sink solves some of that problem. And since I already have mostly 18's, that's what I'm here to find out. I personally Opt'd for the 9660 kit over the 9668 kit for several reasons. Firstly I only do sprint races/TT/DE stuff, no enduro's here so the extra pad thickness (18mm vs 25mm) and the quick-change clip weren't a requirement. It also shaves some weight going this route and gives extra clearance which we'll go into later.
Firstly is the packaging. This is likely the most professional i've seen, even more then Motec stuff. Which I guess should be standard in this price range. Full color directions, each bolts torque specs, etc. Comes in 3 boxes, 1 for rotors, 1 for the rest, and 1 for Pads/fluid. In this case they even threw in 2 bottles of Ferodo racing brake fluid which is a pretty high boiling point too.
The RadiCAL:
The bracket that holds these is quite a bit beefier then the 8350's. This time they opted to use a ARP stud and ARP nut instead of a single bolt. It also clears SB hubs with 0 grinding (yay).
Install was very easy, literally the 4 connections and brake line and you're off and racing. EASY to maintain and troubleshoot is key for me. These rotors are HUGE. Not overly heavy either.
Looking at it from the top you can see these things come all the way up to the top shock bolt in height.
Issues so far. Because of the size of these things I've run into a slew of problems I had to work through. Thanks Dallas for answering texts during the weekend First is wheel clearance. These will not work without spacers, and not because of the spokes, but because of wheel designs we typically use. Both my Eneki's have this raised lip where the spokes attach. This hits the edges of the caliper directly. I have to use (was already using) 25mm of spacer to clear this lip. Even then they are so tight to the wheel the edges hit the wheel weights. So the new rule is all wheel weights go on the INSIDE from now on. Take a look:
Other then that, I cannot wait to slam on these things! We've all been talking about getting new wheels that work anyways, so post it up if yours are different then NT03/RPF1.
Looks awesome excited to hear how they work out for you! Was the space constraints only with the RPF1s as I saw the comment on the bottom about testing a NT03 as well. I'd bet the NT03s offer much more room but not sure which spec you have. I can measure the ID of my 18x10.5 NT03s if that is a helpful data point for you?
RPF1's are among the worst wheels for caliper clearance on the drop center and the whole barrel really. I would be interested to see how you NT03's clear.
Pics installed on the car are with the NT03's, those are the old 18x9.5 +40's. The pics with the brighter wheel on the ground are the RPF's. Both have the same issue because of that "raised" bit that goes up 5/8's inch to meet the spokes - the RPF's being worse by only about 2mm. I assume the 10.5's are the same though right, same design? It's funny because we all bought Eneki's because they were light, affordable, and strong(ish) back then....but as we've all gotten older and progressed our builds it's fair to say we've outgrown them lol. Aight Dallas, time to start making wheels son
I've been drooling over these brakes for some time, now. I'm low-key shopping their "lesser" brakes. The RadiCals are definitely not within my budget. Nice score, dude!
Pics installed on the car are with the NT03's, those are the old 18x9.5 +40's. The pics with the brighter wheel on the ground are the RPF's. Both have the same issue because of that "raised" bit that goes up 5/8's inch to meet the spokes - the RPF's being worse by only about 2mm. I assume the 10.5's are the same though right, same design? It's funny because we all bought Eneki's because they were light, affordable, and strong(ish) back then....but as we've all gotten older and progressed our builds it's fair to say we've outgrown them lol. Aight Dallas, time to start making wheels son
Do I understand correctly that you need a 25mm spacer on both sets of those wheels?
Looks awesome excited to hear how they work out for you! Was the space constraints only with the RPF1s as I saw the comment on the bottom about testing a NT03 as well. I'd bet the NT03s offer much more room but not sure which spec you have. I can measure the ID of my 18x10.5 NT03s if that is a helpful data point for you?
PS- What are you doing with your old kit?
A gentleman msg'd me on here asking about them, so I sold the 8350's, twas the only way I was gonna jump on these lol.
Originally Posted by Construct
Thanks for the post. Great writeup.
Do I understand correctly that you need a 25mm spacer on both sets of those wheels?
Correct. The spokes clear on both with like a 5mm spacer, but trying a 12, 15, 20 and then 25, 25 put the allen head bolts and the top and bottom edges of the caliper itself where you see it on the pics. I had it on the dyno with 0 marks. That inner raised edge on the RPF's is slightly wider so in reality the NT03's would need like 22mm, the RPF's 24mm if that makes sense. The issue is two fold, that inner raised edge which shrinks the overall barrel and the spoke design. TC105's are looking mighty good lol.
Pics installed on the car are with the NT03's, those are the old 18x9.5 +40's. The pics with the brighter wheel on the ground are the RPF's. Both have the same issue because of that "raised" bit that goes up 5/8's inch to meet the spokes - the RPF's being worse by only about 2mm. I assume the 10.5's are the same though right, same design? It's funny because we all bought Eneki's because they were light, affordable, and strong(ish) back then....but as we've all gotten older and progressed our builds it's fair to say we've outgrown them lol. Aight Dallas, time to start making wheels son
Hmm. Most wheels have that bump in the barrel there, its for the drop center. Otherwise you wouldn't be able to mount the tire...lol. Interesting that it's that close. AP really maximizing the space in the wheel.
are they 17 or 18" wheels? Wed tc105n have a similar design and similar brake clearance issues. my Weds sa10r's clear fine
18's course. I'd be looking at the 105x's, but what part didn't clear on yours? The 105n's in your earlier pics seem to have a decent inboard lip on them before the spokes started.
ive never owned TC105s but when i was looking for wheels the Weds importer printed off the engineering drawings in 1 to 1 to make sure it would clear the barrel and it was super duper tight. i believe it will clear a 355 rotor like mine but not 372. Im pretty sure those drawings may be on the weds website
Mar 22, 2019, 11:44 AM
First is wheel clearance. These will not work without spacers, and not because of the spokes, but because of wheel designs we typically use. Both my Eneki's have this raised lip where the spokes attach. This hits the edges of the caliper directly. I have to use (was already using) 25mm of spacer to clear this lip. Even then they are so tight to the wheel the edges hit the wheel weights. So the new rule is all wheel weights go on the INSIDE from now on. Take a look:
Nice score, dude!
