My SR8 has the carbon rotors and they're past their user life. Replacement on them is right around US$10K. I'm not interested in going this route either.
After speaking with the guys at Spring Mountain (spent the weekend there) they're telling me that I have to change calipers if I switch to steel rotors - also to the tune of around 10K. Either way my wallet's in trouble and my little off on Friday morning (I'll post video later) spent about 70% of a brake change budget. (insert a lot of swearing)
If the rotor diameter between the carbon and steels is the same, I'm having a hard time with the idea of switching out calipers. If it's a puck size difference between the steel and carbon calipers for different clamping pressures I can understand to a point but I think it would be far less expensive to keep the carbon brake calipers and adjust the size of the master cylinder's piston to get the correct leverage ratio. Pad fitment may be an issue too - but I'd not be opposed to machining pads to fit if need be. I have the ability to do so.
The suggestion from the guys at Spring Mountain was to find a parted out SR3 or SR8 and see if anyone has a set of brakes they're willing to let go but I'm wondering what sort of aftermarket products may be available? I'm quickly discovering that if it says "Radical" anywhere on the part it's about 100% more than similar off the shelf products. Being that there are SO many different brands of calipers and such out there, there's bound to be a bolt on replacement that works. I'd not be surprised at all if Wilwood made a caliper that bolts right on.
So I'm open to suggestions, comments, ideas. I just know that I need to work on getting my brakes changed over to steel so I'm starting my homework and hoping someone here can help point me in a direction that will yield quality results.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
Richard, I've got one more event in my current set of brakes, and I'll need new rotors, I think. Mine have significant wear in the middle third of the swept area, and I can't imagine being able to turn them.
So... I'm about to go down this journey too. I had some Wilwood contacts back in the day (they sponsored me for a few events), and I've been contemplating digging into their inventory to see what's available. The floating rotors might be an issue -- I don't remember seeing anything like that in Wilwood's lineup.
Another idea might to contact Hi-Spec brakes in the UK, which is the OEM of Radical's brakes. Maybe they will sell directly to you, and I'd bet there would be a cost savings too.
Also, have a look at the thread here about the billet uprights -- and notice the brakes being used in the mockup photos.
Richard, I've got one more event in my current set of brakes, and I'll need new rotors, I think. Mine have significant wear in the middle third of the swept area, and I can't imagine being able to turn them.
So... I'm about to go down this journey too. I had some Wilwood contacts back in the day (they sponsored me for a few events), and I've been contemplating digging into their inventory to see what's available. The floating rotors might be an issue -- I don't remember seeing anything like that in Wilwood's lineup.
Another idea might to contact Hi-Spec brakes in the UK, which is the OEM of Radical's brakes. Maybe they will sell directly to you, and I'd bet there would be a cost savings too.
Also, have a look at the thread here about the billet uprights -- and notice the brakes being used in the mockup photos.
So you bring me to another option - I have the ability to machine uprights and can adapt what ever calipers may fit.
I can also make hats....
Maybe we can come up with something that works out.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
I'm game -- for sure. I also can machine parts with a 3 axis CNC, though my machine is old and I don't have that much experience with 3D machining.
I have a query in with the guys at Hi-Spec. We'll see what they have to say.
I believe our SR8s use a either a R-114 DL or RS-114 DL caliper with Dynalite mounting (tabs as opposed to radial mounting) http://www.hispeccalipers.co.uk/r114-4-range.htm
They offer a four different puck sizes/arrangements so it makes me wonder if that's the difference between the carbon setup calipers and the steel setup? I really want to know why I can't use the calipers I have and adapt a steel rotor and pad setup.
I need to go measure a few things tomorrow, such as piston diameters and mounting distances and see what else I can figure out. Might be time to look at Wilwood's catalog and do a little cross referencing also.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
Does anyone happen to have a 300mm and/or 280mm rotor sitting around that I can get some measurements from?
I'd like to know width and the inner diameter of both the braking surface and the mounting ring.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
I was looking over Wilwood's catalogue and came up with my own set of related questions: what's the dimension of the mounting tabs to the hat? Bolt center and number? Rotor thickness?
It also seems like the 300 - 310 mm rotor dimension has a much bigger choice than the 280mm. And does that move you to a 16" front wheel?
If I understand correctly the 300mm rotors fit in the 15” rims.
I am basing this assumption from Radical offering a 300 mm upgrade kit for both front and rear. https://www.radicalonline.co.uk/products/300mm-Floating-Front-Brake-Upgrade-Kit.html https://www.radicalonline.co.uk/products/300mm-Floating-Rear-Brake-Upgrade-Kit.html
Same rotors & hats (BD0068), and brake pads (BD0011) but different calipers. BC0068 left rear, BC0069 right rear, BC0066 left front, BC0067 right front.
Calipers run £462.00 (inc Tax) each
BD0068 can be separated into the rotors, hats and floating mounting hardware £58.80 (inc Tax)
I was told by Spring Mountain that the conversion ends up being close to US$10k but just off of Radical’s parts site it was about half that and if even my guessing which parts to use from Hi-Spec is close it’s even less from them.
Hopefully I’ll have some dimensions later today.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
Continuation of the above post. I had about 45 minutes of research, part numbers, prices and such listed and internet poof-ka-boom happened when I hit send.
I've measured the front brake system on my car.
Specs are as follows: Caliper is identical to a Hi-Spec 114-DL - http://www.hispeccalipers.co.uk/r114-4-range.htm
My carbon spec'd calipers have piston option 14¦ 2 x 34.6mm & 2 x 41.2mm (45.47cm2) I'm interested to know if any of you guys with steel rotors can give me a measurement of the pistons in your calipers.
Take notice that at the bottom of the specs they list for different rotor diameters. I would guess this would be ear height so there's no reason we can't move up to 300mm rotors if we have to change out calipers (and once again I ask why? - piston differences?)
Calipers from Radical are £462 while the same thing from Hi-Spec is £170.
Rotors are being a bit harder to cross reference on Hi-Spec.
The carbons are 280mm x 24mm They are a 10 point floating setup using 6mm bolts for the mounts. The mounting diameter is 172mm - Hi-Spec offers a 176mm mounting diam and the ID is different soooooo....
I'd like to know what the mounting diameter is for the 280 and 300mm steel rotors - I have a sneaky suspicion that they may be 176 so a hat change would be required. At £180 from Radical for a hat, that's not too hateful on the wallet and better than me trying to machine a set.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
Carbon front rotor dimension:
280mm OD
45mm swept area
190mm ID of rotor surface area
24mm thick
154mm rotor mounting flange ID
172mm mounting bolt hole diameter using 6mm fasteners in 10 mounting points
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
I'll be back in town early next week, but it seems that swapping to a Wilwood rotor is not straight-forward. I think the mount points are different -- Wilwood use 6 or 8 fasteners rather than 10.
I found one Wilwood rotor that uses a 10 on 173mm - and of course I can't find it now. The problem with the Wilwood is that it's only .81" (21mm) wide while we're using 1" (25.4mm).
I measured the carbons mounting pattern at 10 on 172 but there's a possibility that I have a mm of error with my method. My next plan is to put one into the mill and measure points for an exact mounting diameter.
So back to using the 280mm calipers (what's on my SR8) with this rotor: http://www.hispecrotors.co.uk/28025158BAP.html and make new hats? Or, hit Hi-Spec up for custom rotors - they offer so why not? There's a £50 surcharge for first time custom rotors (guessing they put the CAD file on file and call it back up if you order another set) so if you and I were to order two sets we could split the surcharge the first time 'round.
I've still not heard back from Radical's tech department so another phone call is in order bright and early tomorrow morning, as they're 8 hours ahead of me.
I'd really like it if someone here on the site with either an SR3 or SR8 could get the measurements on the pistons in both the front and rear calipers (hint, hint everyone). That's really my sticking point as to which direction I'll proceed. I need to know what the specs are for steel setup calipers.
Broken record time, but if they're similar to what we have with the carbon setup I just can't see why putting pads for steel rotors and steel rotors on the car won't work. I can't get a viable response from anyone associated with Radical other than "We change them out." WHY???
The more I look into this project the more the idea of making my own spindles that fit an off the shelf 300mm rotor and use the calipers I presently have is sounding more and more viable. It's definitely less from a price point of view. May be more time intensive but the savings at the end, being able to use an inexpensive off the shelf rotor and OEM Radical pads, would be worthwhile.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
Finally talked to someone in the technical department at Radical this morning.
Changing things out is a lot easier than I thought it was going to be. I'll have to make new bobbins to change the offset of the rotor and go with 22mm endurance brake pads.
The calipers are different between the carbon and steel rotor setup in that the carbon calipers are better insulated. The carbon brakes operate in the 1000C range (1800F) and the calipers need to have the seals protected from these temps so they have a different piston and seal setup that keeps the heat out of the caliper and avoids boiling the brake fluid. As the tech informed me, I'll actually have a "better thermal system" than a steel setup.
The carbon rotors are thicker than the steel so he said to make the difference up, run endurance pads, as they are thicker to start with. I mentioned pulling the calipers apart and thinning the middle piece so they work with a standard pad but he informed me that I'd have to re-engineer the cross over tube. I may look into this, as I have the appropriate tools to rebend/reshape the cross over tubes - but if I can just get endurance pads, why bother?
He also confirmed that the calipers are the Hi-Spec 114 line and that all the Radicals use the same mounting pattern for the rotors.
I'll be placing an order for a set of four floating 280mm rotors and endurance pads today. Time to do a little shopping.
Once I get parts in hand I'll see exactly what I need to modify on the bobbins in the floating system and knock out a set of them on the mill and/or lathe. - John, let me know if you want to wait and see how this goes for me and if it works, I can probably be talked into making the parts needed for you to follow suit.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
Great news! So are the pistons the same diameter in the calipers used for carbon and steel rotors? Would it be better to make a shim than to use a thicker pad? It seems like using a thicker pad would run the risk of allowing one of the pistons to come out of the bore and loosing pressure if the pads wear too much.
Charley
The pistons are the same diameters but they are an insulated item - have a secondary piece in each piston which I'm guessing is an insulator. Being that I've not actually seen a steel setup caliper I can't verify this, though.
Right after I start emailing Team Stradale about parts I get the following from Radical Tech (Nick is the tech I spoke with, e-mail came from Paul in parts):
Apologies for the delay with this one and I know you have just talked with my colleague Nick who informed me that you have the ability to re-machine your bells to work with the Standard SR8 300MM Disks, if this is the case you would only need to buy new rotors which are our part number BD0066 and BD0067, Nick was speaking to me regarding a thicker brake pad for your calipers however we don’t have a thicker pad for your calipers or SR8 calipers, the only thicker pad we do is for GT3 Calipers and the pad itself is much bigger and won’t fit.
If you did want to change to SR8 calipers you would need part numbers BC0066,BC0066,BC0068 &BC0069
Now there will be a caliper modification required - they are three basic pieces, inner, outer and a spacer between the two parts. Looks as if I'm going to have to pull them apart and mill off a few mm off the spacer thickness and then rebend the cross over tubes (I'll make them a bit more omega shaped as opposed to the U shape they presently are) to fit accordingly. I'll have to shorten the two pieces that hold the pads in place also. Tech at Radical said this is a viable option - was more concerned about the cross over tube fitment than they were about me milling on the center spacer section.
Maybe, just maybe (I'm not too keen on machining them - NASTY STUFF) I can cut the carbon pads down and make a spacer that would go between the backing plate of the standard pads and the pucks. Talk about an insulator! I know they can take the clamping pressures - the carbon pads don't have any backing plate - it's just a chunk of carbon fibers molded to the shape of a pad.
I'll get rotors and pads sourced (price shopping presently) and report back what I find.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
