Rear Disc Brakes

[literarymadness]

I finally did what I have been wanting to do for a while: have Steve Smith over at Twin Cam Racing (Sarasota, FL) upgrade my rear drums to disc brakes and my front discs to vented ones. I ordered the Banks' ones from Lotus Supplies Ltd. and had Richard at Banks groove both the front and rear discs.  In the spirit of "While already down there," I went for aluminum hubs to save future labor costs. I drove my TCS back from Sarasota down I-75 on the West Coast of Florida, then across Alligator Alley (about 200 miles) back to back home just outside Ft. Lauderdale on the Southeast Coast of Florida.  The braking was very intuitive and modulation was easy. It felt like a modern car. Average speeds on I-75 are 75-80 mph and on Alligator Alley, 80-85+ mph.  Even at those speeds, you still get passed or tailgated till you move over.   Keeping up with those speeds and braking at those speeds felt very normal.  Does anybody else have rear disc brakes and how do you like them?

[BDA]

When I built my car, I put Richard's rear disc kit on it. When I got it on the road, the brakes seemed great! The reality was that it had been SO long since I drove it stock that I had no frame of reference. I think they are a lot better than the stock drums. I haven't needed to (nor do I ever want to) but I suspect that I could lock up four wheels even though I'm running 195/50-15 in the front and 205/50-15s in the rear. So, I'm very happy with them!

BTW - I'm running the stock M/C size with dual Lockheed boosters.

Edit: fixed the rear tire size!

[SwiftDB4]

Originally put rear sliding Wilwood calipers on. Definite improvement over drums. But you can never have too much in the way of brakes so later went to vented rotors with 4 pot Wilwoods up front and 4 pot Wilwoods at the rear as well. Have 2 MC on balance bar. Notice huge improvement on track days.

[literarymadness]

@SwiftDB4: Now those are some serious brakes!

[GavinT]

Hi literary,

If I recall, the Banks kit uses Sierra rear callipers, correct?
It looks like you've changed the front callipers as well?
Could you elaborate on those, please?

[literarymadness]

You can't see from the photo but the front are the Vented Disc Kits that include Aluminum Hubs  from Banks/Lotus Supplies and I had Richard add the grooves for me. I thought the rear calibers were from a Vauxhall but I don't know for sure. Maybe someone else on the forum knows.
https://www.lotus-supplies.com/parts/brakes/disk-kits/disc-kit-front-vented-incl-new-alloy-hubs/

[JR73]

Rear calipers are from a Ford Sierra, same calipers as used on Caterham’s for many years (lots of different pad materials available for similar weight vehicles).

The Front calipers used to be from a Peugeot 205 GTI (same calipers where fitted to other Peugeot/Citroen vehicles) but they appear to be a different model (same brake pad, probably a newer Peugeot/Citroen model) as the area that the pads sit into is a different shape to the 205 ones. - Again, quite a range of different pad materials readily available for those calipers.

There used to be a couple of options on those front calipers that would allow for non vented or vented discs, the piston etc was the same but the area that the pads sit in was bolted on and came in different sizes to span the thickness of different discs.

Have raced, trackday’d and now road driven on the same front and rear setup (with twin master and balance bar) for 21 years now and they are more than capable.

[literarymadness]

@JR73: Thanks for the info! Makes me even happier for doing the upgrade.

[GavinT]

Firstly, thanks Literary & JR73.
Richard's front vented kit is all the better for including the alloy hubs.

When I built my car, I put Richard's rear disc kit on it. When I got it on the road, the brakes seemed great! The reality was that it had been SO long since I drove it stock that I had no frame of reference. I think they are a lot better than the stock drums. I haven't needed to (nor do I ever want to) but I suspect that I could lock up four wheels even though I'm running 195/50-15 in the front and 205/50-15s in the rear. So, I'm very happy with them!

BTW - I'm running the stock M/C size with dual Lockheed boosters.

BDA,
Are you using the stock front brake set up with Richard's rears?

[BDA]

Thanks for reminding me, Gavin. I forgot to describe the front brakes in my previous post. No, I have Richard’s vented front brake kit but I saved money and used the iron hubs. I also don’t have grooved discs.

[GavinT]

Thanks, BDA.
The next question is; was there a noticeable improvement with Richard’s vented front brake kit?

I'm trying to nail down if vented fronts are worth it when considering the un-sprung weight penalty.
I'm not sure what the Lotus 47 used but wasn't it pretty much a stock Europa set up on the front?

[Chuck Nukem]

Thanks, BDA.
The next question is; was there a noticeable improvement with Richard’s vented front brake kit?

I'm trying to nail down if vented fronts are worth it when considering the un-sprung weight penalty.
I'm not sure what the Lotus 47 used but wasn't it pretty much a stock Europa set up on the front?

I believe it was. Hard to tell from this photo but it might have the thicker gt6 rotors https://www.fantasyjunction.com/sold/1966-lotus-47/photos#photos-134

I opted not to go front ventilated for that very reason. Wilwood makes the powerlite caliper in two widths so I could go bigger without much trouble if the solid rotor has trouble handling it.

[BDA]

It's hard for me to compare because it was twenty five years between when I drove my stock Europa and I rebuilt it. I have to say that I was impressed by the braking when I put my car on the road so I suspect it brakes significantly better than a stock TCS. Literarymadness would have a better comparison than I. My car should brake significantly better in the rain (rear discs work better than drums in the rain) and in extended braking such as a track day or going down a mountain because it should handle heat a lot better. I don't plan on competing in my car so the real reason I upgraded my brakes is because I had significantly more horse power than a stock TC.

Is it worth the added sprung weight in the front? I can't answer that. I didn't think the added expense of the aluminum hubs was worth it because I doubted I'd be able to notice the difference. If you're planning on competing in your car and you can afford it, I would get the aluminum hubs and vented discs.

BTW - according to this site (https://www.ultimatecarpage.com/spec/5814/Lotus-47-GT.html), the 47 had vented discs all around.

Edit: after checking Chuck's link, it could be that the brakes were upgraded on the one I liked to.

[jbcollier]

I really like the stock brakes.  They work very well.

BUT

They have limited thermal capacity.  They will fade down long hills and on the track.  I'm experimenting with pad materials (green stuff doesn't cut it) but I think vented front rotors are in my future.  Presently I have no plans to change from the rear drums, which I find work very well.

[literarymadness]

@JB   Your S1 is about 300 lbs. lighter than a TC/TCS; that makes a difference too.

I also think the grooved slots also reduce brake fade and prevent glazing. Here are a couple of interesting videos about brake types.

https://www.youtube.com/watch?v=78wbht355R8

https://www.youtube.com/watch?v=5OWM1wttWA8