Rear Disc Brakes

[EuropaTC]

The assumption seems to be that the existing Europa front solid rotor is under-performing, but, as far as I can see, there's no broad evidence to support such an assertion.

I'd go with that statement as well. As someone else has posted, vented discs weren't that common back in the 1960s so there's no surprise that Lotus kept with the solid 232mm disc.  But if heat soak was a problem for them, they always had the option to move to the thicker & larger 245mm disc/caliper of the GT6 as they had those on the Elan+2 and IIRC the later Elite/Eclats. So cost wise it wouldn't have made a massive difference, in fact the added volume might have got them a better deal ?

They added a servo(s) so they obviously had an eye on how the braking effect felt for the driver, or it might just have been marketing, who knows ? But they stayed with the 232 solid disc, so I think that means they thought it worked well enough for a road car.

Rear disc conversions are noted on these forums in many shapes and sizes.  Richard's kit seems well regarded all round. There's also many home brew conversions using a variety of different components. The consensus seems to be that converting to rear discs provides a definite improvement.

Based on that, a vented rear rotor should out perform a solid one, right?
I reckon the same logic should be applied to the front rotors but that doesn't seem to happen.

Personally I think rear discs are an improvement.  I still have the OEM drums and could easily revert but frankly there's more chance of me flying to the moon and back.  However even on the second round of "upgrades" where I changed the front from 232mm to 260mm discs and the rear from 240mm to 258mm, I've stayed with solid discs all round. 

I could easily have fitted vented discs as there are plenty of options but as I only ever drive on the road and either I don't drive fast enough or brake hard enough, I've not had brake fade even with the OEM setup.  So I figured the lighter solid discs would be fine for me. I just wanted a bigger diameter for less pedal pressure.

Even so, I can see the extra security margin with vented fronts, I'm just not so convinced about vented rears.   I know Lotus fit them on the Elise (S1 at least) but I suspect that's because they use the same disc at all 4 corners and adjust the balance with the piston size, so they're saving cash on buying in stuff.

When I did the 2nd conversion I used one of those  infra red thermometers to measure the disc temperature after a run and not surprisingly the fronts were considerably hotter than the rear. I forget the numbers and in any case they would only be comparative F/R rather than absolutely accurate temperatures, but I seem to recall the fronts were roughly double the rears. 

You'd expect something like that anyway, but for me it says "vented rears aren't required" (just yet    )

Brian

[jbcollier]

I have largely stock brakes.  Slotted rotors, green stuff pads and braided brake lines are the only mods.  in normal driving the brakes work GREAT: plenty of power with lots feel.  No complaints there.

Driving from Pemberton to Whistler,  I experienced significant brake fade on the steep, winding descent.  The pedal stayed firm, just the braking power went away.  Pretty classic case of heat overload.  My first step is to try Mintex 1144 pads.  So far, they work great but no mountain passes like the Pemberton run have come my way yet.  Next option will be to space the calipers and fit vented rotors.

[EuropaTC]

I've used those Mintex pads for a while now on both the Elise and Europa. There are no mountain passes around here (Lincolnshire is like a billiards table) but the pads worked very well when we were in Yorkshire. Again no mountain passes where we lived but quite hilly with no speed cameras and I did drive a bit more enthusiastically in those days.

On such a light car as your S1, they might just be enough to do the trick. Before the Mintex I also used Greenstuff and with the benefit of hindsight I don't think they are as good a material although they did have a better initial bite/lighter pedal from cold.

Brian

.....of course the true hero would say "if you've got brake fade then you're obviously using them too much....."   

[GavinT]

Vented brake rotors simply provide better cooling and are less likely to warp and fade. [...]

Cheers, agreed and no dispute from me.

But have you ever warped a Europa disc?
Know anyone who has?
I don't recall any posts reporting warped discs.

Regarding fade, the stock pads don't really handle the heat under arduous conditions. As I say, we switched to DS11 or Black Flash pads. They were well regarded back in the day and while sometimes squealy, performed fine on the road as well.
On my S2, it was always the rear drums that left the party early. When that happens, you tend to push harder on the pedal but that just means you're working the fronts more. Don't recall ever boiling the fluid, though.

[GavinT]

You'd expect something like that anyway, but for me it says "vented rears aren't required" (just yet    )

Yes, that was my point, of course.
It's interesting to observe that since the Europa community started delving into rear disc conversions, people then recognised the need for an appropriate rear calliper size so as to avoid the rears locking before the fronts.

I don't recall anyone being concerned the stock rear drums might lock up first!
That tells us something.

[...]  But if heat soak was a problem for them, they always had the option to move to the thicker & larger 245mm disc/caliper of the GT6 as they had those on the Elan+2 and IIRC the later Elite/Eclats.

Regarding the GT6 discs, I've read that one needs to swap the whole upright, rotor and calliper in order to upgrade. I've never had cause to question this but is it possible to bolt just the GT6 rotor to the Europa hub?
My thinking here is that if it's the calliper bracket dictating the swap and one is looking to install different callipers anyway, then a custom calliper bracket isn't much of an issue?

Thanks . . I'd also forgotten about the Elite/Eclat using the GT6 stuff.
From Googling around other Lotus forums, apparently there's some 265mm discs that fit in place of the 245mm ones on some variations of Eclat/Elite. Interesting, but more research needed.

Here's a (stolen) pic of a GT6 245mm disc on an Eclat upright that's supposed to take a 265mm disc.
I presume that means, apart from the diameter differences, they're interchangeable. Maybe?

[literarymadness]

Banks Europa Engineering only sells one disc kit for the front brake and that is the one I had put on.  My original front rotors were in bad shape and one of my calipers questionable.  So by the time I added up the price for all the individual parts (including the aluminum hubs), the complete kit was cheaper, but not enough to sway me one way or the other. So I called Richard and asked his advice and he talked me into the complete disc kit saying it was track tested and time proven and that was the best option for stock wheels. The aluminum hubs save me 2.3 lbs. per wheel.  The difference in weight between a stock Spitfire rotor and a vented one is less than I thought (a little over a pound increase). Supposedly, the new calipers are slightly lighter. Even if they're not, I still have shaved at least a pound of unsprung weight per wheel. So in the end I wound up with Better Calipers, Cooler Brakes, and Less Unsprung Weight. Works for me!

[JR73]

But have you ever warped a Europa disc?
Know anyone who has?
I don't recall any posts reporting warped discs.

The two HSCC TC’s that we looked after did.
They where built to 5 speed special spec and included the wider rear drums to give them the best of what was possible within the rules. The pads and shoes were race compounds along with the fluids.

The quicker of the two guys used to constantly report that he had ‘run out of brakes’ by the end of a race, both used to consistently finish high up in the results though.

Pads and shoes had to be replaced after each round - qualifying session and a race (front pads had seen a LOT of heat and where generally cracked or starting to break away from the backing plates on both cars), front discs every two/three rounds (dependant on the tracks) and the rear wheel cylinders had to be changed at the same intervals as the seals appeared to cook and fail (sudden loss of fluid was much worse than ‘fade’ or ‘judder’ as they used to report and after a couple of failures it wasn’t worth the risk - both drivers where Barristers!)

Neither driver was particularly interested in doing much maintenance other than getting in and driving the car so double headers where a major concern as changing rear shoes was completely out and they would reluctantly get their hands dirty and change the front pads before the second race (its easy isn’t it?!) - generally all of the above was replaced prior to a double header weekend to give them a chance of making it through safely...

Again, not your average bit of road driving but they certainly weren’t doing any sort of endurance events either.

[EuropaTC]

I don't recall anyone being concerned the stock rear drums might lock up first!

Absolutely no chance !  From memory they were about 25-30% braking effort on the rears and would never lock before the fronts had. I suppose wet roads might swing it, but you'd have to be trying very hard.

Regarding the GT6 discs, I've read that one needs to swap the whole upright, rotor and calliper in order to upgrade. I've never had cause to question this but is it possible to bolt just the GT6 rotor to the Europa hub?
My thinking here is that if it's the calliper bracket dictating the swap and one is looking to install different callipers anyway, then a custom calliper bracket isn't much of an issue?

and

Here's a (stolen) pic of a GT6 245mm disc on an Eclat upright that's supposed to take a 265mm disc.
I presume that means, apart from the diameter differences, they're interchangeable. Maybe?

I have also read the same on LotusElan.net,  Elans with bolt on wheels had the same uprights as the Europa but the knock on wheels had the heavier versions. Both have 232mm discs with type 14 calipers and I've seen posts saying you need to swap the lot. 

On mine (k/o wheels) I swapped the discs/bracket & caliper for the 245mm/type 16 calipers and it's a bolt on job.  Unless it's a concern about the smaller stub axles I'm not sure why folks say you need the heavier set-up, it looks to me as if they'd just bolt on either upright.  The later Triumph uprights had the caliper bracket cast in place so perhaps that's the reason for the statement ? 

I don't know if the Eclat discs are interchangeable. I used Citroen BX 265mm discs on my car but you need to re-drill the mounting holes. The BX comes in both solid & vented versions and once you've re-drilled the mounting holes for the hub, they fit very well, the offsets are very similar. If the Eclat discs look to have been modified then I bet that's what they use.

But 265mm discs won't fit with standard wheels, not even a steel one.

Brian

[Lotuswins]

You can't just bolt on the larger rotor (GT6) to the europa, its all larger bits.....bearings, etc.  IIRC that is.  Besides the larger axle, etc. gives better stability and longevity/reliability if you want to go racing.
I've got Mintex 1144's front and rear with a banks clone kit in the rear.  Sierra (Scorpio) rear calipers and Integra disks.  The braking power improvement on track days is very noticeable.  I took my infrared temp gun to a track day at PIR and measured 320F front and 300F rear after a 15 minute session.  No fade with these pads, at least on a track day (go as fast as you dare).  Just a mostly stock TCS but very happy with the stock front brakes and the Banks design in the rear.

Jerry Rude
4005R

[TurboFource]

Nice write up about brakes.... https://www.gglotus.org/ggtech/europa-brakeinfo/brakeinfo.htm

Discusses the difference in "response" between drums and discs among other things.

[literarymadness]

All Lotus Elise including the least powered S1 to the 2020 current one have rear discs brakes and vented disc brakes upfront. If Lotus in 1995 had felt the 1972 Twin Cam Special brake set-up was a better setup, the 1650 lb Elise (same weight as Fed-spec TCS) would have had that setup. While the TCS has slightly larger drums than previous models, they are basically the same design as on the S1 when the car was introduced in 1966. I am not criticizing the original factory brakes in any way or questioning the ability to stop. But brakes have improved since 1966 and I believe that the Banks Kit (Peugeot 205 GTi vented brakes with aluminum hubs) are an upgrade. The same goes with the Ford Sierra discs I now have in the rear vs. the old drums.

@Turboforce: The article also says "Small, light weight disc brakes sized to be balanced with the stock fronts would be fine. The main advantage won't be more braking "power" as much as matched response times. Matched response times would make it "easier" to apply the brakes rapidly with less risk of locking up the fronts pre-maturely... and therefore easier to use the full braking potential."

I am not a trained driver nor do I race. But I do drive for long periods of time at fairly high speeds in semi-dense traffic, where other drivers occasionally do really stupid maneuvers usually at night (Hey it's South Florida).  In a panic stop, a few feet can make a huge difference and not the time to find out how I should have braked. I'll take any advantage I can get.

[TurboFource]

Not disagreeing! I will probably add rear discs to mine at some point
Just thought it was an interesting article......I thought the point of the different responses was  enlightening.

[Chuck Nukem]

All Lotus Elise including the least powered S1 to the 2020 current one have rear discs brakes and vented disc brakes upfront. If Lotus in 1995 had felt the 1972 Twin Cam Special brake set-up was a better setup, the 1650 lb Elise (same weight as Fed-spec TCS) would have had that setup. While the TCS has slightly larger drums than previous models, they are basically the same design as on the S1 when the car was introduced in 1966. I am not criticizing the original factory brakes in any way or questioning the ability to stop. But brakes have improved since 1966 and I believe that the Banks Kit (Peugeot 205 GTi vented brakes with aluminum hubs) are an upgrade. The same goes with the Ford Sierra discs I now have in the rear vs. the old drums.

@Turboforce: The article also says "Small, light weight disc brakes sized to be balanced with the stock fronts would be fine. The main advantage won't be more braking "power" as much as matched response times. Matched response times would make it "easier" to apply the brakes rapidly with less risk of locking up the fronts pre-maturely... and therefore easier to use the full braking potential."

I am not a trained driver nor do I race. But I do drive for long periods of time at fairly high speeds in semi-dense traffic, where other drivers occasionally do really stupid maneuvers usually at night (Hey it's South Florida).  In a panic stop, a few feet can make a huge difference and not the time to find out how I should have braked. I'll take any advantage I can get.

My thoughts exactly! in DFW it is a miracle if you don't have some one pull out right in front of you on a daily basis. I nearly creamed someone with my M3 who pulled across 2 lanes of service road traffic the other day. He went from a dead stop leaving a parking lot straight to the merging lane of the highway without even looking!! The cost of upgrading to disc all round is negligible compared to to the damage it might prevent in a worst case panic brake scenario. I am not planning to run my car in any vintage racing which would require period correctness.

When my '66 chevy truck was running (all drum manual brakes) it was truly terrifying how little room people give you. I have since upgraded to disc on that...it still doesn't run yet though

[BDA]

When my '66 chevy truck was running (all drum manual brakes) it was truly terrifying how little room people give you. I have since upgraded to disc on that...it still doesn't run yet though

That reminds me of my tow vehicle when I was racing - a Ford Econline 150 (I think... was there a 100?) van. It had a 302 with a two barrel and four wheel drum brakes(!). My trailer and car were pretty light and it towed pretty well. I even got about 13mpg on the highway which is really good for towing a race car.

What you reminded me of is when going to Texas World Speedway near College Station, Texas, there was a stretch of about 10 to 15 miles where every few miles, there was a stop light. If I hit the first one wrong, I hit them all. By the time I got up to speed, there would be another light. The drum brakes were fine for the first four or five lights but those brakes were gone by the time I got to the last two or three lights and it was a struggle not to blow past a red light!

[EuropaTC]

I think the last few comments here illustrate the difference between what we'd like to think (Lotus brakes are great) and modern reality.  This thread has sparked my interest so I did a quick search around for "what's good today ?"  and came up with this page

https://www.consumerreports.org/car-safety/best-and-worst-braking-distances/

It's not a specialist report, just some simple facts. Sporty cars are the top of the list, as you'd expect, and 60-0 comes in around 120 feet in dry conditions.  Now I know some cars will do better, the Top Gear trio of Clarkson/Hammond/May did some stunning numbers with high powered BMWs, etc, but the thing we all face in modern traffic is the average saloon (because that's what we're going to run in the back of !) 

I was surprised to find numbers in the 130-140 feet range, but that underlines how good modern brakes are.  It seems the best cars are under 100 feet, which is pretty impressive (https://www.motortrend.com/news/20-best-60-to-0-distances-recorded/)

And now for our cars.  Well, we all know the cars were praised on every road test so I pulled out my Brooklands books and looked up the numbers.  Not an easy comparison because most UK tests seemed to concentrate on 30mph as the target speed and they came in around 31-32 feet.

Road & Track, Nov '73.  TC Special, Min. stopping distance from 60mph....   171ft.  Yes, I read it twice and unless it's a misprint, that's the numbers.  The S2 fared better, lighter car, similar brakes so you'd expect better and you S2 owners will be pleased to know you can brake almost as well as the average small car today and you can probably outbrake a pickup.

I was surprised. I never considered the OEM brakes as bad but I didn't realise just how far modern systems have come. Sobering really.....

Brian