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Old July 12th 2011, 10:28
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Bogara_ZO Bogara_ZO is offline
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Calipers: Big one or lightweight?

Hi, I've read a lot here about brakes, but haven't found the answer yet. I know there are serious guys here, so please help me and others by collecting the pros and cons in one topic.

Using porsche brakes is a common choice (and well discussed here), but what is the best if you have other pcd? You have countless possibilities,
hard to decide which is the perfect one for your ride. (Yeah, I know that all cars are different, so let's talk about an average GL super beetle with 150 bhp in the back, maximum 17" wheels and a normal weight, basically a daily driver but owner wants having fun on trackdays a few times a year)

On one hand I want the biggest unit available, on the other hand the unsprung weight comes in mind. So what to do then?

I found these options, but haven't tried none of them yet.

1, Get big fixed (originally front) calipers from modern cars for front and rear and match them with some rotors.

+ cost effective way (Alfa, BMW, Mercedes, Japanese Brembos can be found cheap)
+ you can buy parts if need for rebuild
+ awesome braking power can be reached

- mounting could be labour intensive
- maybe too heavy (BMW alloy Brembo weights ~4kg, a Porsche < 3kg)
- hard to find out the f/r bias (they are from front engined cars)
- brake line issue
- requires at least 16" wheels, so all the classic ones are exclused
- spare wheel issue
- hand brake issue
- master cylinder issue

2, Mix the proven Porsche calipers with other or custom rotors

+ easy to get infos of the conversion as they are popular
+ mounting brakets available
+ good stopping power

- not too cheap
- hand brake issue
- 16" wheels at least
- still can be too heavy
- find the correct rotors

3, Use aftermarket calipers like Wilwood, AP Racing, Tarox etc.

+ matches your needs
+ will fit under any wheels
+ lightweight construction
+ can use standard of aftermarket beetle rotors as well

- hard to get infos (if you have don't hesitate to share!)
- $$$
- brake lines
- getting new pads can be comlicated

4, Use a complete setup from a modern car

This is my last idea came to mind recently when I drove a Lotus Elise R and was impressed by the brakes. It would be more than enough for a bug.
Both the beetle and lotus are lightweight cars, with a similar weight distribution and no servo / brake booster(?) ! The Elise has 2 pot calipers in the front and poor slindings in the back, and IIRC ~280mm rotors in all corners, ~22mm MC and handbrake! Not easy to find a Lotus brake kit for sale, but nothing is impossible However I belive - and have read here on the forum as well - on a beetle (nearly) same brakes would be the best bet, that Lotus really made me think it over...and also Chsristian Stelzer's 1303rs (www.vw1303rs.de) has something similar (AP4pot fronts and "just" 2 pots rear)..what do you think about it?
Thanks
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Last edited by Bogara_ZO; July 13th 2011 at 04:38.
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Old July 13th 2011, 08:19
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Hi Zo,

I'm sure there are other opinion but here is mine as a start:
Option 1
Big heavy calipers with lots of custom installation issues.
Option 2
Well proven, lightweight and most installation have been de-bugged by other, plenty of installation experience. More braking than the bug will need - ever. BTW I have fitted 944T/928S4 calipers under 15" wheels. Porsche calipers readily available at reasonable prices. My Merc Brembo 4 pots were more expensive than either of the Porsche Brembo alloy calipers. Scan all the Euro EBay sites?
Option 3
Very expensive but the ultimate performance. All custom build requiring good machining skill for the brackets etc. Details of the AP stuff is comprehensively found on here: http://www.apracing.com/
Option 4
Only Porsche stuff sensible here as the brake bias of all front and mid-engined cars is completely wrong. The Lotus is a production car witha great deal of development time by great engineers to make low grade brake components work on their high(ish) performance car. Transfer that technology across to a bug and I bet you will be disappointed.

Clive
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Old July 13th 2011, 11:31
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Bogara_ZO Bogara_ZO is offline
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Quote:
Originally Posted by evilC View Post
Hi Zo,

I'm sure there are other opinion but here is mine as a start:
Option 1
Big heavy calipers with lots of custom installation issues.
Option 2
Well proven, lightweight and most installation have been de-bugged by other, plenty of installation experience. More braking than the bug will need - ever. BTW I have fitted 944T/928S4 calipers under 15" wheels. Porsche calipers readily available at reasonable prices. My Merc Brembo 4 pots were more expensive than either of the Porsche Brembo alloy calipers. Scan all the Euro EBay sites?
Option 3
Very expensive but the ultimate performance. All custom build requiring good machining skill for the brackets etc. Details of the AP stuff is comprehensively found on here: http://www.apracing.com/
Option 4
Only Porsche stuff sensible here as the brake bias of all front and mid-engined cars is completely wrong. The Lotus is a production car witha great deal of development time by great engineers to make low grade brake components work on their high(ish) performance car. Transfer that technology across to a bug and I bet you will be disappointed.

Clive
Thanks for the answer Clive (as always)! Yeah, I'm keeping my eyes on all European ebay sites

2, only advantage is the weight and maybe the mounting, if you have different pcd it is still far from plug and play

3, it's hard to find your way and do something nobody has done before, based on just numbers and theories..I'm reading a few kit car forums to find something similar to the bug. Btw those "locost" builder guys are happy with Ford and GM brakes, most of them use sliding calipers...

4, I'm still not convinced. Lotus has a 32/68 weight distribution that is not far from the bug's. Based on your bias concern the 944T setup shouldn't work for a bug as it comes from a front engined car with 51/49 weight distribution with notabily stronger front calipers than rears. Despite of it everybody is happy with a 944T brake setup on beetle...These are the things that make me confused, because I'm still with you about same brakes on rear/front..Also Wally suffered / (suffers?) from early locking front brakes as far as I know.

I have only 1 personal experience about this brake stuff. When I upgraded my old drums to discs, I put a bone stock VW unit in the front and a VW Golf4 rear one in the back, both with non vented rotors and stock pads. It was at least twice good as with the drums before, that is a fact. Now which is the right conclusion of the story
1, VW has designed the front brakes stronger -> this is the way, VW engineers alway know what they are doing
2, While making the rear stronger, it was still the front locking first -> Porsche has the way to follow, due to weight distribution these kind of cars really do need bigger rear brakes.

Would be happy to hear other inputs or experiences as well!
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Last edited by Bogara_ZO; July 14th 2011 at 03:41.
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Old July 14th 2011, 07:56
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Quote:
Originally Posted by Bogara_ZO View Post
..........

3, it's hard to find your way and do something nobody has done before, based on just numbers and theories..I'm reading a few kit car forums to find something similar to the bug. Btw those "locost" builder guys are happy with Ford and GM brakes, most of them use sliding calipers...

4, I'm still not convinced. Lotus has a 32/68 weight distribution that is not far from the bug's. Based on your bias concern the 944T setup shouldn't work for a bug as it comes from a front engined car with 51/49 weight distribution with notabily stronger front calipers than rears. Despite of it everybody is happy with a 944T brake setup on beetle...These are the things that make me confused, because I'm still with you about same brakes on rear/front..Also Wally suffered / (suffers?) from early locking front brakes as far as I know.

...........!
My opinion on sliding calipers is that they are primarily a low cost option for the mainstream manufacturers. They will work well on lightweight or underbraked vehicle but they are certainly not the best, which is what I and others aspire to.

My current set up is 944 single pot on the front with 23mm m/c piston and 944T/928S4 calipers at the rear with 19mm m/c piston. Therefore my set up is substantially rear biased and I still get front lock up although now that the pads are bedded in all four will lock together in a panic stop on dry tarmac, which is what I wanted to achieve.
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Old July 17th 2011, 02:03
KAZ909 KAZ909 is offline
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Hi evil C,

Wondering what offset, brand, design etc 15" wheels you fitted that clear 944T calipers, or did you spacers with long studs.
I want to use 15" wheels as good rally tyres are only available in 15"
Thanks John
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Old July 17th 2011, 07:10
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I guess you have to start off with prioritizing a bit;

1) Stopping power
2) Cooling ability of the brakes
3) Weight of the system
4) Ease of installation and those other things

A lightweight bug with around 195wide tires does not need much stopping power to lock-up the wheels. The original system copes with that.

So cooling; Kerscher etc addresses this in them a simple way; ventilated discs, and note; still using standard spaced-out calipers.

The weight bit is interesting; but then you also have to keep close attention to the rest of the setup; wheels, tires etc...
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Old July 17th 2011, 18:38
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This is were I found the tarox brakes setup. For all T1,2,3.
www.deikaferservice.com
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Old July 18th 2011, 07:36
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Quote:
Originally Posted by KAZ909 View Post
Hi evil C,

Wondering what offset, brand, design etc 15" wheels you fitted that clear 944T calipers, or did you spacers with long studs.
I want to use 15" wheels as good rally tyres are only available in 15"
Thanks John
Hi John,

The wheels are 6" teledials (at the moment) and I added 30mm spacers that was as much to fill the arches as to clear the calipers. With those wheels it would need only small spacers ~5-10mm to clear shaved calipers and maybe none at all as the teledials have a very deep and thick well that causes the clearance issues.

The calipers were originally for a 16" wheel with the 299mm disc so since I was already committed to the wheels and the disc, I slotted the mounting holes, added crescent fillers and relieved the pads. All of that was more to fit the disc rather than anything else. I will when the pads have worn revert to the 299mm disc having now got the clearance c20mm between the caliper and the wheel that results from the spacers.

Whilst I agree with you that the gravel and forest stage tyres are mostly 15", the tarmac spec tyres are more useally found in the 16+" diameters especially if you are not to affect the gearing too much.

Clive
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Old July 24th 2011, 11:20
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Bogara_ZO Bogara_ZO is offline
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Quote:
Originally Posted by redhot View Post
I guess you have to start off with prioritizing a bit;

1) Stopping power
2) Cooling ability of the brakes
3) Weight of the system
4) Ease of installation and those other things

A lightweight bug with around 195wide tires does not need much stopping power to lock-up the wheels. The original system copes with that.

So cooling; Kerscher etc addresses this in them a simple way; ventilated discs, and note; still using standard spaced-out calipers.

The weight bit is interesting; but then you also have to keep close attention to the rest of the setup; wheels, tires etc...
i have the same preferences as above. but with~150hp, 17" wheels and spirited driving require more effective brakes than the original ones. The main problem is the non-porsche pattern, and I'm looking for alternative solutions to find the best setup for 5x112 pcd.
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Old July 25th 2011, 18:11
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I think, realistically for a beetle, a ~12" (~300mm) vented rotor is about the biggest rotor you would need. 10-11" would be about perfect. For calipers, lightweight 4-pots would be best, but even 2-pot on each corner would be fine. Matching the calipers to the MC would be the biggest challenge if you choose to mix and match from different manufacturers. Another thing to consider is consumables like brake pads, high end calipers may need specific non-standard pads.

Going with a wilwood 4-pot 11" setup similar to a miata would be a great starting point and you would still be able to use 15" wheels (the best for cheap, sticky tires). My second suggestion would be a 944 turbo setup (12" rotors, 4-pots) with a 911/930 MC, with easier to find parts, possibly cheaper too.
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Old July 26th 2011, 05:47
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Bogara_ZO Bogara_ZO is offline
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Quote:
Originally Posted by Humble View Post
I think, realistically for a beetle, a ~12" (~300mm) vented rotor is about the biggest rotor you would need. 10-11" would be about perfect. For calipers, lightweight 4-pots would be best, but even 2-pot on each corner would be fine. Matching the calipers to the MC would be the biggest challenge if you choose to mix and match from different manufacturers. Another thing to consider is consumables like brake pads, high end calipers may need specific non-standard pads.

Going with a wilwood 4-pot 11" setup similar to a miata would be a great starting point and you would still be able to use 15" wheels (the best for cheap, sticky tires). My second suggestion would be a 944 turbo setup (12" rotors, 4-pots) with a 911/930 MC, with easier to find parts, possibly cheaper too.
Thanks for the input Humble!

As I'm located in Europe I'm willing to mix european car parts. The brake pads is a very good point, that's why I'm trying to use calipers from popular cars. Actually I found a place where they make custom rotors, so maybe I should order a set with standard beetle bearing for the front with my BMW Brembo calipers that originally was used with 316x28 vented rotors. They may clear some 16" as well...the only thing I'm not pleased is the weight: each one is nearly 4 kg, that is a lot! so maybe I should pick up a Porsche caliper that - based on Clive's measurements - weights < 3 kg each

I will check the mentioned wilwood setup as well
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Old July 26th 2011, 11:19
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Something like the wilwood superlite 120-11129 4-pot that takes a 1.1" thick disc. There's tons of rotors and rotor hats to choose from, a long list can be found at summitracing.com and you can order there or get the part numbers and order locally.
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Old August 22nd 2011, 11:51
spannermanager spannermanager is offline
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Its prudent to consider wheel sizes in the mix at the planning stage also, most popular high performance track day tyres are covered by the 15" dia's with a huge range of profiles and compounds available, prices are much higher, and compound choices very limited, together with limited stocks held on the bigger 17/18" diameters.
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Old August 22nd 2011, 14:23
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2.7 boxster calipers are an upgrade option for early 911s which run 15" wheels. I'm not sure what disks they use (3.2 carrera?).

As above speccing a custom package which is balanced would be tricky.

a full 2.7 boxster disk/caliper set should work but is heavier than ideal and possibly to big for 15" wheels.
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Old August 23rd 2011, 06:17
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when i built my car i ran the 944 n/a set up. total overkill and very heavy. i was happy with the balance of them but have changed over to stock disc's on the front with a set of front calipers on the rear with some aftermarket disc's. this works very well on my car used for hill climbs and is light.
if i was to upgrade i would be going for some light 2 pots all round with some vented disc's on the front and solid on the rear all mounted on bells to again keep the wieght down, on the front you could make up some alloy hubs to further ruduce wieght.
even with the stock front brakes and the 17 inch race bubber i now run i can still lock the front up if i push hard enough, only problem i can see is if i do a track day i will be running into temp problems with the stock pads but a better pad and some decent air ducting i think i could get round that.
going to the lotus thing, i have a exige in the workshop that runs the AP set up, the car has a civic type r engine fitted and the brakes are very good, this is partly down to running some very sticky rubber and the cars light wieght.
its not just about the brakes its down to the whole car, big brakes but a light car and small thin tyres you are not going to be able stop quicker than the tyres are goping to let you, again a heavy car on wide sticky tyres will over work a stock set up quite quickly.
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