54 replies to this topic

[tiger99]

The ONLY point I see in rear disks on a Mini is that theoretically maintanance is easier, for example you can see pad wear at a glance,and they are self-adjusting. Now, to me these things matter, but it would be difficult to implement a properly balanced system with rear discs. You would need really tiny discs (ok, larger disks could be turned down) and calipers with very small diameter pistons (at a guess 20 to 25mm). Standard pads, to suit the calipers, could in some cases be machined to reduce the area greatly, to get  a higher working temperature. But what a lot of work all that would be, and you would still have quite a lengthy development program to get it all right. Strictly for those who understand fully what they are doing....

 

Sadly, I have to say that in almost every case good quality alloy drums would be more sensible. Don't bother with cheap alloy drums, the differential expansion the first time they get hot loosens the cast iron liners, and if they don't have a cast iron liner, they will not last very long.

 

And, I would never bother with KAD calipers, considering the excessive cost, and that we don't know the fatigue life for which they were designed. That matters very much for all alloy components that are cyclically stressed. A steel caliper lasts for ever, unless badly designed, an alloy one will eventually fracture.

 

But, I would still like to see a successful disc conversion, if someone manages to produce one.

[Sociopath]

I’m making one.




















Thoughts? Criticism?

[Cooperman]

The biggest problem with that is that as the rear brakes only do around 20% of the total braking on a Mini, those brakes will never get warm enough to work efficiently. How will you find pads soft enough to operate at those really low temperatures?

If rear discs are wanted to reduce unsprung weight on racing Minis, a thin motorbike disc system would be best from a small lightweight bike with thin discs and small pads. If this is not done they will never work properly.

The rear brakes on a Mini really do virtually nothing and are only for passing the MoT, parking and, if the need exists, for handbrake turns.

[A-Cell]

...it also looks heavier than the standard drum set up.

[Cooperman]

Better off fitting Mini-Fin drums if the need to reduce the unsprung weight is so important. Reduction of unsprung weight is the only reason for changing from standard drums, although standard drums are not exactly heavy.

One can see lots of problems with rear discs, but no real advantages. Can't really see them making much difference to lap times in reality.

[Sociopath]

those brakes will never get warm enough to work efficiently.

 

 

 

The rear brakes on a Mini really do virtually nothing

 

 

 

Lack of consistency I’d say. And logic. If rear brakes do nothing on mini why would you want them to be efficient. This is crap talking of those who - if they own mini in the first place - only trailer it to shows. And  those, who never had a mini.

Mini rear brakes are joke. Have they at least had self adjusters (even simple ones 2 discs with a spring on small pivot holding a shoe ) I wouldn’t say a word. Constant need for monitoring shoes adjustment is something that we had to put up with in 50’s. In this day and age that’s simply an absurd.

Never mind track racing or weight reducing, for normal road use you need rear brakes. That’s law. For those who use their minis for more than just showing off, rear brakes conversion should be on top of the list. Unless of course, you’re  masochist and enjoy diving under the car every other week.

There are proper disc brake conversions for every popular modern classic these days . I think it’s fair to assume that mini is quite popular. What do we get  for mini? Billet alloy gadget, ripped of some mountain bike and marketed as a mini brake conversion kit. Automotive industry doesn’t use aluminium in brake systems. At all. There is  probably good reason for that. Like the fact the brakes use highly corrosive liquid to operate.

Oh, the pads are quite tiny



I think they’ll do just fine. No point in talking me down mate. I’m gonna do this anyway. And it’s gonna be great.
 

Edited by Sociopath, 02 November 2014 - 05:15 PM.

[Cooperman]

You asked for 'Thoughts. Criticism'.

Then you get a logical engineering response and don't like it.

Do as you please, but there is no logical reason or advantage for fitting disc brakes on the rear of a Mini. Due to its short wheelbase any 'over-braking' on the rear will cause instability under braking, so the line pressure to the rear if disc-braked will have to be heavily restricted.

[sledgehammer]

Automotive industry doesn’t use aluminium in brake systems.

At all. There is  probably good reason for that.

Like the fact the brakes use highly corrosive liquid to operate.
end quote

 

???

 

lots of cars use alloy components in the braking system - from calipers to abs units

 

brake fluid damages paintwork - but isn't generally corrosive - it has to preserve components ie rubber , alloy , plastic & steel

 

and cooperman  is an confirmed ex rally driver so knows his stuff , esp on mini's

 

you will need a compensator / restricter / bias valve , for that set up + a handbrake for road use

 

but I hope it works for you ,

 

edit - looks like it has an handbrake crank on it - so ignore that

Edited by sledgehammer, 02 November 2014 - 05:26 PM.

[Sociopath]

You asked for 'Thoughts. Criticism'.

Then you get a logical engineering response and don't like it.

Do as you please, but there is no logical reason or advantage for fitting disc brakes on the rear of a Mini. Due to its short wheelbase any 'over-braking' on the rear will cause instability under braking, so the line pressure to the rear if disc-braked will have to be heavily restricted.

Should have added ”constructive” …criticism.

If  not having to touch rear brakes until, most likely in case of mini , the end of its life, is no advantage, what is?

You can adjust line pressure to you liking by turning the knob these days. Less than 20 quid bias valve.

I like criticism mate. Thou, is some objectivity too much to ask?

[Sociopath]

 

 

 

lots of cars use alloy components in the braking system - from calipers to abs units

Automotive industry (don’t confuse with tuning gadgeds makers) uses aluminium composites. No billet.

 

 

 

 

brake fluid damages paintwork - but isn't generally corrosive - it has to preserve components ie rubber , alloy , plastic & steel

 

Given I often see half a mil deep pitting in hardened stainless steel caliper pistons I’m not gonna  comment on that.

 

 

Peace guys. I love minis as much as you do. That’s why I want it to have proper brakes. 

 

 

Edited by Sociopath, 02 November 2014 - 05:54 PM.

[Cooperman]

I have rallied, sprinted, hill-climbed, prepared and restored Minis for over 50 years. I can tell you absolutely that disc brakes are not the way to achieve optimum braking on a Mini. Brakes require a certain operating temperature to work at their best and with the small amount of work done by the rear brakes on a Mini the heat generated is insufficient to warm disc pads sufficiently.

Drum brakes worked well enough to win the Monte Carlo Rally 3 times (or 4 depending on which way you look at it), They have won countless races including long distance events as well.

So how disc brakes, operating at very low temperature, can be an improvement on the standard ones is hard to imagine. It is even hard to make competition rear linings work on a Mini due to the low temperatures.

On long rallies I can adjust the rear brakes in about 20 seconds per side. How is that a problem, especially on a road car. On a race car they can be adjusted after practice and before the race.

Edited by Cooperman, 02 November 2014 - 10:29 PM.

[spiguy]

My only experience of rear disc brakes has been on small cars in the past (wife's car), most recently a 1.4 polo. I hated them for one simple reason - they were doing such little work that they basically just corroded extremely quickly. The calipers were in good working order, no binding, no laziness, just didn't do enough work to keep the disc cleaned up. I put 3 or 4 sets of discs on the back of that car in the space of 6 years.

 

I have to suspect that the same situation could arise on a mini, if the brakes need to be setup to do very little. Do look very smart though, and it's an interesting engineering undertaking to do what you are doing. Be sure to feedback after a while how you find living with them. I think with all these things the proof comes in use. If they work well and turn out to be zero maintenance as you hope, then that will prove them to be a good idea as a conversion.

[Sociopath]

I have rallied, sprinted, hill-climbed, prepared and restored Minis for over 50 years. I can tell you absolutely that disc brakes are not the way to achieve optimum braking on a Mini. Brakes require a certain operating temperature to work at their best and with the small amount of work done by the rear brakes on a Mini the heat generated is insufficient to warm disc pads sufficiently.

Drum brakes worked well enough to win the Monte Carlo Rally 3 times (or 4 depending on which way you look at it), They have won countless races including long distance events as well.

So how disc brakes, operating at very low temperature, can be an improvement on the standard ones is hard to imagine. It is even hard to make competition rear linings work on a Mini due to the low temperatures.

On long rallies I can adjust the rear brakes in about 20 seconds per side. How is that a problem, especially on a road car. On a race car they can be adjusted after practice and before the race.

Well, not everybody’s rallying his mini. 20sec, 20min, 2 hour, what does it matter? It’s still time spent under the car. Every month I’d say if you actually drive your mini.

Oh, and I don’t think mini won Monte Carlo due to the excellent performance of rear drum brakes..

[Sociopath]

I hated them for one simple reason - they were doing such little work that they basically just corroded extremely quickly. The calipers were in good working order, no binding, no laziness, just didn't do enough work to keep the disc cleaned up. I put 3 or 4 sets of discs on the back of that car in the space of 6 years.

 

Rear brakes in my mini will actually have some, except from rusting, work to do. I build an electric mini.








I’ll be carrying 100-150 KG of battery worth extra weigh in the trunk at all times.

 
 


Doesn’t change the fact, that it takes years for rust to build up. Minis rear brakes as they are now, require constant attention.

[Steve220]

That, is EPIC!!!!!!!!