cortina1498
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| posted on 3/2/04 at 04:29 PM |
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in-board disc brakes
Does anybody have any ideas/experience of fitting in-board discs and calipers to a ford sierra diff (bolt on drive shaft type)
cheers
cortiina1498
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ned
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| posted on 3/2/04 at 04:47 PM |
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this is generally considered old hat and dangerous, break a driveshaft and you have no brakes!!
Ned.
beware, I've got yellow skin
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Bob C
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| posted on 3/2/04 at 04:52 PM |
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Should go OK with a solidly mounted diff. Issues I can think of - half shaft CV joint strength/resilience - the shafts are strong enough to slide the
wheels on a granada. Resilience should not be an issue - prototype lotus elan with rubber donuts & inboard brakes was (allegedly) fine when
driving but would bounce back & fro about a foot when the handbrake was on! Other issue is cooling - the diff is not out in the breeze like the
wheels are. Again lightweight car, back brakes don't do too much & reasonably open chassis round there, should be OK I'd say, but make
sure you don't leave the handbrake on while driving! The CV joints will get a bit more hammer than normal, but quite a lot less than when
they're pushing a granada around! I'll be interested to see how you get on!
cheers
Bob C
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Bob C
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| posted on 3/2/04 at 04:55 PM |
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Fair point Ned, the ones I've seen eg Jag - the half shafts are MASSIVE with big ugly hooke joints. Presumably hugely overrated for the
safety.
Bob C
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stephen_gusterson
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| posted on 3/2/04 at 07:28 PM |
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jag rears dont have upper rear wishbones - the drive shafts do that. therefore the UJ need to be up to it.
using inboard disks isnt so old hat from the point of view that the disk and caliper is no longer unsprung weight.
atb
steve
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JoelP
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| posted on 3/2/04 at 07:41 PM |
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what about using them on the front brakes, with an undriven front diff from a 4x4 to hold some driveshafts? you could even remove some internals and
drill the casing to lose some of the weight that it would add. any thoughts?
Beware! Bourettes is binfectious.
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Bob C
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| posted on 4/2/04 at 10:46 AM |
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Inboard front brakes were used on some of the lotus F1 cars (late 70s JPS ones..)
AFAIK GP cars now seem to use outboard brakes, even on the back...????? (look forward to being shot down in flames over that one...)
Bob C
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mackie
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| posted on 4/2/04 at 11:46 AM |
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Hummers have inboard brakes but I think that's to keep them free of water and crud rather than reducing unsprung weight 
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craig1410
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| posted on 4/2/04 at 01:00 PM |
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Surely give that most braking is done through the front it would not be quite so bad to have inboard brakes on the back axle. I wouldn't do it
on the front though in case the driveshaft did break.
It would certainly help to keep the rear alloys free from brake dust!!
Cheers,
Craig.
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blueshift
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| posted on 4/2/04 at 06:46 PM |
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for cooling you might be able to jigger some kind of air scoop to ventilate them..
Inboard brakes do appeal to me but my minimal engineering expertise does not satisfy my well-developed sense of paranoia when it comes to something as
critical as braking (K.I.S.S.)
... that, and our car's already complicated enough imo.
[Edited on 4/2/04 by blueshift]
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Stu16v
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| posted on 4/2/04 at 07:47 PM |
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I think the 'driveshaft' arguement is an unfounded worry IMHO. The amount of braking effort applied, and the amount of time spent braking
is going to be far less than the force/time spent accelerating. The cahnces of the driveshaft parting company whilst braking are going to be very
similar to the caliper lugs ripping off your upright..... I seriously considered ti myself, but didnt for two reasons. Firstly cooling, or lack of,
and second, KISS....
Dont just build it.....make it!
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craig1410
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| posted on 4/2/04 at 10:13 PM |
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Stu,
I don't think it matters if the driveshafts break during accelerating or braking as the net effect will still be no rear brakes! I agree though
that this shouldn't deter giving it serious consideration.
Cooling might not be an issue if you can channel some air down the transmission tunnel after scooping it up behind the bellhousing.
It would certainly be different and quite elegant IMHO.
Cheers,
Craig.
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suparuss
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| posted on 4/2/04 at 10:26 PM |
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i would imagine that the sierra shafts are over engineered for the car, probably based on the largest engine/heaviest car etc (not including the cossy
and v6 ones cos they had bigger shafts) considering they are going to be used on a much lighter car the chances they will break are probably something
in region of zero.
also some audi 80's had inboard disks, not relevent really but thought id mention it! 
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craig1410
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| posted on 4/2/04 at 10:53 PM |
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Superuss,
A friend of mine is a Rally navigator and one of his car club pals has a Sierra rally car which goes though driveshafts like there is no tomorrow. He
describes them as "chocolate" driveshafts.
However, as you correctly state, the Locost is much lighter and should fair better but with sticky hot wide Yokohama's on a rubbery track with a
big V8 or V6 pushing it along it might still be an issue in some cases. Some Cossie shafts might be a better bet for peace of mind.
Cheers,
Craig.
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Rorty
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| posted on 5/2/04 at 03:56 AM |
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craig1410:
quote:
A friend of mine is a Rally navigator and one of his car club pals has a Sierra rally car which goes though driveshafts like there is no tomorrow.
Is it the shafts that fail or the CVs? It's relatively easy to make shafts strong, but the CVs are usually the weak link and they're
bloody expensive to upgrade. I know from experience.
I honestly doubt if there would be any problem in a Locost with axles/CVs or the amount of cooling. I have seen similar setups in much heavier cars
fail (albeit track cars that are constantly on and off the throttle/brakes) due to fatigue caused by the alternate cycling loads.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Stu16v
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| posted on 5/2/04 at 06:39 PM |
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quote:
Originally posted by craig1410
Stu,
I don't think it matters if the driveshafts break during accelerating or braking as the net effect will still be no rear brakes! I agree though
that this shouldn't deter giving it serious consideration.
Cooling might not be an issue if you can channel some air down the transmission tunnel after scooping it up behind the bellhousing.
It would certainly be different and quite elegant IMHO.
Cheers,
Craig.
Also bear in mind that *should* the worst happen, the front brakes are doing most of the stopping in an emergency anyway.
I find with my car that the air going through the transmission tunnel is substantially preheated by the engine, to the point that in the summer the
tunnel is extremely hot to the touch after a good blat. Probably a lot cooler than well worked brake discs, but not ideal.
All food for thought,
Cheers, Stu.
Dont just build it.....make it!
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craig1410
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| posted on 5/2/04 at 09:37 PM |
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Stu,
That's why I was saying to scoop the air up just behind the bellhousing. You can block off the air from the engine bay with a rubber flap seal
if necessary.
Rorty,
I don't know what it is that is breaking on the driveshafts, I am only going on comments from my mate who keep driving past his colleague on
Rally stages due to driveshaft failure... I'll ask him next time I see him and see if he knows any more about it.
Cheers,
Craig.
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