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Rear disk Conversion.
B3Saxo - 25/4/03 at 06:22 AM

Does anyone do rear disk conversion plates for the sierra drive shafts? (IRS)

The ones that hold the calliper at a slight angle. Not 12 o clock. Like kit fits.

Would it fail SVA having rear callipers at 6 o clock? Like F1 cars?


eddymcclements - 25/4/03 at 12:41 PM

The disc-braked Sierras have lugs cast into the rear bearing carriers onto which the calipers mount. The bearing carriers can be bolted onto your fabricated or cast uprights in any orientation (they mount with 4 bolts) so you could have underslung calipers if you wanted. You might find that a. you can't bleed the brakes because the bleed nipples would be pointing downwards/sideways and b. impossible to route the handbrake cable successfully.

Cheers,

Eddy


ChrisW - 25/4/03 at 10:27 PM

Second that! FYI the mounts from the Granada are interchangable (and easier to get hold of)

Chris


zetec - 25/4/03 at 11:05 PM

If you are building an Indy MK supply different uprights for rear disc use, they allow a better route for hanbrake cable.


Woody - 28/4/03 at 07:33 AM

Hello B3 mate nice to see a friendly face on here
I havent a clue on your brake problem just thought i'de say HELLO


sg_frost - 28/4/03 at 10:17 PM

The position of the caliper also has an effect on forces on the road. With the rear caliper at the rear, the disk tries to dig down to the road. Imagine grabbing a vertical spinning plate, which way does the plate go, down. Got a really technical booklet on this from university, can't find it, and should have paid maore attention in class. who cares!!

Had problems bleeding the sierra calipers at the 3 o clock position on the mk2 rally car, unbolted them, moved them to the top, bleeded them, then bolted em back on, simple if your ingenious!!


kingr - 29/4/03 at 08:50 AM

quote:
Originally posted by sg_frost
The position of the caliper also has an effect on forces on the road. With the rear caliper at the rear, the disk tries to dig down to the road. Imagine grabbing a vertical spinning plate, which way does the plate go, down.


Hmmm, can't see this myself, the caliper and disc are fixed in relation to the hub, all that the wheel and upright are going to experience is a rotational force in the opposite direction to the movement of the wheel. Perhaps one of the more knowledgeable people on this board can confirm on deny this?

Kingr


Alan B - 29/4/03 at 11:42 AM

Well I can't confirm or deny, but I agree 100% with your logic..........your hub will see a torque that opposes the wheel rotation.....I can't see how the angular point of application affects anything....


craig1410 - 29/4/03 at 12:09 PM

Nope I can't see this either. Surely torque is torque no matter wehat angle it is being applied at? It would be different if the caliper was mounted to the chassis instead of the axle but this would somewhat limit suspension travel...

I am very interested to see the proof behind this if you can find it because I can mount my calipers in any orientation at present and would hate to miss a chance to optimise something. I was just going to do whatever made the handbrake easiest. I'm using de-dion suspension and so have no torque reaction under power but will have torque reaction under braking which as far as I can tell will just apply tension to the lower trailing link and compression to the upper link. Unless you have strange geometry in the trailing links such as not parallel then I can't see how this would cause the suspension to raise or lower but it would be nice if it could be lowered under braking to counter weight transfer.

Cheers,
Craig.


ned - 29/4/03 at 12:47 PM

so are we saying it doesn't matter where you mount your calipers then? I agree that the torque isn't going to care what direction /angle it's at when the brakes are applied.

Craig, though not avantageous the only decent way of mounting brakes to the chassis would IMO be to have inboard brakes ie bolt them to a chassis member or even better the diff(if it's mounted solidly in the car) or gearbox for rear engined cars only problem is it puts more strain on the driveshafts/splines.


ROM - 30/4/03 at 01:02 PM

I think you are right, the position doesn't matter, although convensionally in F1 we put the rear calipers in front of the wheel and behind the wheel at the front. It does make a difference on the loadings into the wishbone legs though, as it is these that take the torque reaction.

Don't fit them at 6 o'clock unless you don't mind taking the calipers off to bleed them. The porting in the calipers is done so that in their normal position the bleed screw is at the top of the fluid so any air can bleed out. If you mount them any other way you stand a good chance of trapping air and not bleeding it out. You would have to remove the caliper and hold it upright to bleed it properly.

Kind regards,

ROY


flateric - 30/4/03 at 05:37 PM

Inbaord brakes got banned in racing beccause a lot of people got hurt! Basically the driveshafts break and then you have no brakes.

Kind regards,

Eric


Woody - 1/5/03 at 06:33 AM

Inboard disks have the advantage of reducing unsprung wieght and not needing a flexy pipe so better feel at the pedal ,but can only be done on IRS or De dion


craig1410 - 1/5/03 at 12:09 PM

Yes inboard brakes would be possible like on the Jaguar E-Type but as said above here, if your driveshafts break then you are heading straight to the scene of the accident

I still think that positioning the calipers for ease of handbrake attachment and ease of bleeding is the priority. I don't want to have to remove the calipers just to bleed the system and I don't want to have to make up fulcrums to operate my handbrake.

Even on an IRS car, wouldn't the upright take the force from the caliper and therefore simply apply a torque to the wishbones no matter what the angle of mounting. The Formula 1 boys mount them at 6 oc'clock to lower the centre of gravity that little bit more. Bear in mind that these guys are after any improvement they can find, however small and since they are driving on smooth tracks (most of the time...) they don't have to worry about potholes and stones in the road like we do which may damage calipers mounted at 6 o'clock.

I'm going to stick with somewhere between 12 oclock and 9/3 o'clock (rhs, lhs resp.) in line with the easiest handbrake/bleeding position.

Cheers,
Craig.


B3Saxo - 7/5/03 at 11:16 PM

Hello woody!

Hows your project coming along?

Brake problem still there guy's! I'm gonna have to fabricate some brackets out of 8-10mm steel!

Could sell em! Hmm! Interesting!


ChrisW - 8/5/03 at 09:16 AM

quote:
Second that! FYI the mounts from the Granada are interchangable (and easier to get hold of)



Turns out I'm wrong Tried to put these together yesterday and they won't go. Guess I'll have to think of another plan.

I'm using Sierra 1.8 shafts with Granada 2.8i hubs.

Chris