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Saving some weight
Moorron - 28/5/15 at 12:30 PM

Hi guys been a long time not positing on here but can I get some advice.

My MK Indy runs sierra vented front discs at the moment and I'm currently looking to lightening up the car. Which brake kit is the one everybody is using and which pads do you recommend for road use? Is it the rally design ones on solid discs I need?

I bought the car already built and it came with 17” alloys which look great and after driving it for 7 years I don’t mind the harsh ride, but with the quest to lighten the car it seems silly to run such large wheels. If I went from these to 15” lightweight alloys (1.2’s?) and the brake change mentioned above, would I notice much difference in driving? What does ‘un-sprung’ weight reduction feel like?

Does anyone have the weights of the sierra brakes Vs the Wilwood ones and the 15” 1.2 alloys fitted with 888 tyres so I can see what I am looking at.

Angel Acevedo - 28/5/15 at 12:37 PM

I don't know how much Weight you can save with brake discs but coming down from 17 to 15 May save yo a good 2 to 3 kg per corner.
Being rotating mass and due to the fact that this mass is relatively far from the wheel spindle it will be very noticeable
HTH

JAG - 28/5/15 at 01:03 PM

Switching from vented discs to solid discs will save 1-2kgs per disc.

However - if you have Sierra uprights I don't think the Cortina solid disc will fit.

Did the Sierra have a solid disc? If it did you'll also need the caliper to change to suit the solid disc.

mcerd1 - 28/5/15 at 01:19 PM

Yes the sierra had solid discs on the 1.3 engines cars and some of the 1.6's I think

Its a 240mm diameter and about ~9mm thick (check that thickness)

I think that some of the willwood and hispec setups use these discs

[Edited on 28/5/2015 by mcerd1]

Worzey - 28/5/15 at 01:24 PM

I went from the Sierra vented discs to the Wilwood Powerlites with single discs (from Rally Designs). I can't recall exactly what the weight saving was (maybe 1-5kg each side?) but it totally transformed the car.

It eliminated massive bump steer that I had before and made it so much easier to place on the road.

Best upgrade I've made so far.

james h - 28/5/15 at 01:30 PM

I got this kit from Rally Design. So so much lighter than sierra vented discs and calipers.

TimC - 28/5/15 at 05:07 PM

Hi,

Both the brakes and the wheel changes seem like sensible steps. Did I give you the 15" Dunlop steels with the car? Those were pretty light as I recall; they'd look pretty cool in a black powdercoat too.

Just about dried out enough
Just about dried out enough

It still makes me smile to think that you've kept the car for so long. My Striker and MNR have both seen several owners since I sold them.

Cheers,

Tim

Moorron - 28/5/15 at 07:55 PM

Sorry guy I did mean solid discs that are part of the powerlite kit.

I do get evil bump steer to the point I have to watch pot holes closely or it will rip the wheel out of my one hand.

The real pain is the 17" alloy I currently use have almost brand new tires fitted to them and as I horde things they will sit in my shed for 10 years doing nothing but rotting if I buy a new set.

Looks like I will be ordering some new brakes then, I hope it doesn't alter the feel from the sierra setup because I do like it as it is.

Cheers

Moorron - 28/5/15 at 07:59 PM

quote:
Originally posted by Moorron
Sorry guy I did mean solid discs that are part of the powerlite kit.

I do get evil bump steer to the point I have to watch pot holes closely or it will rip the wheel out of my one hand.

The real pain is the 17" alloy I currently use have almost brand new tires fitted to them and as I horde things they will sit in my shed for 10 years doing nothing but rotting if I buy a new set.

Looks like I will be ordering some new brakes then, I hope it doesn't alter the feel from the sierra setup because I do like it as it is.

Cheers


Hi Tim, the car was nicely made giving me a good high step to improve and with this next purchase I hope to improve its performance even more without stressing the engine.

I do have those steel wheels in the garden, never even put them on the car. But I good idea which might save some money and I think a local place does wheel refurb for £30 each, might be worth a try.

Your smile with turn downwards when I tell you I have never tracked it in those 7 years!

[Edited on 28/5/15 by Moorron]

ptrxly - 31/5/15 at 12:33 PM

As an experiment, I machined one side of the cast vented front disc to create a solid disc and removed a spacer from between the caliper halves on the Wilwood Dynalites. This took the weight down from 14.6# / disc to 8.0#, a 6.6 # saving of rotating unsprung weight per corner. The disc is thin (8.5mm) but I have had no issues in a 1000km or so, but I have not yet tracked it yet with the thinner disc. Machining the hat could save even more.

scutter - 31/5/15 at 03:06 PM

THIS page on the westfield world website might help you with your thought processes.

ATB Dan.

Moorron - 3/6/15 at 08:07 PM

Cheers for the link, unfortunately it doesn't really list any of my 'bits'.

Just an update, received the front calipers and the discs. Wow nice bit of kit and should really look nice under the wheels, looking at my flexes (I bought my car already made so don't know spec) they are female ended onto a male to male stud in the caliper, if the thread is the same with the one supplied my Rally Design I may get lucky with them. Length also looks about right too but time will tell.

I will update here with weights of both new and old kit for reference.