Brake 'Down'-Grade - Saxperience

MikeWW · 26th November 2015, 17:29

Hi,
I've seen many post on here about upgrading front brakes with larger calipers, vented discs etc but my situation is slightly different.

I use a 2002 VTR in Loose Surface competition where breaking is really only used to pull up in the paddock.

Much more important to me is un-sprung weight so I'm looking at replacing the VTR calipers and vented discs with something much lighter - say a 1.1 caliper and single solid disc. As I say breaking performance is not really an issue and the car is not road legal anyway so I have no MOT issues.

Can anyone offer any advice on what my options might be;

For example - I've seen post suggesting the VTR caliper and disc are a straightforward fit to a 1.1 but will it work the other way around. What parts will I need - I'm assuming Carrier, Caliper, bolts, discs and pads?
What about pedal travel or servo - any issues there I should think about.

Finally - if I need to re-balance the front v rear breaking effort is this possible on the Saxo.

Any help or advice would be appreciated - if I can make it work I will be selling a full set of VTR front brakes with new discs and pads at a very attractive price!

Thanks

Synister · 27th November 2015, 10:23

Your rear axle will have a spring loaded compensator on it, you can adjust the tension to change the brake bias from what I remember. Or splice the brake lines and run a wilwood bias valve.

Disks, calipers and pads should be a straight swap but there wouldn't be that much of a weight saving imo, that said the less unsprung weight the better.

MikeWW · 1st December 2015, 07:36

Synister,
Thanks for you response. You're right it won't save much weight but if I can find donor parts cheap enough I'll give it a go.

I wasn't aware of a rear brake compensator. Thanks for that info.

chinkostu · 1st December 2015, 22:19

Can you just ditch the fronts completely and leave the rears on if you dont need brakes? Heck even just run the handbrake

Seriously though, the solid disc setup isn't a massive amount lighter. Why not run the rear axle with no brakes as they only do a small amount anyway.

KamRacing · 2nd December 2015, 10:38

Also look at the wheels you use as smaller steel wheels will be lighter than the alloys. With everything done you should certainly notice a difference in handling.

monka · 2nd December 2015, 14:11

The lightest standard brakes you can get are s1 106 bendix calipers and non vented discs

monka · 2nd December 2015, 14:16

Quote:

Originally Posted by chinkostu

Can you just ditch the fronts completely and leave the rears on if you dont need brakes? Heck even just run the handbrake

Seriously though, the solid disc setup isn't a massive amount lighter. Why not run the rear axle with no brakes as they only do a small amount anyway.

There is, according to the info on 106owners, a 2.5kg weight difference per side. Quite a substantial amount esp when that's unsprung weight, and unsprung weight is supposed to be the equivalent of 10x what it is in the car, so effectively like taking 50kg out!!

chinkostu · 3rd December 2015, 12:55

Quote:

Originally Posted by monka

There is, according to the info on 106owners, a 2.5kg weight difference per side. Quite a substantial amount esp when that's unsprung weight, and unsprung weight is supposed to be the equivalent of 10x what it is in the car, so effectively like taking 50kg out!!

Didn't even realise it was that much. can anyone confirm this?

monka · 3rd December 2015, 17:04

all in here

http://106owners.co.uk/forums/showth...rmation-Thread

axsaxoman · 18th December 2015, 08:15

Quote:

Originally Posted by monka

There is, according to the info on 106owners, a 2.5kg weight difference per side. Quite a substantial amount esp when that's unsprung weight, and unsprung weight is supposed to be the equivalent of 10x what it is in the car, so effectively like taking 50kg out!!

while i,m not going srgue with your umnsprung wieght comment --if ther car was really effectually 50kgs lighter --that the differnce bewteen you driving it solo and iwth a nice tidy slim GF --and i don,t think you will see that much dif in performance

If you going down this road then you will need to alter spring rates as well to get the full effect --and from experince of rally cross +auto cross the bouncing up and down willmake it be hard to see any dif -
-make more power --brake later --if you don,t need to brake at corners --you ain,t going quick enough down the straight!!!!!- simple as that---rallycross cars have big brakes

my guess would be your gearing is all wrong so it ain,t accelerating quick enough

dump your load valve on rear --replumb brakes and fit bias valve by hand brake is a must then you decide how much braking ,which could help your turn in at the corners