MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Big Brakes for the Racer

As the midget racers are aware I built Jason's racer over a 4 1/2 month period during the winter of 2006/07.

At the time, budgetary and time constraints meant that I couldn't do what I wanted in the brake and front hubs departments. The car therefore debuted with Wolseley 1500 rear drums and stock front hubs (albeit with taper roller bearings) with modified Austin Allegro discs and Austin Princess 4-pot calipers.

Unfortunately this front set up, while resulting in superb braking, is rather heavy and adds considerably to the unsprung weight. Accordingly I looked around for a lighter set up.

My initial thoughts were to see whether Triumph Spitfire hubs could be modified to fit the Midget stub axles since alloy hubs are readily available here in the UK. This would also mean a greater range of options vis a vis the brake discs (rotors) and calipers because for years I had run a big vented set up on my race Spitfire and later a Ginetta G15.

The trouble is that Spitfire hubs can not be modified in this way owing to the distance between the inner and outer bearing races. Accordingly, as you are aware, I manufactured my own alloy front hubs.

After sourcing the vented discs that I wanted, much measuring resulted in the correct size alloy spacers being machined to adapt the disc bell to the hub:




Deborah Evans

And:




Deborah Evans

The calipers I intended using are American and produced by Wilwood in California. The reasons for using these were:

1. They are way cheaper than the equivalent AP caliper (additionally because I can source them at USA prices).

2. They are lighter than the equivalent AP caliper.

3. They have a larger pad and piston area than the equivalent AP caliper.

Having set up the hub / disc arrangement a small bit of further machining was required to make up a 'carrier plate' which bolts to the front upright and to which is bolted the caliper:


Deborah Evans

Here we see the carrier plate being test fitted to the upright:




Deborah Evans

Here we see how the carrier bolts to the caliper with cap head bolts (that's socket head bolts for you American types!), before the whole thing is attached to the upright as a unit:


Deborah Evans

Some shots of the complete set up:




Deborah Evans

Caliper fitted:




Deborah Evans

The disc is just sub 10" in diameter (9.8"):


Deborah Evans

Last one (note the 'Gucci' front suspension mods). Admittedly the flexible brake hose requires a 90 degree adapter at the caliper so as to reduce kinking (which is in hand):


Deborah Evans

Veeery nice Deborah, but you really shouldn't have put it up until Prop got his car finished :+)
Does the kit fit behind standard wheels or do you have to go up a size?
Graham
Graham P 1330 Frogeye

Deb, i was wandering what the advantage is of alloy hubs?
Loss of unsprung weight... how many kilo's is that and how noticeble is it for the driver?

Would it be intresting for non racers aka fastroad cars?
Arie de Best

Deborah,
I have 13" centre lock minilites. Would these fit? I guess not with 10" discs. Would need 14" wheels?
Neil
Neil (K series)

Oh eeeeevil woman

fancy doing that to poor ol' Prop

he he

oh yes

nice, I do love a good bit of engineering in the evening

bill sdgpm

Can you divulge the source for the calipers?
Also, what grade aluminium did you use for the carrier?
Tarquin

HUH! read it and weep guys...LOL

Im already WAY Ahead of you guys.

Not only do I have the frontline kit with red polybushings, BUT I also have most of the parts for a big brake kit

MGB calipers...using kevlar MGB GT V-8 brake pads, drilled and sloted Spitefire rotors, A Huffknar Spacer to attach the hub to the rotor...all stainless steel brake lines to the tilton master cly set up

then there is the adco 3/4 inch sway bar that will hook up to the barry king wish bones...and of coarse Im using the 40 degree angular wheel bearings all on 7/16 wheel studs so everything fits nicely into my wheels


luckly the only thing left to get is the barry kign wish bone pans, brake pads, Adco sway bar, wheel studs and get all the parts powder coated...everything else I got in a box ready to go.

MGB calipers will be fire engine red, frontline kit is bright yellow, WB pans Black, shocks are chrome, spring is bright yellow...and the rest is ither silver or black


So Im guessing it should do something

Prop...they call me, Tater salad!
Prop

Nice job, heres my attempt with 9" discs & MGB calipers.


Brad (Sprite IV 1380)

You could always try this set up.


brian s

Prop, mgb calipers are sooooooo nineties! ;)

Get some fourpot aloy calipers like Deborahs kit or the mother of all frontbrakes: Brian's 6 pot.

Prop, the people you will run over with your midget will be treated at a very collorfull suspension sight as the last thing they see before leaving this earth.
LOL!!
Arie de Best

Nice brakes but more importantly does this mean Jason is coming back out to play again this season Deborah ?
Dean Stanton

Answering my own question, ive just seen the answer to this on the other brake thread.
Dean Stanton

brian s
Nice 6 spot caliper there BUT , That is a LH rotor on the RH side , the slots are supposed to wipe outwards when rotating not inwards. Willy
WilliamRevit


I'm following Brad's version (similar to others commercially available kits) which comes through at around £150 all up..looks relatively inexpensive for a significant improvement!

The issue for me is how far do you really need to go brake wise on a roadgoing midget. Most of us have increased power, reduced weight and fitted better/wider tyres....at what point do you stop spending money uneccesarily? Vented disks, 6 pot callipers, etc......
l snowdon

>>at what point do you stop spending money uneccesarily

Not a concept I understand; it's all necessary.


A
Anthony Cutler

To answer the questions (in no particular order):

1. Wheel size:

In Class B we are limited to a 13" x 6J wheel with a maximum tyre width of 7.5". Accordingly we run KN Minotaur 6J rims (Minilite replicas) with the slicks and 5.5J rims with the wets. If you look carefully at the hubs you will note the extended wheel studs that require a spacer. I am using a 20mm spacer and with this there are absolutely no clearance problems between the calipers and the wheels. I have a set of pukkah Minilites for my Ginetta G15 and these also will fit with no issues as do Compomotive MS 5 spokes.

We probably could get away with a smaller spacer, although I haven't tried measuring that yet. I wanted the set up as is because I wanted to widen the front track to assist with turn in, especially in the low speed corners such as 'Priory' at Silverstone, where we were getting far too much corner entry understeer.

When the car is not in use we use a set of standard Midget Rostyles as 'transit wheels' (because we don't want to 'flat spot' the race tyres) and even these will fit albeit with an extra 10mm spacer that will be removed prior to racing.

Neil, I have no experience with centre-lock Minilites but I don't foresee them being a problem, although I would want to measure them before committing myself.



2. Unsprung weight:

Arie, as I am sure you are aware, reducing overall weight on any racer is beneficial for performance in all sorts of ways - less overall weight = less weight transfer under under cornering (let alone Newton's Second Law).

Reducing unsprung weight is also of great benefit because it allows the suspension to react better. This is especially so on a Midget (even a road car) with it's rather pre-historic, Austin A35 derived front suspension (when I built the car, during the initial strip down I couldn't believe how primitive the suspension actually was - me being used to double unequal length wishbone set ups). I have little experience with the Frontline front set up (in terms of knowing how much it weighs - but it looks significant) but I am sure it would also benefit.

The alloy hubs with the big brake discs and spacers weigh in at less than the stock hubs/Allegro discs we had before (by around about a Kg) so with, say a 9" Spitfire disc/alloy spacer the saving would be (I'm guessing) around 2-5 Kg) per side. I don't know (yet) the overall weight saving with the new set up on the racer (because I haven't yet done the corner weights) but I'm guessing it to be significant.



3. Materials and Source:

Tarquin, the calipers were sourced direct from Wilwood in the USA - my cousin lives in LA. The sole importer to the UK is 'Rallye Design' and their mark up is HUGE! You can also get them through Peter May, although he gets them from Rallye Design, but I wouldn't wish to comment upon his profit margin given that he is a friend and fellow racer.

With regards to the materials, the hubs and caliper plates are 7075-T6, the disc bell spacers are 2024-T4.



4. Brake size:

I am not convinced that huge brakes are a necessity on a road car because you would just never get them up to temperature. My cousin's Frogeye (recently featured in 'Practical Performance Car') with a Suzuki Swift motor putting out around 125 bhp used 9" Spitfire discs with Wilwood 4-pots and the braking performance was superb. I would suggest that the race set up would only really be of benefit on racers, track day cars and (possibly) high powered K Series road cars

I might be shooting myself in the foot here because I will be eventually offering the big brake race set up as a kit. However I also intend to supply other options such as 9" Spitfire disc set ups, MGB calipers, Princess calipers, or even 9.7" GT6 discs with Girling Type 16 Calipers.



Deborah Evans

Deb's,
are you going to classic Le Mans this year? if so drop me a mail brad_r AT fastmail.fm
Brad (Sprite IV 1380)

Brad,

Unfortunately I am unable to go to Classic Le Mans this year because I will be in the USA at that time.
Deborah Evans

So are you going to be at Road America at all? Blackhawk Farms?
David "wanting to meet a Priestess" Lieb
David Lieb

David,

I doubt it this year. I need to do some research on racing 'Classic Cars' in the USA because, if plans come to fruition, I will be relocating to upstate NY on a permanent basis (and yes Priestess Racing will set up shop over there). That being the case I will be bringing my Ginetta G15 with me to race. :D

Deborah "I SO want to race at Watkins Glen" Evans.
Deborah Evans

That yellow six pot setup seems to leave an awful lot of disc unswept by the pads, or is it not fully in position yet, like the anti roll bar?
Bernie.
b higginson

If Deb moves to NY, can Prop's startup be far behind?

FRM
FR Millmore

Hmm, is Disney working on a sequel, "The Priestess and the Frogeye"?
David "anonymous" Lieb
David Lieb

LMAO
Got to be one of your best David
Robert (Bob) Midget Turbo

if plans come to fruition, I will be relocating to upstate NY on a permanent basis (and yes Priestess Racing will set up shop over there


AH Jez... That did it, Im stoned on love...looks like cupid fired his arrow straight into my engine.


So is there enough race work here in the states or in New york to keep you busy .... after all the only racing in the mid west is drag racing, 1/8th mile circle dirt, and il-legal street racing.

heck even my girl danica patrick had to bail on cart series and go to nascar.

prop
Prop

Hi Willy,

well spotted. When I got the kit I thought there may have been a problem so I fitted both discs and hubs to both sides to eliminate any problems and took many photos of which that was one of them.

Brian
brian s

I used four pot alloy calipers made by kad (UK company)ideal if you dont want to change the disc size or do any type of conversion,just bolt on with no mods,big difference in stopping power but big price too!


Rob Newt

Deborah, there's a good bit of vintage racing around the country and a lot on the east coast so your tow distances might not be too bad. Some very nice people from all over the country who race vintage as well as SCCA post on the MG Experience motorsports forum where I'm sure you'll find more than enough information on racing "classic" cars in the US. http://www.mgexperience.net/phorum/list.php?41
This summer the MG Vintage Racers "focus" event will be at Mosport in Canada and next year they'll be in California. A great group of people in that organization as well. http://www.mgvr.org/ Hope you have a great time on your trip and if things work out welcome to the US.
Bill Young

Bill you are a STAR! Many thanks for those links!

You never know, if it all works out and I relocate to the USA I might well build another race Midget. ;)
Deborah Evans

There's also SVRA, they hold events at large & small tracks all over the country.

svra.com

Dave
Dave Rhine ('78 1500)

Deborah, If ever you put a complete kit of parts out to give big brakes using commercially available (cheap!) parts (I am not too concerned about the weight)like MGB or Princess calipers and spitfire hubs etc etc please put me down for one. But it must fit inside the standard wheel.

David Banks

Deborah

love the kit it looks stunning

but i do have some questions

-what size MC is needed with these calipers wil the std bore suffice?

-the kit is over kill for a road car as you said
to me the upgrade for a road car looks like the 4 pot kad caliper
(with the B caliper setup weighing just to mutch)
but your kit could be interesting if it was able to compete in price with the Kad calliper do you have anny thoughts about the posible price?
Onno Könemann

I love the KAD 4 pot calipers ..... BUT .....

In the USA and Canada there is only one dealership that sells KAD and thats (7 enterprises) and the price tag is vary ... (sohpisticated)!

Almost **** $1,000 **** for just the 2 calipers alone...Nothing else?

http://www.7ent.com/detail.cfm?pageid=981

Yes wildwood calipers are also nice, and a little less harsh on the wallet...STILL Agian around ****$1,000**** but you get the rotors and pads also ... see part# 10008

http://www.dalesresto.com/parts.html


MGB calipers might be sooooo 90's but my wallet is Soooooo 2010...esp. at $160 for a pair of rebuilts from ebay, So for a savings of $840, I'm seriously thinking I can live with a few extra ounces.

Prop...Its cool to be 90's retro
Prop

wow prop that is about twice the price from Kad!
surely you can order direct the shiping should not be that masive
Onno Könemann

I managed to get 10.25 inch OD discs under 13x6j wheels but the standard rivetted steels from the early cars would touch the rivet heads. Pad area is larger than the Midget and the weight is quite a lot lighter.


rob multi-sheds thomas

As Deb said, quite expensive. I paid £50 for the whole lot. :o)


rob multi-sheds thomas

This thread was discussed between 10/02/2010 and 14/02/2010

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.