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MG MGB GT V8 Factory Originals Technical - Costello Suspension

I now have the Costello 5 link suspension fitted to the rear of my B GT V8; and have also fitted their front coil over suspension kit, including their castor adjusting wedge kit.

It's early days yet; I have only covered about 300 miles since the conversion - but first impressions are excellent.

The handling is greatly improved, compared with the earlier suspension which was simply improved spring rates and Knois all round.

Steering is much lighter, and fuel consumption is much worse - because I'm using much more throttle!

All in all I am delighted!

Photographs can be found at:-
Nigel J S Steward


Looks a very nice installation, what year is your car?
Doesn't appear that the coil spring damper units are adjustable for ride height, if so what ride height does it give between chrome strip and road? also are dampers adjustable. My car is rubber bumper based so am wondering what i would need to adjust the front end to, to keep the car level.

K.R Jackson


Any crossmember alterations, what camber adjustment are you using, what spec springs and how are the damper settings working out.

btw Could not open aerial pics

A trip to Bath may be called for.


I saw this setup at the Frontline stand at Silverstone last summer. It is definitely on my shopping list for my V8 conversion. I'm still working on the body mods at the moment so will be a while yet!

I too have a couple of issues in regards to the ride height. I was talking to Tim about his 5-link system and the coil overs are not adjustable. They are designed to give standard chrome bumper ride height.

I used to run my chrome bumper GT with 2.5in lowered rear springs and full race front springs so would not want to return to the standard ride height. I will contact Tim at some point to see if he can supply the kit with some adjustable or shorter coil overs.

Failing that I may ask if I can buy the kit without the coil overs. Then I can take some measurements from the ones he supplies and make a trip to Demon Tweeks and buy a pair of Spax fully adjustable coilovers.

Anyway, it looks an impressive piece of kit, and sounds like it's worth the money. I think Tim mentioned something like £1200, can't remember if that was inc vat or not. How much is he selling the kits for? Doesn't seem to be on the Frontline web site yet.


Paul Grundy

OK Guys, I’ll try and answer all the questions.

Thanks Kevin. My car is 1973 & I’ve owned it from new.

Frontline offer kits for both GTs & Roadsters in both chrome bumper & rubber bumper versions. The ride height at the front can be adjusted in the normal way, but Frontline Costello say that this can be difficult because of the different vehicle weights and different spring rates. Tim says he is working on a chart to show relevant heights.

At the rear you are stuck with the Frontline offering at present by they will be offering an adjustable platform later this year, at the same time as the racing set-up for track use only.

Frontline measure the ride height from the underside of the chrome strip to the centre of the wheel or hub with the car on level ground. They believe, and I agree, that if you measure to the ground you introduce other variables (tyre pressure & size). On rubber bumper cars they normally work to a ride height of 16.5”; on chrome bumper 15.35”.

Paul 1 – Aerial pics should be OK now – you will have to “cut & paste” the URL though!

There are minimal alterations to the cross member; they remove the bump stops and grind a small amount (about 5 mm) from the middle of the bump stop locating bracket to give clearance for the body of the damper.

I’m using the springs recommended by Frontline Costello, in conjunction with the top spec. gas dampers built specially for this conversion by Rhoddy Harvey Bailey. I’ve done about 500 miles in the last few days, and continue to be delighted with the results.

Paul 2 – I think Tim will be pleased to work with you to achieve your objectives. We have decided to lower my car another 5-10 mm in a few weeks time.

In so far as prices are concerned Frontline’s current prices are £1,295 for the rear fit, plus £525 for fitting if you want them to do it; they supply excellent detailed instructions.

The front conversion costs £640, plus £225 for fitting.

Frontline also make a wedge kit to adjust the fore & aft orientation of the kingpin. The standard set-up is about 6.5 degrees, which I think everyone agrees is far too much for modern tyres. The castor wedge slides between the chassis and the cross member and reduces the castor to about 3 degrees. They also recommend adjusting tracking to around 2mm toe in overall.

The Frontline wedge kit costs £68, plus £93.75 for fitting.

I’ve quoted the prices without VAT for the benefit of those of you not in the EU – we need to add VAT.

Tim did warn me that the prices were based on driving the car in with the old suspension and out on the new, but they do not include any structural work should the car require it ( i.e corrosion or accident damage etc) – happily my car didn’t need any extra work!

I hope that this answers all the questions; please bear in mind that these are my answers, and that I have no connection with Frontline Costello, except as a satisfied customer.

Nigel J S Steward

MG Enthusiast's latest issue has a major article on the Costello kits. I haven't read it yet, but it has lots of photos and before/after comparisons.

Thanks for the information re the ride height, I will re-measure mine and see what I've got at the moment, yes chrome strip to centre of wheel, i was having a mental block when I last posted. My car has modified suspension and appears to be about factory V8 ride height. I have a second hand but unused Moss coil over set up for the front end which is of course adjustable, so matching front and rear should not be too difficult.I was also interested to hear about the wedge kit, presumerably this alters the angle of the cross member in relationship to the body by 3.5 degrees leaving you with the preferred 3 degrees.
I have only done about 300 miles in my car since i built it due mainly to a period of poor health, have just got it running again after some ignition problem and am hoping to get it on the road soon. Hopefully the reduction in caster will lighten the steering at parking speeds, I always thought there was a lot of tyre scrub when manoevering.

Kevin Jackson.
K.R Jackson


What is the impact on lining up the stearing UJ when using the wedge kit. It will be out of line. Or is there a second set of wedges to go under the rack?

David Witham
Am I to take it no welding is required for install the rear kit. The front kit is made in aluminium? I’m upset by the wedge kit!


The alignment is pretty critical, as you have surmised.

There is just enough clearance when the rack is correctly adjusted
Nigel J S Steward


When you say "rack is correctly adjusted" do you mean by the shimming described in the work shop manual.

My guess is that it will need alot of shimming. You are rotating the cross member in the horizontal plane around an axis line that runs through the rear edge of the rear cross member mountings. The wedge in Michel's post looks about 5mm thick at the front. If the distance between the front and back of the cross member is the same as from the back of the cross member to the steering UJ I would expect it to be about 5mm out of alignment as well. If the distance is greater then more. This seems alot to correct with the traditional technique of shimms under the rack mountings. What thickness of shimms has had to be used?

David Witham

David Witham

Will you e-mail me; and (subject to consent from Frontline Costello) I'll send you, and anyone else who wants them, the fitting instructions, photographs etc. that Frontline Costello sent to me.

Nigel J S Steward

I've just spoken to Tim at Frontline Costello, who has agreed that I can post the two PDF documents to which I referred above on my website. The URL is:-

I haven't got anything on the front suspension but Michel's link shows "the Wedge".

Hope the above helps - time is a little short at present, but I'll see if I can post some more about the front suspension & the wedge in the next few days.

Nigel J S Steward

Is the wedge available without buying a suspension kit? From whom? How thick is the thick end of the wedge? Does it go above or below the crossmember mounting buffer pads? How much difference does it make? So many questions.

Mike H
Mike Howlett


You would have to ask Frontline Costello about availability - but I would think the wedge would be available by itself as it is separately priced at £68, plus £93.75 for fitting & VAT.

I can't comment on how much difference it makes by itself, but it should make the steering much lighter. Certainly this is the case with my car.

I think Tim "tunes" the wedges when he fits them to suit the car to which they are fitted, so they MAY not be a standard thichness.

It would be worth contacting him - but not until Monday as I know he is out of the office for the next two days.

Contact Details:-

Tim Fenna
Frontline Spridget Ltd
239 London Road East
Batheaston, Bath BA1 7RL

Tel: +44 (0) 1225 852777
Fax: +44 (0) 1225 852292
Nigel J S Steward

This looks like the orrigional set up for MGs that was abandoned for various "handeling" reasons glad to lean that costello has worked it out. Curious to know is this a better set up than the bolt in IRS made by NG cars. Saw a picture in Rogers book and was very impressed.

I haven't tried Frontline's set up (which looks excellent), but I have ridden in a V8 MGB with John Hoyle's (of NG cars) IRS and front coil-over-shock conversion. I was so impressed that I'm going to go down the same (expensive) route for my V8 project. The Hoyle IRS is about twice as much as Frontline's rear kit, but it transforms the car.

The ride is much more supple and compliant, with none of the bumping and crashing you get with the leaf springs on poor surfaces. The rear wheels feel totally stuck to the road, and because it isn't a trailing arm design there is virtually no squat-down when accelerating hard.

Another bonus with both Hoyle's front and rear kits is that camber, ride height and toe, are fully adjustable, with a small amount of castor adjustment possible on the front. The IRS also reduces the unsprung weight by 55 kg, a huge advantage.

Mike H
Mike Howlett

I probably shouldn't say this but I can't help thinking that producing your own (one of, not commercial, for your very own private use)version of the IRS frame couldn't be too hard, given the suprising asking price. It is essentially a bar bolted between the shocker mounting points with a square frame hanging in the middle for the diff and wishbone mounting points. Any one who has ever welded up a tow bar or boat trailor shouldn't find it impossible. The other working parts (diff, coil over shocks, bushes etc are readly enough availiable.

This thread was discussed between 04/04/2005 and 08/04/2005

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