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MG Midget and Sprite Technical - 400 lbs front springs

advice required please

the front of my car is very low which spoils my enjoyment of the type of country back roads I like because the front of the exhaust catches the road surface

I have FL (F'*ng L*ers) front and rear suspension set ups with (supposedly?) standard rear springs and supposedly 340lbs, 1" lower front springs and uprated ARB

I'll never use the car for any kind of sport and as I put I like to drive the sometimes bumpy country roads

so -

would standard ride height 400lbs front spring be too much for the roads I like or would I loose my fillings, half of the cars nuts and bolts and any enjoyment of those roads?
Nigel Atkins

Picture in you profile doesn't look unduly low.
What are your front and rear sill to ground measurements? (underside of sill, not the bottom of the welded flange)
Guy

er, whatever they were in the other thread I'll have to look, same as yours at rear and lower than yours at front

I think the photo is before F'ing L*ers treatment

ETA: I'll have to report back later
Nigel Atkins

Guy,
180 mm rear - 130 mm front
Nigel Atkins

Nigel

All our cars run 400lb, we don't find them too firm at all and we do a lot of touring in them as well as competing.

Another approach is to fit a 1/2" spacer ring between the top of the spring and its socket. that will raise the car an inch. One of our cars has had one of these for years after we fitted lowered 400lb springs then found that for soe of our preferred roads it was not really the ride height we wanted.
Paul Walbran

Sill (ledge) heights for BRB are:

5.5" front
6.5" rear

Quite low; no exhaust scrapes, as it's mounted very close to foor all the way down (I shortened the manifold 'down' pipes for this) and also has the correct slight 'S' at the other end of the pipe so the box is mounted horizontally, too.

A
Anthony Cutler

Nigel. i have 400lb standard length springs, 11/16"ARB, 30% uprated shocks and Superpro bushes on the front of my car and it's not at all harsh and it turns in great,but I still get the exhaust catching short high car park speed bumps for the reasons explained below.


Ant. How did you shorten the down pipes? I've been thinking about how to do it because my 1098 block is a bit shorter than a 1275 one which puts the exhaust that much closer to the ground as the tubular LCB manifold is the same for both engines.

Bernie.
b higginson

Mines 170mm at the front and 185 at the rear, thats with Peter May lowering blocks and lowered 1275 srpings at the front.
It could do with lowering more though, just to fill out the arches better.
BH Harvey

Mine was rebuilt in 2008 using lowered front and rear spring, possibly from Peter May, as shown in the photo.

4 1/2 years and 15000 miles later, it looks a little lower and measures 135mm [front & rear].

Speed humps, bad roads etc can be a bit of a challenge with those at Dunkerque Ferry Terminal being particulalry bad.

With experience, my target would be 150mm in the future.

HTH

Doug Plumb

Bernie, I also shortened my manifold downpipes to run the exhaust as close to the floor as possible. I just chopped them, tacked them with the MIG checked it all fitted them and re-welded. It was a bit of a fiddle but not too troublesome. I got about an inch more clearance which made a huge difference.
Paul (MkI

thank you to all for your replies

Paul,
I thought about the spacer idea but would be happier in myself to change the springs

I was told peopled toured using my present springs but IF it was true then not on the roads I like

your 400lbs spring set up is it OK for uneven country back roads being driven in a spirited fashion would you say please



A,
thanks for the idea but the manifold and exhaust was changed last year so although it still hangs a bit low it I'm very happy with it and as I can't alter it and don't want to pay anyone else to (Sod's Law it woulld go wrong) it can remain, plus I don't want anymore cabin heat (another thread)

I can't trust rubber items at the moment so wont replace engine mounts (not that I've checked if they are thinner as they're the same mounts as when the car was on standard ride height springs and things were OK then
Nigel Atkins

Hi

I have found this thread quite interesting and decided to measure mine. 165mm front, 170mm rear (unoccupied!) sitting on 165/70/R13s. "Standard" front springs with lowering spacers (about 15mm) and Moss lowered rear springs fitted about 12 years ago. I've never changed the front springs so they must be more than 17 years old. Rear springs are getting tired but no clearance issues and the handling is spot on - for me, that is, and we have plenty of good country roads round here even if they do get covered in crud.
Peter B

Thanks Paul. I'd been having trouble seeing how you would be able to weld all the way round the tubes, but I'll give it another coat of looking at now I know that someone has done it

Bernie.
b higginson

You've got me at it now. Just measured mine.

Standard front springs renewed about 12 years ago. Standard rears changed about the same time, but suspect quality, and feel weak to me.

Measure to lower edge of sills.

Front about 6.25"(160mmish) Rear 6.5"(165mmish).

One thing occurs to me. If the sills have been changed (and not fitted exactly as they should have been), perhaps a better measurement is from the floor pan somewhere.

PS 165/70/13 tyres

Lawrence Slater

Mine measures 135mm at the front at 155mm at the rear. I still find this ok, -ve camber trunnions are fitted at the front which are just enough to tuck the fronts into the arches and stop them rubbing on the lip when the suspension compresses.

From the floor to the highpoint on the front arch is 565mm

I like the idea of shortening the manifold down pipe. I like the idea of exiting the exhaust through the sill even more but havent found much experience of this yet

Ive just refitted my hardtop which has dropped it a bit more!





S G Macfarlane

another point of measurement could be bottom of door at back to ground (mine is 295 mm 11 and 5/8")

I'm still interested to know from Paul if possible please if your 400lbs spring set up is it OK for very uneven country back roads when driving in a spirited fashion
Nigel Atkins

Absolutely!!!!!!!!!!!!! We test this aspect frequently :-) In our case, back country roads include both bumpy tarmac and gravel and they are fine for both.

(Sorry I missed your earlier post - internet access has been a bit patchy while we've been on the road)

The only downside we have on such roads is with the rear springs of our UK domiciled midget, as they are (intentionally) lowered springs we inherited from PO. With 2 people and a boot full of luggage when touring we hit the bump stops occasionally. But to us the car (also has 400lb on the front) doesn't feel harsh at all. It's exhaust does kiss the road sometimes though, nearly always at the rear as the silencer is mounted a bit low.

Shame you aren't in NZ Nigel, we offer a try-before-you-buy service with uprated springs, on the grounds that a day's use is not going to affect the life of the spring or ARB and the opportunity gives the customer the chance to answer such questions.
Paul Walbran

Try before you buy wow what a service, well done

I suspect over here you'd get the undecided wanting to try your whole range and patience

I'm now thanks to your help looking at getting a pair of Moss ROAD SPRING SET, front, rally uprated 400lbs, silicon chrome, pair' - http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=1609

luckily (so far) at the same time as having the front done they said they had problems when they fitted the uprated the uprated rear springs (suspect that might possibly even be a lie now) so I ended up with stock rear springs and they are fine so far and plenty of ground clearance

thanks to Paul and all for help I'll report back when I've fully tested them on the Bears Cumbria / N. Yorks tour at the end of April
Nigel Atkins

Hehe, you'd have to be really keen to try a whole range of springs, all I'd have to do would be a little paperwork and not the hard bit getting my hands grubby.

Good luck, look forward to your report back
Paul Walbran

blast, forgot something I've been meanimng to ask for ages - should I have end stops on my 11/16" ARB as I can clearly see signs of lateral movement or would fitting end stops cause the mounting straps to be ripped out of the chassis?
Nigel Atkins

Nigel,
Not sure about whether end stops are needed or not.One of my cars had them, the other didn't.

But what I do know is that the syndrome of the mountings being ripped out of the chassis rails in not to do with lateral movement of the ARB. It occurs when a torsionally stiffer bar is used and is caused because more of the leverage from body roll is transferred to the brackets because the ARB doesn't bend / spring as easily.
Guy

Guy,
fair enough about mounts getting ripped out

I can see from the clean bits on my ARB that there's lateral movement and the standard bars have stops but the thicker bars seem to come without
Nigel Atkins

Always easier to reinforce the mounts before they rip out, rather than repair them once they have!
And it is common ...
Paul Walbran

as I'd have to pay someone to do the work that will have to go on the to-do-list

springs are ordered so there's that much less in the annual Spridget budget that still has holes from the unexpected and having to replace items well before their due time (and often very soon after previous replacement)
Nigel Atkins

well of course it all went wrong, usually does where cars are concerned with me

the new Moss standard ride height front road spring were fitted today and they are EVEN LOWER than the previously fitted lowered springs that were too low

before ordering I checked with Moss 9 emails for different photos of spring with a tape measure beside each

the Moss web site has out of date information on it but I couldn't seem to this across to the chap who was refereeing to a catalogue that I didn't have instead of the web site

the chap was very nice and helpful - I'm not complaining about that

when the springs arrived I unpacked them and measured and compared them to the photo of them I'd been sent

the springs were also marked up with their part number which was correct with web site and catalogue part number for 400lb standard ride height springs

I'll repeat 400lb standard ride height springs

so when fitted see photo - they have reduced the ride ride height to 1" lower than the previous lowered 1" springs that were too low (they lowered by about 1˝” not the stated 1”)
Nigel Atkins

this is car with claimed standard ride height front springs!!!!

Nigel Atkins

this is car with correct ride height

springs were standard before damper conversion and anyone's claimed 1" lower springs or uprated standard height spring

you will notice the difference

Nigel Atkins

you can take off about 5/8" to allow for higher profile tyre on second photo (155/80/13 against 155/70/13)

and allow 3/4" for discrepancy of ‘400lb standard ride height springs’

so that would make about 1˝” difference

but as you can see there more 1˝” difference in the photos

so ????
Nigel Atkins

IMO the stance looks perfect in the first picture.Have you tried fitting standard 1500 springs?
(And would you consider selling the offending lowered springs?)
BH Harvey

My Midget measures 5" front, 5 1/4" rear at sills with Minator 13x5 wheels and 165/70 tyres. The exhaust is as high as it can get (ex-rally car)and I don't hit that, but the front tow rings are forever getting bent. The rear has lowering blocks on standard springs (thanks, Paul W) the front must have shorter springs but they were on the car when I got it and I've never checked them. They are fairly firm, though. It has the 11/16 ARB, as well.

Just thought I'd add a contribution.

D A Provan

Nigel

Sorry, missed your post - been away for Easter playing with other MG's.

Initial thought: There might be a simple cause. We had this problem too and found out there was a cataloging mix-up with Moss between the listings for standard ride height and 1" lowered.
The correct vesion should be MGS40906 is the lowered spring, TMG40906 is the higher ("std") spring.

Dimensions of the springs are:

TMG40906 (the higher of the two) 13.45mm wire diameter, 7.17 turns including the "tails", free length 210mm

MGS40906 (the lowere of the two) 13.02 wire diameter, 6.75 turns, free length 198mm.

That should help identify which springs you have.

I'll measure the height of our standard height 400 lb car and report back.
Paul Walbran

Hi Paul,
yes you’re confirming what I now think but I exchanged about 9 emails with a helpful chap at Moss before ordering in which he provided photos of each spring against a tape measure and explained free height didn’t really relate to ride height directly

So when I got the springs I checked them against invoice and photo, also the part number is clearly marked on each spring

I ordered and received MGS40906 at just under 8”, as per Moss catalogue and information received - my mistake I believed what they stated

I rang them to find the person I’d corresponded with was not in their Tech department but sales but I must say that initially was a better outcome he told me to contact one of their Tech guys – outcome can’t be the springs as they were collected from the correct stores location, perhaps something on my car

It would appear from what someone else has told me and now what you have told me that they would have know that the listing for the springs was incorrect

Also to add to the confusion at the start was the fact that their web site listed four different springs which I couldn’t make the sales chap understand that it was out of date and I only learnt this when Lawrence posted an excerpt from a previous catalogue

I tried checking thoroughly before ordering but Sod’s Law the correct information arrives after the job has balled-up


DA,
cheers

BH,
at the level of the first photo I’d certainly loose my front number plate and probably my exhaust manifold and gasket

yes I will have some lower springs for sale (sold as 1” lower 340 lb) at but not those as they’ll be going back to Moss
Nigel Atkins

"explained free height didn’t really relate to ride height directly" ... for the same spring rate, it will be proportional, but not 1:1 of course as the spring acts about halfway along the lower wishbone, making it about 2:1.

I've looked a few figures up to refresh my memory and done some calcs, which sumarised is that the "std height" springs appear to sit about 1/2" lower than the original ride height. Here we go:

Our 1275 with 400 lb std height springs has the distance from the centre of the front wheel to the top of the wheel arch as 13".

The bottom of it's door is just over 12" off the floor. "Motor" road test was the only one with helpful information about ride height, noting that the bottom of the door was 12-3/4" off the ground. That indicates our car is a bit over 1/2" lower than original.

BMC workshop manual lists spring free length at 9.4", working load 750 lb, spring rate 271 lb/in. That gives 2.77" deflection and a length at working load of 6.63"

TMG40906 has free length 8.27" and rate 400 lb/in. At a working load of 750 lb this gives 1.875" deflection, leaving a height at working load of 6.4". This is 0.23" less compressed length than the manual specifies, resulting in the body sitting a bit under 1/2" after allowing for 2:1 step-up ratio of the wishbone. (Sorry, I don't knwo the precise ratio off hand and forgot to measure it; someone may be able to help with that).

So the calcs give just under 1/2", the measurements on our car give about 3/4" after quite a bit of work, hence my conclusion about 1/2" low.
Paul Walbran

Hi Paul,

as you’re kind enough to give all this information I‘ll reply with what I’ve found

the Moss uprated springs are wound and sorry can’t think of the correct word so I’ll say compress differently to the standard spring

on my car (averaged) distance from the centre of the front wheel to the top of the wheel arch:
previous springs (quoted) 1” lower 340 lbs – 12 and 5/8”
fitted Moss 400 lb (standard ride height) springs – 11 and 3/4”
CHA129 springs previously fitted see previous photo

depending on where I read, the ride height could have been 20 mm lower standard with the Moss standard ride height springs

I quoted on another thread (the/a) Motor road test (May 16,,1964, MK2 Midget) which showed overall ground clearance as 4 and 3/4" whereas all other test show 5” so I added a 1/4” to give 13” to bottom of door – but I’m not quibbling over a 1/4” especially as with the previous lowered spring I only had 11 and 5/8” anyway

you probably already know this but for others - as mine is a later c/b car it originally had slightly longer springs (much debated in another thread), Terry Horler’s book covers this and from the DVD with Workshop Manual
(after GAN5-123837)
free length – 9.85 in (25 cm)
fitted length at 750 +/- 15 lb (337 +/- 6.8 kg) 7.08 in (18 cm)

not that it really matters as there’s only one standard spring now for 1275s that I’ve seen, CHA129 (I even know that part number from memory now)

I’m pissed off with Moss because initially I couldn’t explain to them their web site was out of date and that their springs are wrong and I can’t get them to accept this and now I find from you and Kim that this was previously known

Nigel Atkins

photo of the 3 springs

to the left is the (now) standard 1275 spring (CHA129)

in the middle is my previously fitted 1" lowered, 340 lb spring

to the right the Moss spring and clearly marked up as MSG40906 - sold to me as standard ride height (400 lb)

Nigel Atkins

The shorter spring has a 50% higher spring rate (271 -> 400), so its free length has to be shorter than the stock spring in order to maintain the same loaded length.

Apparently, CHA129 is about 10mm not quite long enough to achieve the targeted stock ride height.

In mass production, I have found that +/-10mm is typical for automotive suspension coil springs.

However, even if they are "in tolerance", it would have been nice for the small volume manufacture of these springs for Moss, if they had checked that they were closer to nominal than that.

Norm
Norm Kerr

Hi Norm,
we did cover spring rate earlier in the thread but wandered off it slightly

the two CHA129 I’ve had photos of over here were both just about 9 and ľ” (248 mm) so 2 mm shorter than my original specified springs but 4 mm above the more usual sized 1275 springs

I did think about fitting the 1500 spring as they’re the same at 271 lb but just a bit longer but know my luck they would have been well oversized in manufacture plus I had CHA129 fitted before and had plenty of clearance (see my first photo)

I’m not sure Moss buy from a small volume manufacturer as they’re modern material springs they’re possibly stock or near on something else

the proof was in the fitting, whatever the Moss catalogue states is wrong and it appears it has been for sometime (see my second photo)

mistakes I can understand, not accepting there is a mistake let alone trying to rectify it is a different matter
Nigel Atkins

Nigel,

How about fitting some spacers under the springs to raise the front to that required. My Austin A40 Farina had spacers each side of about 5mm - 6mm thickness IIRC. I have no idea if they were factory original but I left them there as all worked fine.
David Billington

David,
I did think about it but didn't really like the idea even some may have had them for years plus the spacers are thin so don't raise the height much anyway

I only enjoy driving car and the ratio of days spent serving, maintaining, repairing and replacing shoddy parts againt days I actually get some fun drive in is totally skewed in the wrong direction so I'll see how it goes with the standard springs in for a bit

I now know where I should go for springs next time
Nigel Atkins

Yes I am venting a moan but it is also a warning to save others as this problem has also been wrong before it happen to me

I think I've given Moss long enough to check with their personnel and to contact me – which they haven’t

to warn others –
Moss still haven’t updated their (uprated) Front Coil Springs web page despite it being very out of date and confusing

and as I don’t know differently I assume they still have their catalogue numbers mixed up for their uprated springs

good luck to anyone that orders uprated springs because if they’re wrong it’ll be your fault not Moss’s even if you exchange many emails and photos of springs with them before ordering and then send photos of their springs fitted clearly showing they’re wrong, that certainly wont be their fault but yours
Nigel Atkins

Never quite sure why people don't go straight to Kim at Magic Midget for springs .... can't get better and at a fantastic price.
rachmacb

trouble was I've had bad service from those whose interest is in racing their cars and need to finance this by running a business that doesn't quite give them enough money to race in the fashion they want - I've even been been badly ripped-off by one lot

but now after the event with Moss yes it's Kim I'll be contacting once I've sorted out a few other problems
Nigel Atkins

We ALL have to fund our hobbies somehow - but, most of us are honest and decent!
rachmacb

unfortunately my experiences of the motor trade generally and racers have brought me into contact with those that are or tend towards seeing customers as those they can short change or rip-off

I realise not all are like this and a few are totally the opposite way but even mates in the motor trade tell me about things they've done or things I should do to botch repair and hide things just to get rid of a problem before sale, so passing on the problem to the next owner whilst keeping quiet about it and both are connected to motor racing

as with most of us I'm no angel in life but I don't try to deceive or rip off potential or actual buyers either for work or personally
Nigel Atkins

just seen I didn't put the happy end to the saga as the standard ride height 360lb (uprated) 9.5" springs from Kim Dear at Magic Midget are spot on and excellent value

rachmacb was quite right and I wished I'd took her advice to go to Kim Dear at the start (I certainly paid for my mistake in time and money)

Kim Dear, Magic Midget - http://magicmidget.co.uk/
Nigel Atkins

This thread was discussed between 14/03/2012 and 19/12/2012

MG Midget and Sprite Technical index

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