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MG MGB Technical - ride height

i am aware that the leaf springs have a higher rating because of the very heavy bumpers,so what causes the car to sit higher.is it some thing to do with where the springs are bolted to and if so can i do some mods thanks
daren

Check the archives. LOTS of info on this. You're right about the spring mounting points on RB cars being different to gain the 1 - 1.5 inch ride height change.

Simon
Simon Jansen

The Rubber bumpers rear suspension had more arch to the spring and the front (rear spring) Hanger was extended and reinforced so the hole could be moved down about 45mm. The rear hanger was also moved down.
Of course the shock absorber links were also extended.
There are a number of options.
1-Cure this with money-You can buy flatter springs speciifically designed to reduce RubberBumper ride height. You also need to either shorten or buy new shocker links (expensive here).
2-fit lowering blocks. Place these between the spring and the axle. This requires longer U-bolts and aluminium blocks. You don't need to fit shorter shocker links in this case.
In my case I had also substituted my heavy rear rubber bumper for a new chrome one, and the back rose up about another half inch!.
The problem with blocks is that you may not be able to get blocks thicker than 1 inch, I couldn't. I was also a little dubious about having the axle sitting way up on two inch blocks. A bit too much leverage on the spring I felt especially as mine is a V8. My solution was to fit the 1 inch blocks that I could get, and also redrill the front rear-spring hanger hole. Move it up 45mm. This is easy enough to do accuratly if you use a centre punch and drill small pilot holes. Also use new drill bits unless you like hard work!
That way I was able to get exactly the right height. I also did not have to buy new shocker links.
I left the rear hanger alone as it looked way too hard to get at.

With your front springs-You could cut off the 1.5 inch upward extension on the front cross member, and reposition the steering rack. But thats alot of work and most people just buy new shorter (& up rated) coil springs.
Incidentally, if you go the "new rear spring" path, I suggest that you don't get uprated springs there. The current thinking on MGB optimal handleing is hard front springs with a big front anti sway bar. Soft rear springs that allow the back of the car to roll a bit and keep the most amount of rubber on the road.
It is very imortant to get the ride level. Once you have done this you will be astonished at how much better the car takes a corner.
Peter

I should re phrase- not so much "allow the rear to roll" but rather.
The heavy front suspension keeps the car level. The soft rear springs allow the live axle to move more freely and keep the tyres on the road.
If you get my 'Drift' ho ho.
Peter

Also forgot to mention
You need to cut about an inch off the rear rubber bump stops. This is very important, and very easy to do. If you don't then there is not enough rear suspension movement and I found that about half way through a corner alot of oversteer would suddenly (and unexpectantly) appear out of nowhere. The outside bumpstop contacts and leverage through the outside wheel causes the inside wheel to get very light. Easy enough to handle in dry weather , but if the road is wet you will fishtail unpleasantly(if your reflexes are fast enough) or spin the car. Six or seven rotations (I had my eyes closed for a circuit or two) on one occasion.
I cut them off insitu with a hand saw. Took about 5 minutes.
peter

I've had problems getting my 78'b to a nice ride height, i bought a suspension kit to convert it to chrome bumper height (shorter drop links, shorter rebound straps etc) but theleafsprings have never settled which has resulted in a nose down stance!

So as the front end is nice and low, i've bitten the bullet and gone for race rear leaf springs with a 2.5" drop as the car is used for trackdays - i'm just hoping these are nice and low - knowing my luck they will be to low!! I will be fitting them this weekend...
Gavin Jewkes

Drill those hangers Gavin, that tail will step out i bet. You can always shift the bolt back if the springs settle.
Peter

thanks for that,i purchased a lowering kit from mgb hive
i converted to chrome bumpers a year before.the lowered springs for the rear are made for rubber bumpers so the springs were wrong to start with ,can i fit 1 inch lowered chrome bumper springs to sort the problem out.the car is sitting at least 2 inches to high it looks like a hot rod thanks
daren

Gavin,
Are these multileaf springs, if so who is the supplier and what is the cost?

Could you also after fitting let us know the centre of wheel to chrome strip dimension, it would be most helpful.
Thanks,

Kevin Jackson.
Kevin Jackson

To verify the correct ride height, measure from the fender opening down to the center of each wheel nut. In all cases, the measurement should be 13.5 inches.

MGBs with lots of miles will sag (be less than 13.5 inches) in the rear. New rear leaf springs are fairly cheap (about $50/each) but it is a messy job installing them.
Tom Fisher


Tom,
Do you mean 13.5 inches for rubber bumper or chrome bumper cars? My '77 B sits way too high in the rear. My guess is that a PO fitted lower front springs and didn't touch the rear ones. What is involved in drilling new mounting points for stock CB springs on a RB car?

Many thanks,
Dave
David Plantz

hi tom do not buy thease springs they measure 15.5 inches from the chrome strip to the center af the wheel and ive put 1 inch spacers which means the ride height would be 16.5 inchs.i think that it would of been better to purchase 1 inch lowered chrome bumper springs and then add a spacer iff needed.it seems that after maket spares are poor quality. thanks daren
daz

Daz - i'll be fitting the 2.5" lowered leafsprings Friday and i'll post some pics up of the ride height -it seems like its a gamble with new springs as to what height you get! i was going to order the 1" lowered ones but i was paranoid they still might be high....
Gavin Jewkes

I meant 13.5 inches for the chrome bumper cars (62-74). I got my new rear leaf springs from Victoria British.

T.R. Fisher

Just for info Daz,

I fitted the springs today and its gave me this drop,

http://img.photobucket.com/albums/v98/GavinJ/14-04-06_1834.jpg

But bear in mind the car has not moved or been driven since they have been fitted so are likely to settle even more when in use.

Cheers
Gavin
Gavin Jewkes

thanks for that gavin,would you say the car sits nice and level with the standard lowered front springs as your front springs are 1 inch lowered.have you purchased chrome or rubber bumper lowered springs as the rubber bumper springs have higher rateing. where did you get the springs from and iff its worked out well have you the part number thanks for that daz
daz

Hi Daz,

At the moment the front end is sitting a bit higher - but this is mainly becuase i'm in the process of a v8 coversion and it was sat without an engine for a while and the engine has only been recently been fitted - so it really needs to be driven around before i can look at what the ride height is once it's all settled down again.

Plus with me having a v8 fitted it will differ to yours - the front was sitting at chrome bumper height before so around a 1" drop.

The springs i have fitted are from moss and they are the 2.5 inch lowered race springs. Now as to whether they are for a chrome bumper or rubber bumper is a mystery to me!

When they were delivered on the invoice it had got 'chrome bumper lowered race springs' even though i had ordered r/bumper springs. So i called Moss and after being passed round to a few people i was told that the race springs they have are used for both c/bumper and r/bumper application so they would be fine!

If you give me a few weeks the v8 conversion will be complete and i'll be able to put some miles on it and then take another photo of the rear ride height to help you decide!



Gavin Jewkes

thanks for that ive decided to order 1 inch lowered chrome bumper springs, then iff there to high i will fit the 1 inch spacers and then as a last result i will re drill the front brackets on the rear sus thanks . bye the way what engine have you took out of your mgb anything special,i have a standard low mileage engine bolted on a fast road head 285 cam k a n air filters aldon dizzy 4 branch manifold, spent alot of money to gain 30bhp. theres no extra power unless you rearly rev it as a result it uses more fuel than a v8 ,i think i shoild of gone fot a v8 conversion thanks daren
daz

Gavin,

Could you take a measurement from the centre of the rear wheel to the underside of the chrome strip please, it would be useful for comparison with my converted V8 75GT rubber bumper car which is about 2" too high at present. I am hoping at some stage when funds are available to swap in a Jag IRS but at the moment a respray is on top of the priority list, so a swap to the new springs that you have may be an interim solution.

Kevin.
Kevin Jackson

Hi Kevin , i will do next time i'm down there as its not stored where i live - it will be tuesday night before i can do any measuring.

Cheers
Gavin
Gavin Jewkes

Kevin
Check out the ride height info at the following website

http://www.mgb-stuff.org.uk/rideframe.htm

Barry
Barry Parkinson

This thread was discussed between 11/04/2006 and 16/04/2006

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