Lowering the Maestro

[6r4Nut]

I was thinking of lowering the MG. What is a reasonable amount to lower it buy, and where is the best place to buy springs from?

Also is it actually worth lowering it, will I notice much difference in the ride comfort and handling.

Would appeciate any commment people have.

[E_T_V]

It all depends on what you want from your car. If you do a forum search you'll find a few recommendations on lowering and I found a place to buy lowering springs from too with a weblink etc.

It also depends on what car you have. 2.0 O series seem to have an issue with speed bumps and sumps meeting at speed especially if you drop it by 2 inches. My turbo is lowered 1 inch and looks ok. (not driven it yet though!). My camper will be lowered by 1 to 2 inches I think, (but is having 16inch alloys fitted instead of the 13 inch steel wheels so it'll look like a 4x4 unless I lower it a bit!).

[mgdavid]

>>>will I notice much difference in the ride comfort and handling
===probably not; but you will convince yourself that handling is better and will not want to admit that ride comfort is worse :laugh:

[Fast Guy]

Also is it actually worth lowering it, will I notice much difference in the ride comfort and handling.


It depends what springs you put on. Chances are any lowered springs will be stiffer, so your ride won't be as comfortable as before.
I had -2" race springs on my montego (something silly like 500lbs front and 400lbs rear I think or maybe vice versa???) and on all but the smoothest of roads it was not very nice. A good fast bumpy bend would have you skipping across the road to the outside of the bend :horror:

[Jack]

Whilst a lot of people say it is not the thing to do (the uneducated!), cutting your springs will work. In fact, the standard diesel / MG springs have 35mm between coils and some lowered springs say they lower the car 35mm - coincidence?

The way to do it is dismantle the strut until you have a bare spring. Cut a coil with a grinder or plasma torch. Then heat the coil at 1/2 coil round from the cut end. When it glows red hot, turn the spring over and press it to the ground. This flattens the end so that it sits in the spring carrier correctly.

As there are less coils, the spring will be uprated too!

I did this on my other half's Renault 5 when the end of a coil broke. It go it thru the MOT no probs.

If you still don't believe me, read "Chassis Engineering" by Herb Adams. It's a chassis bible sold at most places like Demon Tweeks, Amazon etc. He says cutting springs is preferable to buying new uprated ones!

Now I'll just sit back and wait for the flak from those who don't believe this.

[E_T_V]

I'll agree with most of that post but not quite all.

Removing a coil from the spring doesn't uprate it. The spring is has just the same rate as before but less travel. (To uprate the spring you must used stronger steel or thicker coils or both!).

The result is that your ride quality will be pretty much the same but it will be easier to "bottom out" the suspension as it has less travel, i.e. where the spring runs out of delection and the rubber bump stops take the vehicle load rather than the spring.

There can also be the issue that the spring can sometimes become "dislocated" from the spring seat if the suspension is suitably decompressed. i.e. the spring can fall out of its seat if it isn't retained in it somehow.

There are also metallurgical issues with heating a spring up to red hot but I'll not worry you too much as it will just make the end of the spring far less springy, but as it sits on the spring seat it won't matter much.


All in all though it is certainly a very viable way of lowering your car cheaply and retaining good ride comfort. I think I'll be trying it with my van when I find some spare springs.

[PegasusTurbo]

Hi folks,

The general rule I follow when lowering Maestros is thus.

15" wheels no more then 1" lowering
16" wheels no more then 2" Lowering
17" Wheels perhaps as much as 2.5" I will see soon.

The above rule will prevent regular damage to your sump. Unless of course you like scaling speed bumps at ramming speed ;)

[E_T_V]

Or have one of the rally spec sump guards that I'm thinking about fitting to my van. Then it really will be an armour plated tank!

[Jack]

Removing a coil from the spring doesn't uprate it. The spring is has just the same rate as before but less travel. (To uprate the spring you must used stronger steel or thicker coils or both!).

Sorry, but I disagree. Here is the maths (bear with me on this one!):

You can determine the rate of your coil springs by measuring them and using this formula:

Spring Rate = Gd4 / 8ND3 (the 4 and 3 are supposed to be "to the power of").
G = torsional modules for steel (11,250,000)
d = Wire diameter in inches
N = number of active coils
D = Mean coil diameter in inches (that's the diameter of the coils as you look down the spring, not the wire)
8 = A constant for all coil springs

The G factor in the equation is always the same for coil springs made from steel. A titanium spring would require another factor.

The coil wire diameter (d) can be masured with a caliper. It will be the same for the whole length of the spring unless its a variable rate one, on which case this won't work. For our example we'll assume a wire diameter of 0.62 inches.

Determining the number of active coils needs some judgement on your part. The key word here is "active". If the ends of the spring are flattened or ground, these coils are not active, since they rest on the mounting pads. When counting acting coils, only consider those that can move as the srping is compressed. For this example we will assume the spring has 10 active coils.

Determining the mean coil diameter can be done with a tape measure. Measure the diameter of the circle which the spring makes as you look down it. Measure from the centre of the wire to the centre of the opposite wire. For the example we will assume a coil diamiter of 5 inches.

Plugged into the formula, these figures get:

Coil spring rate = 11,250,000 x 0.62 x 0.62 x 0.62 x 0.62 / 8 x 10 x 5 x 5 x 5
So, Coil spring rate = 1,662,337 / 10,000
Coil Spring Rate = 166 lbs/in

So you can see that if you cut 1 coil from the equation you get:
Coil spring rate = 11,250,000 x 0.62 x 0.62 x 0.62 x 0.62 / 8 x 9 x 5 x 5 x 5
Coil Spring rate = 1,662,337 / 9,000
Coil Spring rate = 187 lbs/in

This amounts to an 11% increase or proportionate to the amount cut from the spring.

It makes absolute sense if you think about it. If you imagine a car spring and try to compress it one inch by hand, it is very difficult. If you then make the same spring 10 metres long, it is much easier to compress one inch. This is purely because of more active coils and so the rate has gone down.

On the spring dislocation issue, this won't happen if the spring is flattened at the end as I described.

Also, I should have pointed out that when heated and bent, the spring should be left to cool naturally, not be quenched as that may cause it to become brittle and crack in use.

[E_T_V]

Nice technical explanation there. Yes I can't fault your logic there and nicely illustrated too. I'm still trying to get my head around the physics of how that can happen but I agree you are right. I approached the problem from a materials point of view (I'm a materials enginner by trade) rather than an engineering one, and my logic was if the material is the same then how can it become stiffer, but I can see now it is all down to the geometry of the system, if coils are removed then the remaining material must deform more to give the same deflection which means that a higher load is needed.

Spring dislocation is still possible even if you flatten the end of the spring, as the damper may allow the whole spring to pull out of its seat when the suspension is decompressed, although it is far less likely if you flatten the spring, and the less coils you remove the less likely it is to occur too. I think I might have to draw a picture to explain how that can happen!

Also as you said severely quenching the steel is probably a bad idea, but also don't allow it to cool too slowly either and make sure you heat the minimum amount of spring as you can, (as heating the spring softens if it is slowly cooled afterwards).

Great technical debate. Keep up the good work.

[Jack]

I see what you mean with the spring falling out issue. It should be easy to check when re-building the strut. If you need spring clamps to put it back together, there should be enough pressure on the strut to prevent the spring popping out.

[B18 GPC]

Every Car Should Be Lowered. Go For It...

So Low That The Tops Of Wheels Are In the Arches All Round :)

[Paulr]

Tell me a bit more about that sump guard? My Turbo Maestro was lowered before I got it and the sump/PAS pipes etc all look terribly vulnerable under there - I worry every time I get near a speed hump!

[John S]

Every Car Should Be Lowered. Go For It...

So Low That The Tops Of Wheels Are In the Arches All Round :)

Thought I'd come back and see what's going on these days :) ...

I don't agree. I think the Maestro should be only lowered by 1 inch as any lower just makes the ride crashy and uncomfortable. The ultimate setup would probably be Spax or Koni 1" lowered top adjustable suspension. I'm looking into getting some Spax for the Turbo but at £350 I'll have to save up a little(!). 2" lowered suspension just doesn't allow enough travel to absorb the 'shock' when you hit a pothole - a similar feeling to sitting on a sledge and being towed along the tarmac.

John

[E_T_V]

Tell me a bit more about that sump guard? My Turbo Maestro was lowered before I got it and the sump/PAS pipes etc all look terribly vulnerable under there - I worry every time I get near a speed hump!

There were a couple of sump gards produced by rover, (i believe SMC on e-bay still have one). There are two different types, one for the 1.6 and one for the 2 litre cars. They are VERY heavy duty and weigh 21kg. I've currently got two, (one used and one brand new). If needed I'll try and dig out the part numbers of them.

[6r4Nut]

Thankyou for all the comments people, looks like I am aiming for around 1" as I don't want to lose my sump.

What is it roughly going to cost me to buy the springs?

[E_T_V]

http://www.dfaulknersprings.com/

Last time they were about 75 quid I think.

Although there is always the option of cutting your original springs down if you feel brave enough.

[Paulr]

Sorry to hi-jack the thread heer, but could a sump guard be made from aluminium? 21kg would add a fair bit of weight at the front and I suspect give even less ground clearance.

How much are they, roughly? Do you have a photo of one?