Shortening front springs

[Freebird]

Hi Guys

At risk of sounding like a real skinflint again, the Spitfire sits too high at the front as most 1500s seem to.  We fitted a pair of springs that I took off the Vitesse yesterday, they were a good 2" shorter free length, but of course stiffer - so it's still too high.

This artical suggests it's OK to cut a coil out and to quote:

http://auskellian.com/paul/links_files/performance_enhancements.htm#front

"The least expensive way to lower the front is to simply cut one free coil off one end of each of the stock springs. This shortens and slightly stiffens the springs, and the pigtail left by this operation will compress and not be an issue once installed in the car. On the Spitfire 1500, this will result in the desired installed static coil length of about 7 inches."

So, has anyone tried it?

Glen.

[Freebird]

Same piccy twice - nice - this is what I meant to load up. This is with the Vitesse spring in there.

[Clive]

Martin (with the yellow 2.5 spitfire) had chopped vitesse springs fitted when he had the original 1500 engine in the car. It worked, nothing broke over he many thousands of miles the car was like it BUT it never looked right, having the chopped end. Really needs flattening a bit, not sure how possible that is without destroying the springiness.
I would buy a set of proper lowered springs, probably the 330lb moss ones. Not a huge expense. Of course, you could try chopping first, see if you like it?

Now, must go out and faff with front brakes.....

[starman]

Freebird wrote:

Hi Guys

At risk of sounding like a real skinflint again, the Spitfire sits too high at the front as most 1500s seem to.  We fitted a pair of springs that I took off the Vitesse yesterday, they were a good 2" shorter free length, but of course stiffer - so it's still too high.

This artical suggests it's OK to cut a coil out and to quote:

http://auskellian.com/paul/links_files/performance_enhancements.htm#front

"The least expensive way to lower the front is to simply cut one free coil off one end of each of the stock springs. This shortens and slightly stiffens the springs, and the pigtail left by this operation will compress and not be an issue once installed in the car. On the Spitfire 1500, this will result in the desired installed static coil length of about 7 inches."

So, has anyone tried it?

Glen.

Hi Glen-

I tried it for many years (I wrote the article too) and I've used this method on other cars.  It works, but I agree with cliftyhanger that it's not the best option and it's better to install stiffer, shorter free length springs to achieve the same ride height.  Moreover, as I mention later in the article, lowering reduces the amount of bump travel, so it's best to stiffen enough to compensate for the loss of bump travel to avoid contacting the bump stops under normal handling conditions.  I use 350 lb/in, 9 inch free length coils and I'm very happy with them.  They increase the wheel rate enough to almost exactly offset the loss of bump travel that comes with the lowering, yet they aren't too stiff so as to make the ride jarring or degrade the handling.  The 330 lb/in TriumphTune TT4302 springs that many vendors sell will achieve roughly the same thing.  Merlin in the UK sells 2.5 inch I.D. coil springs in various free lengths and rates.  The cost difference in shortening you old ones and buying the right new ones is the cost of a new pair of springs, which is about 70 USD or about 45 GBP.  

Stiffening up the front without stiffening up the rear tends to add more understeer, but this is largely ameliorated by the improved geometry in turns due to a lower c.g. and reduced body roll and so the net result is a Spitfire that has a little bit of understeer (instead of a lot), which is what you want anyway.  Cheers-

[JohnD]

Glen,before you chop your springs, have a close look at the shock absorber and the spring seat.    A lot of shockers, sold as "For Triumph model X" are nothin gof the sort=, and have the seat too high.  Your's look nicley new, unless you've painted them, and the seat looks a bit high to me,  so I fear you have been misled.

The correct height of the seat above the lower eye is well known, except I can't remember what it is just now!  Please do a search here - I'm sure that others and even I have quoted it in the past.

John

[Freebird]

JohnD wrote:

Your's look nicley new, unless you've painted them, and the seat looks a bit high to me
John

Hi John

They are deffo not new, the whole front end looked like it had come off the Titanic before Joe and I set about them with a wire brush and a load of paint at the weekend.

The spring seats are loose and sit on a step actually, with the spring off they are free to slide upwards. Not seen that before.

Thanks for all the advice everyone.

Glen.

[Freebird]

cliftyhanger wrote:

I would buy a set of proper lowered springs, probably the 330lb moss ones. Not a huge expense. Of course, you could try chopping first, see if you like it?

Now, must go out and faff with front brakes.....

Yes, Moss 330s are on my "wish list" trouble is that list has a higher value than the car  :-/ They are £75 a pair probably plus P&P.

[Clive]

Youch ??)

Canleys have a 330lb 1"lower spring at £22 each
http://www.canleyclassics.com/searchforapart/?ptno=F67

But the angle grinder does look strangely attractive ;D

[Freebird]

cliftyhanger wrote:

Youch ??)

Canleys have a 330lb 1"lower spring at £22 each
http://www.canleyclassics.com/searchforapart/?ptno=F67

But the angle grinder does look strangely attractive ;D

Mmm, a bit better, probably £65 inc P&P.

The angle grinder does look attractive, but I fear the spring will be far from it.

Now go out and get those hubs off!

[JohnD]

The spring seat should be 82mm above the centre of the bush eye.
That's 3 1/4" - on your phot I think your's is maybe more.
Even if it's only a little  more, the geometry exagerates it when it comes to ride height.

Long discussion at : http://www.tssc.org.uk/index.php?option=com_fireboard&Itemid=55&func=view&id=70944&catid=195#70944

John

[Freebird]

JohnD wrote:

The spring seat should be 82mm above the centre of the bush eye.
That's 3 1/4" - on your phot I think your's is maybe more.
Even if it's only a little  more, the geometry exagerates it when it comes to ride height.

Long discussion at : http://www.tssc.org.uk/index.php?option=com_fireboard&Itemid=55&func=view&id=70944&catid=195#70944

John

Cheers John

I will have a measure when daylight allows. When you say the geometry exaggerates it, the spring/shock is the hypoternuse of a roughly 45 deg triangle is it not, so if it was 45 Deg a 1" extra spring length = 0.707" extra ride height. Or am I missing something.

Paul

Excellent artical if I may say so mate....

Glen.

[JohnD]

I'd put it a different way.
Consider the lower wishbone.
The shocker eye is nearer the pivot than the trunnion, by ?a fifth?.
So if the eye is pushed down by 1" (say) then the trunnion goes down by 1.2"
(extra spring seat height x length of wishbone/pivot to shocker bush length)
Please do the measurements for me - I can't remember, and it's cold and dark tonight!

John

[Freebird]

That does make absolute sense, thanks.
But it's cold and dark here too so measurements will just have to wait.....

[bodders1]

Freebird:  PM sent....

[cammmy]

I was going to get a set of CW springs for the saloon but the shipping was going to cost more than the springs. Went at them with the angle grinder and handling = massively improved.

[Tim Bancroft]

Freebird,

Have a look here:

http://www.dfaulknersprings.com/index.htm

[tiggrr1]

timbancroft61 wrote:

Freebird,

Have a look here:

http://www.dfaulknersprings.com/index.htm

I second that Tim.

I ordered a set of springs from them a couple of years ago at around 3.15pm and they were with me next morning by 11.00am.

Very friendly on the phone aswell.

[Nick Jones]

Great link - thanks Tim!

Nick

[thebrookster]

I have also been led to believe that Gareth Thomas is selling the progressive springs for spitfires again just now, not used them myself but those who have used them all seem to have good things to say about them. If I had a spitfire just now they are what I would be considering, IIRC not too bad price wise either. I couldn't tell you of they would solve your height issue, but I thought I would throw this into the discussion seeing as guys are discussing springs!

I hasten to add that I have no connection to GT or the sales, simply that I picked this up on the grapevine the other day.

Cheers,

Phil

[uksnatcher]

Before you cut...

Standard spit 1500 springs are rated at 180lbs and sit compressed at 8" on a spit
Standard spit 1100 (MK2?) springs are rated at 150lbs and sit compessed at 7.5" on a spit.
Standard GT6 (Vitesse?) springs are rated at 200lbs and sit compressed at 8" on a spit

GT6 free length (unladen) is 12.5"
Spit 1500 free length is 13.2"
Mk2 ? spit free length is 12.2"

Spit 1500 kerb weight approx 850kg
GT6 kerb weight approx 878kg
6 cyl engine weight 181kg
4 cyl engine weight 99kg

If you cut the coil off a standard 6 cyl spring you will loose the rating of 200lbs down to possibly 170lbs or less and that will be very soft, managable but speed bumps and braking will be bouncy, bouncy.

Been there...added full adj shocks and 480lbs springs, headache over.  ;)

[heraldcoupe]

uksnatcher wrote:

If you cut the coil off a standard 6 cyl spring you will loose the rating of 200lbs down to possibly 170lbs or less and that will be very soft, managable but speed bumps and braking will be bouncy, bouncy.

Surely cutting out coils is a method used to stiffen, rather than soften suspension? It's the same principle as shortening a torsion bar,

Cheers,
Bill.

[uksnatcher]

By cutting the spring you loose height, the strength of the spring is also reduced.

480lb springs are free length 9" and compressed to 7.5" on 1500 spit BUT the thickness of the coil is increased and the ID stays at 2.5", so more strength but less movement so less bouncy or travel if you like.
Unfortunatly standard shocks have the spring base fixed too low to add the uprated springs,hence people adding shocks with adjustable spring bases or spacers betweeen the chassis and shocker.

[Clive]

Sorry, but that is wrong. If you reduce the length of spring, the rate WILL go up.

Simple analagy. Get a bit of metal, plastic etc (ruler is ideal) gently apply a foce at the end to bend it. Now try the same force but at half way. It is stiffer. Same thing with springs.....

[uksnatcher]

Apologies, thanks Clive and Bill rate does increase by cutting coils, weird science..! i personally didnt like the handling so uprated the springs/shocks.  :)

[Freebird]

JohnD wrote:

The spring seat should be 82mm above the centre of the bush eye.
That's 3 1/4" - on your phot I think your's is maybe more.
Even if it's only a little  more, the geometry exagerates it when it comes to ride height.

Long discussion at : http://www.tssc.org.uk/index.php?option=com_fireboard&Itemid=55&func=view&id=70944&catid=195#70944

John

Finally got round to measuring them and they are about 90mm, so this explains the nose high stance. Bodders1 has offered me some Spax adjustables that he says measure 75mm so I am going to go for them.

Next Saturday they will be fitted  :)