Chopped springs??

R

Renault17

Active member
Fellow Frogger
Joined
May 11, 2001
Messages
314
Location
New Zealand
Hey Guys,
I figured that sbuject line would either get people interested or on their hobby horse!! mallet

My 17 has uneven rear spring heights after being re-tempered (I have said this before in other posts) - anyway the guy that did it won't listen so I am gonna sort it out myself. It has altered the negative camber on the front 1/2 a degree from one side to the other.

I have come across an R17TL that can donate some springs and rather than get some other springs made up thought I could cut some first and see how close I get. I have had mates do it, rather dodgily, but I have others that have done it (safely) and to good effect.

Other than making sure that the spring is not shortened to the point that it is loose in the strut (i.e hold it in or don't cut it so short in the first place) are there any tips for lowering by cutting the springs?? In terms of X amount of the coil should lower it X inches- or is it the measure twice cut once principle??

I am only after about 1-1.5" off the height- and hopefully even this time too.... If this doesn't do what I want I'll have to bite the bullet and get some hardened,lowered ones made up. I figured I'd give this a go as it only takes about twenty minutes to drop the whole arse end (axle) on a R17. :D

Ben
 
Ben, I reckon you’d need to use something like (free height of coil/fitted height of coil) x desired drop in height. It should be relatively easy as there’s no leverage ratio to take into account like on wishbones.

I got a quote from a place called Aurora Springs for custom springs for the rear of my R12 – only $152 a pair! I didn’t get it done so can’t comment on their service.

<a href="http://www.industrialsprings.com.au/contact.htm" target="_blank">http://www.industrialsprings.com.au/contact.htm</a>

They needed to know:

Material Diameter - Removing paint or powder coating with wire buff
Inside Diameter - Measuring both ends (or outside diam.)
Total Number Coils
Finish On Ends - Ordinary round wire / ground flat / eye (if eye, is eye in centre?)
Free Length - Free height of coil standing unloaded
No of Inactive Coils - How many coils on either end do not work (no coils in contact with mounting surface)
Special Notes - Is the total no coils critical for location? or any other notes
Installed Height - The length of the spring installed in the car sitting at normal curb height (measure over pit or 4 post hoist)
Trapped Length - Measure the spring length with the suspension at full droop (fully extended )
Suspension Ratio - Does spring work on a 1:1 ratio directly over axle, or on a swing arm with a ratio eg 2:1 or 2.2:1 or 1.8:1 etc.

Finally, here’s a link to a site with some spring theory:

<a href="http://home.earthlink.net/~bazillion/design.html" target="_blank">http://home.earthlink.net/~bazillion/design.html</a>

Hope that helps.

Stu
 
I am not an advocate of cut down springs , but if you are going to do it, use a 4" angle grinder with a cutting disc, not an oxy set. Also on a 17 use some cut down 12 or 17 fronts as they will have 1 or 2mm thicker wire thus making the spring stiffer, lessening understeer and weight transfer on takeoff. As you said the rears come out so easily you can just cut off a bit at a time and lowering it to the ground without shocks to see the result. I doubt very much the ability of a rear spring to alter the front camber of your car.
Alan.
 
alan moore:
I am not an advocate of cut down springs , but if you are going to do it, use a 4" angle grinder with a cutting disc, not an oxy set. Also on a 17 use some cut down 12 or 17 fronts as they will have 1 or 2mm thicker wire thus making the spring stiffer, lessening understeer and weight transfer on takeoff. As you said the rears come out so easily you can just cut off a bit at a time and lowering it to the ground without shocks to see the result. I doubt very much the ability of a rear spring to alter the front camber of your car.
Alan.
Click to expand...
Hey Alan,
the spring heights were reset- and are different- this basically has the same effect as jacking one side one the rear. This was enough to alter the camber on the front from 1 degree even to 1.5 on one side and 1 degree on the other. The spring heights side to side on the rear are different by about 1.5-2cm. I have tried jacking one side at at time and the cambers come back close to being even. This is why I am keen to try the rear spring height- it's also a fairly easy procedure.

With the angle grinder vs the oxy torch is that to prevent distortion in the spring or a more even/precise cut Alan? I was going to use an angle grinder anyway....

Thanks for those tips Stuey. I'm really gonna have a go at it, and if it doesn't come up even I'll get some made up - NZ $135 a pair I am told- as long as I have most of the info that Stuey mentioned above.

Cheers Ben
 
I got my front springs compressed and i too have the impression that one side was compressed a smidgeon more than the other....

As far as my back springs are concerned, i took the angle grinder route :D
I chopped'em without taking'em off the car, they look better matched than my fronts. I've gotta get ones compressed though 'cos the back springs have always been a bit 'dead' (previous owner must've towed a lot).

And yeah, if you lift the back end, youve gotta do it by lifting the back axle or else your springs pop out.

Cheers
 
G'day Ben,
I agree that a 20mm difference on the rear could cause .5 deg neg on the front, I just didn't realise the amount of sag you were talking about. I had 16mm wire springs in the rear of my 15, giving about 200lbs per inch wheel rate, an upgrade of about 300%.
Alan.
 
Just the thought of chopped springs makes me cringe.... eeeeeeeeeeeeeeeek!
 
Hey Alan,
yeah it is quite a difference! What did uprating the springs by that much (300%) do to the overall handling balance of the car? Had you uprated/altered the front setup too? Mine also has a stiffer swaybar in the rear- will stiffening the rear up to that degree (with the harder springs too) make it skittery in the wet?

Hey Xsara- cutting the springs isn't particularly dangerous- all you are doing is shortening a spring, as long as the location points are the same- and it's located properly (i.e safely) I don't really see the drama with it.
 
My 15 had 50% uprated front springs, Konis all round, standard sway bars, 13X6 wheels. It handled fairly neutral, but needed more brakes on the track. I had the record in class at Mt Cotton hillclimb for some years. Was an OK ride on all but rough country roads where the back end was often in the air at high speeds. (Needed more travel) Front was 120mm from sub-frame rail to the road. The 15 was set up level and had 2.5deg neg. camber and 4 deg castor.
Alan.
 
alan moore:
My 15 had 50% uprated front springs, Konis all round, standard sway bars, 13X6 wheels. It handled fairly neutral, but needed more brakes on the track. I had the record in class at Mt Cotton hillclimb for some years. Was an OK ride on all but rough country roads where the back end was often in the air at high speeds. (Needed more travel) Front was 120mm from sub-frame rail to the road. The 15 was set up level and had 2.5deg neg. camber and 4 deg castor.
Alan.
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Geez Alan,

what was yor tyre wear like with 2.5 degrees on the front!!

Now for some learning....Why such high caster levels? Did it have very heavy steering- what size tyres did you have on that? Were they adjustable konis? Off the top of your head - how much room was left in the rear gaurds (looking side on to the car) from your tyres- I am hoping to get the car level which will mean the tyres will be just about level with the gaurds on the rears.... roll_lau

120mm from subframe to ground sounds lower than mine! I'll have to measure it tonight!
dance
Ben
 
With my R15, having gone in the Grand Prix Rally and various track days and hill climbs, I started out with different model springs, mucking around with what I could get my hands on, finally common sense took over and I got new springs made up. I have Koni's all round, disc rear end, stiffer sway bars and once the koni guy's had talked to me how I wanted the car to handle and talking about it's history of handling on different tracks. They had an idea of what I needed and up rated the shocks and ordered a totally new set of springs. The front shocks now have an adjustable spring mount as well so I can move the front up or down. Also as the springs are so sort yet hard, taking them in and out is so easy, none of those life and death stories anymore, it has made the biggest difference to the cars handling, it's like chalk and cheese.
I really recommend just spending the money and getting the shocks matched to a new set of springs, but you have to be sure if you want a firm or hard ride. As I only use my car now for rallies, track days and French car days, as the ride is quite hard. I hope this helps........
Top Performance "Koni" Rick Kemp
1 Trade Place Vermont,
Melbourne Victoria Australia 3133
Ph, 03 9873 1722 Fx, 03 9874 2200
dance
 
Ben,
The tyres actually wore flat, it depends on how you drive. 4deg castor is standard on a 15. I had 205/60/13 tyres on the car both ends and fitted without flaring or cutting any guards.I had a tiny 13" steering wheel and had no problems. Get some decent rubber and get to the gym if you have trouble with steering weight. I would now fit 15x6 with 195/50 now given the price and variety in that size.
Alan.
 
alan moore:
Ben,
The tyres actually wore flat, it depends on how you drive. 4deg castor is standard on a 15. I had 205/60/13 tyres on the car both ends and fitted without flaring or cutting any guards.I had a tiny 13" steering wheel and had no problems. Get some decent rubber and get to the gym if you have trouble with steering weight. I would now fit 15x6 with 195/50 now given the price and variety in that size.
Alan.
Click to expand...
Hey Alan,
yeah I run 15 *6 with 185/55/15's - these still have clearance issues- so I won't be running 195/50-15's even though they are more common (cheaper) tyres. I think the main problem with mine in regards to steering weight- is because I don't have the rack height set correctly.

So you still reckon with 2.5 negative camber it wore evenly- you must have been driving flat out all the time to get that!

Seeya Ben
 
The rack height will affect the bump steer (toe change ) as the suspension moves up and down.You can set this up correctly at home with a simple tool and plenty of time. Buy the book How To Make Your Car Handle by Fred Puhn to tell you how. I would suggest on the wheel front that the wheels are offset too much to the outside as I could easily fit my fingers between the tyre and guard on the rear, the front having no worries.
Alan.
 
I just remembered that my wheeltrack was only 25mm greater with the 6" wheels and quite possibly if yours is greater, a line bisecting the ball joints would have the greater part of the tyre outside of the point where this hits the ground causing heavy steering. Have a look at the way an Indy or F1 car has the offset(heaps to the inside) although probably not directly comparable, an F1 car with a 17.
Alan.
 
Hey Alan,
thanks for those tips, I'l try and check that book out at the local library. The offset is correct- they are the same offset as the standard renault wheels- whatever that is! It's actually the inner guard- basically where the font guard attches to the firewall is where it's rubbing.

I'm gonna try and use this other 17 I am gonna get to compare rack heights and enable me to get some degree of self centre-ing back (it has none presently) and reduce the steering effort some.

Cheers Ben

ps the heights on my 17 are; front (one finger!highly technical measurement.... mallet )
rear (two and a half fingers- 1 and a bit inches)
 
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