Originally Posted by
Taily
indeed so... Yet unlike you I don't rely on unproven heresay from the internet.
For everyone else with an open mind here are both sides of it.
I'll eleborate, if you cut stock springs they will be slightly stiffer but still too soft for the reduction in travel from missing coils, the stock coils add much needed wire length, not stiffness is what I was trying to say. The reduction in height is not compensated by the increase of stiffness...
If you imagine a coil as a long bar with one end stuck in a wall:
Make the bar shorter and it will be harder to bend from less leverage and harder to twist as there is more twist per distance of material... make it longer and it will be easier to bend from added leverage and easier to twist from less twist per distance of material.
Thats the way i see it, there's formulas to work out spring rates, but in essense the manufactured rate of the spring doesn't change ie; a 500lb wire coil is still a 500lb wire coil, yet I still think the reduction in height is not compensated
by the stiffness gained from cutting coils and by the time the stock spring is stiff enough from removing coils (any noticeable change without measuring equipment) it would not be captive or effective in travel (would coil bind).
Looking at the practicality of it: Take some stock springs at 330mm cut to 300mm and compare to some low king springs at 300mm and 30% stiffer, not that I like or endorse them, it is just their data straight from their catalogue.
kings springs:
- 30mm drop which is 10%.
- 30% stiffer
stock springs at 330mm and cut 30mm off:
- 30mm drop which is 10%
- 10% stiffer is my guess?
Now the legality of it:
Everyone needs to be careful about public advice that contradicts what is contained within the various acts in reference to altering installed components by welding or friction cutting fitted components, or reducing the suspension travel by more than one third (a standard spring W series Holden has a front suspension travel of only a shade over 90mm before the bumpstop first touches - how you measure installed spring travel depending on the variant) - however do not confuse jounce and rebound with suspension travel as they are two very different things. So standard front coils that have had an amount of wire removed that results in a reduction of travel of more than30mm in the eyes of the (RMS at least) is outside the Act and is not a permissable modification. HOWEVER.... Should you install manufactured lower springs that reduce the ride height in this way then the suspension travel value changes doesn't it?
The better option (of the lot) is to retain full suspension travel (bear in mind that suspension travel is the one safeguard against the inherrent cracked chassis issues our busses have) and fit either approved dropped spindles or a combination of lowered (not cut) coild and dropped spindles. As I mentioned earlier they also have another benefit in they realign the tie rod end pin centre closer to an ideal point which improves bump steer imessureably (much nicer on the road).
Hopefully that spells it out in a way that most will understand. It gets to be a slippery slope if you get caught cutting suspension components however the reason many AIS and insurance peeps turn a blind eye and don't want to know (until they can use it to deny your claim) is that nobody wants to deal with the legal burden of proof that goes along with identifying modified components.
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