|
Is it safe to chop my springsfr€$h&m1nt¥
@freshandminty
Club Retro Rides Member 99
|
Jan 13, 2013 20:52:30 GMT
|
So to chop springs you literally take an angle grinder to them and cut equal amount off each side?
Is it best to cut in line with where the current last coil stops so it just ends in the same place but one coil higher?
Any how to guides on here?
Cheers Phil
|
|
|
|
|
VIP
South East
Posts: 8,293
|
|
|
So to chop springs you literally take an angle grinder to them and cut equal amount off each side? Is it best to cut in line with where the current last coil stops so it just ends in the same place but one coil higher? Any how to guides on here? Cheers Phil If by 'each side' you mean each spring then yes. You wouldn't want to remove material from each end of the spring, as you'll want to retain one flattened end to help seating. Where you cut is irrelevant, you remove as much material as you require to gain your chosen ride height. It could be one coil, it could be 2.5. Coil springs which have the same diameter their entire length are much simpler to cut than 'pigtail' or 'beehive' springs, where the diameter changes at one of both ends.
|
|
|
|
|
|
Jan 14, 2013 10:22:45 GMT
|
MOT official take on cut springs (from memory): Cracked/fractured springs are not a reason for rejection providing they seat correctly once the vehicle has been jacked off the ground. And providing they don't affect the operation of any bearings or mounts. Springs that have been cut in order to lower the ride height or altar the handling are to be treated in the same way. I can get the exact wording but it is along those lines As far as I'm aware from current MOT law, a cracked or fractured spring would fail an MOT. How ever cut springs are not cracked or fractured so I don't see as that would cause a problem also long as with the car jacked up they can't be pulled out.
|
|
|
|
Clement
Europe
ambitious but rubbish
Posts: 2,095
|
|
Jan 14, 2013 13:22:31 GMT
|
I don't see why it would alter the spring rate, it just shortens suspension travel doesn't it?? The only case I see where cutting coils would stiffen the springs is if they are of variable rate along their length and you cut the 'soft' end. I'm really not sure if this makes any sense in English but it really does in my head
|
|
Last Edit: Jan 14, 2013 13:22:49 GMT by Clement
|
|
|
|
Jan 14, 2013 13:30:54 GMT
|
I don't see why it would alter the spring rate, The bar that the spring is wound from has a certain strength. That strength is spread over a certain amount of coils - when you chop a coil off, the rate per coil is increased. At least that's how I've always understood it. It's not entirely straight forward though as geometry alterations in certain suspension designs can decrease the effective rate with shorter springs.
|
|
|
|
VIP
South East
Posts: 8,293
|
|
Jan 14, 2013 15:54:30 GMT
|
I don't see why it would alter the spring rate, it just shortens suspension travel doesn't it?? The only case I see where cutting coils would stiffen the springs is if they are of variable rate along their length and you cut the 'soft' end. I'm really not sure if this makes any sense in English but it really does in my head A coil spring is simply a straight bar wound into a helix. Unwind it, fix one end, and place a weight on the other. The bar will deflect a certain distance. Now shorten the bar [same as cutting a coil] and place the same weight on the end of the bar. The deflection will be a smaller distance. It's all about leverage. If you half the length of the bar, the same weight will deflect the bar half the distance.
|
|
|
|
Clement
Europe
ambitious but rubbish
Posts: 2,095
|
|
Jan 14, 2013 16:12:04 GMT
|
Aaah I think I see. Like compressing the spring over a quarter of its length will require the same pressure whatever its length? Hence the same pressure will cause a shorter movement if the spring is shorter?
Sorry for the noob question, I should have asked that in the daft question amnesty thread.
|
|
|
|
|
|
Jan 14, 2013 17:33:59 GMT
|
Get the grinder out. Stop being a girl!
|
|
|
|
|
|
Jan 14, 2013 18:52:28 GMT
|
i love these threads. Yes its fine! No don't do it!
|
|
1974 Lancia Beta Saloon 1975 Mazda 929 Coupé 1986 Mazda 929 Wagon 1979 Mazda 929 Hardtop 1982 Fiat Argenta 2.0 iniezione elettronica 1977 Toyota Carina TA14 1989 Subaru 1800 Wagon 1982 Hyundai Pony 1200TL 2-dr 1985 Hyundai Pony 1200 GL 1986 Maserati 425 Biturbo 1992 Rover 214 SEi 5-dr 2000 Rover 45 V6 Club 1994 Peugeot 205 'Junior' Diesel 1988 Volvo 760 Turbodiesel Saloon 1992 Talbot Express Autosleeper Rambler 2003 Renault Laguna SPEARS OR REAPERS
|
|
VIP
South East
Posts: 8,293
|
|
Jan 14, 2013 19:47:45 GMT
|
Aaah I think I see. Like compressing the spring over a quarter of its length will require the same pressure whatever its length? Hence the same pressure will cause a shorter movement if the spring is shorter? Sorry for the noob question, I should have asked that in the daft question amnesty thread. Not quite. A 12" 100lb spring and a 10" 100lb spring will both compress the same amount under the same weight. The poundage rating is how much weight is required to compress the spring one inch. Compressing these springs to a quarter of their respective lengths will require different weights. The 12" spring requires 300lb to compress it a quarter of its length (12"x25%=3"@100lb/inch). The 10" spring requires 250lb to compress it a quarter of its length (10"x25%=2.5"@100lb/inch).
|
|
|
|
|
|
|
Jan 14, 2013 20:44:12 GMT
|
ouch my head hurts anyone know if i cut my springs on the Carry van will i need shorted shocks ?
|
|
sorry i cant spell
|
|
|
|
Jan 14, 2013 20:50:47 GMT
|
I would say leave them alone. cutting springs on its own is not dangerous. wading in with an angle grinder if you don't really know what you are doing and what the consequences are, is not recommended
|
|
1974 Lancia Beta Saloon 1975 Mazda 929 Coupé 1986 Mazda 929 Wagon 1979 Mazda 929 Hardtop 1982 Fiat Argenta 2.0 iniezione elettronica 1977 Toyota Carina TA14 1989 Subaru 1800 Wagon 1982 Hyundai Pony 1200TL 2-dr 1985 Hyundai Pony 1200 GL 1986 Maserati 425 Biturbo 1992 Rover 214 SEi 5-dr 2000 Rover 45 V6 Club 1994 Peugeot 205 'Junior' Diesel 1988 Volvo 760 Turbodiesel Saloon 1992 Talbot Express Autosleeper Rambler 2003 Renault Laguna SPEARS OR REAPERS
|
|
|
|
Jan 14, 2013 20:56:48 GMT
|
If you have to ask simple questions about cutting your springs, I would urge you strongly not to bother cutting your springs.
|
|
|
|
|
|
Jan 14, 2013 20:59:23 GMT
|
Your shocks remain the same. No need to change them.
|
|
|
|
|
|
Jan 14, 2013 21:06:13 GMT
|
But that's way over simplifying it - what if the stock shocks mean that the vehicle is sat completely on the bump stops after only a mild drop. Being a small japanese van there's a pretty good chance that the OE setup doesn't have a great deal of travel to start with.
|
|
|
|
|
|
Jan 14, 2013 21:11:33 GMT
|
|
|
1974 Lancia Beta Saloon 1975 Mazda 929 Coupé 1986 Mazda 929 Wagon 1979 Mazda 929 Hardtop 1982 Fiat Argenta 2.0 iniezione elettronica 1977 Toyota Carina TA14 1989 Subaru 1800 Wagon 1982 Hyundai Pony 1200TL 2-dr 1985 Hyundai Pony 1200 GL 1986 Maserati 425 Biturbo 1992 Rover 214 SEi 5-dr 2000 Rover 45 V6 Club 1994 Peugeot 205 'Junior' Diesel 1988 Volvo 760 Turbodiesel Saloon 1992 Talbot Express Autosleeper Rambler 2003 Renault Laguna SPEARS OR REAPERS
|
|
|
|
Jan 14, 2013 21:22:34 GMT
|
As far as I'm aware from current MOT law, a cracked or fractured spring would fail an MOT. How ever cut springs are not cracked or fractured so I don't see as that would cause a problem also long as with the car jacked up they can't be pulled out. I'd understand your confusion as a lot of testers arent even sure of the rules. I've copied this directly from the MOT inspection manual today: Where a coil spring is incomplete, cracked or fractured at an extreme end where the spring locates on the spring mount, it should only be rejected if :- The function of the spring is impaired following jacking, the spring ends do not locate correctly when the vehicle is lowered into the normal running position without assistance These criteria should also be applied to springs that have been deliberately shortened or modified in order to lower the suspension
|
|
|
|
|
|
Jan 14, 2013 21:29:27 GMT
|
Which is why you wire the spring into the cup. It is the relocating that the MOT test cares about.
|
|
|
|
|
|
Jan 14, 2013 22:26:23 GMT
|
anyone know if I cut my springs on the Carry van will I need shorted shocks ? If they are anything like the earlier SuperCarry, one coil on the front is fine, two pushing it and three will have you on the bumpstops with NO suspension travel left. As said by the others, if you're not sure what you're doing, then please, please, please don't attempt this. I'm going to assume that the Carry (the ones with the 'bonnet' instead of the flat fronted Super Carry) has coil springs all round? You need to establish how much travel you've got before you even think about cutting any springs. From what I remember, there is only about 40mm of travel, so lowering the car by 40mm takes to straight into ZERO suspension. Very far from ideal. I chopped my springs just to see how much it lowered by, then went and got some coilovers made to my own specification based on what I found by chopping the springs. It was a lot of work, but well worth it and it drives brilliantly as a result.
|
|
|
|
|
|
Jan 15, 2013 10:08:49 GMT
|
Cheers , ye the carry has the bonnet and springs all round , I get you now about the travel and will look in to it . I'm Capable enough to cut the Springs but just hopping someone had done one and I could copy there results . Thanks everyone for the advice . Cheers d
|
|
sorry i cant spell
|
|
|