mild lowering (yeah another lowering thread) - for stance and a slightly tighter ride
- Thread starter J1MMY
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Zeb - I've done a lot of reading on the forum about lowering the front and the general consensus is that the only way to do it is to chop the rod. Is the only reason for not using a shorter spring the fact that it falls out when the car is jacked up or is there a problem with normal road use too? If you're only looking for a small drop, say, no more than an inch, could you do it the old-fashioned way?
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Yes, I had lower profile tyres on my old convertible, 185 65's on the front and 195 60's on the back.
I used rover's inbuilt lowering system, knackered springs !!
Although remember the aspect ratio (profile) is a percentage of the tyres width, so if you go up in width and come down in profile the tyre can actually end up the same diameter. In fact that's usually what you want to preserve speedo accuracy.
I used rover's inbuilt lowering system, knackered springs !!
Although remember the aspect ratio (profile) is a percentage of the tyres width, so if you go up in width and come down in profile the tyre can actually end up the same diameter. In fact that's usually what you want to preserve speedo accuracy.
Interesting points, are adjustables available still?
As for the wheel/tyre issue, maybe this will be of help to some?
http://www.miata.net/garage/tirecalc.html
Used a lot in other forums if changing wheels to help work out arch clearances as well as speedo deviances and differences in rolling diameters.
Again, at the risk of offending purists, Northants tyres do a line in cracking US old skool rims torque thrusts, and lots of choice with offset/backspacing. Having looked at the space with the current std wheels, I think a 7j rim should go in there, subject to the right offset. Certainly wouldnt want to risk much more in the rear, unless anyone knows different?
As for the wheel/tyre issue, maybe this will be of help to some?
http://www.miata.net/garage/tirecalc.html
Used a lot in other forums if changing wheels to help work out arch clearances as well as speedo deviances and differences in rolling diameters.
Again, at the risk of offending purists, Northants tyres do a line in cracking US old skool rims torque thrusts, and lots of choice with offset/backspacing. Having looked at the space with the current std wheels, I think a 7j rim should go in there, subject to the right offset. Certainly wouldnt want to risk much more in the rear, unless anyone knows different?
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How about trying some coil spring clamps ? ebay no 220159032979
Interestingly there is an article on cutting coil springs in this months Practical Performance Car, they claim it's all perfectly safe etc.. As long as the spring remains under some compression when fully unloaded.
Apparently the problem with the P6 fronts are that they operate in a slight arc, which can push them out of the seat.
Interestingly there is an article on cutting coil springs in this months Practical Performance Car, they claim it's all perfectly safe etc.. As long as the spring remains under some compression when fully unloaded.
Apparently the problem with the P6 fronts are that they operate in a slight arc, which can push them out of the seat.
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Whilst I remember, I spotted a slight problem with shortening the pushrod as a means of lowering the front, that is that the spring rates remain the same, so you end up with lower but just as soft front suspension. Plus you've moved the location of the bump-stop in relation to the ground, so there's even more chance of bottoming out.
Now this may be what some people want, but maybe not, so as well as shortening the rod you would need uprated springs to stiffen it up, and possible fit bigger bump stops.
Now this may be what some people want, but maybe not, so as well as shortening the rod you would need uprated springs to stiffen it up, and possible fit bigger bump stops.
Hi Jimmy, welcome to the forum!
You may have guessed by now I have a few "views" on P6 suspension, so apologies if I'm repeating.
When looking to change anything on the suspension of any car it's important to analyse what you're trying to achieve first. In this context I'd say there are basically four categories you're trying to address:
1 Appearance This is where lowering belongs - it has nothing to do with ride or handling (unless you overdo it and have no suspension travel left!!) As a general rule, the longer the suspension travel you have available on a car the more likely you are to be able to engineer a good ride and good handling - so lose suspension travel at your peril!
2 Ride This one is obvious!
3 Handling People often assume this equates to stiff springs. No. Rather this is about what happens to the car on the limit, either stable in a corner or changing direction between a sequence of corners. So here we are talking "understeer" vs "oversteer" and "turn in". You can have brilliant handling with a really soft rolly polly ride - the French are good at that.
4 Grip Or how fast you can go before a hedge appears! If 3 above is badly wrong this one will go haywire, but if the handling is within reasonable bounds then grip is determined by how wide the tyres are and by the underlying suspension design. As a tyre corners it tries to roll off the wheel rim. This means that the tread is no longer at right angles to the wheel. Really clever F1 designers spend a lot of time trying to ensure that at maximum side force the suspension has moved the wheel out of the vertical and positioned it so that the tread of the tyre is flat on the road. You won't achieve that in a road car, so the discussion is about how bad the compromises are. The P6 is pretty good at the back. The de dion keeps the wheels vertical to the road at all times, so all you need to do to improve is fit a tyre with a stiffer sidewall - usually achieved by going for a lower profile. At the front the P6 is a disaster, there is very large camber change in roll. Best solution is to try to set the tyre / wheel at a promising camber and then try to eliminate the roll.
So, what would I do in your position? If I read you right you want it to look a bit cooler and to be a bit "sharper"? Next question is how big is the budget? If huge then disregard the next bit and either pm me or do a search on some of the other suspension and handling threads.
Ok, in rough order of cost.
1 I'd change the springs - you're almost certainly going to do this anyway cos the old ones will have sagged badly. Before you shell out, have a long chat about handling which will allow you / us to chose spring rates and lengths that will suit. This should achieve an improvement in roll stiffness front and rear and give you an opportunity to do a little bit of lowering. The ride quality of the P6 (thanks to the long travel suspension) will stand a hefty uprate in spring stiffness without losing peoples dentures!
2 Better dampers. Quite expensive (effectively now only one supplier - AVO - after Koni sold out and haven't made any more) but radically reduces front end lurch on turn in.
3 Uprated front anti roll bar. Easy to fit - just have a front wing off(!). Again major improvement in steering but you need to know you're going to do this before you choose the springs otherwise you could finish up with terminal understeer as well.
After these it's on to the sexy bits. Wheels and tyres. The cheapest solution is SD1 Vitesse 15" wheels with 195/70 X 15 tyres. That's pretty well the correct diameter and you ought to get away without bodywork. You can go up to 205/65 X 15 but you need to skim the back of the wheel. Serious bodywork is to be avoided if possible because the first thing you lose is the bit of metal on the base unit that holds the rubber that the back doors seal onto. If you can stand the car without door sealing rubbers then no problem.
After the Vitesse wheels it all gets a bit difficult. The P6 has the wheels set unusually far into the body and therefore needs a very odd ET rim. Best bet is Jeep wheels and accept some compromises on bodywork, tyre size etc. Or buy bespoke wheels eg Minilites!
Hope that helps - I suspect there might be a few follow ups though!
Chris
You may have guessed by now I have a few "views" on P6 suspension, so apologies if I'm repeating.
When looking to change anything on the suspension of any car it's important to analyse what you're trying to achieve first. In this context I'd say there are basically four categories you're trying to address:
1 Appearance This is where lowering belongs - it has nothing to do with ride or handling (unless you overdo it and have no suspension travel left!!) As a general rule, the longer the suspension travel you have available on a car the more likely you are to be able to engineer a good ride and good handling - so lose suspension travel at your peril!
2 Ride This one is obvious!
3 Handling People often assume this equates to stiff springs. No. Rather this is about what happens to the car on the limit, either stable in a corner or changing direction between a sequence of corners. So here we are talking "understeer" vs "oversteer" and "turn in". You can have brilliant handling with a really soft rolly polly ride - the French are good at that.
4 Grip Or how fast you can go before a hedge appears! If 3 above is badly wrong this one will go haywire, but if the handling is within reasonable bounds then grip is determined by how wide the tyres are and by the underlying suspension design. As a tyre corners it tries to roll off the wheel rim. This means that the tread is no longer at right angles to the wheel. Really clever F1 designers spend a lot of time trying to ensure that at maximum side force the suspension has moved the wheel out of the vertical and positioned it so that the tread of the tyre is flat on the road. You won't achieve that in a road car, so the discussion is about how bad the compromises are. The P6 is pretty good at the back. The de dion keeps the wheels vertical to the road at all times, so all you need to do to improve is fit a tyre with a stiffer sidewall - usually achieved by going for a lower profile. At the front the P6 is a disaster, there is very large camber change in roll. Best solution is to try to set the tyre / wheel at a promising camber and then try to eliminate the roll.
So, what would I do in your position? If I read you right you want it to look a bit cooler and to be a bit "sharper"? Next question is how big is the budget? If huge then disregard the next bit and either pm me or do a search on some of the other suspension and handling threads.
Ok, in rough order of cost.
1 I'd change the springs - you're almost certainly going to do this anyway cos the old ones will have sagged badly. Before you shell out, have a long chat about handling which will allow you / us to chose spring rates and lengths that will suit. This should achieve an improvement in roll stiffness front and rear and give you an opportunity to do a little bit of lowering. The ride quality of the P6 (thanks to the long travel suspension) will stand a hefty uprate in spring stiffness without losing peoples dentures!
2 Better dampers. Quite expensive (effectively now only one supplier - AVO - after Koni sold out and haven't made any more) but radically reduces front end lurch on turn in.
3 Uprated front anti roll bar. Easy to fit - just have a front wing off(!). Again major improvement in steering but you need to know you're going to do this before you choose the springs otherwise you could finish up with terminal understeer as well.
After these it's on to the sexy bits. Wheels and tyres. The cheapest solution is SD1 Vitesse 15" wheels with 195/70 X 15 tyres. That's pretty well the correct diameter and you ought to get away without bodywork. You can go up to 205/65 X 15 but you need to skim the back of the wheel. Serious bodywork is to be avoided if possible because the first thing you lose is the bit of metal on the base unit that holds the rubber that the back doors seal onto. If you can stand the car without door sealing rubbers then no problem.
After the Vitesse wheels it all gets a bit difficult. The P6 has the wheels set unusually far into the body and therefore needs a very odd ET rim. Best bet is Jeep wheels and accept some compromises on bodywork, tyre size etc. Or buy bespoke wheels eg Minilites!
Hope that helps - I suspect there might be a few follow ups though!
Chris
What is the width & offset of the std p6 wheels?
Had another look at the way they sit in the arches and reckon that another 2" can be had in wheel width, as long as the offset is reduced accordingly (so the extra width moves outwards not inwards), additionally running on lower profil tyres will tighten the sidewall as the 185 14's on mine are probably as bulbous as say a 215 45 on a 7j rim.
Here is another good tool - again some may know it but like the miata calculator, with this and a tape measure you can closely estimate what will and won't work in the arches
http://www.1010tires.com/WheelOffsetCalculator.asp
Had another look at the way they sit in the arches and reckon that another 2" can be had in wheel width, as long as the offset is reduced accordingly (so the extra width moves outwards not inwards), additionally running on lower profil tyres will tighten the sidewall as the 185 14's on mine are probably as bulbous as say a 215 45 on a 7j rim.
Here is another good tool - again some may know it but like the miata calculator, with this and a tape measure you can closely estimate what will and won't work in the arches
http://www.1010tires.com/WheelOffsetCalculator.asp
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New Member
Probably the best wheel / tyre site is this Wheel and tyre bible which has now expanded to two big pages, make a cup of tea and have a good read !
Chris did a lot of measurements a while ago, and posted the results In this thread
Chris did a lot of measurements a while ago, and posted the results In this thread
mightily informative site, that
All I need to know is the width & offset of my std wheels - the rest of the calculating is easy.
Chris, I've re-read you post and am I correct in thinking that you have within your means the ability to source/supply different suspension components for the P6?
Out of curiosity (and maybe posting the last thing that anyone will reply to :O ) has anyone seen a P6 on air ride or "juiced"?
All I need to know is the width & offset of my std wheels - the rest of the calculating is easy.
Chris, I've re-read you post and am I correct in thinking that you have within your means the ability to source/supply different suspension components for the P6?
Out of curiosity (and maybe posting the last thing that anyone will reply to :O ) has anyone seen a P6 on air ride or "juiced"?
Hi J1MMY
None of this stuff is available "off the shelf" in conventional (say) Escort or Demon Tweeks terms, but once you've decided how you want the car to behave it's not difficult to get made (and probably no more expensive). Key thing is to understand what you want the car to behave like.
Once you understand what you want there are several places to make springs, Ian uses a firm in Sheffield, I know of one here in Bristol and Alan at Leighton Buzzard will make them for you as well. Alan's your guy for a front anti roll bar - he can also do you a rear one (they don't have one as standard at the rear). Alan will also get shocks made up for whatever valving you want depending on your choice of springs, or go to AVO's or check Ebay for 2nd hand Koni Classics (now out of production). Note the front shock is difficult cos it works upside down because of the strange front suspension design (ie gets longer as the front goes down). You might want to convert the front lower mountings to a Nylock instead of the split pin and washer arrangement as well.
I've not yet had the opportunity to measure standard steels to calculate the offset - presumably you have some, why not measure your own? And let us know too!!! My impression is that they are set further into the arch than my optimised Vitesse wheels, so you might finish up with a rubbing problem on the side of the boot floor? Certainly I wouldn't want to go above 195's on the standard rim section irrespective of rubbing issues. To keep the same diameter that would need 195/75 X 14's. The P6 has another trick up its sleeve when calculating clearances at the back. Don't forget that with the de dion the rear track changes depending on ride height, so as you go over a bump the track gets momentarily wider, if you jack the car up it gets narrower.
If you need to, pm me and I'll let you have my phone no for a chat.
Regards
Chris
None of this stuff is available "off the shelf" in conventional (say) Escort or Demon Tweeks terms, but once you've decided how you want the car to behave it's not difficult to get made (and probably no more expensive). Key thing is to understand what you want the car to behave like.
Once you understand what you want there are several places to make springs, Ian uses a firm in Sheffield, I know of one here in Bristol and Alan at Leighton Buzzard will make them for you as well. Alan's your guy for a front anti roll bar - he can also do you a rear one (they don't have one as standard at the rear). Alan will also get shocks made up for whatever valving you want depending on your choice of springs, or go to AVO's or check Ebay for 2nd hand Koni Classics (now out of production). Note the front shock is difficult cos it works upside down because of the strange front suspension design (ie gets longer as the front goes down). You might want to convert the front lower mountings to a Nylock instead of the split pin and washer arrangement as well.
I've not yet had the opportunity to measure standard steels to calculate the offset - presumably you have some, why not measure your own? And let us know too!!! My impression is that they are set further into the arch than my optimised Vitesse wheels, so you might finish up with a rubbing problem on the side of the boot floor? Certainly I wouldn't want to go above 195's on the standard rim section irrespective of rubbing issues. To keep the same diameter that would need 195/75 X 14's. The P6 has another trick up its sleeve when calculating clearances at the back. Don't forget that with the de dion the rear track changes depending on ride height, so as you go over a bump the track gets momentarily wider, if you jack the car up it gets narrower.
If you need to, pm me and I'll let you have my phone no for a chat.
Regards
Chris