The twitchy front end - help me solve it
Discussion
As the title says, the front end still isn't 100%.
On main roads it's pretty ok but it's the back roads that are pissing me right off.
I wasn't sure if I was just being too fussy but, since I got the chance to drive alinton s Cerb and it felt like a "normal" car, I know there's something that needs to be changed / adjusted / fixed / etc.
I've got 16" Spiders and the tyres on it are Marshall (they came as a new spare set with the car), but it was similar with the Avons that came on the car.
So far I've done the following
New springs (all round, they were needed as the originals were knackered. Supplied by Trackcar)
Checked everything to make sure nothing is loose / worn (nothing found)
Got it tracked, etc (as per settings I got off here and which are now posted on page 6 of the "equivalent parts" thread, but I'm open to correction on these)
Set the damping on my AVO shocks to three "clicks" from stiffest setting
Changed the power steering fluid (and plan to do it again as this was the single biggest improvement to the front of the car)
Oiled and greased the steering column where it is sleeved going through the bulkhead and just below the steering wheel
Oiled and greased the UJ's on the steering column (in the car, I didn't take them out as they were seriously tight on the splines)
Adjusted tyre pressures up and down (running at 27psi at the moment as this is the pressure the car seems to work best at)
So folks if you lot can throw suggestions at me I'm happy to try them, even if it seems like it's something I've tried already, as I may have missed something or done something wrong.
On main roads it's pretty ok but it's the back roads that are pissing me right off.
I wasn't sure if I was just being too fussy but, since I got the chance to drive alinton s Cerb and it felt like a "normal" car, I know there's something that needs to be changed / adjusted / fixed / etc.
I've got 16" Spiders and the tyres on it are Marshall (they came as a new spare set with the car), but it was similar with the Avons that came on the car.
So far I've done the following
New springs (all round, they were needed as the originals were knackered. Supplied by Trackcar)
Checked everything to make sure nothing is loose / worn (nothing found)
Got it tracked, etc (as per settings I got off here and which are now posted on page 6 of the "equivalent parts" thread, but I'm open to correction on these)
Set the damping on my AVO shocks to three "clicks" from stiffest setting
Changed the power steering fluid (and plan to do it again as this was the single biggest improvement to the front of the car)
Oiled and greased the steering column where it is sleeved going through the bulkhead and just below the steering wheel
Oiled and greased the UJ's on the steering column (in the car, I didn't take them out as they were seriously tight on the splines)
Adjusted tyre pressures up and down (running at 27psi at the moment as this is the pressure the car seems to work best at)
So folks if you lot can throw suggestions at me I'm happy to try them, even if it seems like it's something I've tried already, as I may have missed something or done something wrong.
simonsparrow said:
Mine used to be very twitchy on S03 Bridgestones, but had been fine on Goodyear F1s, both 16" and 17", so maybe the tyres? Could you swap wheels with your friend for an afternoon to see if that makes the difference, then at least you'd know if you're on the right track. 
That's one I hadn't thought of doing.
That'll be put on the list, thanks.
Any more suggestions / ideas folks?
I'd suggest dropping the tyre pressure, as 27 is too high. That will make is dance a little at the front. Same with the suspension, soften her up a little.
Other than that get rtid of the budget tyres and have the tracking adjusted by 0.5 degrees towards toe in until it feels more stable.
Other than that get rtid of the budget tyres and have the tracking adjusted by 0.5 degrees towards toe in until it feels more stable.
ridds said:
I'd suggest dropping the tyre pressure, as 27 is too high. That will make is dance a little at the front. Same with the suspension, soften her up a little.
Other than that get rtid of the budget tyres and have the tracking adjusted by 0.5 degrees towards toe in until it feels more stable.
Other than that get rtid of the budget tyres and have the tracking adjusted by 0.5 degrees towards toe in until it feels more stable.
I run 24psi all round.
ridds said:
I'd suggest dropping the tyre pressure, as 27 is too high. That will make is dance a little at the front. Same with the suspension, soften her up a little.
I had the tyre pressures lower, down as far as 20psi at one stage, to try it out and it's been happiest at 27 so that was why I left it there. I'll try dropping it again.
I'll try softening the suspension this evening.
How firm should it be (if I push down on the wing of the car should I get much movement in the suspension)?
ridds said:
Other than that get rtid of the budget tyres and have the tracking adjusted by 0.5 degrees towards toe in until it feels more stable.
Are those tyres really that bad?
It's not a make I'm familiar with, they were brand new and came with the car so I just fitted them.
As for the tracking, do you mean to adjust it a bit, go for a drive, adjust it again, drive again, etc?
The last time I got it set up there was a big improvement in the handling at the front as soon as I drove it out so I left it at that.
Ireland said:
How firm should it be (if I push down on the wing of the car should I get much movement in the suspension)?
Play about?
Try nine clicks or more from hardest and see how it feels...
I'd definately look at getting some well respected (by cerbera owner) tyres too, never heard of either avons or the other brand on a Cerb - and cant honestly think why you'd want budget tyres when decent toyo's/goodyears and the like are reasonable on mytyres.co.uk, especially when you consider they keep your 360bhp sportscar and more importantly yourself on the black stuff.
When you replaced the springs did you notice if theride hieght was adjustable with a scewed collar on the shock? If they are maybe your ride hieght is too low, this not only makes the car likeley to ground out on rough roads, but alters the camber of the wheel (how upright the wheel is to the road) and so reduce the contact patch of the tyre. The trouble is I don't know how high the ride hight should be as standard. As far as I know Marshall tyres are a cheap tyre make, I'm on toyos and they seem ok.
Ireland said:
Looks like I'm going to have a bit of work to do.
Any more ..... ?
I cant help but feel this is part of the fun of the car, if I drove ours more I'd probably start playing about with the settings too.
Let us know how it feels at different click settings - I'd be interested to hear the results. I should think a much softer front will help the car feel alot less nervous.
edit: The budget tyres could always become quite entertaining given a trip to an airfield or something, we've got a set of very very old S-02's which are probably too hard to be worth fitting to the car now, but everytime I look at them in the shed I think of sliding the Cerb about at Brunters.
Who knows, perhaps the owner did know something and they actually suit the car better than we're giving them credit? Sorry if I sounded a bit quick to dismiss them.
Edited by BCA on Thursday 5th April 12:41
BCA said:
Who knows, perhaps the owner did know something and they actually suit the car better than we're giving them credit?
I actually don't think he did know much about it, no did he use it much.
It had only done a couple of hundred miles in the previous six months.
The first day I went to see it he wouldn't bring it out until the road was bone dry, and it had rained a light shower about half an hour before hand.
I'm surprised that someone so fussy put cheap tyres on it.
BCA said:
Sorry if I sounded a bit quick to dismiss them.
Don't worry about it, I'll still sleep tonight.
Right, it's time for the first update .....
The first thing I did before I even went near the car was went out and bought a decent tyre-pumping head for the air line and it turns out my old one was a mile off.
I set the pressures at 22psi (front) and 24psi (rear) as per the manual.
Then I had a look to see if the ride height can come up much more, and it can't.
The ride height is adjustable, but if I go any further the springs will become coil-bound.
I'd like to raise it a slight bit as there is evidence of a small amount of rubbing on the RHS wheel arch, and this could cause twitching.
I may end up changing the front springs again at some stage.
I reckon I pissed my neighbours off big time tonight will all my spins up and down the road trying out different things.
After all my messing about, the one thing that gave the biggest improvement was when I softened the damping right off on the front shocks.
I'm not sure how many "clicks" from full they are at now (I can check another day and report on that) but there has been a big improvement by doing it.
I will need to do some more to it in order to get it fully sorted, but I'm well impressed with how much it's improved after tonight's messing about in the garage.
So if there are any more suggestions, lets have them.
The first thing I did before I even went near the car was went out and bought a decent tyre-pumping head for the air line and it turns out my old one was a mile off.
I set the pressures at 22psi (front) and 24psi (rear) as per the manual.
Then I had a look to see if the ride height can come up much more, and it can't.
The ride height is adjustable, but if I go any further the springs will become coil-bound.
I'd like to raise it a slight bit as there is evidence of a small amount of rubbing on the RHS wheel arch, and this could cause twitching.
I may end up changing the front springs again at some stage.
I reckon I pissed my neighbours off big time tonight will all my spins up and down the road trying out different things.
After all my messing about, the one thing that gave the biggest improvement was when I softened the damping right off on the front shocks.
I'm not sure how many "clicks" from full they are at now (I can check another day and report on that) but there has been a big improvement by doing it.
I will need to do some more to it in order to get it fully sorted, but I'm well impressed with how much it's improved after tonight's messing about in the garage.
So if there are any more suggestions, lets have them.
Ireland said:
Right, it's time for the first update .....
After all my messing about, the one thing that gave the biggest improvement was when I softened the damping right off on the front shocks.
I'm not sure how many "clicks" from full they are at now (I can check another day and report on that) but there has been a big improvement by doing it.
I will need to do some more to it in order to get it fully sorted, but I'm well impressed with how much it's improved after tonight's messing about in the garage.
So if there are any more suggestions, lets have them.
After all my messing about, the one thing that gave the biggest improvement was when I softened the damping right off on the front shocks.
I'm not sure how many "clicks" from full they are at now (I can check another day and report on that) but there has been a big improvement by doing it.
I will need to do some more to it in order to get it fully sorted, but I'm well impressed with how much it's improved after tonight's messing about in the garage.
So if there are any more suggestions, lets have them.
Excellent, I wouldnt fiddle with changing springs just yet if the dampers have yielded such improvements that quickly. As for the rears rubbing slightly, I wouldnt be too concerned, though there is nothing to stop you stiffening up the rear dampers just a tad...
I'd also pump the fronts to 24, we tend to run ours with the same pressure all round and it feels pretty good.
How many clicks are you from the stiffest setting now? Keep updating with your progress, I like these kind of posts.
I got very little done tonight as I'd just pulled the car over the pit when the electricity went off and I didn't fancy trying to balance a torch on my shoulder while I worked on the car.
I did get to check the settings on the front shocks and they are currently at 10 "clicks" from the SOFTEST setting.
I've left the back shocks and springs alone for now as it doesn't bottom out any more, and it is pretty steady since I fitted my "custom" drop-links last week.
I did set the tyre pressures the same all round, but at 25psi not 24psi.
That'll be an easy one to adjust next day if I want.
I did also find a small amount of movement in the inner mounting / pivot-point of the lower RHS arm so I need to investigate that more as well.
It may just be a missing shim (washer ?), rather than wear, as the movement appears to be only along the length of the bolt and not in all directions.
That's as far as I got before the lights in the pit went out, so it gave me an excuse to go driving and I have to say the front is now about 70% better than it was last week.
I purposely picked roads that I knew hadn't been Cerb-friendly for me in the past, and it was way better tonight than when I drove there before.
I actually felt a lot more confident in the car when I was driving with one hand on the wheel and the other on the gearstick, that it would stay pointed the direction I wanted it to point.
I'd confidently say that the single biggest improvement came from softening the front damping quiet a bit.
I'm not planning to do anything to the car over the long weekend, other than drive it, so if there are any more helpful suggestions keep them coming and they may be tried next week.
I did get to check the settings on the front shocks and they are currently at 10 "clicks" from the SOFTEST setting.
I've left the back shocks and springs alone for now as it doesn't bottom out any more, and it is pretty steady since I fitted my "custom" drop-links last week.
I did set the tyre pressures the same all round, but at 25psi not 24psi.
That'll be an easy one to adjust next day if I want.
I did also find a small amount of movement in the inner mounting / pivot-point of the lower RHS arm so I need to investigate that more as well.
It may just be a missing shim (washer ?), rather than wear, as the movement appears to be only along the length of the bolt and not in all directions.
That's as far as I got before the lights in the pit went out, so it gave me an excuse to go driving and I have to say the front is now about 70% better than it was last week.
I purposely picked roads that I knew hadn't been Cerb-friendly for me in the past, and it was way better tonight than when I drove there before.
I actually felt a lot more confident in the car when I was driving with one hand on the wheel and the other on the gearstick, that it would stay pointed the direction I wanted it to point.
I'd confidently say that the single biggest improvement came from softening the front damping quiet a bit.
I'm not planning to do anything to the car over the long weekend, other than drive it, so if there are any more helpful suggestions keep them coming and they may be tried next week.
Something else to check is the condition of the lower arm bushes ( get in there with a crow bar and give the arm a tweak) and make sure the anti-roll bars are free to move in their bushes and linkages.
also I found re-fitting the front spoiler helped a little bit at high speed ( had to make it first mind)
Finally recheck the front and rear toe and camber and this makes a BIG difference on how they handle bumps
Matt
also I found re-fitting the front spoiler helped a little bit at high speed ( had to make it first mind)
Finally recheck the front and rear toe and camber and this makes a BIG difference on how they handle bumps
Matt
Today, a friend of mine who is a Chassis and steering boffin, suggested taking out the top adjuster on the rack (as my steering felt stiffer when at 90 degrees each way.) and inspecting the bar for lube, it was dry as a bone. we lubed it by packing with grease, and it is 100 percent better a real improvement. This bar also has the teeth meshing at the bottom as well as sliding. Try that if you havent already!
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