Adjusting ride height for track day

[a.jenkin]

Evening All,

I have been adjusting my suspension this evening in preparation for combe trackday on the 24th.

I have H&R coilover suspension on my 172 which is set quite low

Its quite noticeable when I go out for a "fun" drive that there's scrubbing when cornering hard.

I don't know how low exactly the suspension is currently set so before I started, the way I measured it was that there was 25mm of thread left for height increase on the shock. Using this method I raised the height by 10mm, leaving 15mm left of thread.

Wheels back on and out for a test drive... no noticeable difference the car feels slightly more bouncy but cornering seems just as bad (or maybe worse?) than before..

So, need some advice from you good people! Have I adjusted it wrong? I assume to raise the height you de-compress the spring allowing more height. Are coilovers naturally lower than normal suspension on their maximum height?


Adam

 

[The Boosh!]

What offset are your wheels?

Are they cup turinis or are they trophy ones?

 

[a.jenkin]

Im not sure, I think when I bought it last year it said trophy ones on the advert.

 

[The Boosh!]

Could be why. Since yours is a 172 the 'correct' (although the trophy offset isn't wrong) would be the 172 cup offset. The Trophy turinis are the 'correct' offset for the 182.

I may be completely wrong here so don't take what I say as gospel, but it could be the reason behind it

 

[a.jenkin]

Hmm, that kinda makes sense, I've always thought that the front wheels look further inside the arch than maybe they should.. Hopefully someone can confirm the offset differences

 

[CHRIS172CUP]

Let them rub the arches away then they won't rub anymore. No point raising them up it's a pain in the arse.

Just cut the bumper mount off and you'll be fine. Mine is set low and it doesn't rub at all anymore.

 

[.Kev.]

Had mine set silly low and you can see marks on the drive shaft and on the inner chasis leg. (caused by hard right handers and it being too low) Ive raised it now, 90mm from the bottom thread on my FK's, drives much better.

Ive also used the camber adjustment slots to dial in -1 degree of camber. Handled realy well at Snetterton yesterday. Still trying to get the set up right though.

 

[a.jenkin]

thanks guys - not sure about just letting them rub the arches away! raising the suspension was fairly straight forward. I will probs raise it by another 5-7mm and see if it makes any more difference.

I think as the spring is extended further, there is more travel/bounce in the spring which is why it seems just as bad/worse than before.

Would still appreciate some advice on the offset differences between Trophy/cup turinis.

 

[rich-6]

The spring doesnt change in length the more you wind it up or down, It just brings the damper shaft out the body! AFAIK the more you raise it the more comfy it should become ie softer.

Odd how yours scrubs though I have 37 offset OZs on my 182 on H&Rs wound as low as poss on the back and the front to match the stance, Doesnt scrub at all cornering, I was told it should scrub its nackers off! Admittedly it does catch when travelling with some pace down some uneven country roads but only when it gets rough on the straights

I was under the impression around 43 was the offset for 172s so it shouldnt catch if they are trophy wheels unless it is the bumper bracket in which case it can be bent up or cut off!

My advice would be to take a wheel off and look for teh ET mark which wil give us more idea what wheels they are

 

[drhowser]

I'm not sure about the offset or scrubbing issue, but does the op realise that changing the ride height will have an effect on the other settings, ie. camber, castor etc?

I seem to remember that the standard 172 wheels are et 46, but I also ran 37's.
They were fine with 45 profile tyres, but rubbed on the rear with 50's

On et 43 I can comfortably run 205/50/15 track tyres with chunky shoulders and have no rubbing issues at all.

 

[a.jenkin]

ok, bit of an update - not a great one

on the way back from wk today my gf hit a bump in the rd.. scrub scrub ( as usual ) however there after the passenger side is scrubbing on the smallest of bumps.. this is the result ..

The metal bumper mount has bent down and over.. im surprised they tyre didnt puncture.. obviously this is a pain in the arse and i need to get it sorted asap!

so im not sure what todo height wise now.. leave as is, or put it back to as it was before. here are some more pics of the shock and side-shoot.. i dont think this is stupidly low, but cant believe the problems im having..

 

[Bluebeard]

How soft has it been set?

It looks quite low, and if its low AND soft, you will encounter a s**t load of problems!

Where in Bristol are you?

 

[a.jenkin]

Temple Quay.. i set it higher by 10mm last week but i think its just made it softer :/

 

[Bluebeard]

If all you've done is adjust the height, then that won't affect the damping.

Put it up another 10mm and set the dampers a bit harder. Should cure it.

 

[drhowser]

that doesn't look good!

is the wheel as close to the strut as it looks in that picture too?
have you had a good look around all the mounting points, whishbones, etc, too?

definately pop through to daniel, he'll have a good look over it for you i'm sure.

 

[Bluebeard]

that doesn't look good!

is the wheel as close to the strut as it looks in that picture too?
have you had a good look around all the mounting points, whishbones, etc, too?

definately pop through to daniel, he'll have a good look over it for you i'm sure.

I never mentioned anything!!

I'm driving past temple quay tomorrow actually.....

 

[a.jenkin]

They are only height adjustable, not damping.. Im not a coilover expert but think they have become softer because the spring is now less compressed by 10mm. I'm assuming this is the correct way to raise the height with coilovers?

 

[drhowser]

sorry dude,

I thought that was why you were asking, knowing you to be pretty helpfull and all

do you not think that tyre and wheel looks close to the shock in the picture?

 

[Bluebeard]

^^ LOL! I was only messing. I'll help anyone if I can. And yes, that shock/tyre arrangement looks a bit squiffy to me!

If thy're not damping adjustable, you cannot make them softer. Not possible! lol.

The higher you make it, the MORE compressed the spring will be.

Are you sure you've not lowered it more????

 

[a.jenkin]

In the pic the wheel is on full lock, but it does look close :/ offset problem as they are thophy turinis maybe??

What time u passing temple quay! appreciate if you could take a look if your around.

 

[drhowser]

They are only height adjustable, not damping.. Im not a coilover expert but think they have become softer because the spring is now less compressed by 10mm. I'm assuming this is the correct way to raise the height with coilovers?

no. the spring is compressed exactly the same amount. only the platform has moved.

it is possible to run into problems at the other end of the adjustment, where the spring is being compressed between the platform and the top mount.
but here the spring is just resting on the platform with the weight of the car holding it down.

 

[Bluebeard]

Is Temple quay by the SS great Britain?

I'm going to Backwell at about 10am and will be coming back through at about 11am.

Failing that, I work in Coalpit heath and will be there 1pm-530pm tomorrow afternoon.

 

[drhowser]

^^ LOL! I was only messing. I'll help anyone if I can. And yes, that shock/tyre arrangement looks a bit squiffy to me!

If thy're not damping adjustable, you cannot make them softer. Not possible! lol.

The higher you make it, the MORE compressed the spring will be.

Are you sure you've not lowered it more????

b**ch.....

 

[Inferno]

Ouch! Been there, done that my friend. Looks worse than it really is.

 

[a.jenkin]

s**t!... its just clicked how this now works.. so to raise the suspension the bottom platform should move up the shock, not down like I have done it..

So the way I measured it was 25mm of thread left under the platform before I started, I adjusted that down to 15mm.

What I should of done to raise it was raise the platform so 35mm of thread is left beneath the platform.

If this is the case, i feel like a right noob

 

[drhowser]

that's it.

i've just been looking at some pictures of mine and others cars. you are definately loooow at the moment

 

[a.jenkin]

ffs! I wish someone picked that up on my first post when I explained my method!

Anyway, I understand now

So its my imagination that it feels more bouncy, I understand now that its impossible

So, i've got some repairs and adjusting to do before combe on sat!

Big thanks drhowser! :clap:

 

[drhowser]

welcome fella.

if you are going to track it, i would get the geometry checked too, just for peace of mind.
it wouldn't need to be far out to kill your tyres pretty quickly!

it could well feel more bouncy because of the suspension changes, the most efficient height would have the wishbones parallel to each other. i imagine yours are pointing towards the ground in the centre of the car at the moment?

 

[Tony Hunter]

I hate it when people mess around with things like this,it;s just not worth it.
a.jenkin I'm not having a go but it's not easy as it seems,as said before it changes every thing not just height.
Please get it set then get it all set up and checked and leave it alone.

 

[The Boosh!]

Agree with Tony. I raised mine by a couple of turns and it fucked the handling. Changes all sorts raising/lowering it (toe/caster/camber iirc?). Defo get it re-set up.

 

[Soot1e]

The spring compression on a racetrack corner is going to more than on a road corner, how ever fast you can can corner on a road, the suspension is going to be working harder on the track. I would raise the ride height by an extra 10mm. on what you would think is suitable for the road. You don't want to be having problems during your session/s on track. Beware of Avon Rise and Quarry corner if your set up is too low, or you'll end up in the armco.

 

[a.jenkin]

Thanks guys, I know that ive f**ked this up good and proper.. and now have time against me for getting this right for saturday. I know that before I adjusted it everything was setup professionally by the prev owner, however this for me was still to low and scrubs when when I corner hard on normal roads. That's why before combe I wanted to get it raised so I did'nt have any problems. my fault for not doing it sooner.

I think the best chance of getting this right for going on track is to set it back to as it was.

Go out, take it steady and hope for the best.

Then take it somewhere, get it raised and all adjusted properly.

 

[Tony Hunter]

Good boy

 

[drhowser]

you'll have fun at combe anyway!

have you driven there before?

 

[a.jenkin]

Loads of times as a passenger, first time driving! Im quite nervous, but looking forward to it

 

[Tony Hunter]

It will be my first time at Coombe as well,never been there before,should fun,but we are only there for testing.
See you there,we are on a trade stand by the cafe.

 

[drhowser]

you're there too Tony?

bugger, I'll be working as normal...

I'm keen to see the burpscud in action as well..


a.jenkin, if you've been as a passenger I think you should have a pretty good idea of your way round.

looks like decent weather too

 

[Bluebeard]

Combe is frigging awesome. Just awesome.

 

[Slammed172]

do you not think that tyre and wheel looks close to the shock in the picture?

They always run that close if your low and have camber, as long as they don't touch then its fine.

Most people don't run that low so their adjuster is more in line with above the top of the tyre rather than lower down.