Suspension tech question!

[MARK A]

I've been playing around with the ride height on my 172 for a while now and I'm still not 100% sure if the relationship between fr and rr is perfect. Having seen 'Performance French car' had an article about ride height I went and bought the mag today. Having read the article they helpfully concluded that whatever they did made no difference:S There's me thinking there may be some decent advice on ride and set-up

I have two questions. Firstly, what height are ppl running fr and rear on their coilies at the moment and what would be 'recommended'?? Having spoken to a few decent rally prep companies back in my Pug days I was told to run the car pretty level and the only reason for having a raised rear ride height as stock was to account for rear passengers. On the flip-side, I was also told that having the rear slightly higher than the front aids handling (something to do with weight transfer) and improves steering feel. Is this true? I'm currently running the rears 300mm from the centre of the wheel to the arch and 318mm at the front. Even though the rear arch is closer the car still sits nose down! Here's a pic:

Secondly, in the PFC article they sited the rear springs as being a problem. This was due to them becoming coil-bound over bumps. I understand the downsides to this and having looked at my springs, some of the coils are touching when just the cars' load is on them! There is space between a number of the coils but not all of them. Is this the norm on a lowering spring (I remember the apexs that came on the car looking the same) or is it a problem? Any advice would be wicked

 

[Ex-User (19928)]

Yep, should have the rear higher than the front.

Rear is obviously made to account for luggage and passengers, but then again, they don't expect you to demand handling whilst ferrying people about. It's made the height it is at stock for a balance between feedback, grip and ride comfort.

Also, the harder you make your suspension, the less forgiving it will be when you're on a undulating road.

 

[MARK A]

So whats the optimum for handling??

 

[Ex-User (19928)]

lol.

Don't have a 172 on coilovers so couldn't tell you.

It's personal preference, though some setups will be favoured over others in general. Trial and error or just have someone do it for you (Mark Fish/GDI/YS etc).

 

[MARK A]

Was gonna get it set up by a pro but I'm getting married in a few weeks and money is a bit tight at the mo! I'm sure that they must consider a certain balance between front and rear to be optimal! It will go and have a full set-up after the wedding but I just wanted to get the best out of it for now! I guess it also depends on spring weight and damper settings too!

 

[Gaz_]

these are the rears off H&R's (borrowed pic)

as you can see even these are coilbound at the top, but are better than the gaz units i've seen.....

how do the apex look?

 

[Andy_J]

Ma FK's are pretty badly coilbound at the back.. dont have a photo tho.

 

[CHRISK172+]

I have FK's on my 172 with Koni adjustable socks. From what I could tell at the rear, the spring has to be this short to get the range of adjustment that coilovers offer, otherwise theres no point to them. They are only adjustable in height. The fronts compress the spring when lowering. Most coilovers will go low enough to rub the arches so you need to be careful how low. Some will tell you to rip your liners out. Mine is set pretty level around 600mm from ground to arch, maybe front looks a liitle lower as the sill points down at the front, only just tho. May still lower the front upto another 10mm. Have my Koni shocks set on softest. The ride is still more than firm enough and is a little unsettled on bumpy roads. I would only consider paying for setup if trackin it, which I won't be.

 

[Gaz_]

Alot of guys on here (me included) have their cars too low for a 'good' set up. I reakon the max you should be going is 30mm from standard ride height..

 

[Dan_cup]

Alot of guys on here (me included) have their cars too low for a 'good' set up. I reakon the max you should be going is 30mm from standard ride height..

think your rite there, im in the same boat running too low but its a comprimise.

my car is a sure footed on an uneven back road now but its gonna be expected when it 50 -60mm lower than it was.

 

[Gaz_]

What a r****d, i meant reckon lol. I think mine is fine on A roads, but can become a wee bit lairy on the bumpy B road stuff. If i raised it it would be alot better imo with more suspension travel etc.

 

[MARK A]

What a r****d, i meant reckon lol. I think mine is fine on A roads, but can become a wee bit lairy on the bumpy B road stuff. If i raised it it would be alot better imo with more suspension travel etc.

Does the suspension travel increase when you raise the car on coil-overs? I thought the spring stayed the same length? I know what you mean about the bumpy b-roads. Mines perfectly fine but would probably struggle to keep up with a standard car on the really lumpy stuff!

 

[Gaz_]

hmmmm not sure, but there is more piston length (way hey )to dampen the force if it is raised, so more travel in the damper rod/piston = better damping properties?

 

[Fred@BTM]

theres a few tricks with coilovers

 

[Gaz_]

do tell
also what was yours running when the guy from PGTI (or who ever) said it was one of the best he'd driven? Billies?

mine also sits about this high.... low but not slammed

 

[Fred@BTM]

yeah our own Bilstein kit

can't tell everything, then i would make no money!

 

[Gaz_]

ahh well worth a try lol!!!!

i'd imagine alot of it is height dependant, with how it behaves on the bumpy stuff tbh

 

[Fred@BTM]

H&R's its just a simple ride height setup, camber setup and toe adjust

 

[MARK A]

H&R's its just a simple ride height setup, camber setup and toe adjust

Can you adjust the fk's for me fred?? If so, I reckon I may have to bite the bullet and come and see you

 

[Fred@BTM]

of we can course, speak to middo if you need a reference

 

[MARK A]

of we can course, speak to middo if you need a reference

 

[izibizi]

after many trial and error I found that raising the front gives much better handling on my 172 with H&R's
now its 3cm higher on the front (measured from wheel arch) which gives me more caster and just enough travel, thinking of getting even higher
rear end is wound down completely and OE bumpstops are shortened to half of their lenght to equal bump and rebound travel (now the rear beam can travel 6cm up and 6cm down)
hope any of this helps

 

[Ali]

IF motorsport spent hrs settin mine up...Then told me they were shite! LOL

Ah well chin up.

Mine's running .6deg toe in, 1.2deg -Camber. All RS shims to the hubs.

Height is sensible now as i looked a t**t going round car parks with it scubbin!

 

[Fred@BTM]

of we can course, speak to middo if you need a reference

god must've been pissed when i wrote that LOL!!!

 

[Middo]

of we can course, speak to middo if you need a reference

lol!

did a top notch job. highly highly recommended. That do you fred

 

[MARK A]

after many trial and error I found that raising the front gives much better handling on my 172 with H&R's
now its 3cm higher on the front (measured from wheel arch)

This seems to run very 'front up' too

 

[Gaz_]

standard trophy (one of the best 'out the box' handling cars )

looks shocking, but the forward rake is very pronounced, who are we to argue?

 

[MARK A]

standard trophy (one of the best 'out the box' handling cars )

looks shocking, but the forward rake is very pronounced, who are we to argue?

My god!!!!!! What a shocker!! That looks bloody terrible! It has to be the ultimate 172/182 though:S It's strange how it sit so different to the cup racer 197!

 

[Gaz_]

cup racer is a track car though, nice smooth surfaces

 

[Fred@BTM]

i set my cars so the sills are perfectly parrallel to the floor

 

[Gaz_]

Must be something in the way the trophy sits, for renault to adjust its stance to the above though?

mine sits like this, (old pic mind) I tried to keep the natural rake towards the front

 

[MARK A]

Wired stuff! Skipp Brown (pug rally guys) told me to set my 106 and 306 Rallyes so the sills were level with the floor too Fred (using their Billie dampers and custom springs!). I've been playing with the set-up on my coillies all day today aswell. I've ended up raising the front height about 25mm (so the car sits much more level) and the difference has been very very interesting. The car no longer feels compromised by the lumpy stuff and handles my local 'test tracks' much more like my old 182 cup but without the roll that used to occur. It really is a lot better (than the previous set-up on my 172). The car sits pretty level now with the front arch noticably higher bit the lower sill still slightly lower at the front. I was really suprised that it made any difference. I wonder why the Trophy is so high at the back? It defo handles well as stock! What would a 'level' Trophy handle like though I wonder???????

 

[MARK A]

i set my cars so the sills are perfectly parrallel to the floor

Like this!!!

So why the 'trophy tilt' ?? Is the Trophy still a compromise ?? Designed for rear passengers?? Has anyboy dared to 'meddle' with a Trophy's suspension??? Could it be better??

 

[Fred@BTM]

of course it can be better, needs to be about 80mm lower! LOL

 

[MARK A]

of course it can be better, needs to be about 80mm lower! LOL

 

[Gaz_]

yeah, i know skip browns, they are about 10mins form my house!!!!

 

[MARK A]

yeah, i know skip browns, they are about 10mins form my house!!!!

They seem like a really genuine bunch of guys and are certainly well reguarded! They subscribe to the 'level with the floor' theory like Fred. I've made mine much more level now and the car is way better. I don't know if it's purely down to the increase in front ride height allowing the car to cope with the rough stuff or the 'level/balance' of the of the car that's done it. Either way I'm a lot happier. I think the car was just too low before. I guess that even though the spring length/stroke doesn't alter, there's now more damper stroke for the given spring stroke. This is maybe controlling things more too.

Here she is now:

I think she could still come up on the front a bit but I'm a little wary about loosing some steering feel. I think I'll come up another 10-20mm and see what it's like

 

[Middo]

looks spot on!

 

[Andy_J]

lower it all by 10mm now and your jammin!

 

[CHRIS172CUP]

this is how i got the H&R's lower at the back. both adjuster nuts underneath the spring platform.

p.s. Mark, that looks really good. I want mine even lower at the back.