Tyres rolling over, stiffer suspension needed?

[JB21]

Off topic slightly but one for the guru's. Recently fitted a rear cage, an old MSV one which bolts into the front and rear seat belt points, now on my first track day after fitting I had noticeably more oversteer. At first I thought it was down to a slippery damp Oulton and worn R888s but after a search it seems in fitting the cage this has stiffened the chassis, leading to more oversteer, this sound about right?

If so how can I combat this without spending money on coilovers, RARB maybe or rear camber shims?

 

[Dr Fox]

Or an Ignis....

If I bought an ignis I'd then need to buy coilovers, a turbo conversion and a dif before pulling everything off it, not quite the simple fix I was hoping for but it would be fun until a traffic cone wrote it off...

Thanks to @harvsurrey for the suggestions:

New cup shocks - good shout as one was replaced 4 years ago and might not be a proper cup one as the tyre was catching on the OSR under load.
Standard springs - do you mean stick with existing ones or replace with new standsard springs?
Rear arb - I'll look into these
Adjust front camber to -2.5 - the most the guy doing the alignment could get was -1.5 using the camber bolts, what else do I need to achieve more?
A touch of toe out maybe 10 mins total - I'll see if I can dig out the print out to see what it was set to

30psi hot on the tyres - I had been at this but might need to try a little higher if the above doesn't improve the rolling over, thanks for the help!

Off topic slightly but one for the guru's. Recently fitted a rear cage, an old MSV one which bolts into the front and rear seat belt points, now on my first track day after fitting I had noticeably more oversteer. At first I thought it was down to a slippery damp Oulton and worn R888s but after a search it seems in fitting the cage this has stiffened the chassis, leading to more oversteer, this sound about right?

If so how can I combat this without spending money on coilovers, RARB maybe or rear camber shims?

I think a rear arb would make it even more oversteery?

 

[JB21]

Yep, looks that way, maybe some rear camber will help. It's more fun anyway.

 

[SWL16]

Interesting read, I have a similar problem with mine, except I run PS3s. So when I wear the outside edges I actually end up ripping up the rubber blocks.

I replaced my suspension with all new cup shocks and eibach pro-kit springs and the wear seems to have started again. I wonder if the negative camber might help...

Only trouble is I do 10k a year on the road. Any idea of the impact wear wise?

 

[Dr Fox]

Hmm, maybe springs won't help me out then... Do you run a rear anti roll bar?

I've been looking at the rear dampers and think it might be worth replacing them with cup dampers...

 

[STEVE.M]

34 psi cold, you on drugs! They'll be at 40+ psi before you know it.

Au contraire.
Starting with standard pressures, and then reducing them when hot, would seem a more intelligent option to starting with 22 cold and hoping you don`t damage the carcass of the tyre before it reaches 30.
In true Cliosport style, people bang out their mantra without considering the question, or the tyres in question, road (PS3) or designated track day (888) or even if it`s FWD or RWD.

If running something like PS3 or T1R, higher pressures for track use are recommended over road use, and it`s best to start from vehicle manufacturers recommendations from cold.

Exhibit 1.
http://catdrivertraining.co.uk/tyre-pressures-track-days-a-quick-guide/

Alternatively, though I suspect it is a RWD (911) based thread, the concept of playing with pressures to influence understeer/ oversteer, goes further than the average CS brain can manage, deserves consideration.

Exhibit 2.
http://www.trackdayguru.com/tyre-management.html

Anyway. I`m all out of hot air now.

 

[JB21]

TLDR

 

[JamesBryan]

Au contraire.
Starting with standard pressures, and then reducing them when hot, would seem a more intelligent option to starting with 22 cold and hoping you don`t damage the carcass of the tyre before it reaches 30.
In true Cliosport style, people bang out their mantra without considering the question, or the tyres in question, road (PS3) or designated track day (888) or even if it`s FWD or RWD.

If running something like PS3 or T1R, higher pressures for track use are recommended over road use, and it`s best to start from vehicle manufacturers recommendations from cold.

Exhibit 1.
http://catdrivertraining.co.uk/tyre-pressures-track-days-a-quick-guide/

Alternatively, though I suspect it is a RWD (911) based thread, the concept of playing with pressures to influence understeer/ oversteer, goes further than the average CS brain can manage, deserves consideration.

Exhibit 2.
http://www.trackdayguru.com/tyre-management.html

Anyway. I`m all out of hot air now.

I agree, but he's not using T1r or PS3's it's R888.

Starting with 22 psi would also be bad you're right. I'd suggest 27 cold to end up with about 33 hot.

 

[...]

Au contraire.
Starting with standard pressures, and then reducing them when hot, would seem a more intelligent option to starting with 22 cold and hoping you don`t damage the carcass of the tyre before it reaches 30.
In true Cliosport style, people bang out their mantra without considering the question, or the tyres in question, road (PS3) or designated track day (888) or even if it`s FWD or RWD.

If running something like PS3 or T1R, higher pressures for track use are recommended over road use, and it`s best to start from vehicle manufacturers recommendations from cold.

Exhibit 1.
http://catdrivertraining.co.uk/tyre-pressures-track-days-a-quick-guide/

Alternatively, though I suspect it is a RWD (911) based thread, the concept of playing with pressures to influence understeer/ oversteer, goes further than the average CS brain can manage, deserves consideration.

Exhibit 2.
http://www.trackdayguru.com/tyre-management.html

Anyway. I`m all out of hot air now.

I don't overly agree with the opinion on road tyres , heat in the compound needs to be managed and over inflation with increase heat on a smaller contact patch which in turn overheats the rubber and overheated rubber turns to jelly

Run a set of wets/ inters on a drying track and see what happens.

Motorsport derived tyres have a different construction , sidewalls are stiffer and carcase construction is different to a road tyre.

Rubber compounds and depth are such to retain an amount of heat more consistently

You would then use pressures to manage a tyre temp and normally you will find a pressure will only rise 2 to 3 psi over a given time unless you use extreme cold temps (thus inducing reduced contact patches due to over inflation)

Most Motorsport tyres will run happily at very low pressures due to stiff sidewalls and will gain temp if the ambient track temp is already high.

You never work back from a high starting temp , as heat generated induces a pressure increase , more you manage a small pressure rise and actually look for an even optimum temp across the tyre .

It's actually not rocket science , however suspension and how it behaves starts to change what you see , you would then look to see what they read across the tyre to understand what's having the effect.

Managing oversteer and understeer with pressures is a brutal way to treat a tyre and comes with drawbacks as it will only work in a short time window usually



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[Dr Fox]

Just to keep the thread updated, I've changed the rear dampers and it turns out that they were both pattern parts and both knackered... I replaced them with OEM cup shocks and hoping this improves things, I'll see if it helps on track along with a higher starting pressure and see how I get on before deciding on the rear arb.

 

[...]

find out the optimum pressure , and work to that end of , get start pressures out of your head , its the hot running temp/pressure thats really important .
Once you know this you can work out how long you can run for and how hard before they tip over this ,
then either back off for a lap or come in and take a break.
rear anti roll bar will help , and if i was you if the rears are fresh i'd stick on fresh fronts .


the trouble with setting up cars is the change to the rear will likely have an effect on the front , so what you want is a base starting point .

4 fresh shocks and 4 fresh tyres really is the way to start as hard as that might be to hear , you have no idea how often people chase a problem that is due to stuff not being right ..... the other terrible thing is chasing the track ......... green tarmac is horrid and as it evolves so does handling and it happens most days as temps change .........

get those fronts swapped , and get a full geo done , then tell us what its doing .

 

[Sam Linssner]

I'm running R888R's on a set of 15's on my 182 with standard cup suspension. During a track day on Friday, I noticed that I seem to be wearing the sidewall slightly. I run the tyres at 30psi hot so I don't think it's because the pressure is too low?

I'm wondering whether it's because the standard cup suspension is too soft for the tyres and whether something stiffer might help? I don't care about 'lows' and don't want a cheap nasty set of coilovers so I'm looking at the Cooksport springs, do you think a set of these would help?

Has anyone else come across this issue?

View attachment 184434
View attachment 184435

Mine do that. Sure it isn't a mixture of heat and kerbs? (I run 30psi hot with coilovers and camber)

 

[CamMoreRon]

Off topic slightly but one for the guru's. Recently fitted a rear cage, an old MSV one which bolts into the front and rear seat belt points, now on my first track day after fitting I had noticeably more oversteer. At first I thought it was down to a slippery damp Oulton and worn R888s but after a search it seems in fitting the cage this has stiffened the chassis, leading to more oversteer, this sound about right?

If so how can I combat this without spending money on coilovers, RARB maybe or rear camber shims?

Yes that's absolutely what's happening.. your chassis is basically a big spring linking the front and rear axles together, so if you change the stiffness of that spring (i.e. by fitting a very stiff frame inside it) you're going to change the handling of the car.

In basic terms what's happened is your stiffened chassis is transferring more torque (as in from the body rolling) to the rear axle, so you're getting more load transfer there and less grip.

Rear camber shims will probably be your cheapest option, as they'll help the tyres cope a bit better with the extra load. Other than that, you're down to changing springs / ARB.

 

[CamMoreRon]

I'm running R888R's on a set of 15's on my 182 with standard cup suspension. During a track day on Friday, I noticed that I seem to be wearing the sidewall slightly. I run the tyres at 30psi hot so I don't think it's because the pressure is too low?

I'm wondering whether it's because the standard cup suspension is too soft for the tyres and whether something stiffer might help? I don't care about 'lows' and don't want a cheap nasty set of coilovers so I'm looking at the Cooksport springs, do you think a set of these would help?

Looking at this pic I'd say that your tyre wear problem is entirely down to soft suspension and too much body roll.

Sorry I can't recommend a cheap fix but I think you're going to end up chasing your tail if you try anything other than stiffer springs & dampers. Maybe a rear ARB will be your cheapest option, but if you like the handling of your car as it is then I'd avoid that as it'll change it noticeably.

ETA: Stiffer springs will of course change the handling too, but if you buy them as a full car set they'll generally provide a more balanced increase in stiffness than adding an ARB will.

 

[Dr Fox]

find out the optimum pressure , and work to that end of , get start pressures out of your head , its the hot running temp/pressure thats really important .
Once you know this you can work out how long you can run for and how hard before they tip over this ,
then either back off for a lap or come in and take a break.
rear anti roll bar will help , and if i was you if the rears are fresh i'd stick on fresh fronts .


the trouble with setting up cars is the change to the rear will likely have an effect on the front , so what you want is a base starting point .

4 fresh shocks and 4 fresh tyres really is the way to start as hard as that might be to hear , you have no idea how often people chase a problem that is due to stuff not being right ..... the other terrible thing is chasing the track ......... green tarmac is horrid and as it evolves so does handling and it happens most days as temps change .........

get those fronts swapped , and get a full geo done , then tell us what its doing .

The fronts look to be in a lot better condition and I had a full geo set up done less than a year ago when the camber bolts were fitted so I'm reluctant to replace them with standard dampers and have this done again. I'm thinking I'll see how I get on with the new rears and higher pressures and if no better, replace the front dampers and fit cooksport springs at the same time before getting the geo done again.

I'm happy with the hot grip at 30psi but when cooled, they were down to about 20psi. I think this is partly why they've worn as they have so that's why I'm curious to know what pressure difference others see between cold and hot pressures. Perhaps I'm being too enthusiastic and overdriving them...

Mine do that. Sure it isn't a mixture of heat and kerbs? (I run 30psi hot with coilovers and camber)

Quite possibly... I aim for the same, do you know roughly what they drop down to cold?

 

[Sam Linssner]

The fronts look to be in a lot better condition and I had a full geo set up done less than a year ago when the camber bolts were fitted so I'm reluctant to replace them with standard dampers and have this done again. I'm thinking I'll see how I get on with the new rears and higher pressures and if no better, replace the front dampers and fit cooksport springs at the same time before getting the geo done again.

I'm happy with the hot grip at 30psi but when cooled, they were down to about 20psi. I think this is partly why they've worn as they have so that's why I'm curious to know what pressure difference others see between cold and hot pressures. Perhaps I'm being too enthusiastic and overdriving them...



Quite possibly... I aim for the same, do you know roughly what they drop down to cold?

24/25psi I think. Maybe less. Rears never really used to get that hot.

 

[...]

The 30psi dropping to 20 does not sound right

I would expect a 2 to 4 psi increase on a tyre like an 888

10 psi is akin to a tyre not designed for track work with large amounts of tread movement the 888 is a track tyre

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