I’m looking for technical help or recommendations on: __suspension setup
Hi all
Our Eunos has some aftermarket coilovers fitted (unsure of the brand - first pic). They work fine with some F1 rims and uniroyal rain tyres (2nd pic)
However, I recently purchase some rims with track tyres that have a larger offset than the F1s (3rd pic). Fitting to the car there is serious tyre rub whenever we hit a bump. I’ve increased the height of the coilovers but still on larger bumps we get rub, which I’m thinking could be dangerous at high speed.
Question then - has anyone upgraded the springs on an existing aftermarket coilovers setup? I’m wondering if this would solve our problem (as the car won’t bounce so much). Would prefer to do this over ‘rolling the arches’ as we’d lose the classic look of the car.
I’m by no means an expert but have dabbled with many cars in my time.
You’d be better off buying coilovers with adjustable damping and specc’ed springs. (Unless these are adjustable) youl find most setups the spring and shock are matched and adding stiffer springs to a damper will give an undamped ride feel and lots of horrid bounce.
The car doesn’t seem low enough to encounter tyre rub, those coils must be very soft? Are the wheels spaced away from the strut/ arch correctly etc? Lots of possibilities here!
I agree with what is said above, first step, what are the specs for wheels and tyres that didnt rub and what are the ones that do? It may be advisable to raise the coilovers again while you work this out (unless you dont use it much) and stiffen it up too . I wouldnt consider any other change to the coilovers such as changing the springs though myself.
If your change has pushed the wheels further out then rolling the arches could fix it but if the problem is moving the tyres inboard then it wont help. It think it was a flyin miata YT video where they described rolling the arches as rolling the inner wing lip up (so no visual change to the car) and pulling the arches as taking this further once you have rolled the lip to give maximum clearance. I did this to my MR2 and it was really not obvious though and it only affects the top of the arch and a few inches either side.
If the problem is with the wheel sitting out too far, you may see a small line around the tyre where the rubber has been cut slightly by whatever it is catching. It may only be happening at one end so you may have to take all 4 wheels off if you cannot identify where is it rubbing from the outside,
Generally, the widest rim is 7" with max 28 offset using a 195 50 15"
The 205’s you have there run the risk of pulling the arch at the front with steering lock on. (The R888 was generally wide too)
Because you will have extra grip the car has the potential to roll more in corners. Stiffening and even raising the car to make them work with no body mods is going to make the car so stiff you won’t like it and will struggle on B roads as bumps will be trying to throw you in the ditch.
The tyres and wheels that don’t rub are F1 ultralights 15x8 with tyres 195/50 15.
The ones that do are on 15X9 with 195/50 on the front and 205/50 on the rear.
Just taking the latter on a test drive sees cuts into the tyres as they are obviously sticking out an extra inch (the offsets appear similar) and at the back are that bit wider and taller with the larger tyre.
Although I really like the ultralights, and they are indeed, ultralight, the gold rims do look amazing on the car though regardless of the rubbing issue maybe too sticky for the road.
I think I’ll leave spring adjustments until I’ve had a go on a track (this Sunday at brands hatch open pit). I might consider rolling the arches at some stage - any recommendations for someone to do that in the West Essex / NE London area?
I think the rolling arches idea is a good one. Possibly the most elegant solution as retains the classic look but accommodates the bigger wheels. I shall you tube it, thanks
Had neg camber already. And yes, should have checked the rim size do’h. Unfortunately made an assumption that since the tyre sizes were the same, that the rims would also be. They weren’t.
Yes my thoughts exactly - maybe the coils are very soft. The ride is abit bouncy, not harsh at all, which is nice for cruising but not so good for a track day. I’m thinking that stiffer springs would stop the tyres hitting the rims.
9" wide rims will slow down all but the most powerful MX5s and will remove some nimbleness from the handling.
195 tyres on 9" rims are nearly 1.5" narrower than the rims. Please don’t take your car on track with that set up.
Coilovers have the spring rates matched to the dampers. Adding stiffer springs may cause a mis-match.
Negative camber might tuck the tops of the tyres into the wheelarches at the cost of extra tyre wear.
As mentioned, the best solution is to have wheels and tyres that fit. Someone who tracks a 300hp car will want to buy the 9s from you.
For what it’s worth, the NB2 which I use for coaching on track days has a choice of 15x6s with 195/50s or 16x6.5s with 205/45s. Both sets are more than enough tyre for MX5 power and we always have a lot of fun using them.
Then again, my previous race car with a lot more than standard power used 15x9s with R888s in 225/45. Because it was also my daily driver and was crashy on those I tried a set of 15x8s with AD08s in 205/50. The car became more comfortable and quieter on the road and more precise on track, without losing any pace.
Thanks for the pointers. You clearly have some experience, which I don’t! Hence posting here in the first place.
We are tracking at brands on Sunday with 15x8 F1s and standard road tyres (195/50/15), and ‘sport’ suspension set pretty low. ‘Sport’ not ‘track’ because it’s ride-height adjustable but no damper variable settings. First proper go on a track in it so we shall see how that goes.
It’s just for fun and if I’m honest the wider wheels were an aesthetic choice more than anything else.
You’re welcome. Yes, I coach people who want to get up to track day speeds or to move up from there to racing, both with safety and fun very much at the forefront.
Enjoy Brands. Do 10 minute sessions to start off with so you get used to all the stuff you have to do when you arrive at a bend. Remember to keep your hands at a quarter to three on the wheel and to maximise your vision around and across and beyond corners to give yourself time to think through what you need to do.
Maybe build up to 15 minute sessions but bear in mind that road tyres will build up heat after that amount of time once you’ve started finding some pace.
This is probs the best guide to the track. Scott Mansell is my hero. I watch his guide as a reminder the day before I go to any track: https://www.youtube.com/watch?v=JhFVqTskao4
Dave, as with many non UK “instructors” what matters is not what oil you put in the car or however great you were in Australia. Telling people they can take out track day insurance does not cover you or your customer if the worst happens. If a wheel falls off your car and the insuing incident puts you client in a wheelchair for life, who supports their young family? Even if your car drops oil, the car or cars go off and someone is killed, or even just results in their £40k PCP car being written off? You are selling a service and that takes you out of "just being on a Trackday, you now have liability. Where on your website does it say how much liability insurance you have? £10 million is usual. No TDO wants the risk of uninsured “professionals”, or does not fully understand their liability, and until you hold the relevant UK recognised licences, that is how the law will see you.
