Fidgety Handling - E89 35iS

[Zcott]

Morning all

I’ve noticed that our 35is is a little bit ‘fidgety’ on the road.

The previous owner has gone up a tyre size front and back -

235 / 35 / 19

and

265 / 30 / 19

Both non run-flats.

Could this be the cause, or are the larger widths a tried-and-tested mod on the 35iS?

Cheers

 

[Brian H]

HI @Zcott,

What tread depth do you have left on the tyres? I have noticed on other models when the tyres are getting to the end of their life they can cause the characteristics you mention.

Brian

 

[Zcott]

Hi Brian

The fronts are only about 30% worn - the rears are barely scrubbed in.

 

[Brian H]

OK, just a thought....

Different topic, did your car have a cherrished plate on when new starting? S1 xxx

 

[Zcott]

I'm not sure Brian - I never saw the HPI report.

 

[Redline]

Next is to adjust tyre pressures a little. Many run at slightly different pressure than recommended.

Are the larger tyres on the standard rims?
Any spacers fitted?

What tyres are they?
The tread pattern or the rubber itself combined with tyre pressure can induce tramlining when you touch while lines.
The suspension on the E89 is quite brutal - I find Sports mode rides better.

 

[Zcott]

Thanks Redline.

The fronts are Michelin Pilot Super Sports. Only a year old and a couple of K miles.
The rears are brand new 'Ditchfinders' that the dealer fitted at minimal cost.

The wheels are 19" M Double-Spoke Style 326 (8" and 9" widths). The rim widths are suitable for the larger width tyres.

The existing cheapo-rears will be getting binned and replaced with Michelin Pilot Sport's asap. I wanted to check if the move up to 235 / 265 widths was a common choice amongst owners before deciding on whether to keep the fronts and just buy new rears, or replace all four (with new 225 / 255 widths).

 

[Redline]

Have pilot sport 4 on my E85 and well pleased with them.

Don’t think the additional 10mm should be the cause of your problems. The cheaper tyres on the rear might cause problems at speed or if driven enthusiastically. Their construction is likely to be quite different to the Pilot SUper Sports.

Have you had anyone look under the car just to make sure nothing is amiss? Incorrect wheel alignment too is worth checking.

SWMBO has Bridgestone Potenza RFT on her E89 but they are standard 225/255s. No problems with those.

 

[Zcott]

Cheers Redline.

I was thinking along the same lines myself.

I’ll order a pair of Michelin SuperSports or PS4’s for the rear in a 265 and see how I get on.

A geometry check will be next on the cards if I still think it’s wandering slightly.

TBH, it’s not worryingly fidgety - it could of course just be me getting used to the new car.

 

[Brian H]

Thanks Redline.

The fronts are Michelin Pilot Super Sports. Only a year old and a couple of K miles.
The rears are brand new 'Ditchfinders' that the dealer fitted at minimal cost.

The wheels are 19" M Double-Spoke Style 326 (8" and 9" widths). The rim widths are suitable for the larger width tyres.

The existing cheapo-rears will be getting binned and replaced with Michelin Pilot Sport's asap. I wanted to check if the move up to 235 / 265 widths was a common choice amongst owners before deciding on whether to keep the fronts and just buy new rears, or replace all four (with new 225 / 255 widths).

I think your proble lies with the ditchfinders, I cannot see the minimal small extra width giving issue.

 

[John Thompson]

Morning all

I’ve noticed that our 35is is a little bit ‘fidgety’ on the road.

The previous owner has gone up a tyre size front and back -

235 / 35 / 19

and

265 / 30 / 19

Both non run-flats.

Could this be the cause, or are the larger widths a tried-and-tested mod on the 35iS?

Cheers

Hey,

I use the same size on my 35i but are Bridgestone Potenza run flats, although the ride is quite tiring the car is planted and runs like it's on rails.so I wouldn't thought it is down to your tyres.
Very nice looking car though, I'm terribly envious

 

[Twin Turbo]

You can look at tracking, I had 0 toe - made it twitchy at the front but provided a more positive feel into turn into corners. (not the greatest drive on the motorway - as I had to correct the car more frequently)

I also had a maximum camber to make the rear more stable -

And some coilovers helped

But depends what your looking to achieve - a GT Car or B road monster

Different requirements = different solutions

 

[Twin Turbo]

TBH I rate MP 4's over MPSS - the MP4's are a great all-rounder.

For some reason, mt MPSS are always screaming

 

[Zcott]

Thanks guys.

Figured if I'm spending £420 on 2 rears, then I may as well just spend £720 and get 4 brand new boots. Will flog the 235/35/19's Michelin Super Sports on eBay. They have 6-7mm of tread, so might get a reasonable-ish price for them.

So, Michelin Pilot Sport 4 S's on order... in the recommended 19" widths of 225 / 255.

 

[Redline]

Thanks guys.

Figured if I'm spending £420 on 2 rears, then I may as well just spend £720 and get 4 brand new boots. Will flog the 235/35/19's Michelin Super Sports on eBay. They have 6-7mm of tread, so might get a reasonable-ish price for them.

So, Michelin Pilot Sport 4 S's on order... in the recommended 19" widths of 225 / 255.

I hope you're impressed with them when you get them or it's

 

[Zcott]

They'll do the job.

Every review I've read has said they are an improvement over the SS. They suggest that the only area where the SS had a (slight) edge, was on a dry racetrack. I don't do many miles on dry racetracks!

 

[Zcott]

Good Michelin PSS v PS4S review here...

 

[Dino D]

Can I please be first in line to help you send the ditchfinders up in smoke (and check that LSD is all ok)?

Probably won’t take more than a few secs with that engine though!

 

[Zcott]

Lol... there will be no ceremonial burn-out (as knowing my luck I'd set the back of the car on fire!).

 

[Dino D]

Ill being a fire extinguisher....and marshmallow.
No charge, all part of the service