Non runflats and poor handling.

DoctorDee · Post by **DoctorDee** » Thu Jun 19, 2014 1:17 pm

I got a puncture on my rear tyres on my 2012 Z4 2.0.

Read around on here and decided to replace both rears with Goodyears Eagle F1s.
These are not RunFlats, but are meant to be amongst the best conventional tyres.

The ride has improved with the suspension now far less crashy on the pretty crappy roads around my home, but the handling is much worse.
The back end feels wallowy, and the traction/stability control light comes on often during bends - it had never flashed in 15 months of often enthusiastic driving before the new tyres.

Anyone experienced anything similar. Got any suggestions?

Dr z4 00 · Post by **Dr z4 00** » Thu Jun 19, 2014 1:32 pm

Hi, have you checked tyre pressures and had the wheel bolts re torqued? Could be low!!

DoctorDee · Post by **DoctorDee** » Thu Jun 19, 2014 1:44 pm

Yeah, I thought it might be that, but naively assumed that since they were professionally fitted - they'd have put the right pressure in.
But given how comfy the rear end feels, I guess under-pressure is probably the problem.

Another look around here tells me that people don't run conventional tyres at the same pressures as runflats.
Anyone got any good suggested pressures for Eagle F1s on the rear?

DR-Z · Post by **DR-Z** » Thu Jun 19, 2014 2:15 pm

Have you still got runflats on the front? Changing these will make the biggest difference.

hopz121 · Post by **hopz121** » Thu Jun 19, 2014 6:00 pm

DR-Z wrote:Have you still got runflats on the front? Changing these will make the biggest difference.

+1 if so thats what your problem is, i would never mix run flats with non run flats, they have totally different handling properties as insurance may be invalidated.

Also i have found when changing to non run flats increasing the pressures helps.

Another thing to bear in mind is that new tyres take a while to bed in due to the release agents in the rubber.

Garvin · Post by **Garvin** » Thu Jun 19, 2014 6:47 pm

In all my (very) long driving career and countless numbers of changed tyres I think I can count on the fingers of one hand with a couple to fingers to spare the number of times a 'professional' fitter has put the correct pressure in a tyre. Coupled with the fact that there are probably no published tables for pressures in non run flat tyres for these cars, I can confidently predict that the pressures are not optimal.

The Goodyear Eagle F1s are reported to have softish sidewalls and coupled with low pressure will almost certainly make the back end feel wallowy. I would see what pressure is in the tyres at the moment and increase by 10psi to start with and go from there - it will be a bit trial and error until they feel OK.

However, that may be easier said than done with run flats still on the front which will cause some 'imbalance' in handling twixt front and rear.

Keithark · Post by **Keithark** » Thu Jun 19, 2014 7:22 pm

I had a terrible experience with run flats on the front a F1's on the rear, they DO NOT mix, change them ASAP,mine was leathal running this combo!(35i)
Hope this helps

Keithark · Post by **Keithark** » Thu Jun 19, 2014 7:28 pm

Just to add I now have eagle F1 all round and could not be happier, fantastic ride and handling .
Highly recomended
40psi rear 38 front,is what I use and for me it's great.

New2Zed · Post by **New2Zed** » Thu Jun 19, 2014 7:36 pm

That's one busy six hours.
Can't wait to get my run flats off but they've only done 750 miles.
Why BMW why?

flybobbie · Post by **flybobbie** » Thu Jun 19, 2014 10:27 pm

I have Eagles on my 17 inch. good tyres. They last about 20k miles. 38 front and 40-42 rear seems ok I had a bit of slippage and traction light on, on gritty roads until I changed the rear dampers. Also a bit of judder when pulling away, cured with the new dampers.

DoctorDee · Post by **DoctorDee** » Fri Jun 20, 2014 6:27 am

Thanks for the advice everyone.

Eagles for the front on order!
More air going in to the rears as soon as I get a chance this morning!

SmartTOP ordered - what next?

Bad_Pritt · Post by **Bad_Pritt** » Fri Jun 20, 2014 6:59 am

DoctorDee wrote:
SmartTOP ordered - what next?

You're asking a dangerous question: http://www.z4-forum.com/forum/viewtopic.php?f=2&t=43545

DoctorDee · Post by **DoctorDee** » Thu Jul 17, 2014 4:59 pm

OK, after a nightmare of a time when I had the RunFlats up front and traditional rubber at the back (the Stability/Traction Control light was on CONSTANTLY) I now have Eagle F1s all round and I cannot believe the improvement.

Better ride, same handling. Wasn't cheap, when all I really needed was a single replacement tyre, but it was worth it!

hopz121 · Post by **hopz121** » Fri Jul 18, 2014 10:08 am

DoctorDee wrote:OK, after a nightmare of a time when I had the RunFlats up front and traditional rubber at the back (the Stability/Traction Control light was on CONSTANTLY) I now have Eagle F1s all round and I cannot believe the improvement.

Better ride, same handling. Wasn't cheap, when all I really needed was a single replacement tyre, but it was worth it!

Glad you got it sorted,

Just goes to show how mixing tyres isnt a good idea and does affect the cars handling.

lux · Post by **lux** » Fri Jul 18, 2014 10:29 am

Do you have to let your insurance company know if you change to non run flats?

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