No quite so planted

L

Leesfarm07

Senior member
 Telford, Shropshire
I recently changed my RFT's for Michelin pilot sport 3's (255/35 and 225/40) and was amazed by the difference....However it suddenly doesn't feel quite so planted on uneven roads. I've checked the tyre pressures and all seem okay (unless my gauge is a bit crap) but it feels a little like the wheels are moving around by themselves. What are the most common bushes that wear that might give this 'floating' slightly 'disconnected' feel and does higher or lower pressures in the tyres help....any info appreciated :thumbsup:
 
Rear trailing arm bushes and front rear wishbone bushes (these would be my fist port of call) :)
 
What pressure are you using? Only reason I ask is that generally the pressure shown in the door is for RTFs and not Non RFTs
 
rft,s are well known for tracking ruts on there own, mine are terrible both on my x3 and z4 .
 
I had both those things replaced with poly items and still wasn't 100% happy. I then replaced the droplinks and ARB bushes and only now am I happy with how it handles and drives.

The feeling the op gets is similar to how mine was. Very floaty and almost as if the wheels had a mind of their own.
 
hopz121 said:
Rear trailing arm bushes and front rear wishbone bushes (these would be my fist port of call) :)
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Cheers :thumbsup: would you go OE or opt for these polybush thingies
Angie4m said:
What pressure are you using? Only reason I ask is that generally the pressure shown in the door is for RTFs and not Non RFTs
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I never thought of that...I just went with the door pressures...wonder what everyone on non RFT's is running at
 
ben g said:
I had both those things replaced with poly items and still wasn't 100% happy. I then replaced the droplinks and ARB bushes and only now am I happy with how it handles and drives.

The feeling the op gets is similar to how mine was. Very floaty and almost as if the wheels had a mind of their own.
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That's exactly it...as if the wheels are a little loose and are pulling left and right all by themselves
 
I find my Zed is very sensitive to tyre pressures. With Goodyear Eagle F1s I use 32 front and 34 rear (staggered set)

Experiment a little as others prefer their own settings and I find a couple of psi each way makes a difference.
 
I recently changed my pressures to non run flat rear 36 front 33 much better on conti 5's. Great grip and slightly softer ride.
 
There's a huge number of old postings on recommended tyre pressures, when changing from RFT to non RF, on this forum. Having read through most posts when I changed to non RFT, it appears that the majority verdict is to reduce the fronts to 31-33 psi (2.1-2.3 bar) and the rears to 32-34 psi (2.2-2.4 bar) but always with more pressure in the rears. Having said that, I also suffered the type of handling the OP complains of and it really ruined the driving experience. I changed and renewed absolutely everything I could, wishbones and bushes, RTAB and limiter shims, drop links and ARB's. I fitted new Bilstein B8 shocks and new top mounts front and back and a genuine BMW front strut brace. The car is now much better but not quite as securely planted as I would like when on my summer18 wheels and tyres 225/40 front and 255/35 rear. With my winter 17" (all 225/45) it is definitely more stable and planted. My very experienced indy (Andy at Walkers) advised me that he has seen this many times over the years. It appears that some E85's are just not happy on bigger wheels and wider tyres! There was an industry report some years back that concluded that the E85 suffered a form of rear wheel steer (particularly when RTAB's were worn) that spoiled the handling, apparently this is more noticeable with wider tyres on the rear.

It keeps us sufferers concentrating hard when driving at speed though doesn't it, the German autobahns are a real bum clencher north of 100mph!
 
paulgs1000 said:
I find my Zed is very sensitive to tyre pressures. With Goodyear Eagle F1s I use 32 front and 34 rear (staggered set)

Experiment a little as others prefer their own settings and I find a couple of psi each way makes a difference.
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I think I'll buy a decent gauge if they're that sensitive. I was working off my foot pump gauge which is a bit old school I know.
Midhurstman said:
There's a huge number of old postings on recommended tyre pressures, when changing from RFT to non RF, on this forum. Having read through most posts when I changed to non RFT, it appears that the majority verdict is to reduce the fronts to 31-33 psi (2.1-2.3 bar) and the rears to 32-34 psi (2.2-2.4 bar) but always with more pressure in the rears. Having said that, I also suffered the type of handling the OP complains of and it really ruined the driving experience. I changed and renewed absolutely everything I could, wishbones and bushes, RTAB and limiter shims, drop links and ARB's. I fitted new Bilstein B8 shocks and new top mounts front and back and a genuine BMW front strut brace. The car is now much better but not quite as securely planted as I would like when on my summer18 wheels and tyres 225/40 front and 255/35 rear. With my winter 17" (all 225/45) it is definitely more stable and planted. My very experienced indy (Andy at Walkers) advised me that he has seen this many times over the years. It appears that some E85's are just not happy on bigger wheels and wider tyres! There was an industry report some years back that concluded that the E85 suffered a form of rear wheel steer (particularly when RTAB's were worn) that spoiled the handling, apparently this is more noticeable with wider tyres on the rear.

It keeps us sufferers concentrating hard when driving at speed though doesn't it, the German autobahns are a real bum clencher north of 100mph!
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Looks like I could end up tinkering with everything as you did. I'll start with the basics. I had it hunter aligned when it was on RFT's but whether it needs doing again perhaps now I'm on normal rubber.
 
How many miles have you done ? Fixing the pressures will help a lot, but 3-400 miles scrubbing in will too.

I wouldn't have expected a 'sudden' change with new tyres if your RTABs or other bushes were on the way out.
 
Bing said:
How many miles have you done ? Fixing the pressures will help a lot, but 3-400 miles scrubbing in will too.

I wouldn't have expected a 'sudden' change with new tyres if your RTABs or other bushes were on the way out.
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Hi Bing. I've prob done maybe 1000 miles or so on the new tyres. My partner was using it and commented she didn't like driving it as it was wandering over the bumps. I drove it again and agreed it didn't feel right. I'm beginning to wonder if maybe she's hit a pothole or something and knocked the tracking out slightly. The tyres aren't showing any sign of uneven wear though. It did seem a bit sudden. The other thing I had was the puncture warning light come on which prompted me to check the pressures. Seem to remember they were 32 all round
 
Hmmm. If it's not been done recently it might be a good idea to have an alignment done... Though changing tyres shouldn't require it done again. 1000 miles is more than enough to scrub them in. I guess the other thing is wheel balance - maybe some weights have fallen off ?

Start with pressures though - only 20p to change them :D
 
Try M settings when you have an alignment done too, i found this helped loads with my car and now it drives great.

The M has less Rear camber than an M sport or SE car so feels more planted on high speed corners etc.

I replaced my bushes with Poly itmes and have never looked back the car drives great on them, i have changed the shocks and springs on my car too which made a big difference, but this wasnt a cheap option :)

I run 33 Psi Front and 36 Psi Rear with my car on Goodyears
 
+1 on the pressures, if you drive past a sainsburys petrol station just call in - free air! Or just pay the 20p elsewhere I try and check mine every couple of weeks and found that on 17's fronts at 32psi rears at 35psi and it gets rid off all the tram-lining. Definately worth checking and a little bit of experimenting using a digital pressure gauge on a petrol station forecourt before you start spending money on bushes you may not need
 
hopz121 said:
Try M settings when you have an alignment done too, i found this helped loads with my car and now it drives great.

The M has less Rear camber than an M sport or SE car so feels more planted on high speed corners etc.

I replaced my bushes with Poly itmes and have never looked back the car drives great on them, i have changed the shocks and springs on my car too which made a big difference, but this wasnt a cheap option :)

I run 33 Psi Front and 36 Psi Rear with my car on Goodyears
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I wondered that when I sent it the first time. Although it's not an M it has the M wheels which are a different offset to the 108's. I'll have a chat with the Hunter guy and see what he did it on last time
 
yer i have to say, my alignment was out, and before you could go into corners tap accelerater and rear was wanting to step out

since the hunter alignment last week, it hasnt done that since , even with been more heavy footed in the rain
 
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