tramlining

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DaveZ4C

Member
Anyone got any tips/advice for best way to stop the Z4 from tramlining?

The car seems very skittish and doesn't inspire confidence on country roads. I think the electonic steering might be a little oversensitive.

I've driven sports cars (Audi TT, 350Z, S2000) and reasonably quick cars (Type-R, GTi, etc) on these roads before, but didn't see this problem in any of these. I'm used to driving quickly and confidently on road and track (police-trained rather than hooligan), but I don't have the same confidence with the Z4.

Is there anything I can do to steering, tyres, suspension, etc? Or is it something that you just get used to with the Z4?

Dave
 
1) Tires: Main reason why cars tramline. Harder sidewalls induce more tramlining. Symmetrical tread patterns induce more tramlining. STICKY rubber induces tramlining. On the Z4 you get 2 out of 3, hard sidewalls and sticky tires.

2) Alignment: Negative camber up front induces tramlining. Zero toe or slight toe-out induce tramlining. Z4 set up with a lot of negative camber up front (-.9 I think is the factory spec, I could be wrong, it's off the top of my head...Max camber without shorter springs or camber plates is -1.7~1.9), plus zero toe or slight toe-in. If your alignment specs are set to have some negative camber and zero toe or slight toe out, correcting both will reduce tramlining.

Unfortunately, everything that goes to reduce tramlining also reduces overall grip. Obviously tires, especially with run-flats and the super stiff sidewalls, will have the biggest effect on tramlining. If it doesn't lessen or nearly go completely away after swapping for non-runflats, then adjust the suspension setting accordingly (dial out negative camber and toe-in a little).
 
Thanks Hack. Very useful. You seem to know your stuff.

I guess the obvious differences between other sports cars I've driven and the Z4C 3.0 are (1) the RF tyres with harder sidewalls and (2) the electronic steering. As you say the alignment can contribute to tramlining, although I'm guessing it shouln't be a major factor in the difference between the Z4 and other sports cars I've driven.

Can you/anyone recommend a good non-RF tyre - with good balance of road grip, durability and cost.

You didn't mention the electronic steering - is this something I can/should do anything about? Does the Sport button help the problem or make it worse. In the MC didn't they ditch the electronic steering for better handling? Is it something you simply get used to?
 
Lose the runflat tires. THE best upgrade you can do for your car, trust me. They are the root of ALL evil, including tramlining. BMW really screwed its customers by forcing runflats with no option for a "real" tire.

In a few years, the technology will likely improve and they'll become more commonplace. But right now, they're NOT ready for primetime.
 
Michelin Pilot Sport PS2 made a huge difference on eliminating the tramlining for my '07 Coupe with the Sports Package. The OEM 050A RFTs bordered on being dangerous for how badly they would dive into pavement grooves and cling to steering lines you didn't initiate at the steering wheel.
 
Love my RFT's but they do tramline some. Not so bad that I'm willing to change over though. Been hashing around the idea forever and I'm sticking to them. I will be buying some after the first of the year, if they last that long :rofl: ! Gotta wait for taxes - just had a major disaster in my house. If anyone has any or knows anyone who does/will, please let me know. I don't mind if they've seen some asphalt, I'm hell on them anyway :evil:
 
fire-n-ice said:
Love my RFT's but they do tramline some. Not so bad that I'm willing to change over though. Been hashing around the idea forever and I'm sticking to them. I will be buying some after the first of the year, if they last that long :rofl: ! Gotta wait for taxes - just had a major disaster in my house. If anyone has any or knows anyone who does/will, please let me know. I don't mind if they've seen some asphalt, I'm hell on them anyway :evil:
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You would think there'd be lots of them around.... with so many swapping them out.

BTW sorry to hear about the house issues..... not too bad I hope!!
 
Service mechanic here said two lbs difference in air pressure in the tires will cause this problem also not to mention low air pressure.
 
rc'Z said:
Service mechanic here said two lbs difference in air pressure in the tires will cause this problem also not to mention low air pressure.
Click to expand...

Are you saying that the problem will be reduced if I increase (or decrease?) the tyre pressure or simply make sure they're identical left/right/all round?
 
I'll second the vote for the Michelin PS2's. Easily the best thing I ever did to my car ... handling, ride quality, and noise all improved.

And, with the weight savings of non-RFTs, you can afford to carry a tire repair kit or small air compressor :wink:
 
Damn where you been beaker? Yea, I'm one of the few who doesn't mind the RFT's so much. I know changing out would give me a little better ride, but I truly don't mind them. Never bitched about them really. I like bumpy rides! :D
 
UK question. I've been looking on the internet for best place to buy non-RFT tyres for the Z4C 3.0 and it's a bit of a mine-field.

Any recomendations on best place to buy good road tyres (not track or super-sticky) for the Z4C without paying an arm and a leg?

And can most tyre-fitters be trusted to fit these without damaging the rims?

Dave
 
Why o why do BMW persevere with RFT's on the sportier models and versions of their cars. Maybe an option at purchase would be the way to go. At least with the Z4M they ditched them.

I too have advanced driver training and taught it for a while too. My 2.5 with M suspension, 17" wheels and runflats was dreadful for tramlining and as a consequence I rarely drove it in the 1st lane on motorways due to the grooves left by the HGV's made it see-saw about. Really qquite a dissapointment for a car like the Z4. I did find increasing the 30F and 33R pressures by a couple a psi did help but couldn't understand why! In hot weather (annual Provence trip) it seemed to be better and I put that down to hot tyres being a little more flexible. If you read various forums changing to normal tyres transforms the cars. Obviously you'll need the M mobility kit or similar. BMW's own driver training programme based in Munich and the 'ring use Michelin Pilot Sports on non M Z4's and popular choices are Goodyear F1's (they did well in a detailed EVO roadtest - see November 07 UK issue) and Pirelli P Zero Rosso's. All three are variously fitted to big marque sports cars as standard. Expensive but worth it.

I now drive a Z4M and I was struck with how unaffected by tramlining and compliant the suspension is and the marked increase in grip with the standard Conti tyres. Again if you read the forums they are nowhere near as good as the above tyres so I'm doing my best to wear them out!
 
DaveZ4C said:
UK question. I've been looking on the internet for best place to buy non-RFT tyres for the Z4C 3.0 and it's a bit of a mine-field.

Any recomendations on best place to buy good road tyres (not track or super-sticky) for the Z4C without paying an arm and a leg?

And can most tyre-fitters be trusted to fit these without damaging the rims?

Dave
Click to expand...


I used to use 'my tyres' and 'black circles' have good reputation too. As for fitting, my local ATS will fit new tyres (not secondhand ones for leagal reasons) with no problems and my BMW dealer swopped worn for nearly new RFT's (just before I traded it in!) for £7 ea IIRC. I would use BMW as RFT's are hard to remove and BMW have all the kit.
 
Thanks Ian in Lancs - Extremely helpful replies.

I'll try your suggestion of a few psi more in the tyres and then change to Michelin, Goodyear or Pirellis when it's time to change them. It does say a lot when BMW training themselves ditch the RFTs for the Michelins!! I'll have a look at the two tyre dealers you mention - thanks for that.

You added "Obviously you'll need the M mobility kit or similar" - I've no idea what this is. Will I need this when I change to normal tyres?

Dave
 
M Mobility kit - just found it with a quick search - BMW puncture repair kit for non-RFTs since the Z4 doesn't have a spare.

:thumbsup:
 
DaveZ4C said:
"Obviously you'll need the M mobility kit or similar" - I've no idea what this is. Will I need this when I change to normal tyres?

Dave
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As you'll not have a spare you'll be stuffed when you have a puncture. The M mobility kit is a can of puncture sealant and a 12v compressor to reflate the tyre(s). You can of course source them wherever but BMW package them as the 'M mobility kit' for M3's and Z4M's. Take a look in the boot of a Z4M. You'll see them on top of the battery box. The alternative is a space saver but then you'll need a spanner and jack. Better to pump goo in the tyre and some air and drive somewhere to sort it out properly. Hence M mobility kit.
 
DaveZ4C said:
rc'Z said:
Service mechanic here said two lbs difference in air pressure in the tires will cause this problem also not to mention low air pressure.
Click to expand...

Are you saying that the problem will be reduced if I increase (or decrease?) the tyre pressure or simply make sure they're identical left/right/all round?
Click to expand...

Sorry for the delayed response, both front tires have to be the same, both rear tires have to be the same. There was two lbs difference in the front and he said that was part of my pulling problem. All four tires were too low. He set the front at 32 and the rears at 35. I believe for the SI with sport suspension, they should be 33 and 38. He seemed to imply that these cars are sensitive to air pressure. The car now seems to track better and dance less than it did.

Sears also sells the flat tire/mobility kit, Slime and a 12 volt compressor, about $39 if I remember, pretty cheap next to most kits and Slime has been on the market for many a year.
 
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