FiestaMk7.com Owners Resource

Got an S1600 on the standard 17s and on anything other than completely flat, snooker table-smooth roads (yes, in Britain, I know!), the car's just so nervous. The slightest road imperfection will pull the car off line, sometimes with a surprising amount of force.
I'm in the unlikely situation where my brother's TDCi Titanium handles better than my S1600. Of course, my car has more physical grip (in the dry, anyway) and less bodyroll, but the Titanium feels more planted, more stable and inspires more confidence.

Is it entirely the fault of the tyres? The standard tyres - Bridgestone Potenza RE050a - do seem to have attracted a lot of online criticism for tramlining. What tyres are other people with 17s using?

Or are 17s just too big a wheel for the Fiesta? Before the Titanium, my bro had a Mk6 ST and no matter whether on the standard Pirelli PZeroNeros or later Toyo T1Rs, that just wouldn't stop tramlining either...also on 17s. Coincidence? Eventually, the ST went back for that very reason, to be replaced by the Mk7 Titanium.

I want to straighten this out, as the PCP is up first thing next year. If I can stop the handling issues, the S1600 is a keeper. If not, I think it's got to go back and maybe a Mk8 (Mk7.5?) Titanium X 125ps Ecoboost will take it's place.

Any thoughts/comments/suggestions?

Have you had the suspension geommetry checked? Not just tracking, but alignment of the castor and camber front and rear. Tyre pressures can also make a difference. Although the sticker on the car says one tyre pressure you may find Bridgestone say something else? Has the car done it since new? It could even be down to tyre wear, not in tread depth but the walls of the tyres weakening so that when they hit the ruts in the road they move around a little to much.

Thanks for the reply.
Not had geometry checked, but I shall do.

Tyre pressures, threw some odd curveballs into the mix.
I've got them at the level Ford say (handbook & sticker inside door shut), which is 31F/26R.
Couldn't find anything about Bridgestone recommended pressures, but it was searching other sites that proved interesting...or rather, confusing:
F1AutoCentre's website says the pressure should be 30F/30R.
Kwik-Fit says it should be 40F/42R.
Both National Tyres & Tyresafe.org say it should be 41F/42R.
The latter two recommendations seem incredibly high, to me.

New tyres on the front, a couple of thousand miles ago and the problem was experienced on both the old and the new.

I'll be somewhat astonished, and a little dismayed, if nobody else here with 17s has noticed the problem.

Just been on the tyre safe website, it gives two sets of pressures. I would say the higher figures are for a fully loaded vehicle, i.e. four adult sized passengers and a boot full of luggage.

I've got winter wheels and tyres on my titanium at the moment and run them at 32psi front and back. They are 15's though, but when i go back to the 16's in the summer i'll run them around the same.

I had terrible trouble with tramlining on my old Focus, bit the bullet in the end took it into work and changed all the settings back to factory and the drive home was so different after I'd done the geommetry. The only thing i'd suggest is try to go into a tyre specialist, not kwik fit or a fast fit centre. We have a couple down here that i know are good, but i don't know what you have up there to do geommetry for you.

Be interested to know how you get on though.

I changed the standard 16s on my ZS for ST170 17s & mines not felt very stable on dual carriage ways/motorways since. I use the same size tyres as on standard fiesta 17s so the speedo stays correct, with around 30/32psi front & rear. At first I thought it was down to the fact I was using budget tyres but then after thinking about it there is a bit of stretch on the tyres to get them to fit the wheels, (fiesta uses 205/40/17, focus uses 215/45/17), so think this causes the problem. I'm guessing there's a stretch on the standard fiesta alloy/tyre combo as I'm sure the alloys on the fiesta & focus are the same width.

I have a new Fiesta as in the new model - I got 205/40 on 17 inch wheels and the tramlining is awful. I have had the car for three weeks and last weekend was in the Highlands - the car went over a bit of road which had been patched - so there was a join in the tarmac - the car went onto the other side of the white lines. Luckily nothing was coming.
I have a little side road on the way home - which has been patched along its whole length - and the car tramlines right the way along - even at 30mph its almost impossible to control. And its a narrow road so there is no room for error.
And it tramlined very badly again today, its like driving on ice.
All with two hands on the wheel.
I am by no means a fast driver, I have had 6 Fiestas in 19 years and never ever had anything like this - the car has only done 1200 miles. I am going to take this up with Ford as it is IMHO dangerous

What year is the car?

i used to get tramlining all the time with my fiesta st with 205/40/17's, but dont get any tramling at all with the zs and 195/45/16's.
will never want to go to 17's again.

As said before, get your suspension geometry done, and switch tyres. Try UniRoyal RainSport 2s, Yokohama Parada Spec 2s or Kumho KU39s. I have had all these and none have caused tramlining. If your car still does with a set of those tyres after a geometry alignment, then yes, you should consider the more expensive alternatives.