I’ve recently replaced the original 14” BBS alloys on my 1994 Eunos (with part-worn 185/60 R14 Kumho tyres) with a set of 15” alloys from a Mk2, wrapped in 195/50 R15 Goodyears.
The Goodyears are a matching set, all with around 6mm tread, but getting old – from memory the date stamp is 2012. An external check before they went on showed no visible cracking, bulges or damage.
Here’s the thing – the car now tramlines quite badly, and the steering feels very twitchy at lower speeds – it feels like the fronts are very sensitive to road undulations, dips and ridges, and are being pulled accordingly.
This is not something I noticed at all on the original 14” wheels/Kumhos – neither on the road (it’s a daily driver), nor on three track weekends – it tracked perfectly at all speeds. My 1996 VR-Ltd has 15” wheels with 195/50 15s as standard, and exhibits none of these traits.
I’m thinking of temporarily swapping the 15” wheels from the VR-Ltd to eliminate either tyre issues, or tracking/set up issues – but before I do, any ideas?
Last time I heard of any MX5 ‘tramlining’ was on a Miata, with a Honda S200 engine in it. One of our previous members bought a bored out 2L engine from FM, with new pistons, cams etc and he said it tended to tramline a bit, that engine seems to have dissapeared entirely, as Black Bullet (former member) bought the actual car, but it did not have the 2L engine onboard. (I asked him)
Frankly, unless you car is either turbo’d or S/C, I’d be tempted to get rid of the Goodyear’s (are they F1’s?) as I had a full set on mine, and the tread was cracking away from the casing, within four years. Goodyear said the tyres were guaranteed for around four years, so they would have qualified for replacement, but due to various problems, i was unable to do anything about it. Been on Toyo’s since - second set on this year, and no problem with them at all. Tramlining? never- on any tyre. Back to Kumho’s ?
H1S VRB -
I should clarify my post above, there are two versions of ‘Tramlining’ - !) following grooves in the road (usually caused by HGV’s etc, 2) And the American term, which means “laying them down” (Tyre spin) I assumed you meant the latter, but you probably meant the former, sorry about that.
As in 1) the original wheels and tyres on my car - 16" Bridgestones did this, which I got rid of by downsizing to 15" wheels and tyres instead. End result, better handling all round, which was what I wanted. In your case, I doubt it’s the 15" upgrade responsible, and in any case 2012 tyres are past their use by date.
Those tyres are old and hard and worn to a different car set up. I suggest you lose them as soon as possible, before they take you into a ditch.
Tramlining is usually because of hard square tyres not being flexible enough to adapt to the variations in the road surface. One of the selling points of the early radials with the wrap-around tread was that they did not tramline, whereas the cross-plys were notoriously bad for it. An old hard worn tyre performs like a cross-ply.
I had a set of wheels that had “nearly new looking” tyres on them. Seemed like an absolute bargain at the time but they were terrible when fitted on two different cars. Turned out that as they had been sat in one position on the ground for about 4 or 5 years they had formed a “set” ie. “only flat on the bottom” as the saying goes. Not so silly as it turns out that the saying goes.
Also, many years ago, i bought some slick tyres for my race bike that were new but old as it were. They were hopeless and nearly killed me at Brands Hatch during a practice session.
As far as tyres on a MX5 go. I have never experienced such a difference that a good new matching set of the right type of tyres can make to a factory production car. The difference is night to day.
Those flat set tyres mentioned above went on a light van and seemed OK. But that light van had been designed to run on old chewing gum wrapped around the rims if need be.
The MX5 is a very precise chassis critical car and the tyres are the first line of attack in the whole set up. Therefore the tyres need to be spot on to get the best out of the car. Anything less and the car can feel ill at ease at least and dame unpleasant before getting to the worst.