Hey all,

I currently have Dunlop SP Signature Sport 205/45R17 non-run flats, and these things tramline like nothing I've ever experienced on any car in my life. I can't take it anymore -- they literally follow every single groove, bump, and line on the road and make the already twitchy MINI far worse in the handling department as a result.

Two questions:

1. I was thinking of putting 50s on the stock 17" rims -- is this a good or bad idea? The main reason why I want them is to help improve the bump steer that MINIs suffer from -- when I drove a friend's MINI that had 50s it was subtly improved, and any improvement in that department is highly welcome. My current tires are the standard 45s that come with 17" MINIs.

2. What would you recommend for all-season sport tires that don't tramline like these Dunlops do. It's time to get rid of these things.

Thanks,
N

 

I'm no expert on tires, but it may be hard to tell if the subtle improvement that you felt was mostly due to the taller sidewalls, a different tire make/type, or differences in tire wear or pressures.

I read the Tire Rack comparison test on your tires and, while they finished 2nd out of 4, TR said they would like "a small improvement in road manners." They didn't specifically mention a problem with tramlining or bump steer, however.

The 205/50/17s would be about .8" taller (greater in diameter) than your 205/45/17s; that's about .4" of extra sidewall all around the tire. The extra sidewall flex should yield a somewhat more compliant (softer) ride at the cost of some turn-in and steady state cornering crispness. The taller tires will also weigh a pound or so more, and raise the car about .4". Some here have apparently knowingly chosen that trade-off, however.

Tire Rack carries several highly rated HP and UHP A/S tires in the 205/50/17 size.

Sorry that I can't recommend a specific tire or tire size for a sure cure.

 

I don't have a definitive answer for you but I want to point something out:

If a tire is labeled as 205/45R17, its sidewall is not 45mm tall, but instead 45% of 205mm, or 92.25mm. A 205/50R17 would be (0.50 x 205mm) 102.5mm, giving you an increase in sidewall height of 10.25mm, or a 20.5mm increase in diameter (around 0.8"), as was mentioned previously.

 

Maybe it is your suspension causing some or most of the tramlining. Maybe your lower control arm bushings are wearing out. I even noticed a reduction in tramlining when I added a lower stress brace. I would not think that the sidewall height would make that much difference in tramlining.
I have used 205/40-17, 215/40-17, 205/40-18, and 215/40-18 tires on my Minis and never noticed much difference (or problem) in tramlining.

 

Thanks for the answers so far, gents.

My shocks are Koni FSDs that are about a year and a half old, and I actually replaced the stock lower front control arm bushings with poly bushings around a year ago, to make the steering crisper.

Would any of those two things contribute to tramlining? It's really, really bad in my car.

 

If you first noticed the increase in tramlining right after the shocks and bushings switch, they might be a prime suspect. My understanding is that suspension, wheel, and tire changes designed to enhance handling crispness might also increase tramlining on uneven surfaces, but you seem to be describing a level of tramlining beyond any expected normal change.

Other suspects might be old (hard) or badly worn ties, or alignment issues.