carlosamg50

Hi guys

Just picked up a 2021 GLS63, tyres are very good, brakes look fine etc. but it tramlines a little when crossing the lane lines on the road and also seems to a little out of control when braking harder when giving it a bit, as if it cant handle its mass and wants to get out of shape, anyone else experience this? I think I have my tyre pressures a little off, with 34 all round, would that be a factor with the symptoms I describe, it doesn't feel out of sorts cruising at motorway speeds, no shimmy when braking etc.

Car is fitted with factory 22's and Conti Sport 6 tyres.

Thanks
Carl

mikapen

My first thought was tire pressure.

A bit of tramlining is to be expected with wide tires, but I'd be concerned about your braking experience.

Start with your gas flap tire pressures to see if that helps. Good luck.

carlosamg50

Gas cap pressures seem low given the vehicle size, power, wheel size etc. something like 32 front and 31 rear, and other threads on the forum suggest running a bit higher than gas cap.

Thanks for the reply, will make some adjustments and see how it feels.

mike7513

It's because you are driving a massive, powerful vehicle on summer tires or tyres in the winter in the UK. What you are experiencing is your car telling you to give it some winter tires.

My GLS 450 with the 23's behaves the same way in Michigan right now. In the states we would describe it as "squirly". It's your/our tires.

carlosamg50

Never even thought about the summer tyres in winter, it’s cool here rather than freezing but I guess a few degrees above zero is too cold for the high performance tyres.

Thanks for the response

mike7513

My pleasure.

I'm not going to embarrass myself by attempting a Celsius conversion but both manufacturers of the tires that will fit the 23' wheels considers about 45 degrees the cutoff for summer tires.

EWL5

Summer tires become dangerous below 4°C!

carlosamg50

It’s around 4 here during the day at the moment, will keep the throttle mashing for the warmer temps, thanks guys.

Took it for granted, last couple of cars had M+S tyres fitted and my G Wagon didn’t bat an eye lid on these cold days LOL.

mikapen

Then you're not using the Loud Pedal enough....

AKSwift

When we lived in the UK, the local tire guy always enjoyed it when I asked him for winter tires. I was his best customer, no one else bothered. I remember that the rear wheels on the Smart Fortwo (2010) were particularly hard to find and, therefore expensive. Or so I thought - 23" tires are in a whole different league.

That said, having learned to drive in Germany, I'd never think about taking summer tires out below 7C. My Swedish neighbor likes to tell me about one of his teenage jobs being to put studs into the tires - I wouldn't go that far...

nc211

Ours (21's staggered) has always wiggled when going over the marker tape lines on the road. It's the alignment setup which pushes one side against the other (and eats the tread). Keeps it stable at high speeds, but if one side can push the other, it will.

carlosamg50

So weather temperatures have improved, driving at around 13 degrees today, still feels unstable, like its constantly adjusting itself on road, and the active roll bars are grabby so pulling the car left to right with wind or road undulations, just not a planted ride.

I dropped the tyre pressures to 34 and 33, no difference really, just feels light and unsettled, with a lot more body roll than I thought with the active roll control etc.

It does have Yokohama tyres front and Continental rear rather than Conti all round, both brands and summer and M0 spec, may influence traction a tiny bit but the lack of control and unsettled feeling on motorway driving can’t be down to tyres, right?

mike7513

You're still only at the bottom range of the temps for these tires. And as nc211 added you are always going to have that with the staggered setup running over lane markers, repairs that have been made by sealant rather than cold patch, etc, if you continue to run a summer tire even if it's 85 and full sun. And even if you switched to a smaller wheel and an all season tire you are just gonna mitigate it some more, it's never going to go completely away. I had a loaner 450 that had the 21's on it with all season rubber and same thing just not as violent.

wildta

It's called tramlining:
https://en.m.wikipedia.org/wiki/Tram...ed%20sidewalls.