Stiff tyres?

[Thelongterm]

Something odd is occurring when I turn slowly (2-3 mph) over road imperfections and pot halls that we have aplenty around here.

It sounds like the tyres (I think it's the rear) are 'catching'  and making this knock sound when going over an imperfection as turning the steering wheel slowly.

The tyres are what I got with the car and still have around 4.5 to 4.9 mm left on average all-round. 

Looking at the date code tells me the back 245 45 17 are from 2016 (these are Dunlop sport maxx), the front 225 45 17 are 2018 vintage and are Pirelli P7's so not cheap tat.

 

Can it be that the tyres lost their flexibility considering the back is six years old and the back are three+ ?

The callipers at the rear were serviced and greased after buying the car in August and the front wheels roll freely.

 

Any idea?

 

 

[NemesisUK]

Has this only started since the weather turned colder?

 

[Thelongterm]

26 minutes ago, NemesisUK said:

Has this only started since the weather turned colder?

 

Started about two month ago.

[NemesisUK]

It's common in the colder weather for wide profile summer tyres to 'crab' 'clunk' or 'snatch' as the sidewall compound stiffens in the lower temps.

My RC does it turning out of my driveway, first time it happened I thought I'd run over a brick!

[Thelongterm]

Is softer compound tyres like Yokohamas or Uniroyal have more give in colder weather? (Thinking about the next set).

[NemesisUK]

Just now, Thelongterm said:

Is softer compound tyres like Yokohamas or Uniroyal have more give in colder weather?

No significantly. One would need to go for winter or all season tyres

[Thelongterm]

Thanks for the info, I never had this profile on previous cars (Yaris and Avensis) so learning something new every day. According to other forms for Mercedes Benz cars, the level of wear and age are factors contributing to the issue.