'Interesting' discovery on tyre metrics...

[mmm-five]

Prompted by a post on another forum regarding tyre weights, I thought I'd spend some of my not-so-busy day investigating tyre weights. However, once I got into the data (which in some cases I think requires a huge pinch of salt) I realised there is quite a range of sizes for any specific metric in tyres.

In the example below, using 265/40r18 tyres (as I was interested in the new PSS), there seems to be a range of 50mm between the 265 with the narrowest usable tread, and the widest.

There's also a 2kg difference between the lightest and heaviest. Wonder if those same people who spend thousands on lightweight alloys to reduce their unsprung mass actually bother to check that their sticky/sporty tyre is cancelling out that benefit?

I also noticed differences in the overall circumference of the tyre, but I've not put that in the table as I didn't collect it at the same time. Although there doesn't seem to be any correlation between widest and biggest circumference.

 

[original guvnor]

Very interesting mmm-five.

Seems you pay a penalty for RF's in weight as well as ride quality.

I might be being thick (quite possible!)but how can the Conti Sport Contact 3 have 284mm of tread if the tyre is only a 265? I thought the 265 in the tyre size was the width of the tyre in mm ?

 

[Anonymous]

Continental Sport Contact 3 has the widest tread and the lightest weight, interesting stuff..

 

[mmm-five]

Seems you pay a penalty for RF's in weight as well as ride quality.

None of them are runflats, as I was researching tyres for the Z4M.

I might be being thick (quite possible!)but how can the Conti Sport Contact 3 have 284mm of tread if the tyre is only a 265? I thought the 265 in the tyre size was the width of the tyre in mm ?

That's why is suspect some of the data - albeit mostly from the official spec sheets. Maybe different companies measure tread differently
I suppose it's possible that the 265 part is the width where the tyre fits to the rim, rather than the tread width, so you'd have one tyre that looks stretched, and one that looks like it bulges out?

This could be the reason some people are adamant that their 265/275 tyres don't rub, when someone else (with a different brand/model of tyre) is adamant that they do.

 

[pvr]

Interesting, especially as I really need to look at new rears for mine ...

 

[ga41]

Definitely interesting. Thanks for posting.