Tyre Size Dilema

[Skyliner33]

From my door jamb Vel Exec.
These tyres tun at between 9psi F & 12 psi R lower for the same load; this is why VW fit this tyre to the Vel Exec; its more expensive , but the ride is 100% better at the lower pressures.


View attachment 55512

Interesting. Wonder why they have different load ratings for different widths.
Wonder what they are basing this on.

 

[chriscroft]

I know,
I know



But tis true.
She's a 14 week old Border Collie who's absolutely lovely, but nuts, called "Clue"

 

[Peatey]

I know,
I know

View attachment 55513 View attachment 55514

But tis true.
She's a 14 week old Border Collie who's absolutely lovely, but nuts, called "Clue"

 

[chriscroft]

Interesting. Wonder why they have different load ratings for different widths.
Wonder what they are basing this on.

Well, I actually know the answer to this...... But you may not believe me.....
It comes from Newtons 3rd law of motion...... Action and Reaction are equal and opposite.
So if a wheel is carrying load of say 700kg; the the tyre must carry the same load; now if the foot print of the tyre is larger (wider tyre) then the load per unit area is less; so the required pressure in the tyre lower......
And thats after a few bottles of Birra Moretti

 

[chriscroft]

but the 235/55/17 do ride so much better with their lower pressures

 

[Skyliner33]

Well, I actually know the answer to this...... But you may not believe me.....
It comes from Newtons 3rd law of motion...... Action and Reaction are equal and opposite.
So if a wheel is carrying load of say 700kg; the the tyre must carry the same load; now if the foot print of the tyre is larger (wider tyre) then the load per unit area is less; so the required pressure in the tyre lower......
And thats after a few bottles of Birra Moretti

To be fair there are too many variables to put it down to such a simplification. It is far more complicated than that. That argument might work if the van was sat on a cylindrical column of air.

 

[The Van Cave]

I know,
I know

View attachment 55513 View attachment 55514

But tis true.
She's a 14 week old Border Collie who's absolutely lovely, but nuts, called "Clue"

 

[The Joiner]

Great beer

 

[cy294]

One benefit is you can run the 235/55 at a lower pressure for the same load carrying; this makes a significant difference to improved comfort.
Oh and on other little thing, is pure vanity, (van-it-y....)
The narrower tyres look absolutely pathetic & pants.........
and the wider tyres look gorgeous; manly; up for it; particularly with spacers......

@cy294, I've got a set of 4 * 235/55/17's with delivery milage Goodyear Vector 4-Seasons Gen2, you can have for a steal .

View attachment 55508

Just sent you a PM.

 

[cy294]

Thought I revisit this thread. In the end I stayed with 215/60/17. I replaced the two tyres that I needed, but now the other pair need replacing.

I am not happy with the ride and find it jumpy. So thinking of 235/55/17 which are slightly wider. Question I have is, can I run one set as 215/60/17 on one axle and the other as 235/55/17 in readiness to have all 235/55/17's if that makes sense?.

 

[sparkzer]

yes...as long as the tyre on the same axle are the same size, you can mix it up front to back. i run 245's on the front and 275's on the back