Raised profile

[IanA2]

I've just changed the tyres on the SL500 and raised the profile from 55 to 60. I cannot believe how much more comfortable it has made the ride.

 

[television]

I've just changed the tyres on the SL500 and raised the profile from 55 to 60. I cannot believe how much more comfortable it has made the ride.

I will never understand how a car can be comfortable running around on a 30-35 profile on 8½ inch wheels or with a 225 tyre.. OK my SL has 285 rears and the profile at 35 is OK

 

[IanA2]

My SLK had low profile tyres (can't remember exactly how low) and they were not too bad compared to the SL500 (92 model), but I think old R129's have a pretty firm ride. The SL60 (98 model) has lowish profile but is a much more forgiving ride than the 500.

 

[stats007]

Maybe the dampers/bushes/springs are past their sell-by date?

 

[C240Sport97]

doesn't this mess up the rolling diameter, speed readings, cruise control etc etc

 

[Dieselman]

doesn't this mess up the rolling diameter, speed readings, cruise control etc etc

It's a 3.7% uplift assuming 245 - 16 tyres.
This will affect the speedo but nothing else as all the tyres still have equal RR.

 

[IanA2]

Maybe the dampers/bushes/springs are past their sell-by date?

I had wondered along those lines...is there any definitive test?

 

[IanA2]

It's a 3.7% uplift assuming 245 - 16 tyres.
This will affect the speedo but nothing else as all the tyres still have equal RR.

225 - 16 garage guy told me it was a 5% uplift....I don't know for sure but it is higher.

 

[Dieselman]

3.5%.

For dampers just give each corner a good bounce. It should feel fairly stiff.

I suspect you would feel a significant difference from fitting new dampers and springs.

 

[rf065]

225 - 16 garage guy told me it was a 5% uplift....I don't know for sure but it is higher.

If you have changed from 225/55x16 to 225/60x16

then you have increased the rolling circumference of the tyre by 3.44%

This puts your speedo & mileometer out by the same margin, over & above any discrepancy that may have been there to begin with.

Russ

 

[IanA2]

Having changed the profile the speedo is now more accurate!!