load index/rating

[rpsxr]

what could be the concequence of putting on tyres with a load index of 92 instead of the recommended 96? (oem 255/35/19Y96 v 255/30/20Y92)

thanks.
robert

[bam_bam]

Risk of failure. There aren't a lot of options with 20s.

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Load index is as you would expect the maximum service load of the tyre. IE, not the level it will go pop at but the maximum it should be run at under normal conditions.
92 is 630kg and 96 710kgs.

In *theory* 4x630 is 2,520kgs so under the maximum weight of the car and
Given that the weight dist of the rs4 is 58/42 so the front tyres share approx 986kgs or 493kgs each.

However I have no idea to hand if this is static load or if you need to account for additional load transfer for car dynamics (under braking for example).
I would expect under 1g braking that this weight transfer could easily hit 70/30 or higher. Assuming 1700kg weight that puts 595kg's of load on each front tyre...
If the weight distribution hit 75% then you'd exceed the load of the tyre.

With the OEM 96 load tyre you'd need to shift over 83% of the weight forward which I don't think you could physically do in the RS4.

My view is that those four bits of rubber are the only thing keeping you out of trouble - If you are going to skimp on something then tyres are not the place to do it.

[rpsxr]

thanks for that!

wasn't going to skimp, but more looking to get conti 5p's in 255.
so i would just have to look for 275's to get the right load index then...

thanks

r

[bam_bam]

Load index is as you would expect the maximum service load of the tyre. IE, not the level it will go pop at but the maximum it should be run at under normal conditions.
92 is 630kg and 96 710kgs.

In *theory* 4x630 is 2,520kgs so under the maximum weight of the car and
Given that the weight dist of the rs4 is 58/42 so the front tyres share approx 986kgs or 493kgs each.

However I have no idea to hand if this is static load or if you need to account for additional load transfer for car dynamics (under braking for example).
I would expect under 1g braking that this weight transfer could easily hit 70/30 or higher. Assuming 1700kg weight that puts 595kg's of load on each front tyre...
If the weight distribution hit 75% then you'd exceed the load of the tyre.

With the OEM 96 load tyre you'd need to shift over 83% of the weight forward which I don't think you could physically do in the RS4.

My view is that those four bits of rubber are the only thing keeping you out of trouble - If you are going to skimp on something then tyres are not the place to do it.

^ that's nice Arthur...

[barryrs]

This was the result of putting 94 on my S6 instead of the correct 98

http://audis rs.com/ftopic34024-0-asc-0.php - remove the space

[rpsxr]

that's great thanks!
prob going to go back to 19's because on 20's i can't really find the right size vs load index.

thanks all

robert

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what about 275/30/R20's?
http://www.camskill.co.uk/m63b0s343p0/C ... _275_30R20

[rpsxr]

yes i know. had a look at them. however, first of all price difference over the 19s (especially when you need 4) and second now we have to look at the difference in circumference (if thats the right word) and the speedo being off, and last rubbing. on 265 it's rubbing a little already. i could prob then change spacers etc, but it'll become quite an expensive exercise i think...

i'm also wondering if the ride will be better with 19s; then i actually mean the handdling...

thx robert

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In my experience the bigger wheel aspect is purely for looks. If you want handling then you want smaller wheels.