[xj] Tire impact on body roll

I rebuilt my front suspension a little while ago when
they couldn’t align it any more… and I replaced the
roll bar bushes… and the thing seemed to roll about
the same.

I got a flat tire the other day and found out that my
car has S rated tires, not V rated tires…

Would this make an “incredible” difference? Would it
make a $500 difference that 4 tires would cost?

John__________________________________
Do you Yahoo!?
Friends. Fun. Try the all-new Yahoo! Messenger.
http://messenger.yahoo.com/

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

Oh, you’ll feel a difference, yes. It won’t be incredible, but you’ll feel
it.

Doug Dwyer
Longview, Washington USA
1987 Ser III XJ6
1988 XJS V12From: “John Elwood” exeterxj12c@yahoo.com

I got a flat tire the other day and found out that my
car has S rated tires, not V rated tires…

Would this make an “incredible” difference? Would it
make a $500 difference that 4 tires would cost?

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

John, you ask

" I rebuilt my front suspension a little while ago …and I replaced the
roll bar bushes… and the thing seemed to roll about the same… my
car has S rated tires, not V rated tires…

"Would this make an “incredible” difference?

All other things being equal (which is hardly ever the case), the better
bracing of the V rated tyre will improve adhesion and response. However,
the more effective the tyres, the greater your body will roll in extremis,
because the speed at which they begin to slide will be higher. If you want
better adhesion AND less roll, uprate the anti-roll bar as well as the
tyres. If you want a practical demonstration, try following a briskly
driven standard Mark 2 saloon on very high quality radials. The suspension,
which was designed for 1950s cross-plies, can produce spectacular roll
angles.

“Would it make a $500 difference that 4 tires would cost?”

I think the answer has to be based on subjective assessment. I like the
stable feel of wide tyres (235/60), and those which fit best on the OE 6
inch rims are V rated.

I haven’t fitted anything less than V to our Jags in the last 20 years and
have paid the extra money, but I’m sure there are some very good quality H
rated tyres out there too - as listers will probably confirm.

cheers
George===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

John Elwood wrote:

I rebuilt my front suspension a little while ago when
they couldn’t align it any more… and I replaced the
roll bar bushes… and the thing seemed to roll about
the same.

I got a flat tire the other day and found out that my
car has S rated tires, not V rated tires…

Would this make an “incredible” difference? Would it
make a $500 difference that 4 tires would cost?

In principle the differences between various manufacturers and
type/pattern of tyres are greater in this respect than speed rating
alone, John. Watch Formula 1…:slight_smile:

Also tyre pressure will vary car behaviour over quit a wide range
irrespective of speed rating and manufacturer. Watch NASCAR…

For sure; for runs at V- rated speeds you most certainly need that
rating. Otherwise a lower rating will do - if legally allowed, but
almost invariably real high speed tyres run harsher, particularely at
lower speeds.

The incredible difference is only between real bad tyres and real good
ones. Within sedate(d…) driving the difference is minimal. Excessive
rolling is more likely your driving style - you need more roll bar, or
possibly tyre pressure - you need more air…

Your call…

Frank
xj6 85 Sov Europe (UK/NZ)===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only