Tire sidewalls have different characteristics depending on the speed
rating. The more flexible, the higher the speed rating. Your suspension was
calibrated for V-rated tires.
Changing to a stiffer sidewall in the same aspect ratio (lower speed
rating) will alter the handling. You probably won't notice anything
different in everyday driving, but there will be a small change.
As I understand it, the primary reason for automaker chice of tire speed
rating is that it coincides with (or exceeds) the car's own maximum speed.
This is desirable from a liability and safety perspective.
You can use a lower speed rating so long as you never exceed the speed for
which those tires were designed.
I have moved down from V to H rated tires on several cars and it has
worked out well for me. There are no US or Canadian roads where legal
speeds tax the capabilities of either rating.
Check out the customer reviews on tirerack.com after you put in your
make and model. That might help you choose a tire.
I do believe strongly in keeping the exact same tires on all four
wheels. Sometimes mix and match is ok, sometimes it works out horribly.
I was in the same situation and inquired at the dealership about it.
The dealer recommended I stay with the v rated tires. He told me of an
instance where another customer went with h rated to save some money and
was back within a couple of days to switch to the v rated because the h
rated tires changed the handling characteristics so much he did not feel
safe with them. I bought h rated myself because of the cost of the v's
(the h rated were half the price) and there is a definite change in how
the car handles. I notice it most when going over large bumps or heaves
in wide sweeping turns at speed. The car wobbles and there is a
moment when you feel you could lose control if your not paying
attention. I'm sure the handling is still secure, but that strange
little wobble is a bit disconserting. BTW 'Tegger', my understanding is
that higher speed rating gives stiffer side walls, not more flexible,
allowing quicker turn-ins and a generally more controlled ride. I
believe the softer sidewalls are what's causing the handling anomaly I'm
experiencing since my change to h rated tires.
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