Tire size decision

  • Thread starter Thread starter William Liao
  • Start date Start date
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William Liao

Hi guys,

My 740 came with Pirelli P2000's at 185/65 R15 and I've always fitted the
same type & size tires when going for tire change. This time however after
I've read about the new Pirelli P6 (not the P6000), I've been tempted to try
them. Unfortunately the local Pirelli dealer told me he can't get any P6 at
185/65 R15 anymore, so if I really insist on them I can either get 195/60
R15 or 195/65 R15.

Firstly, do you guys think the P6 is better than the P2000? I look for
quietness, smoothness, low fuel consumption and long lasting when I choose
tires. Traction is important of course, but I drive my 740 conservatively
most of the time... afterall it's not a sports car. I didn't like the P6000
because I've been told the "wave" tread pattern tires are louder than the
traditional tread pattern like the P2000.

Secondly, if P6 is really worth getting, should I get 195/60 or 195/65? I'll
loose a bit of tire diameter with the 195/60 (and thus ride comfort), but my
speedometer & odometer will only over-read by 1% while the 195/65 will
under-read by 2.1%... and I prefer having an accurate odometer &
speedometer. Or alternatively is there any way I can re-calibrate my
instrument to read accurately with the new tire size?
_________________
Will
'90 Volvo 744 GLT (B230F) - daily driver
'73 Volvo 164E - awaiting repair & restoration
 
Have you considered Michelin MXV4 Plus? Based on the criteria you
described, they seem like a perfect match. I have had 3 sets on 3 different
cars and have been extremely pleased with them. Also, I'd go with the
195/60/15 size ... you will not notice any significant ride reduction
quality in my opinion and the spedo error will hardly be noticable .... 1/2
mph off at 50 mph and 1 mph off at 100 mph.

.... Larry
 
Larry said:
Have you considered Michelin MXV4 Plus? Based on the criteria you
described, they seem like a perfect match. I have had 3 sets on 3 different
cars and have been extremely pleased with them. Also, I'd go with the
195/60/15 size ... you will not notice any significant ride reduction
quality in my opinion and the spedo error will hardly be noticable .... 1/2
mph off at 50 mph and 1 mph off at 100 mph.

... Larry
Click to expand...

And you'll probably find that the speedo has a greater error than you're
introducing with the differing tire size. If you can find a measured
distance on the road somewhere you can calculate how your speedo is
doing now, then pick the tire size that cancels out some of the error.
My guess is you speedo reads high, going with the 195/65 tires will
lessen the error.
 
Re: speedo. I run on "correct" tire dimensions on my s80. When my meter says
140km/h real speed is 128km/h. Thats +9% error. Was same with my previous
V40. Here in Sweden, the motorways often have white lines across the lane
which are 500m apart - for police helicopters to measure yr speed.... These
lines are good use when you want to check yr speedo. distance(m)/time(s) x
3,6=km/h

//Johan
 
Larry said:
Have you considered Michelin MXV4 Plus? Based on the criteria you
described, they seem like a perfect match.
Click to expand...

I agree. Superb tires.
 
JohanE said:
Re: speedo. I run on "correct" tire dimensions on my s80. When my meter says
140km/h real speed is 128km/h. Thats +9% error. Was same with my previous
V40. Here in Sweden, the motorways often have white lines across the lane
which are 500m apart - for police helicopters to measure yr speed.... These
lines are good use when you want to check yr speedo. distance(m)/time(s) x
3,6=km/h
Click to expand...

The problem is that the spedos here in the U.S. are not recalibrated
and they assume you are using European sized tires. What's 4-8%
slower driving going to hurt anyways?

My 240 with the manufacturer's suggested tires would read 5-8MPH
faster than the actual speed. We have one of those traffic radars
in town on a trailer - that shows you your speed - and darn it if
the Volvo isn't way off. Driving 45mph(spedo)? Tells me 39. I
went past one on a rural road the other day and it read 57mph
when my spedo said 65. Egads.

Next set is going to be taller.
 
So what whatever the spedo shows - you still want to know real speed - thats
what they fine u for.. :-)
 
JohanE said:
So what whatever the spedo shows - you still want to know real speed - thats
what they fine u for.. :-)
Click to expand...

Well, going 58 when you think you are going 65 kind of sucks.

OTOH, might explain why Volvos don't get pulled over as often.
 
My 240 with the manufacturer's suggested tires would read 5-8MPH
faster than the actual speed.
Click to expand...

Which 240 and what size tires do you have? It is a common error to
put 185/70R14 tires on non-turbo wagons which specify 185R14. This
results in a 7% difference in tire circumference and therefore
speedometer reading versus actual speed.
 
I run 225/60/15 on mine. Not sure why anyone in the USA would care about
1-2 mph error in the speedo at 70-100 mph. As stated before, rarely will
you find a car that is dead on from the factory.
 
I was going to pop it in my pocket and hop over with it!! I saw another blue one
today with a 340/360 at the house as well. I don't think he is VOC but you never
know.

Keep up the good work mate, from Peter.

:
: : > I would always advise to use 195/65/R15 size tyres on 700/900 models. This
: is my
: > personal thought on the matter and is also the tyre in the middle of the
: > recommended sizes in the handbook. I found that this size gives me a very
: > accurate speedo reading, so accurate that I can drive past a Gatso at
: 36mph
: > indicated and not trigger the Gatso which is set for 37mph.
:
: Thanks for the recommendation. To be honest I'm leaning more towards
: 195/65/R15 as well, more rubber which will give me slightly more ride
: comfort and better fuel economy. Except the greater speedo error that's
: holding me back... but after reading what the other guys have said here, I
: think 195/65/R15 might be a better idea than 195/60/R15.
:
: > Are you still hoping to restore that 164 William? To give you a little
: incentive
: > there is a 1973 164 in Blue with A/C and only 32,000 miles on it's clock
: going
: > for £4,750, not 35 miles from me.
:
: Sounds like a fantastic deal, mate!! Except one small problem... it'll cost
: more than it's worth to ship it to Ausralia... :-(
:
: _________________
: Will
: '90 Volvo 744 GLT (B230F) - daily driver
: '73 Volvo 164E - awaiting repair & restoration
:
:
 
I ended up buying Pirelli P6 at 195/65 R15. Since I only bought a pair, the
guys at the tire shop fitted them on the rear, contrary to the normal
practice of fitting new tires on the front. He told me if I'm mixing wider
tires with narrower ones, the wider ones should always go on the back. So
now I have a pair of brand new Pirelli P6 at 195/65 R15 on the rear and used
(but not worn) Pirelli P2000 at 185/65 R15 on the front... and as you'd
expect, I feel a pronounced understeer...
_________________
Will
'90 Volvo 744 GLT (B230F) - daily driver
'73 Volvo 164E - awaiting repair & restoration
 
So fit the new ones on the front, I do as a matter of course when buying two
tyres at a time. You need the front wheels to grip when braking and the slightly
wider tyres will also give better grip when cornering.

All the best, Peter.

: I ended up buying Pirelli P6 at 195/65 R15. Since I only bought a pair, the
: guys at the tire shop fitted them on the rear, contrary to the normal
: practice of fitting new tires on the front. He told me if I'm mixing wider
: tires with narrower ones, the wider ones should always go on the back. So
: now I have a pair of brand new Pirelli P6 at 195/65 R15 on the rear and used
: (but not worn) Pirelli P2000 at 185/65 R15 on the front... and as you'd
: expect, I feel a pronounced understeer...
: _________________
: Will
: '90 Volvo 744 GLT (B230F) - daily driver
: '73 Volvo 164E - awaiting repair & restoration
:
:
 
I take it you do not have antilock brakes or traction control on the vehicle
as they would probably have gone "squirrely" by now with the different tire
sizes front and rear. Also, different tire sizes front/rear will cause a 4
wheel drive system to fail prematurely .... for what ever it's worth.

..... Larry
 
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