Wheel fitment 940.

[XCR]

Originally Posted by Laird Scooby

What are you measuring it against? Have you measured any of your other cars? I've only ever had one that has been accurate to within 1mph through the rev range and that is my 827 Sterling - last count i had owned 235 cars and i've owned a few more since then, i'm not even going to bother trying to remember them all.

Out of those, i've only checked the speedos on a few of them against either sat-navs or GPS mobile speedo apps.

If you think they're from anunscientific source, download the app and do your own checks, i don't talk cowshed confetti, i've been an engineer all my life so there is no need, if it doesn't work then it doesn't work - simples. No need to dress up the facts as something they're not, enhance, embellish or otherwise.

I had already advised you of the app i had used and invited you to download it and do your own checks, you then proceed to extract the urine. Get your facts right first!

1. GPS
2. Yes, I said so. In each car I've owned I've used a Garmin with a readout of my speed using GPS
3. 235 cars ? I'm not surprised you know so little about each of them, you must have only had each one for a few weeks/months on average....

3. Cool your boots man, and read back to yourself some of what you've written....
FACT : To achieve a discrepancy of 70 to 55 mph you need to fit ENORMOUS WHEELS. Something that would be both obvious and probably unrealistic/unachievable too.

[Stephen Edwin]

None of my business. But. Easy does it? We all have different ideas and perceptions and make an effort to help each other.

As it happens, David and I debate often, BUT, David works very hard to help forum members.

[Laird Scooby]

Originally Posted by Stephen Edwin

1985? Oh yes there was heavy snow about then one night lasting in to the next day. I had a broken windscreen in the beginning of that flurry. Most cars seemed to get around OK. Where I was.

Anyways. Thank you for reminding me about tall and skinny. (Sounds like a modern coffee.) That could tip a decision between different tyre sizes.

My guess is. If a car maker specifies tall and skinny, that's a bonus in snow. Most makers specify a tad wider which as Dai says is better when there is no snow. Work out what is best for oneself.



.

We had a few days of it round my neck of the woods in 1985, not many days admittedly, unlike winters of 1981/2 and 82/3 where we had 18ft snow drifts across the road, front garden, fields opposite etc.

As for tyres, think back to the early 70s when my 144 was first new. To get a tyre with anything lower than a 70 aspect ratio/profile was pretty much unheard of. The Jaguar XJ6 was considered to have "exotic" tyres because they were 205/70HR15, rated for up to 130mph. The XJ12 had the same size but VR rated for 149mph and that was really exotic!

Like most things in life, car manufacture is a compromise. Manufacturers have to find something that will suit most people, most of the time in most weather conditions and at most speeds.

Like Dai said, wider and lower profile is much better on dry roads but won't give such a compliant ride. Most manufacturers these days are fitting wide with (what used to be considered) ultra-low profile tyres of 55-60% aspect ratio as standard. Once upon a time, a Fiesta would have been delivered with 145SR12 tyres, then they moved to 13" wheels and had (from memory) 155/70 on most of them with 175/70HR13 on things like the 1300S/Ghia models - obviously talking Mk1 and pre-XR2 days here.

As for modern coffee, way too confusing! Closest i get to ordering anything resembling a modern coffee is a large latte with an extra double-shot of espresso in the bottom before they mix it.


For the amount of time we usually get snow in this country, or even icy roads and the amount of time i actually spend driving on those roads, changing to winter tyres isn't of any benefit to me. Even living out in the sticks where we don't always get the gritting lorries round it still doesn't make much sense.

[Laird Scooby]

Originally Posted by XCR

1. GPS
2. Yes, I said so. In each car I've owned I've used a Garmin with a readout of my speed using GPS
3. 235 cars ? I'm not surprised you know so little about each of them, you must have only had each one for a few weeks/months on average....

3. Cool your boots man, and read back to yourself some of what you've written....
FACT : To achieve a discrepancy of 70 to 55 mph you need to fit ENORMOUS WHEELS. Something that would be both obvious and probably unrealistic/unachievable too.

Basically you have no experience of cars or life then. I know a hell of a lot about all the cars i've owned, now let me see - have you ever owned a Datsun Skyline? A genuine UK model Datsun Skyline, not an import?

The way you're coming across is as a contentious member and i use that in both senses of the word, i try to be helpful on here and yet you come along and because you're being a brand obsessed article, insist that Garmin is the best GPS - yes, it probably is - i was working on Garmin Sat-navs in the mid-late 90s, long before they were commercially available to the domestic market. As i said, i try to be helpful on here and i'm sure many people will confirm that but you seem intent on getting some kind of argument out of it. You know absolutely nothing about me and from what you've displayed so far, even less about cars!

That, is my last word to you on this subject or any other.

[XCR]

Originally Posted by Stephen Edwin

None of my business. But. Easy does it? We all have different ideas and perceptions and make an effort to help each other.

As it happens, David and I debate often, BUT, David works very hard to help forum members.

If this aimed at me then please, take a look at who is using the angry face.
Honestly, I ask for a little advice and I'm served an abbreviated version of War and Peace. Without a definitive answer.
The question was simple. I've compared sizes and the differences are negligible BUT am I missing something regarding potential drivetrain or gearbox issues ?

As you state, modern winter tyres are a little more sophisticated.
Winter weather is not all snow and when was the last time you saw a tyre cut through the compacted snow anyway ? It grips the surface and, when cornering, a greater surface area will assist that.
Thanks for your help.

[Laird Scooby]

Originally Posted by Stephen Edwin

None of my business. But. Easy does it? We all have different ideas and perceptions and make an effort to help each other.

As it happens, David and I debate often, BUT, David works very hard to help forum members.

Thanks Stephen!

[XCR]

Originally Posted by Laird Scooby

Basically you have no experience of cars or life then. I know a hell of a lot about all the cars i've owned, now let me see - have you ever owned a Datsun Skyline? A genuine UK model Datsun Skyline, not an import?

The way you're coming across is as a contentious member and i use that in both senses of the word, i try to be helpful on here and yet you come along and because you're being a brand obsessed article, insist that Garmin is the best GPS - yes, it probably is - i was working on Garmin Sat-navs in the mid-late 90s, long before they were commercially available to the domestic market. As i said, i try to be helpful on here and i'm sure many people will confirm that but you seem intent on getting some kind of argument out of it. You know absolutely nothing about me and from what you've displayed so far, even less about cars!

That, is my last word to you on this subject or any other.

Honestly, have you been drinking ?
I can state for the record that I have never, ever owned a Genuine Uk model Datsun Skyline. I'm quite certain of that, yes.
I honestly don't know whether Garmin is the best brand of sat-nav as I've never owned any other. I certainly don't insist it as you inaccurately suggest.
Contentious member ? In both senses of the word ? Member being the word, right ? You're calling me a dick/knob/wanger/throbber, right ?
Very funny, you're a very funny guy.
Why do you think I don't know much about cars ? We hardly know one another.

If your last sentence is to be believed, that sir is to my utter relief as I will avoid your self obsessed rhetoric posing as an answer to my questions.
I only wish that other forum members could be so fortunate.

[cumbrianmale]

Originally Posted by XCR

But, but, what about the butter ?

Why salted of course. It’s winter after all and there’s salt in the grit so you want a fair comparison.

Laird Scooby. You may be an engineer but do try to give your advice without sounding as though you’re past makes your advice somehow more relevant.

XCR. Try to not get so bristly. Maybe take that knife and butter and have some nice crumpets and a cup of tea.

Or in other words let’s all take a breather and try to get on with one another or I will put my moderator’s hat on and start issuing warnings and suchlike nonsense that I would rather not spend my Saturday morning doing.

That is all.

[tofufi]

Originally Posted by Laird Scooby

However, if you want to keep the 16" wheels, the 215/60/16 will cause a bigger speedo error than you already have, reading 70 when you're doing probably 55. If you download a GPS speedo app such as "Speedy", you'll probably find that at 70 mph indicated on the speedo, you're only doing 60-62mph in real life. Volvo speedos are notoriously over-optimistic!

Dave,

The difference in the (rolling circumference of the) two tyre sizes XCR quotes should be about 1%. Pretty much negligable on a speedometer reading. It'll hardly make the speedometer read 55mph when going 70mph unless something was seriously out before.

You'd see as much of a difference going from a worn set of tyres to a new set.

Surprised you say Volvo speedometers are optimistic, mine reads 70 when the sat-nav reads 68. With standard 15" alloys.

[XCR]

Originally Posted by tofufi

Dave,

The difference in the (rolling circumference of the) two tyre sizes XCR quotes should be about 1%. Pretty much negligable on a speedometer reading. It'll hardly make the speedometer read 55mph when going 70mph unless something was seriously out before.

You'd see as much of a difference going from a worn set of tyres to a new set.

Surprised you say Volvo speedometers are optimistic, mine reads 70 when the sat-nav reads 68. With standard 15" alloys.

Hallelujah !!!!