Believe it or not, this kept me awake last night!. I was wondering what speed my wheels are rotaing at when travelling at 100mph (I lead a very lonely and dull life ). Based on standard Octy VRS wheels with 205/50/R17 tyres, from a mental calculation I did in bed (god help me!!) I came up with approximately 1000rpm. I cannot be bothered to work this one out myself so I am relying on you lot to do it for me and perhaps you can work out the Furby VRS's 205/45/R16 for me at the same time!!. :P

Unless you turn the wheel slightly, then wheel speed with differ left to right.

Unless you turn the wheel slightly, then wheel speed with differ left to right.

...???, OK roughly then!.

205/50 R17 is a 637mm diameter - multiply by Pi gives ahem. 2000.18 (just using Pi to 2 d.p) So, 2000mm circumference will hopefully give easy calculations later.

100mph means in one minute you'll cover 1.666666667 miles, using the highly inaccurate *8 /5 gives 2.6666666667 kilometres. Ahem... thick moment In 2.666666667km, a 2000mm circumference will rotate 1333 times toughly, so I guess this is the RPM? :confused:

Please someone tell me I'm bloody wrong.

I assume the lack of response means I'm right?

I assume the lack of response means I'm right?

Not sure, I am dissapointed that we don't have a mathamatical genius out there who cannot wait to get stuck into this most important question. We need answers, NOW!!!!!

I assume the lack of response means I'm right?

Assuming the tyre size is right, it looks fine to me. But then as I've proved countless times before, I'm no mathematical genius

Chris

Looks good to me Jason - you are hereby appointed forum Professor.

Unless you turn the wheel slightly, then wheel speed with differ left to right.

Why :confused: (I'm not trying to be smart its just too early in the morning to be trying to figure it out).

Why :confused: (I'm not trying to be smart its just too early in the morning to be trying to figure it out).

If you're turning, you don't want both wheels to spin at the same rate ... the wheel on the outside needs to travel further than the wheel on the inside of the turn, or you will carry on going straight on

Chris

Looks good to me Jason - you are hereby appointed forum Professor.

I am in way qualified to uphold that role.

I put it down to a one off, and the lucky outcome that the wheel diameter of a 205/50 R17 multiplied by Pi came out at such a nice number.

If you're turning' date=' you don't want both wheels to spin at the same rate ... the wheel on the outside needs to travel further than the wheel on the inside of the turn, or you will carry on going straight on

Chris[/quote']

I understand that alright, maybe it was just the way I read it, actually it was the way I read it . I read it in such a way that unless you turned the wheel slightly (ie turn it slightly from straight) then there would be a difference between right and left, it just got me thinking.

Don't mind me, I did a night shift Wed, Thur & Fri and got VERY little sleep yesterday

205/50 R17 is a 637mm diameter - multiply by Pi gives ahem. 2000.18 (just using Pi to 2 d.p) So' date=' 2000mm circumference will hopefully give easy calculations later.

100mph means in one minute you'll cover 1.666666667 miles, using the highly inaccurate *8 /5 gives 2.6666666667 kilometres. Ahem... thick moment In 2.666666667km, a 2000mm circumference will rotate 1333 times toughly, so I guess this is the RPM? :confused:

Please someone tell me I'm bloody wrong. [/quote']

Jason, I did maths as my main subject at uni and can tell you that you are spot on for your rounding. Using different measures of rounding my results varied from 1320 - 1340. Of course with tread wear you will get a range of measures but the overall rpm should only vary by a few rpm.

Additionally the furby on the figures quoted at the start of the thread will rotate somewhere in the 1430 - 1445 rpm bracket at 100mph.

205/50 R17 is a 637mm diameter - multiply by Pi gives ahem. 2000.18 (just using Pi to 2 d.p) So' date=' 2000mm circumference will hopefully give easy calculations later.

100mph means in one minute you'll cover 1.666666667 miles, using the highly inaccurate *8 /5 gives 2.6666666667 kilometres. Ahem... thick moment In 2.666666667km, a 2000mm circumference will rotate 1333 times toughly, so I guess this is the RPM? :confused:

Please someone tell me I'm bloody wrong. [/quote']

That just what I got last night too !!!

At speed with the tyres heavily loaded trying to push the car through the air there will a small degree of slippage therefore I think Jason you ought to add another 1 or 2 RPM

Or to put it another way the weather is crap & thats why we all have time to be on the Interweb on a Sunday Afternoon debating things like this

Makefish, another thought to keep you awake at night, something I saw on a teee shirt last week & I quote "Cover me in Chocolate & throw me to the Lesbians"

Now has that thought stopped you worrying about your tyre RPM

...............Makefish, another thought to keep you awake at night, something I saw on a teee shirt last week & I quote "Cover me in Chocolate & throw me to the Lesbians"

Is there a formula for this?

Is there a formula for this?

Dont know of one but if you find it let me know. Not sure if its inthe adults version of Willy Wonkas Chocolate Factory