how fast would you go for every 1k revs in 5th gear for both TT and NA?

With standard wheels/tyres

 

TT - 26.4 mph

NA - 23.9 mph

do you know how to work it out for different wheel sizes?

here you go ;)

 

Change the tyre profile and RPM figures to suit

Clever stuff, i like that :D

Absolutely nothing to do with Zeds, but my Dodge Ram in lock up (top gear)

does 38mph for every 1,000rpm.

V8`s are lazy.

 

Alan.....

i dont get the conversion. the wider the tyre the theoretical top speed increase???

 

i put in 17" wheels at 235 wide @ 45 profile and it gave me a top speed of 176.7 mph at a 255 wide tyre it goes up to 181?!?

 

well i thought an na wouldnt go that high?

i dont get the conversion. the wider the tyre the theoretical top speed increase???

 

i put in 17" wheels at 235 wide @ 45 profile and it gave me a top speed of 176.7 mph at a 255 wide tyre it goes up to 181?!?

 

well i thought an na wouldnt go that high?

 

The tyre profile is a percentage of the tyre width . So 45% of 255 results in a bigger sidewall and larger circumference than 45% of 235. You need to lower the tyre profile to correct it.

 

It would with enough power and the larger tyre size you gave....although check the rpm I think I might have put it higher than stock.

Try this link....

 

http://www.miata.net/garage/tirecalc.html

 

It tells you the profile to keep the rolling circumference the same if you increase wheel size

The tyre profile is a percentage of the tyre width . So 45% of 255 results in a bigger sidewall and larger circumference than 45% of 235. You need to lower the tyre profile to correct it.

 

It would with enough power and the larger tyre size you gave....although check the rpm I think I might have put it higher than stock.

 

so a 235/45/17 wheels is what percentage?

Edited January 18, 200916 yr by hellraiser

so a 235/45/17 wheels is what percentage?

 

235/45/17 means the tyre profile is 45% of 235.

 

To retain the same diameter/circumference (or as close as possible) when fitting a 255 tyre, then you would need to fit a 255/40/17

 

The link Tonyb posted is very handy for working out the correct tyre sizes to fit.

Edited January 18, 200916 yr by Yowser

235/45/17 means the tyre profile is 45% of 235.

 

To retain the same diameter/circumference (or as close as possible) when fitting a 255 tyre, then you would need to fit a 255/40/17

 

The link Tobyb posted is very handy for working out the correct tyre sizes to fit.

 

gotcha!:D

235/45/17 means the tyre profile is 45% of 235.

 

No way is the tyre 105.75 mm tall!

No way is the tyre 105.75 mm tall!

 

Except it is ;)

Well my TT on 18's does like 32mph at 1000rpm so :P to your figures

Well my TT on 18's does like 32mph at 1000rpm so :P to your figures

 

with your 265/35/18 rear wheels its doing 27.1 mph per 1000rpm.

Edited January 18, 200916 yr by Yowser

Quote:

Originally Posted by phill82

No way is the tyre 105.75 mm tall!

Except it is ;)

 

but what dimension of the tyre is that exactly? If it were the tyre walls either side of the wheel added together then that would seem to fit, making the distance between the outer edge of the rim and the outer edge of the tyre 53mm(ish).

but what dimension of the tyre is that exactly? If it were the tyre walls either side of the wheel added together then that would seem to fit, making the distance between the outer edge of the rim and the outer edge of the tyre 53mm(ish).

 

thats what i would say it is. tbh i thought the 45 was the side wall in mm so i thought mine were 45 mm high?! doubling that would be 90 mm so i wasnt far out LOL

so its the side wall x2 which is 45% of 255. is that correct, tyres hasve always confused me. so do offset messurments

with your 265/35/18 rear wheels its doing 27.1 mph per 1000rpm.

 

Well my speedo is bang on with GPS till about 60mph so f**k knows :tongue: all lies i tell ya lies :tongue:

http://www.driverstechnology.co.uk/Tyre-size-coding.htm

but what dimension of the tyre is that exactly? If it were the tyre walls either side of the wheel added together then that would seem to fit, making the distance between the outer edge of the rim and the outer edge of the tyre 53mm(ish).

 

no, it is the actual height of the sidewall as a percentage of the tyre width

 

235/45/17 sidewall height is 105.8mm (10.5cm)

Edited January 19, 200916 yr by Yowser

202 MPH for me!!!!!!!! :D

I've made a scale diagram of a 17inch wheel with a 235/45 tyre, one going on 106mm tyre wall, and the other 53mm wall:

I just popped outside and quickly measured a stock zed wheel -

 

245/45/16 and it came out at just over 10cm on my crappy kids 15cm ruler.

btw 235/45/17 is the wrong tyre profile for a Zed, it should be 235/40/17