road spped with diff. tyres

[eliteforce32]

whats the equation or if some one tell how to know my road speed..... 33 tyres, 86 model SC lux, standard 5spd box and diffs? can some one help

cheers
simon

[-Scott-]

Real speed = Indicated speed x new tyre diameter / original equipment tyre diameter.

This is still a very rubbery figure because:

Your speedo is 18 years old and may not read correctly even with the original size tyres.
Your 33" tyres may not be exactly 33" tall.
The OE tyres were probably exactly the nominal size.

But, it's probably close enough.

Cheers,

Scott[/list]

[+dj_hansen+]

I did this when i ran 33"s for a little while...

Factory tyres are around 30"..... so thats a 10% increase in rolling diametre.

Knock 10% off your speedo reading.

Its not all that accurate... but works

[Utemad]

Check your speed with a GPS and figure out the percentage your speedo is out by. Then drive that percentage slower.

[spazbot]

should be out by about 10% on the lux so if ya clock says 60 your prolly doing 54 or so

[De-lux]

do what utemad did with the GPS idea, but get a bit of white-out and put a dot on your speedo next to 100, 60 etc, just the main speeds that you need to be careful of. simple, yet effective

[DamTriton]

should be out by about 10% on the lux so if ya clock says 60 your prolly doing 54 or so

Udder ways around...........

10% larger tyres = 10% more speed at same revs = indicated speed + 10%.

60 indicated = 66 actual.

[MY45]

should be out by about 10% on the lux so if ya clock says 60 your prolly doing 54 or so

Udder ways around...........

10% larger tyres = 10% more speed at same revs = indicated speed + 10%.

60 indicated = 66 actual.

Gary is right

[eliteforce32]

thanks guys! great help