imprezahubbard

hey peeps just booked my car in for a set of 4 egegal f1 gsd3 tyers and just noticed they are 205/45W16 and think my old ones are 205/50Z16
so not being to clued up on tyers will i be ok with them will they fit ? and whats the difference?

500

Speed rating. Z is 150+mph and W is 168mph

imprezahubbard

oh ok so they will fit? was worried bout the diff between the 45 and the 50

imprezahubbard

just worried they might mess up my acceleration or my speedo

alcazar

iTrader: (2)

WHY would you change the profile? Yes it will mess up the speedo.

imprezahubbard

Wasnt my idear was just tge tyers kik fit slected for me when they typed my number plate in

piehole1983

iTrader: (7)

As said on your other thread, 3.5% difference on the speedo. Not too bad but I also have to ask why the profile change?

Edit: did you say kwik fit selected them?

imprezahubbard

yes mate

imprezahubbard

ive red alot off people useing these tyers with great reviews so guess ill have to wait and see

joz8968

iTrader: (13)

As mentioned, the rolling circumference of the 45 profile tyre (one full revolution of the tyre) will be 3.35% less than the OEM 50 profile. Or will have travelled 64mm (2.5") less.

So slightly better acceleration......at the expense of top speed. But I doubt you'll notice, anyway.

Aesthetically, the lower sidewall profile will look nicer (although that's subjective, obviously)... As well as lowering the car nearer to the ground ever so slightly, by 10mm.

imprezahubbard

Thanks that's made me fill much better it's just the speedo I'm mainly worry bout now

joz8968

iTrader: (13)

Don't forget, manufacturers build in a small overread in the speedo (from 40mph onward), so that you're doing slightly less actual mph than that indicated. It's designed to temper against going over speed limits.

So the fact that the overall gearing will be lowered, will probably bring the speedo very close to the ACTUAL road speed, anyway. So I wouldn't worry too much.

If you have a GPS-based gismo - speed trap detector, phone app or whatever - then you can do a comparison test (and obviously just go by the accurate GPS speed).

If not and/or if in doubt, just do an indicated, say, 5mph less than the speed limit, so as to build in a 'potential licence points saving lol' compensation...

Steve001

iTrader: (7)

I always thought that larger tyres/wheels made the speedo under read so you have nothing to worry about

See here http://www.tyresizecalculator.com/ty...ror-calculator

joz8968

iTrader: (13)

Yes you're right - fail on my part.

So yeah, going to a smaller overall rolling radius will cause a small speedo overread... So, as you say, even less to worry about.