Does wheel size effect speed??

[sincy]

got a VZ ute with the 15" chasers.. just bought some 19 wheels.. will there be a big difference, if any in the speed/acceleration/anything else i should know about.. and is there a way to fix it??

cheers

[HARVZ-6]

roller diameter is not much different.. speed will be slightly out most likely

can be recalibrated to suit by holden

[sincy]

roller diameter is not much different.. speed will be slightly out most likely

can be recalibrated to suit by holden

thanks.. will the speed be higher or lower???

[MUT4NT]

its either way usually

[Exidor]

If the tyres are of a larger diameter than stock your speedo will show
a lower reading than true. eg 10% larger diameter tyres =10% lower KPH approx.
Also larger diameter tyres will be like lowering (taller) your diff ratio.
ie your rpm will now drop at a given speed.

[Troy711]

Tire size calculator

This should help you

[murph_1989]

go to holdens and get it recalibrated

if u go bigger ur speedo will show a lower speed that what you are doing
dont ask me the margain etc

[Travy]

All depends on overall diameter not just wheel size.

The tyre size calculator listed above tells you exactly the percentage its out by.

[TUF UTE]

i dont believe holden can recalibrate it .... not if it has more than 12 kilometres on it. i may be wrong though.

[ducker85]

roller diameter is not much different.. speed will be slightly out most likely

can be recalibrated to suit by holden

WRONG

the rim size wont affect your speedo until you get 20's or larger, as long as you run the correct tyre profile, the 19's are actually 100% perfect for yuor over all diameter were the 18's are 2mm smaller affecting the speed the slightest

i know anything that come factory on 15's in the ex models can run 19's fine, the VE changed there tyre profile and you can get 22's on them before affecting the speedo

to go further if you fir the incorrect tyre profile to your stock factory wheel this will f*ck up your speedo more then the 19's will

[ashbox]

i dont believe holden can recalibrate it .... not if it has more than 12 kilometres on it. i may be wrong though.

thats only the kilomteres they can't adjust.
they'll be able to correct the speedo cos its just a tweak of the software.

[ducker85]

thats only the kilomteres they can't adjust.
they'll be able to correct the speedo cos its just a tweak of the software.

but there no needs to if you go 15's to 19's the speed DOESN"T change at all, not 1km, nothing.

trust me I've spend many hours in my wheel shop asking questions and i've run these wheels and double checked with the GPS speedo

[JBDrifter]

Anyone know how much Holden charge for recalibration of the speedo?

[ScoHar]

as for acceleration you may find your car slightly slower, as bigger wheels usually mean more weight (of course depending on wheels its quite a broad statement) and 10kgs weight difference can end up being quite a difference. I had 18's on my VP and it goes a lot (can actually feel the difference) better with 15's on I think they were about 10kgs difference per wheel. theres some sort of calculator on the net that can tell you how much 10kgs is when its rotating or somewhat.

as for the speedo, it'll be out by bugger all but you can get speedo pulse changers or something that you can change the pulse outputted by the gearbox going to the speedo.

[harvs01]

I have a sv6 std rims were 17" have now got 18"s and the speedo is 2k out. eg i go 70 by speedo the actual speed is 68. as test through the check you speed things they have on the freeway's

[WogBoyz]

mine vs ute came stock with 16's ive now got 18s with low profiles does that mean my speedo could be slightly out?

[ScoHar]

I have a sv6 std rims were 17" have now got 18"s and the speedo is 2k out. eg i go 70 by speedo the actual speed is 68. as test through the check you speed things they have on the freeway's

it prob was out by 2kms with 17's too.

[ScoHar]

mine vs ute came stock with 16's ive now got 18s with low profiles does that mean my speedo could be slightly out?

ever so slightly prob un-noticable.

[TVR-190]

as for acceleration you may find your car slightly slower, as bigger wheels usually mean more weight (of course depending on wheels its quite a broad statement) and 10kgs weight difference can end up being quite a difference. I had 18's on my VP and it goes a lot (can actually feel the difference) better with 15's on I think they were about 10kgs difference per wheel. theres some sort of calculator on the net that can tell you how much 10kgs is when its rotating or somewhat.

as for the speedo, it'll be out by bugger all but you can get speedo pulse changers or something that you can change the pulse outputted by the gearbox going to the speedo.

with the walkinshaw clubby its 3 seconds quicker around a track with 20's over the standard 22'' rims

[cntcm3]

ive got 19's on my SV6 n my speedo hasnt changed, i checked it against my sat nav

[Jesterarts]

with the walkinshaw clubby its 3 seconds quicker around a track with 20's over the standard 22'' rims

Yep... can't get good tracking with 22's... nor 20's.

If they didn't have the massive brakes on the clubby and put 18's, it would have been even quicker.

Getting bigger wheels on a car will not affect the speedo reading by much so long as you put tyres of a legal diameter on, so max 15mm diameter increase.

Good luck with the wheels.

[woody13666]

the main thing that generally will be effected is your acceleration usually increase of tyre size gives slower acceleration and a higher speed then is indicated on your speedo,having 19-20's might put your speedo out slightly by 1-3km's but at a higher speed of 100km etc

[ducker85]

I have a sv6 std rims were 17" have now got 18"s and the speedo is 2k out. eg i go 70 by speedo the actual speed is 68. as test through the check you speed things they have on the freeway's

All cars are out anyway from factory they have a 4% allowence or something my Dad's BRAND NEW STOCK AS A ROCK VE SSV is 4km out at 114 he's doing 110 is car is 100% box stock and has less then 30,00kms

wheels 15 to 19 DONT NOT AFFECT YOUR SPEEDO

[GMHCalais]

All cars are out anyway from factory they have a 4% allowence or something my Dad's BRAND NEW STOCK AS A ROCK VE SSV is 4km out at 114 he's doing 110 is car is 100% box stock and has less then 30,00kms

wheels 15 to 19 DONT NOT AFFECT YOUR SPEEDO

if everyone is so worried. theres also other ways to measure if your out.
hence your trip computer that can show the speed your doing electronically.

i did it with mine and it said i was doing 60, but the electric speedo said i was doing 58 so its hard to say? ive only got 17's on the calais must i add..

[TMM]

Trip computer is only as accurate as it's calibration - it'll need recalibration if you put a different diameter wheel/tyre on. Same goes for the dial.

If you want an accurate speed use a GPS.