speedo

[danny1.0l]

hi guys hope you can help ive just fitted 15 inch alloys to my k11 and wen i drove it for the first time after i fitted them i noticed the speedo was a bit lazy and was just wondering whether the speedo will get back to normal after a while or will i need a calibration on my speedo:question:

 

[dodzy31]

many speedos are ran off the revolutions that your wheels take. So if you increase the size of your wheels then it would be slower than usual as it the wheels takes slightly longer to do a full rotation.

So yes you do need your speedo recalibrating.

 

[danny1.0l]

does anyone know how much it will cost to get my speedo recalibrating

hope someone can help coz lazy speedos are no good

or could i get a instrument gauge panel with rev counter then wire it in to my existing one even though it dosent have a rev counter see its coz i have a l model k11

 

[Noddie]

does anyone know how much it will cost to get my speedo recalibrating

hope someone can help coz lazy speedos are no good

or could i get a instrument gauge panel with rev counter then wire it in to my existing one even though it dosent have a rev counter see its coz i have a l model k11

the wheel size will affect all speedo's as the engine revs to car speed ratio is ultimatly guverned but the size of the wheel. remeber that tire profile will make a difference, when i had 15's i had lower profile tires (50) and the difference was minimal (maybe 5mph at 70) mabe its the slower exceleration you are noticing? as bigger wheels means less exceleration.

 

[Alexx117]

many speedos are ran off the revolutions that your wheels take. So if you increase the size of your wheels then it would be slower than usual as it the wheels takes slightly longer to do a full rotation.

So yes you do need your speedo recalibrating.

Im sorry but i have to disagree..

For every turn your wheel makes you will be covering more distance with 15"'s that 13"'s so you will be going faster than your speedo says, its called rolling radius but can be minimized by tire profiles.. you will notice a difference in acceleration how ever you will gain a few mph top end.

As far i know though i dont know how to fix this, when i had 15"'s on my 1.0 i just went past a few speed signs to check or got someone in front to drive at a certain speed limit (Y)

Sorry if i mis-interpreted you dodzy but i thought id clear things up.

 

[dodzy31]

^ ^ ^
Yes you will be covering a longer distance but the speed of a full rotation of a 15" would be longer than a 13", no? Assuming both tire profiles are the same on each wheel and both wheels are span at the same speed etc etc.
Thats basically what i meant to say.
But at the end of the day he still needs it recalibrating, i think we can agree on that.
I suppose you could ask a garage if they could do anything or ask if they knew how you could go about getting it done.

My initial post was a bit hazy though so i apologise for that.

 

[Alienfish360]

plus you've got a CG10, a 1.0 with 15" wheels will be a bit lazy

 

[Alexx117]

Im not sure how it would go about being calibrated but it all depends on the circumferance of the rim and tyre like mine are 15"'s with 195/45/r15 tyres and a 13" rim with say a 155/70/13 tyre is pretty much exactly the same size

 

[matt1987]

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

try this then you can decide yourself aslong as your speedo is nearly right i wouldnt worry

 

[capnmchl]

The CG10 speedo, with 13"s is about 10% out anyway. 77 on the speedo came up as 70 on my sat nav.

Borrow a sat nav, and hold it at a steady speed (easiest is probably 30, 60 and 70) on the satnav, and see where the speedo sits.