Hi guys,

Sorry if this is in the wrong category but i don't know where it should go.
I just changed 2 front tyres and got a wheel alignment done. Now my speedo is about 10-15kms off.
The speedo totally flies now, driving at around 60, it shows 75ish.

What could be the problem? or did the employees decide to throw in a 3sgte for me for free?
Thanks

Are the new tires a larger size than what was on there? Large tires/smaller tires will throw off the speedometer reading.

well if you want something done right you have to do it yourself

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Yeah, you go ahead and put the car on the alignment machine in your garage...

oh wait - you don't have one. Silly me.

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maybe he does, he can afford a 400,000 $ machine in his garage

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man why did you post this i'm going to change my tires and get a alignment too ..........geez now i think i'm just gonna get my tires and not do alignment.

This post has been edited by 808celica: Sep 26, 2007 - 6:52 PM

That is strange.
How do you know the speedometer is actually off by 10-15km? Did you drive next to a car asking how fast they were, or get clocked?
I don't think an alignment would mess with the calibration of the speedometer. Putting a bigger size tire could effect it.

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^tire size changing it by 15 km? i think that sounds like a little much... I jumped from 15in-17in without a change (live data read on my code reader told me so )

i have 18"s and my didnt change but 1mph over

ok wheel size will not effect speed alone... if he has say 14" wheels and with the tires he had on the total diameter of the tire from top tread to bottom tread was say 20" and this place put on tires that from top to bottom are only 18" that would show his car going faster than it really is on the spedometer - likewise if you put larger tires on your car like total top to bottom of say 22" your speedo will show that your slower than you actually are going. my guess is they gave him the wrong tire size. id start by checking the numbers marked on the sidewalls and compare them to your older rear tires. like if the fronts are 215 50 16 and the rears are 215 60 16, then there you have it, they gave you "smaller" tires

Also Toyota Speedos generally run about 6 mph faster than you are actuallygoing,so it wont be that far out, When my GPS speedo shows 70MPH the toyota speedo reads 74MPH and thats with 18inch wheels.

Well im 100% its off, by a fair amount too..
I dont claim to be a professional driver or anything, but i know roughly whats 60km and whats 70-75km....
Also when i drove on a 60km limit street... im driving 60... and its either everyone around me is speeding or im really only going 50kmph...

As for tyre size... my front 215's were replaced with fresh 215's so that cant be the problem.
Thanks for the replies guys.

185/60/14 and 215/35/18 are different things
I changed from stock to 205/55/15 and my speedo is off by 3 miles per hour

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205/55-15 IS stock size for a GT...