Can I fit 165/65 R15 on toyota Aygo 2016 ? ​​​​​​​

[Rav-IV]

Hi all, 

I drive an Aygo 2016. I have on the car 165/60 R15, and I have very limited choice of tire models that I can fit.
Did anyone try or know if I can fit the 165/65 R15 on the car ? I would like to fit the Michelin CrossClimet+?

 I was told that this can interfere with the ABS system and the Speedo.
I am not worried about the Speedo as I currently have about 5% allowance from the original speed.

Raviv

[FROSTYBALLS]

You need to check the effect on the speedometer using one of the many online wheel size calcu!ators.

in the UK, the speedometer must never show an indicated speed less than the actual speed, and never more than 110%.  Additionally, for all actual speeds between 25 mph and 70 mph (or the vehicles' maximum speed if it is lower than this), the indicated speed must not exceed 110% of the actual speed, plus 6.25 mph.

For example, if the vehicle is actually traveling at 50 mph, the speedometer must not show more than 61.25 mph or less than 50 mph.

Using the following website, your speedometer will under read, which is illegal - https://www.autopartuk.com/tyre-calculator/

[Rav-IV]

2 minutes ago, FROSTYBALLS said:

Thanks FrostyBalls, when the speedo shows 60mph my actual driving speed is 56mph.
With the new tire size that will bring the speed back to about 58.7mph so I will still be legal.

Thank you for this site - really helpful

Would you know about the details of the ABS ? will it be triggered as the wheel role is longer ? or even the tire pressure (TPM) system ? would those be affected ?

 

 

[Yugguy1970]

ABS would only be triggered if you have different ratios front to back, or across an axle, which makes the wheel speeds different.

[FROSTYBALLS]

5 minutes ago, Rav-IV said:

Thanks FrostyBalls, when the speedo shows 60mph my actual driving speed is 56mph.
With the new tire size that will bring the speed back to about 58.7mph so I will still be legal.

No. The website I linked, show that with the new tyres, the speedometer will show 60mph when  the actual speed will be 61.6 - which means the speedo will show less than the actual speed (under reading) and will be illegal.

Where are you getting your figures from?? If a sat nav, the speed shown on a sat nav is an average over a given number of points, and isn't an accurate reflection of actual speed.

[Rav-IV]

I see Frostyballs, Yes, I get the speed from Waze, and I see what you mean. 
So if I currently travel at 60mph, my SatNav shows 56.5mph ; So technically my actual speed is 4% below the actual speed. 
Putting the larger tire, the speedo will show 60mph while my actual speed should be around 58mph.

Which means my actual speed is still less than the Speedo speed ? or am I getting it completely wrong ?

 

[FROSTYBALLS]

Forget the Waze figures.

Using one of the online ca!culators (eg like the one I linked which shows the calculation in red below the tyre comparison), with the proposed tyres the actual speed will be 61.6mph, but the speedometer will show 60mph. Which means the speedometer will show less than the actual speed and be illegal.

[Hornet3D]

4 hours ago, FROSTYBALLS said:

You need to check the effect on the speedometer using one of the many online wheel size calcu!ators.

in the UK, the speedometer must never show an indicated speed less than the actual speed, and never more than 110%.  Additionally, for all actual speeds between 25 mph and 70 mph (or the vehicles' maximum speed if it is lower than this), the indicated speed must not exceed 110% of the actual speed, plus 6.25 mph.

For example, if the vehicle is actually traveling at 50 mph, the speedometer must not show more than 61.25 mph or less than 50 mph.

Using the following website, your speedometer will under read, which is illegal - https://www.autopartuk.com/tyre-calculator/

Wow, now there us a very useful web site.  I have been asked the same question by family and friends in the past if only I had known about this site.

[Rav-IV]

Just an update:

I went to my local police station, and I asked for their help to find out my actual speed. I told them what I want to do with the tires. 
They were happy to help me in measuring my vehicle speed by using a laser speed gun measurement.

Below are the results: 

Speedo (SP) measurement  vs Police Measured speed (PL) vs Waze Speed (SAT)
SP:20 MPH       PL: 18       SAT:18
SP:30 MPH       PL: 28       SAT:27
SP:40 MPH       PL: 38       SAT:38
SP:50 MPH       PL: 47       SAT:47
SP:60 MPH       PL: 56       SAT:57
SP:70 MPH       PL: 66       SAT:67 

They calculated that changing the tires will still keep me legal from speed point of view due to the offset of the Speedo.
However, they added and told me that I will need to do 2 things:

a. Make sure the insurance is aware of this change (as this is a vehicle change)
b. To check with DVLA if this change requires a new MOT as it may change the 'vehicle' characterises and handling - the police is not checking tire sizes even in an event of an accident unless they deemed to be 'a complete wrong fit to the car'. 

[FROSTYBALLS]

Well you seem to be determined to make the change regardless, so do whatever you want.