[GaKu]

Thanks for the very detailed information.

I will be changing to Michelin crossclimates soon and was wondering on the size I should get. I have a 2011 model and tyres are 185/65R15 and want to upgrade to 195/65R15. I was wondering if this would result in an incorrect odometer reading and also affect DTE and fuel economy readouts in the long run.

[Surferdude]

@Gaurav
Hopefully someone in Europe or the UK can answer this for you. Our cars come standard on 195/65R15 although I believe there were Some very early ones on 185s.
I'm on my tablet atm so I don't have access to the conversion chart. I'll try to get back to you tomorrow. There will be a slight difference but not a lot.

[CraigB]

Thanks for the very detailed information.

I will be changing to Michelin crossclimates soon and was wondering on the size I should get. I have a 2011 model and tyres are 185/65R15 and want to upgrade to 195/65R15. I was wondering if this would result in an incorrect odometer reading and also affect DTE and fuel economy readouts in the long run.

A width change wont affect your odometer or other readout, radius would but then you would decrease the profile to allow for a larger rim.

[Surferdude]

Thanks for the very detailed information.

I will be changing to Michelin crossclimates soon and was wondering on the size I should get. I have a 2011 model and tyres are 185/65R15 and want to upgrade to 195/65R15. I was wondering if this would result in an incorrect odometer reading and also affect DTE and fuel economy readouts in the long run.

A width change wont affect your odometer or other readout, radius would but then you would decrease the profile to allow for a larger rim.

It will Craig. Height is 65% of the width.  65% of 195 is more than 65% of 185.

[CraigB]

Oh 

So that would equate to a 6.5mm radius increase...is that correct   which would then mean moving down to a 60R 

[Surferdude]

Oh

So that would equate to a 6.5mm radius increase...is that correct which would then mean moving down to a 60R

No it's diameter. 
To put things in perspective,  you have 8mm of tread depth (x2). Which can go down to about 1.5mm legally, so you have a certain amount of leeway to play with. In the overall scheme of things,  6.5mm isn't much. As I said,  a small difference. It might not be enough to worry about.

[Surferdude]

In this case, at 100kph on the speedo,  your actual speed would be 102kph

[GaKu]

Just found a website that did some calculations:

                                                      185/65-15             195/65-15         Difference

Diameter inches (mm)           24.47 (621.5)          24.98 (634.5)         0.51 (13) 2.1%
Width inches (mm)                   7.28 (185)          7.68 (195)         0.39 (10) 5.4%
Circum. inches (mm)           76.87 (1952.5)       78.48 (1993.34)    1.61 (40.84) 2.1%
Sidewall Height inches (mm)   4.73 (120.25)          4.99 (126.75)         0.26 (6.5) 5.4%
Revolutions per mile (km)   824.25 (512.16)     807.36 (501.67)    -16.89 (-10.49) -2%

Seems like this would mean that I have to adjust my readouts by 2%

Agree?

[CraigB]

I meant diameter

[Surferdude]

That's correct.
Unfortunately,  while I've been answering your posts, someone has split the topic off.
A bit frustrating when the discussion is active.
Ill try to move over the other relevant posts.

[Surferdude]

They're all in place now. You might need to go back up the page to follow the thread.
Shambles is on the ball tonight. 
As you worked out yourself,  100 on the speedo is 102 actual.
Not really worth worrying about.

[GaKu]

Well, here the speedo actually shows about 10% more than actual (when compared to GPS and also roadside speed meters). My friends with other cars also say the same. I am thinking that may be due to some law in order to accommodate for larger tyres (EU laws are weird). Thats why I have never been able to get reliable readouts for fuel economy but thought the odo would be right...but maybe not after all.

[Shambles]

Unfortunately,  while I've been answering your posts, someone has split the topic off.
A bit frustrating when the discussion is active.

Sorry 'bout that.

GaKu's request would have got lost/buried inside a stickied "for info" post. Yeah, maybe I should have held off

[The Gonz]

Yeah, maybe I should have held off

Don't go all liberal do-gooder welfare softie on us, Donald Steve. Swing that club like a real boss.

[Surferdude]

Unfortunately,  while I've been answering your posts, someone has split the topic off.
A bit frustrating when the discussion is active.

Sorry 'bout that.

GaKu's request would have got lost/buried inside a stickied "for info" post. Yeah, maybe I should have held off

No probs. All got sorted in the end.
Just confused me 'coz I often just useethe back option on the tablet and I was going back and being told the posts weren't available. 

[Asterix]

I run 185/65-15 winter and 195/65-15 summer.

The 195 makes the speedo read more accurate. Compared to GPS:

Tyre         Speedo        GPS
185/65:        90          84/85
195/65         90          86/87