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[Darth Loo-knee]

I believe he has only changed the width of his tyre so why would this affect his speedo?  :-/

Because the second set of numbers, 65 in this case, is the Aspect Ratio, i.e a percentage of the width of the tyre for the profile

Admittedly, the speedo won't be out by much and is probably still within the manufaturer's tolerances... But it will read inaccurately compared with the previous reading with the correct size tyres

I have always been under the illusion that the speedo would be effected if someone was to put lower profile tyres on or smaller wheels
I don't think by having more narrow tyres on will effect the speedo

[Lazydocker]

I believe he has only changed the width of his tyre so why would this affect his speedo?  :-/

Because the second set of numbers, 65 in this case, is the Aspect Ratio, i.e a percentage of the width of the tyre for the profile

Admittedly, the speedo won't be out by much and is probably still within the manufaturer's tolerances... But it will read inaccurately compared with the previous reading with the correct size tyres

I have always been under the illusion that the speedo would be effected if someone was to put lower profile tyres on or smaller wheels
I don't think by having more narrow tyres on will effect the speedo

As above, the profile of the tyres is the 2nd set of numbers, which is actually a ratio of the width.

Like I say, the difference is probably very small, but there will be a difference

[Darth Loo-knee]

" changed my tyres from 205/65/R15 to 195/65/R15 and this would give me 10mm each side extra clearance."

The size of tyre that the guy posted in his original post says the width of the tyre has changed.....from 205 - 195...
The 65 which is the tyre wall has stayed the same
The R15 which is the size of wheel has stayed the same.

Am I wrong then?

[Lazydocker]

" changed my tyres from 205/65/R15 to 195/65/R15 and this would give me 10mm each side extra clearance."

The size of tyre that the guy posted in his original post says the width of the tyre has changed.....from 205 - 195...
The 65 which is the tyre wall has stayed the same
The R15 which is the size of wheel has stayed the same.

Am I wrong then?

Yep

This link explains it with pictures

Like I said, the sidewall is measured as a 5age of the width. So change the width with the same aspect ratio and the actual sidewall size changes. In this case by 6.5mm

[Darth Loo-knee]

" changed my tyres from 205/65/R15 to 195/65/R15 and this would give me 10mm each side extra clearance."

The size of tyre that the guy posted in his original post says the width of the tyre has changed.....from 205 - 195...
The 65 which is the tyre wall has stayed the same
The R15 which is the size of wheel has stayed the same.

Am I wrong then?

Yep

This link explains it with pictures

Like I said, the sidewall is measured as a 5age of the width. So change the width with the same aspect ratio and the actual sidewall size changes. In this case by 6.5mm

Well if your right I am gonna Eat Obi 
I have looked at your link... and erm I aren't that hungry 
I still don't think that the wall if what you say is 65% of the width of the tyre looks anything like it.. so there 

[Lazydocker]

" changed my tyres from 205/65/R15 to 195/65/R15 and this would give me 10mm each side extra clearance."

The size of tyre that the guy posted in his original post says the width of the tyre has changed.....from 205 - 195...
The 65 which is the tyre wall has stayed the same
The R15 which is the size of wheel has stayed the same.

Am I wrong then?

Yep

This link explains it with pictures

Like I said, the sidewall is measured as a 5age of the width. So change the width with the same aspect ratio and the actual sidewall size changes. In this case by 6.5mm

Well if your right I am gonna Eat Obi 
I have looked at your link... and erm I aren't that hungry 
I still don't think that the wall if what you say is 65% of the width of the tyre looks anything like it.. so there 

Would you like ketchup with that sir

[Darth Loo-knee]

" changed my tyres from 205/65/R15 to 195/65/R15 and this would give me 10mm each side extra clearance."

The size of tyre that the guy posted in his original post says the width of the tyre has changed.....from 205 - 195...
The 65 which is the tyre wall has stayed the same
The R15 which is the size of wheel has stayed the same.

Am I wrong then?

Yep

This link explains it with pictures

Like I said, the sidewall is measured as a 5age of the width. So change the width with the same aspect ratio and the actual sidewall size changes. In this case by 6.5mm

Well if your right I am gonna Eat Obi 
I have looked at your link... and erm I aren't that hungry 
I still don't think that the wall if what you say is 65% of the width of the tyre looks anything like it.. so there 

Would you like ketchup with that sir

I aren't sure that will help me to get it down ode lad 

[TheBoy]

As others have said, far more likely that the camber is out, than an occasional speed bump.

I suspect the Just Tyres manager was talking out of his backside.  But if it works for you

[omegod]

" changed my tyres from 205/65/R15 to 195/65/R15 and this would give me 10mm each side extra clearance."

The size of tyre that the guy posted in his original post says the width of the tyre has changed.....from 205 - 195...
The 65 which is the tyre wall has stayed the same
The R15 which is the size of wheel has stayed the same.

Am I wrong then?

Yep

This link explains it with pictures

Like I said, the sidewall is measured as a 5age of the width. So change the width with the same aspect ratio and the actual sidewall size changes. In this case by 6.5mm

Well if your right I am gonna Eat Obi 
I have looked at your link... and erm I aren't that hungry 
I still don't think that the wall if what you say is 65% of the width of the tyre looks anything like it.. so there 

Im not having it either Daz!

 I fink der jus tryna confuse me wid all dem numbers

[aaronjb]

Am I wrong then?

Yes, and Lazytinker is right

http://www.carbibles.com/tyre_bible.html

Oh and the ever useful http://www.miata.net/garage/tirecalc.html which says you'd see a 2% difference in the speedo reading (indicated 60mph would be a previously indicated 58.8mph - hardly worth worrying about, really, given that difference will shrink once you take into account 'real world' tyre squish)

As for going over humps.. when they put the humps in outside my old house I had to drive down the middle of the road to avoid them entirely in the MR2 (it wasn't lowered that much, either!)

[feeutfo]

Utter 'dangle berries' I'm afraid.

What's happened here is, you've gone to a company offering a service. Fair enough.

Trouble is, as said, that service does not include camber setting.... Or even measuring. Camber is vital on the omega. Tracking/toe is all that's been addressed which is a fraction of the story with this car. Camber should be set to minus 1degree 10 mins for stock set up.

 So rather than admit that fact, they have come up with some BS to deflect that they don't have a clue with this vehicle. Or of they do they should have informed you.

So as said, utter 'dangle berries'.

Sorry.

See wheels in motion web site.

[feeutfo]

In fact, thinking about it, eventually. The cheeky tinkers have had the Gaul to sell you a more expensive set of tyres as well. Being wider.

[Lazydocker]

In fact, thinking about it, eventually. The cheeky tinkers have had the Gaul to sell you a more expensive set of tyres as well. Being wider.

Narrower 195 instead of 205

[feeutfo]

Arse! Long day.   

[Lazydocker]

Arse! Long day.   

What did you decide on the LPG inspection?