Tyre sizes .. have i got this right.

[owas]

So I've got my e34 MOT'd and on the road.
It's fitted with some old budget 225/60/15 tyres that are lethal.

Am I right in thinking that 205/65/15 will fit fine on the rim just be a tad smaller in diameter?

More choice and slightly cheaper than the 225s.

Would the mobile fitters from one the chains care about fitting a different size, it does ask if you've checked the sidewall

 

[mtt.tr]

so the 205 is the width, the 65 is a percentage of the width

so your diameters would be
205 dia = 648
225 dia = 650

205x0.65= 648 rounded
225x0.60=650 rounded

i think ive worked that out correctly, possibly not but will soon know

 

[Ubique]

The first number is essentially the width, so you'll end up with the ridiculous-looking narrower tread than the wheel rim that some kids think is the bees-knees.... If you intend to go for that, I'd check with your insurer first.
Chinese ditch-finders in the correct size appear to be ~£65 each on black circles, less on fleabay, Falken can be had for £366 for a full set.

 

[mtt.tr]

The first number is essentially the width, so you'll end up with the ridiculous-looking narrower tread than the wheel rim that some kids think is the bees-knees.... If you intend to go for that, I'd check with your insurer first.
Chinese ditch-finders in the correct size appear to be ~£65 each on black circles, less on fleabay, Falken can be had for £366 for a full set.

that would depend on the rim, normally there is a something in the owners manual or the plate on the door jamb

 

[Bullet2012]

15 x 25.4= 381
225/60 = 135
205/65 = 123

225/60x15= (135+381) 516
205/65x15= (123+381) 504

i think, but ready to be corrected

 

[Ubique]

Well, yes - but if the specified tyre width is 225, then that will be the one intended for the standard rim, anything else is incorrect for the vehicle and therefore should be notified as a modification to your insurer (same goes for speed ratings). I don't really get involved with tyres on a daily basis but know when something looks or measures incorrectly.

 

[weldingnovice]

Don't think you can fit narrower tyre than specified for particular model.

As said listed on the vehicle somewhere, oversized/speed not so much an issue.

 

[mr haynes]

From memory the 205's were a standard fitment but will depend on the rim width

 

[owas]

Says both on the sticker

 

[mr haynes]

If you have standard fitment wheels then, at a guess, the lower spec cars would have the narrower tyres.
If it is not more than 7" wide rims 205 will be fine

 

[Ubique]

The sticker doesn't mention the rim width, just the various size/pressure combinations.

 

[PhillipM]

The rim size will be stamped on the inside of the rim somewhere usually.

 

[owas]

7"

 

[mr haynes]

205 tyre will go that fine

 

[tom2207]

205/65-R15 vs 225/60-R15 Tire Comparison - Tire Size Calculator | Tacoma World

225/60-R15 tires are 0.14 inches (3.5 mm) larger in diameter than 205/65-R15 tires and the speedometer difference is 0.5%

www.tacomaworld.com

 

[Nomad]

I'm relaxed about changing tyre widths up or down a couple of sizes each way, on my BMW my winter wheels were same size as standard but the winter tyres were slightly narrower.
If your car has modern ABS or a "new generation" computerised dash it's best to keep the rolling radius of the tyres about the same as original so the system doesn't get confused.
A good website for comparing old & new https://www.willtheyfit.com/

If you decide to change the sizes up or down 10+ sizes for the crazy wide tyre on narrow rim (or narrow tyre on wide rim) look loved by some "car customisers" it gets risky.
For the changes you are looking at I'd say no need to be concerned about worst-case scenarios or notify your insurers but others have different opinions.

 

[Fastdruid]

+1 for notifying your insurers, many won't give a stuff, others want to know if you fit winter tyres!

We had similar with a Mazda 6 MPS, original tyre size was 215/45R18 which are both expensive and very limited choice, changed to a 225/40R18 as it was about half the cost for better stickier tyres! Very slightly out on the speedo but not enough to worry about.
Insurer didn't care as long as the wheels weren't being changed (BUT again, some do) and that telephone call would have been recorded in case there were any issues later.

 

[tigdlo]

Some tyre manufacturers list appropriate rim widths on their website, for example Toyo CF2 has an approved rim width of 5.5" - 7.5".

For comparing tyre sizes I use this, https://tiresize.com/comparison/

 

[owas]

I had them fitted on the weekend and personally think they look much better than the 225s which looked too fat to me.