From my understanding, 2 different sizes fit the 16" wheels:

205/50/16
225/45/16

Does that mean that 225/50/16 would also work?

It not so much fitting the wheels as keeping the same overall diameter. 225/50/16 will give a 20mm larger overall diameter affecting gearing speedo etc

To put that into perspective, the difference in diameter between 205/50/16 and 225/45/16 is just 2mm.

Ahh ok i think i get it now..

So if the diameter difference between 205/50/16 and 225/45/16 is just 2mm, whats the width difference? 20mm?

Yes, although this value is affected by the rim width, i.e you could put a 225 on a 7.5" or 8" rim no problem but the actual tyre width would be slightly different.
IIRC the rim width on all Coupé 16" rims is 7" so not an issue.

If that was the case then won't the 225/45/15/16 be the ideal choice since its 20mm wider (bigger contact area) and just 2mm difference in diameter (2mm less won't cause that much uncomfort would it)?

225/45/16 is fine and is the standard tyre size on post '99 coupés, it does offer more grip at the expense of being more prone to tramlining

Cool. Didn't know that it was standard on post 99 coops.

Thanks for your help Ed!

In the time honoured fashion, I have a calculator that might help here

It's the rolling radius that counts here.

205/50/16= 612.2mm

225/45/16= 609.7mm This is 0.4% smaller than standard meaning your speedo will over read by 0.4% (indicated 80mph will be 79.7mph)

225/50/16= 632.2mm This is 3.2% bigger than standard meaning your speedo will under read by 3.2% (indicated 80mph will be 82.5)

One thing to remember, is that your speedo will over read anyway. By changing to a slightly larger rolling radius, you might even make it more accurate. Taking a 5% under read on your speedo (like mine is with 205/50/16) the above become;

205/50/16= 5% under read
225/45/16= 5.4% under read
225/50/16= 1.8% under read

The 225/50/16 should therefore be OK really. Pointless though, in that you won't gain anymore grip from wider tyres (lets not go there though ), and they'll prob be dearer than 205/50/16s.

I've been toying with the idea of 205/55/16s next time. You get another 10mm of sidewall for more comfort, the same grip as the compound can be the same (same model of tyre), the speedo will be more accurate, and they're cheaper by £10 a corner.

Interesting Trappy. Thanks for the comprehensive calculations

I was looking at the Falken 452's and the price difference between 205/50/16 and 225/45/16 is about £20. I would like some wider tyres but wondered if this was worth the extra premium. Will the wider tyres make any noticeable difference?

205/55/16 sounds interesting but surely the bigger sidewalls will compromise handling?

After lots of reading on the subject, it appears that wider tyres will just stretch your contact patch making it wider and thinner. This has no effect on grip, but there was an intersting article in Performance Car recently where a 'techy' from Prodrive was interviewd in a handling article.

He said that wider (and therefore lower profiled) tyres, will improve turn-in response at the expense of ride quality meaning the suspension has to be adjusted to compensate, undoing the benefit of the tyres in the first place. Secondly wider tyres lose some of the 'self righting' of a thinner tyre. Lastly, he said they reduce the feedback from the road, making it harder to feel the break-away point and on the limit balance.

There was quite some emphasis on the relationshp between the sales people (who want de big rims!) and the people setting up the handling and that best handling cars out there are those that have a good influence from the techies. I'll try to scan and upload it, bloody good read

55 profile will probably make it handle a bit 'sloppier', but the billy/ eibachs are loosening my teeth after nearly 30k miles, and I think a smoother ride would make most road cars faster in the real world. At anything over 50mph on a bumpy back road, there's the very real sense that I might be airborne at any minute...

Trappy

Very interested in your comments - I am just having a set of wheels refurbed and was going to buy a set of 205/50/16.

Your comments about using 55 intesests me for 2 reasons:

1. I live in Sheffield and the roads are lousy so 55's would mean for comfort.
2. My coupe has the front lips on and I have caught them on speed bumps and my drive 3 times already.

Questions

a) I presume 55's would lift the body of the car higher off the ground?
b) would there be any problems with clearance within the wheel arches?

cheers spookone

If you put 205/55/16 on instead of 50s you would only raise the car (in theory) by 2.5mm, dont think you notice it

Thanks for your comments Trappy. I look forward to the article.

Roads in Glasgow are terrible as well so the 55's would be a strong consideration. I would be interested to know what the clearance on the arches are like too as the current 205/50/16 look very close to them.

Anybody?

I need to order my tyres :-)

Questions

b) would there be any problems with clearance within the wheel arches (or anything else) using 205/55/16 on 16" VT wheels?

Desperate to buy a set of new tyres so this is a repeat of my entry on another thread but...

Will 205/55/16 cause any problems with clearance in the wheel arches?

Come on, one of you experts MUST KNOW

Is your car lowered spookone?

Need to be a bit careful here peeps, the numbers on the sidewall do not necessarily relate to the real world.
205/50/16 has a diameter of 611mm
205/55/16 has a diameter of 632mm
So you would actually be raising the car by 10.5mm and reducing the arch clearance by the same amount.
You could try it but I think you may find it rubbing.

Hi Kelv

I have only had it a few months so I am not entirely sure - have been wondering as it does seem a little on the low side.

But to be honest I dont think so???

I was asking Joe @ Countrycrusising and he mentioned that 55's should be ok.

Not the words I tend to entertain when it comes to tyres, I much prefer definitely to should

So you advise against it then Ed?

Yes, it's not a standard size for the car and unless someone posts that they have run this size for a significant length of time with no problems I wouldn't touch it myself.
Glancing back through the comments on this thread, it should clear the arches, it may improve ride comfort, it may make the handling a bit sloppier.
Too much conjecture, not enough proof for me

Thanks for your opinions Ed

Hi Kelv

What decision have you come to regarding the 55's?

I am desperate to lift my front lips that additional 10mm off the road and get a more comfortable ride on the pot hole filled roads of Sheffield.

As Ed has mentioned above... has anyone ran 55's and did you have any probs?

Why don't you be the pioneer of 55's and let us know how it works out?

Ok - let me know how you go on first - then I will give them a try :-)

I am still tempted ?!?!

Someone must have pioneered the 55's...

Anyone?

spookone, if there was someone that have tried them, they would have said something by now.

A little touchy arent you?

I was just trying to inject a little humour into the question of 55's - if you don't want to play, you don't have to.

I think you do need some sleep :-)