Tyres... The usual Q with a twist!
 

OK, so one of the questions that pops up all over social media is 'what is the biggest tyre I can fit to x'...

On the 850, I've always agreed with the masses in that a 215/45x17 is the biggest tyre that you can fit to a lowered 850.

Some tyre sizes here to highlight the differences:

205/45x17 (std): 24.3in diameter
215/45x17: 24.6in diameter
205/55x16: 24.9in diameter

I've included the 205/55x16 because that is the size I'm currently running on my 850R - they fit fine and are a std size for an 850 IIRC.

Which leads me to my question...

My imported 850R came fitted with 205/50x17 tyres (?!) These are 25.1 in diameter, so not too dissimilar to the 205/55x16s. I didn't get to drive the car with them fitted as the tyres were ... past their best shall we say :D

I was wondering why nobody suggests this size (205/50x17) for lowered 850s - do they rub anywhere when the car is driven enthusiastically or if the boot is full? I like the idea of a slightly taller sidewall as my aging body can't take low profile tyres any more :D

Thanks, and sorry for repeating a well worn question...

Oh goody a tyre thread. Now you all know the rules:

1) Contestant No.1 says "They're black and they're round"
2) Contestant No. 2 says "I buy the cheapest."
3) Contestant No.3 says Brand X are so much better than Brand Y, this on track-days. The inference being he has the talent to tell.
4) Contestant No.4 says much the same thing as No.3, only with ever more delusion. Something about a brake-conversion? This vast talent finds himself on here. We mustn't point this out, it might be damaging.
5) Contestant No.5 with a set he cheerfully admits were 5-6 years old and hardened, comes to the conclusion this 'new' brand is far better than his old. He'd never buy the old brand again.

We mustn't take the unmerciful, but it's funny so we do anyway.

OK, on your marks...

205/50x16 are the factory fitted size on the 850 with 16" wheels

55 profile tyres will/do rub on full lock

I had 4 new tyres fitted last year, the day before we went into lockdown. National Tyres decided it would be a good idea to fit two 205/50R16 and two 205/55R16 tyres and one of the 55 profile tyres was on the front where it rubbed on full lock. Once changed to the correct 50 profile there was no more rubbing

To keep it factual, isn't the size that now escapes me - as found on the 16" XC biggest? It's what I use, high walled, it's the most comfortable and cheapest too. My winter set are narrower. Again, as factory sizing.

They all rub on inner wings, and I live with it.

I run 205/40/17 on mine, lowered on coilovers, no rubbing at any time loaded or not. 😂

Thanks everyone.

Interesting that you find that 205/55x16s rub 4x4 - I haven't had any issues with mine! I guess its down to tyre designs as well as the dimensions (how square the shoulder is?) My Hankook 4S2 all season tyres are slightly rounded at the shoulder which might explain the difference.

Oh well, I guess I'll play it safe and stick with 215/45x17 afterall :D

tyre shape can alter dependant on the rim width its usualy marked on the rear of the wheel eg 7 or 7.5 j also the condition of the lock stops can affect whether a tyre rubs the arches..

I have had my 850 T5 since it was 3 years old and the original tyre size is 205/55/16

Yeah, thats why I fitted 205/55x16 to mine - I believe the early cars had 205/50 but the later ones had 205/55s - I've seen owner's manuals stating both

Tyre Size
 

My V70 T5 came with 205/50x16 fitted and the O/S front rubbed on the inner wheel arch (N/S was fine) even though the steering stop was not worn. Never had any MOT advisory about this.

Now changed to 205/55x16 (with thicker C70 blue steering stops) and the cost was less than the 205/50x16, but haven't done enough mileage to notice any major difference yet. There may be a slight improvement in comfort but this could be due to the old tyres being stiffer due to ageing.