Tyres: Alternatives to KU31s

[Silvia]

Do you really think 7 mm over the 15mm legal radius change limit would get me into trouble?

[JBT]

thanks Guran, the difference in circumference between 205/45 and 205/50 in 16" is about 60mm -not enough to worry about legally considering there might be 50mm difference between a new and used up tyre in one size.

JBT your "rolling diameter" is confusing as I would think the diameter is always similar, rolling or not. are you meaning circumference, a measurement I find that cuts through a lot of bull.... ?
I'm thinking if I get new tyres then it would be good to try to address my concerns at the same time - (high revving in 1st and 110kph) and rough ride over corrugations.
Going to 50 series may address these issues, seems cheaper ($104 for KU 31), and could even wear longer.
There doesn't seem to be a downside.....

Yes, as stated several times, if you go to a higher profile the actual speed of the car will be higher at a given RPM in any gear - the indicated speed will remain the same. Whether you will notice it or not is debatable and whether it is legal is also a question mark. Rolling diameter is the common term used. However, circumference is a function of diameter so it is six of one and half a dozen of the other.

The downsides to what you are planning are that it may be illegal, may cause a deterioration in handling, your odometer will under read and there will most likely be no perceptible improvement in ride.

[Silvia]

"Yes Tom - 50 series are much more comfortable and look fine on the car - there are pics of mine on the NB wheel thread on n this forum. I would look at any of the performance 50 series tyres - KU31, Michelin, Toyo T1R or R1R, Federal etc."

From a well known member here who rides on 205/50 16's on his NB
I tend to listen to those with experience....

[Guran]

Do you really think 7 mm over the 15mm legal radius change limit would get me into trouble?

Actually it's a diameter change not a radius change ...

But to answer your question, it's up to you, the police, the TMR and your insurance company. Why take the risk of being defected or having an insurance claim knocked back when there are simple and inexpensive legal alternatives?

[Silvia]

not the first time the law has been proven an ass....I doubt there's any real reason to knock back a slight change in size where it has been agreed there is little change in characteristics but an increase in safety through better riding on rough roads.
A 50 series tyre would seem to be a good answer to the often reported harshness of the ride of the 16" 45 series supplied as stock...
But I'm always ready to listen to alternatives...perhaps there's a more comfortable 45 series 16" tyre available?
Or a legal 50 series 16" alternative ?
Switching to 15" wheels (albeit with cheaper tyres) would be a costly alternative and you'd have to question the legality of that too, I suppose?

[JBT]

I tend to listen to those with experience....

...as long as the answer is the one you seek. Good luck.

[sailaholic]

Change to 15, it will be legal, better, and cheaper in the long run. Get some used 6ul rims, they come up semi frequently and fit 205/50 tires, or 195 if you want too save some $.

Other than that look for a comfort tires (these are often "quiet" tires) in the right size and work on you're rim change down the track.

Sent from my GT-I9100 using Tapatalk

[Guran]

I'm getting confused. You started asking about tyre sizes to change your gearing. Now you're asking about tyre sizes to change ride comfort. What exactly are you after? If you want to change from 45 series to 50 series on a 16" wheel, you'll have to go narrower tyre width to stay legal (up to 25mm narrower is OK). But what's the point? You'll have the same thickness of tyre wall between your wheel and the road, so ride is unlikely to change much, and it's likely to reduce cornering grip and braking grip.

Seriously, a set of used 15" wheels isn't all that expensive. You'll save a bundle on tyre costs and enjoy a more compliant ride. Have a search of the for sale ads here, and try searching eBay.

[Silvia]

True I was considering a change to slightly raise what I find to be slightly low gearing. Then I found the other concern, that of the ride being somewhat harsh and skittish, could also be addressed at the same time by a slightly taller tyre.
Perhaps you can understand the evolution of thought , aided by the input from here.
I think the NB8B series 3 is about the pinnacle of the MX5 evolution, engine power,looks,gearbox etc. - that's why I bought one recently.
Having dríven in most countries , I find the roads here among the worst, and what would be a great ride in say,Japan or U.S. struggles here due to the roughness of the roads .Adjustment to the ride to compensate for this would be a good thing .The tyres (and it now seems the wheels also) seem to be the way to an answer....
If 15" wheels are affordable , I could keep the 16" ones for selling the car as original I suppose as they are a good look.

[Guran]

You're dead right about our crappy roads. Ever tried Sydney? Low profile tyres on big wheels are absolutely incompatible with them. A bit more sidewall height (not just profile number) and lower pressures (try 29psi) works wonders for ride comfort.

[Silvia]

I've started a new topic here on changing from 16" to 15" wheels...
The 15" stock setup is a much smaller size than the 16" is, so there might have been a diff. change to compensate??

[MINX]

You could try these from Michelin

[scud]

Well i just got around to getting new tyres. Michelin pilot sport 3. Bit pricey but had previous experience in a k24 integra and they had so much grip. Incl wet conditions.

I got them from spinning wheel tyres and im glad i finally got some good rubber. Car has transformed a whole lot more. Im running 195/50r15 nba wheels.