Hi all, I'm getting feed up with 50 profile on R16, I can't be bother getting new rims so i'm thinking about instead of getting another set of 50 profile, try 55 or even 60. that would mean:

going from current: 225/50/R16 to 225/55/R16 or 225/60/R16.

I have noticed that my speedo was reading faster than i'm going, eg, speed read 110km/h when the speed test things on hume hwy reads 102km/h. And I know why, the 50 profile on R16 is kinda small for a family car!

Just wanted to hear what people's opinions are to assist me in deciding before I go get new tyres.

Cheers.

Just get your speedo recalibrated; why go for a tyre with a higher sidewall and restrict your choice to a less peformance oriented range of tyres?

as usual, jimmy is correct..... what is the benefit of getting largeer profile? isnt it more desirable (performance wise) to get lower profile? just get ur speedo recalibrated

as usual, jimmy is correct..... what is the benefit of getting largeer profile? isnt it more desirable (performance wise) to get lower profile? just get ur speedo recalibrated

I'm not after much performance, the firm ride is well and truely settled in and I'm begining to think that the 50 is giving me too much input from the road.

in terms of handling, 55 can't be that bad compared to 50 can it? 55 will give me lower rpm going at 100km/h as well.

Actually I'm curious in testing driving on two stocky 15" steel rims to test out how the car handles compared to the 225/50 I have now. Of-course it'll be worse, but i'm interested in seeing how worse and whether or not it'll be satifactory for my every day driving needs. I can always put my 225/50 s on when I go for a spirited drive.

i'm running 215/60-16's and i find they are a good comprimise between ride and handleing but like everyone else has said get ur speedo done! Mine is out somewhere between 5 and 10kph at 100. I got booked twice in 2 days in this car just after i bought it! :rant:
(It's going to tamworth in the next few weeks to the nearest place with a dyno and certification to assess speedos.)

lucky for me, when my speedo reads 100km/h, i'm actually going slower, probably 95km/h.

I haven't been booked in my Magna yet, touch wood. I don't really drive anywhere where I can speed too much.

225/55/16 is the one that would give you the closest match to the standard tyre as fitted.This is the size i plan to put on once i am able to wear my Kumho's out

225/55/16 is the one that would give you the closest match to the standard tyre as fitted.This is the size i plan to put on once i am able to wear my Kumho's out
That's what I was thinking. Sounded like it had the wrong tyres on there to start with which is why the speedo is soo far out.

the only problem with the 225/55/R16 was, they cost all up around $1100 for 4. I had to change tyres due to a puncher and I wanted 225/55 s but it was too expensive. and they wouldn't install only 2. so I am using 225/50 again, oh well. speedo being out isn't too bad as long as no one else is driving it other than me.

the only problem with the 225/55/R16 was, they cost all up around $1100 for 4. I had to change tyres due to a puncher and I wanted 225/55 s but it was too expensive. and they wouldn't install only 2. so I am using 225/50 again, oh well. speedo being out isn't too bad as long as no one else is driving it other than me.
Yup, Magna's are good for obscure tyre sizes. It was cheaper for me to get 235/45's than 225/50's in 17's. Why didn't they allow 2 tyres only? There's nothing wrong with that as long as you're matched left and right.

Larger wheels isn't always the best handling, in actual fact its rarely the case. i woudlnt go larger than 16's unless i wanted the wank appeal

the only problem with the 225/55/R16 was, they cost all up around $1100 for 4. I had to change tyres due to a puncher and I wanted 225/55 s but it was too expensive. and they wouldn't install only 2. so I am using 225/50 again, oh well. speedo being out isn't too bad as long as no one else is driving it other than me.
Yep, as I mentioned in another tyre thread, 55 profile tyres are very expensive. Ask any owners
of Mazda 626, 6, Ford Telstra etc that need 205 55 R15.

Larger wheels isn't always the best handling, in actual fact its rarely the case. i woudlnt go larger than 16's unless i wanted the wank appeal

That's because your car is about as big as a 16" wheel. Agreed though that there is a point of diminishing return in improved handling, i.e. 18" on a magna is optimal for road only use, 17" if you want to be able to do dirt tracks too, and 19" strictly for smooth roads only.

You only have to look at the profile on racing cars to understand what works best!! :)

Thats where the money is spent on research for 'performance' rather than appeal.

Check out the profile on open wheelers ...

Also consider the fact that not only are you reducing sidewall roll, that when you decrease sidewall height you are opening yourself to more options in terms of ultra high performance tyre compounds. Open wheelers, F1 cars etc use such high sidewalls because they don't run active suspension, and so rely on deflection of the tyres only. In terms of touring cars etc they run higher sidewall tyres to allow for high load carrying ability.

Also consider the fact that not only are you reducing sidewall roll, that when you decrease sidewall height you are opening yourself to more options in terms of ultra high performance tyre compounds. Open wheelers, F1 cars etc use such high sidewalls because they don't run active suspension, and so rely on deflection of the tyres only. In terms of touring cars etc they run higher sidewall tyres to allow for high load carrying ability.

rims too large increase unsprung weight too much, thats why touring cars dont go over 17's, smaller cars for racetrack often have 16's, and racetracks are smooth surfaces. the weight of the rim bouncing under the car cant be too great in comparison to the weight of the car itself, or it throws the car around with it.

on the F1 cars they dont have active suspension, but neither do most of the other cars using low profile tyres, and the cornering G forces are way higher than road cars. but they dont have much suspension travel, if thats what u mean by active? also i dont know what high loads a touring car needs to carry, they are a stripped out tub with as little weight as possible, a lot lighter than the road cars they based on, unless u mean cornering load?

even for serious drag cars, u dont see any ultra low profile slicks, because they cant flex enough to get a decent contact patch for grip and go.

truth is that huge rims and rubber band profile tyres is just a automotive fashion trend, a hard ride and instant steering response only gives an illusion that its the fastest best performing thing, but if u look at real race cars, they need some sidewall flex, and keep the size of the rim as small as possible while still fitting over the large brakes.

also im curious exactly how u can recalibrate a speedo?

^^ Agreed with unsprung weight; a heavier overall wheel mass will also mean less suspension control in terms of extra stress on springs/dampeners. A larger mass wheel also has greater centrifugal force which can increase steering effort. A larger or open design wheel allows greater cooling airflow to the brakes however increases aerodynamic drag, so it's a catch 22. It's all about compromises :)

Yes I do mean active suspension in terms of having wheels that can articulate up and down in relation to the chassis. In terms of carrying load I believe the importance in race applications is the potential for cars to corner with so much force that they often lift up on two wheels. You just can't afford for a wheel to crack and then later fall apart when going 300kph down the straight.

Agreed though that 19" wheels for road use is really just for looks, which is why I classified them as street only tyres that aren't really practical; there is a point of diminishing return when trying to reduce sidewall flex as you obviously have more wheel weight, greater steering effort, higher cost of tyres and wheels, increased risk of damaging wheels/getting flat tyres.

A speedo is recalibrated at the instrument cluster, where a potentio meter is installed temporarily inline with the reading chip, then when the correct amount of compensation is achieved you either solder in a correct value resistor permanently or just leave the potentiometer there for future readjustment.