Hi guys,

I recently purchased a second-hand set of 17'' TJ VR-X mags to replace my 15'' steelies. The tyres on it aren't the best and are due for replacing, these are 235/45R17; which from what I understand, are not a legal fitment. The 225/50s listed as standard fitment for the VR-X throw out my speedo by +1.5kph @ 100kph, however 215/50s are out approximately -0.5kph @ 100kph.

Has anyone fitted 215/50s to their 3rd Gen? Good? Bad? Ugly? Any advice would be appreciated :)

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The placard on my TJ says the minimum load rating is 94 and, if memory serves me, the speed rating is H.

It seems 235/45R17 is a point of conjecture on the forum, as many have said - and referred to the Tyre and Rim Manual to substantiate, though I've not seen it myself - that you cannot legally fit a 235/45 on a 17x7" rim.

That is true but many people disregard that and fit 235/45R17 on 17x7. It requires at least 7.5" wide weels. You will find 215/50 will cost more as it is a rarer size. Best is to fit 225/50 and then get your speedo caliberated.

The 225/50s listed as standard fitment for the VR-X throw out my speedo by +1.5kph @ 100kph, however 215/50s are out approximately -0.5kph @ 100kph.

Have you validated that your speedo is accurate to within less than 1km/h? Unless you have, I think your concern over this level of speedo error is misplaced...

IMO this question comes up too many times.
What's your factory tyre sizes on the placard in the car?
Mine is 215/60/16 and a 235/45/17 is 21.1 mm smaller in diameter. The rules only allow + or - 15mm, so 235/45/17 is OUT for my TJ AWD.
225/50/17 is only 7.6mm smaller than my standard 16, so is OK.
235/50/17 is only 2.4mm larger than standard. perfect.
and 225/55/17 is 14.9mm larger - arguably that's OK.

if your standard tyre happens to be a 215/65/15, then it's 3.9mm smaller than my standard 16 and that makes the last one a rule breaker but the 235/45/17 is still a rule breaker too.

The +/-15mm rule applies to NSW. I can't remember what the rule is in QLD but it's on the motoring authorities website.

Cheers,

IMO this question comes up too many times.
What's your factory tyre sizes on the placard in the car?
Mine is 215/60/16 and a 235/45/17 is 21.1 mm smaller in diameter. The rules only allow + or - 15mm, so 235/45/17 is OUT for my TJ AWD.
225/50/17 is only 7.6mm smaller than my standard 16, so is OK.
235/50/17 is only 2.4mm larger than standard. perfect.

and 225/55/17 is 14.9mm larger - arguably that's OK.

if your standard tyre happens to be a 215/65/15, then it's 3.9mm smaller than my standard 16 and that makes the last one a rule breaker but the 235/45/17 is still a rule breaker too.

The +/-15mm rule applies to NSW. I can't remember what the rule is in QLD but it's on the motoring authorities website.

The placard on my TJ says its 205/65R15 94H as OE fitment.
According to Queensland TMR's Modification Guide the scope of fitment must within +15mm and -26mm diameter of OE fitment wheel and tyre combination, and width can be 1.3x widest available tyre for model.

So, keeping that in mind, any of the below should - in theory - be suitable, in order from closest to rolling diameter to OE to least:

215/50R17 (-1mm)
225/50R17 (+9mm)
225/45R17 (-14mm)
or, though its not legal, 235/45R17 (-5mm)

(Calculated using Tyre Size Calculator on etyres.co.uk)

So, keeping the above in mind, the question is has anyone used anything other than a 225/50 or 235/45 and what was their experience?

i fitted the ralliart enkei's with 225/50's on my TJ Exec
before fitment my speedo was over reading by 3% so when my speedo read 100kmh i was only doing 97kmh
now when my speedo says 100kmh my gps says 101kmh

Personally I'd go the 225/50s, as they're more common than 215/50s. And like the_ash said, even though it's a little larger than standard, it'd make up for your speedo under reading.

There's absolutely nothing wrong with a 215/50s on the VR-X rims - 215 and 225 are the ideal tyre widths for a 7" wide rim in my opinion. Mitsubishi even used a 215/55 tyre on the 17x7" 380s - unfortunately they're about 20mm larger than your factory wheels.

The legalities with aftermarket tyres & wheels across all states relates to the Rolling Diameter (effectively the radius). Its measured by doubling your sidewall high and adding the diameter of the rim in mm. You sidewall height is a percentage of your tyre's width. - i.e. 235/45/R17 would be calculated as RD = 2(0.45x235) + (17"x2.5) = 644mm.

In most states you're only allowed to change the rolling diameter by 15mm +/- front and back. In QLD you're allowed to have 15mm on the front and 26mm +/- on the rear tyres.

Now your standard tyres are 205/65/R15. These have a rolling diameter of 648mm. See this (http://www.alloywheels.com/Tyre_Calculator) calculator. The 17" rims with 235/45/R17 you have a rolling diameter of 644mm. This is only a 4mm difference and completely legal. And your speedo would barely be knocked out by only 0.5km/hour as well.

The legalities with aftermarket tyres & wheels across all states relates to the Rolling Diameter (effectively the radius). Its measured by doubling your sidewall high and adding the diameter of the rim in mm. You sidewall height is a percentage of your tyre's width. - i.e. 235/45/R17 would be calculated as RD = 2(0.45x235) + (17"x2.5) = 644mm.

In most states you're only allowed to change the rolling diameter by 15mm +/- front and back. In QLD you're allowed to have 15mm on the front and 26mm +/- on the rear tyres.

Now your standard tyres are 205/65/R15. These have a rolling diameter of 648mm. See this (http://www.alloywheels.com/Tyre_Calculator) calculator. The 17" rims with 235/45/R17 you have a rolling diameter of 644mm. This is only a 4mm difference and completely legal. And your speedo would barely be knocked out by only 0.5km/hour as well.

No one is saying the 235/45R17 is not a legal fitment in terms of OD. They are illegal on 7" wide rims. They require a minimum of 7.5" width. A 235/50R17, however, can be fitted to a 7" wide rim due to the extra sidewall height providing extra flex.