Tyre Sizes??

[Mortster]

The newage wheels have 215/40's on, the ST2 I just got have 205/40's on.

The speedo in the V1 with the converter is pretty much 100% as I check it against GPS every so often ( My Bug with UK clocks under reads by 5mph )

Will 205's change the rolling circumference, and therefore the speedo reading?

[scotty]

Originally Posted by Mortster

The newage wheels have 215/40's on, the ST2 I just got have 205/40's on.

The speedo in the V1 with the converter is pretty much 100% as I check it against GPS every so often ( My Bug with UK clocks under reads by 5mph )

Will 205's change the rolling circumference, and therefore the speedo reading?

Now that is a very good question Nick as always wanted to know .

[C. J.]

Yep but not by much

[Mortster]

Originally Posted by Mortster

The newage wheels have 215/40's on, the ST2 I just got have 205/40's on.

The speedo in the V1 with the converter is pretty much 100% as I check it against GPS every so often ( My Bug with UK clocks under reads by 5mph )

Will 205's change the rolling circumference, and therefore the speedo reading?

Im a nupty! Got mu numbers mixed up! Newage is 215/45, ST2's are 215/40.

[Scott.T]

It will change a touch but the newage will look under-tyred and illusion of higher stance.

[C. J.]

Put them on the classic

[Mortster]

There on HiHo, just look visibly smaller than the white wrx wheels I had on it.

Thought they might have had the wrong tyres on, but a quick search says that's the normal size for a classic on 17's

Will have to fit the Apex springs and lower it a tad

[scotty]

Just checked the pictures of my old classic with black st2 alloys was running 225/45/17

[Mortster]

Originally Posted by scotty

Just checked the pictures of my old classic with black st2 alloys was running 225/45/17

225's is sti newage rim size?

[Scott.T]

225 can just go on a classic but not advisable to use 45 profile.

[scotty]

Originally Posted by SilverSurfer

225 can just go on a classic but not advisable to use 45 profile.

Why is that scott ?

[Scott.T]

Originally Posted by scotty

Why is that scott ?

A number of issues really. Speedo accuracy and depending on wheel offset - outer arch clearance, inner arch clearance and tyre to shock clearance.

Classic Standard tyres on the 16's were 205/50 x 16, so to match the rolling radius this equates to :

Preferred sizes :
215/40x17 (will give a speedo error of +1.2%)
215/35x18 (will give a speedo error of +0.61%)
225/35x18 (will give a speedo error of -0.54%)

Non-Preferred sizes :
215/45x17 (will give a speedo error of -2.2%)
225/45x17 (will give a speedo error of -3.6%)

45 profiles normally end up on Classics if they have moved from a Newage, as these use 45 profiles on their 17's and 40 profile on the 18's.

[scotty]

Originally Posted by SilverSurfer

A number of issues really. Speedo accuracy and depending on wheel offset - outer arch clearance, inner arch clearance and tyre to shock clearance.

Classic Standard tyres on the 16's were 205/50 x 16, so to match the rolling radius this equates to :

Preferred sizes :
215/40x17 (will give a speedo error of +1.2%)
215/35x18 (will give a speedo error of +0.61%)
225/35x18 (will give a speedo error of -0.54%)

Non-Preferred sizes :
215/45x17 (will give a speedo error of -2.2%)
225/45x17 (will give a speedo error of -3.6%)

45 profiles normally end up on Classics if they have moved from a Newage, as these use 45 profiles on their 17's and 40 profile on the 18's.

Wow that is good info to know Scott

[riiidaa]

guys, you just need to know the manufacturer's recommended spec for a given wheel size on their car and then use an online rolling radius calc to get the nearest difference in overall rolling radius when changing tyre profile.

From memory for 17"s on Impreza

classic is 205/40/17 OEM (correction, 215/40/17)

newage is 215/45/17 OEM

correct me if your owner's handbook says otherwise

for the calculator go here http://www.carbibles.com/tyre_size_calculators.html and scroll to 'Comparing tyre sizes'


HTH

[Scott.T]

Originally Posted by riiidaa

guys, you just need to know the manufacturer's recommended spec for a given wheel size on their car and then use an online rolling radius calc to get the nearest difference in overall rolling radius when changing tyre profile.

From memory for 17"s on Impreza

classic is 205/40/17 OEM

newage is 215/45/17 OEM

correct me if your owner's handbook says otherwise

for the calculator go here http://www.carbibles.com/tyre_size_calculators.html and scroll to 'Comparing tyre sizes'


HTH

On a classic 205/40x17 is an option but it is the cheap option (and quite a common option due to wheel/tyre pacakages from aftermarket suppliers offering this size) due 205/40's are cheaper then 215/40. The preferred size is 215/40x17

[riiidaa]

Originally Posted by SilverSurfer

On a classic 205/40x17 is an option but it is the cheap option (and quite a common option due to wheel/tyre pacakages from aftermarket suppliers offering this size) due 205/40's are cheaper then 215/40. The preferred size is 215/40x17

Thanks for clarifying, I'll edit my post - was probably recalling my MG Rover 17"s

[S6VBY]

the ST2 speedlines fitted to my v5 sti ra has 215/45/17,changing them to 225/45/17