Please check my track width maths

[Gibbon]

Hi

Long story but I need to change the track width of my MA61 to keep the boys at rego happy.

I think I've worked out what sized rims I need to comply.

For the front - the OE track width is 1465.

Currently, with my 7" +38mm rims, I have a width of 1430.

So, to increase my track width, I need to subtract 17.5mm from each rim?
(1465 - 1430 = 35 / 2 = 17.5mm)

Which means I need a +20.5 7" rim. You are allowed to increase track by no more than 25mm - or 12.5mm each side - so the rims I would need have to be between +20.5 and +8 at 7".

Have I worked that out correctly

Thanks.

[ill-minded]

if the OEM track width is 1465mm using the standard 14x7 +8 wheels (i think.. someone tell me if im wrong lol) then you would be able to run another 12.5mm wider on each side, this would allow you to run wheels with offsets between +8 and -4 (-4.5 to be exact, but they don't make rims with half a mm increments)

on a side note, i thought the NCOP's didn't allow for you to make the track width narrower than OEM which would mean that your wheels aren't legal.

this is how i've interpreted what you've said at least

[Gibbon]

on a side note, i thought the NCOP's didn't allow for you to make the track width narrower than OEM which would mean that your wheels aren't legal.

this is how i've interpreted what you've said at least

Correct - but I have modified hubs and brakes, and the disc face sits further in than OEM - hence the bigger offset than OEM.

However, that aside, is my maths correct in working out the offset sizes?

[wilbo666]

Your calcs look good...

But can you bring up the fact that 5.5" +27 wheels were an option [not sure if it was an Aus option?] (XX celica or the L type in the USA? came with 5.5" +27 offset wheels)?

In that case when Toyota changed from +27 -> +8:
+27 -> +8 = 19mm wider a side -> 38mm total increase in track. (Toyota didn't abide by the NCOP it seems )

Which would lead to the OE track with +27 rims to be...
OE Track of 1465mm - 38mm -> 1427mm (Scrapes you in by 3mm? lol)

Cheers
Wilbo

[Gibbon]

Your calcs look good...

But can you bring up the fact that 5.5" +27 wheels were an option [not sure if it was an Aus option?] (XX celica or the L type in the USA? came with 5.5" +27 offset wheels)?

In that case when Toyota changed from +27 -> +8:
+27 -> +8 = 19mm wider a side -> 38mm total increase in track. (Toyota didn't abide by the NCOP it seems )

Which would lead to the OE track with +27 rims to be...
OE Track of 1465mm - 38mm -> 1427mm (Scrapes you in by 3mm? lol)

Cheers
Wilbo

Oh yeah

But the first question they will ask is - Where's the proof ??

Would that sort of thing be in a old sales brochure?

Thanks
David.

[GA61XX]

You say "but I have modified hubs and brakes, and the disc face sits further in than OEM"

Q:- did you get an engineer's report for this up grade..???

If not, why not... as an engineers report will cover all mod's... inc' track..

[wilbo666]

Oh yeah

But the first question they will ask is - Where's the proof ??

Would that sort of thing be in a old sales brochure?

Thanks
David.

The factory tyre placard?

Cheers
Wilbo

[GA61XX]

here's a pic...

[Gibbon]

You say "but I have modified hubs and brakes, and the disc face sits further in than OEM"

Q:- did you get an engineer's report for this up grade..???

If not, why not... as an engineers report will cover all mod's... inc' track..

Yes - it's fully engineered - but - with the new NCOP you cannot decrease the track width from OEM. Regardless of what the engineer says is ok - the Rego boys will knock it back.

[GA61XX]

That sux...

But anyway my GA61 XX has a track of 1450mm with stock 15" x 6" supra wheels....

The stock wheels for this car are the same as the RA60/5's.. 14" x 5.5"... (long gone)
So track may even be 1440mm with these wheels..??

i hope this helps...

cheers

[wilbo666]

That sux...

But anyway my GA61 XX has a track of 1450mm with stock 15" x 6" supra wheels....

The stock wheels for this car are the same as the RA60/5's.. 14" x 5.5"... (long gone)
So track may even be 1440mm with these wheels..??

i hope this helps...

cheers

Is the 1450mm value measured or Toyota quoted?

Also 15"x6" are +20, 14"x5.5" are +27...

Cheers
Wilbo

[GA61XX]

Is the 1450mm value measured or Toyota quoted?

Also 15"x6" are +20, 14"x5.5" are +27...

Cheers
Wilbo

The 1450mm value is measured ...

[GA61XX]

Just found this info...

Make Toyota
Model Celica XX 2000 S
Production Year 1985

Wheelbase 2610 mm (102.8 in)

Front Track 1420 mm (55.9 in)

Rear Track 1380 mm (54.3 in)

Length 4660 mm (183.5 in)
Width 1680 mm (66.1 in)
Height 1310 mm (51.6 in)
Ground Clearance 155 mm (6.1 in)
Length / Wheelbase Ratio 1.79
Weight 1210 kg (2665.2 lb)
Weight Distribution (front/rear)
Fuel Capacity 61 litre (13.4 Imp gal , 16.1 US gal)
Steering Type rack & pinion
Steering Turns (lock to lock) ??
Turning Circle Diameter 11.8 m (38.7 ft)
Suspension (front) I.MS.CS.TraLi.TA.ARB.
Suspension (rear) I.STA.PR.CS.ARB.
Brakes (front/rear) VeDi/Dr-S

[GA61XX]

General Information
Make Toyota
Model Celica XX GT 2800 Twincam

Chassis and Dimensions
Chassis Type 2+2 FHC
Number of Doors 2

Wheelbase 2615 mm (103 in)

Front Track 1440 mm (56.7 in)

Rear Track 1400 mm (55.1 in)

Length 4660 mm (183.5 in)
Width 1685 mm (66.3 in)
Height 1315 mm (51.8 in)
Ground Clearance 155 mm (6.1 in)
Length / Wheelbase Ratio 1.78
Weight 1255 kg (2764.3 lb)
Weight Distribution (front/rear)
Fuel Capacity 61 litre (13.4 Imp gal , 16.1 US gal)

Wheels (front) 6JJ x 15
Wheels (rear) 6JJ x 15
Tyres (front) 195/60 R 15
Tyres (rear) 195/60 R 15

[floody]

7" +8 is stock, how have you ended up with 7" +38 rims on it now?
Don't buy shadow offset rims in future? Sell them to someone with a Lancer or something and get something which fits?


Why do you people make all this so complex?
And you can quote Celica XX specs all you like but whatever is quoted by Toyota Australia for the MA61 is what he'll have to abide by.