Increasing track/offset

[af300e]

In Victoria we are allowed a track increase of 25mm OA on the front axle and 50mm OA on the rear (for live axle, 25mm for IRS). For us it's also dependant on the specs of the components rather than the car, so if for example you used the front struts off an ma61 (original wheels +8 offset) you could run -4.5 wheels.

Sounds like you you poor WA guys are getting well shafted.

[CrUZida]

for WA or NCOP?
for front susp, NCOP says (P38 LS-LS3/4?)


i read that as, if you swap in cross-member, LCA's, struts and steering from another car, it is then based on the donor parts?
but whatever components are used, you have to keep within 12.5mm each side to protect bearings and scrub radius?

Looking back at this,

If you can find a car that runs -25 offset from factory, you should be able to install those components in the car, and thus run up to -37.5 on your car.
I can't find anywhere in the NCOPs that states how wide flared mudguards can be.

However, tyre width will be your killer.
I'm guessing that the TT142 came out with 205's ?
If so, 30% wider is your legal limit, so 265's.
Maximum rim a 265 is legally allowed on is a 10" rim

If the TT142 only came with 185's, then those figures are reduced to 235 and 9"

[camshere]

Looking back at this,

If you can find a car that runs -25 offset from factory, you should be able to install those components in the car, and thus run up to -37.5 on your car.
I can't find anywhere in the NCOPs that states how wide flared mudguards can be.

However, tyre width will be your killer.
I'm guessing that the TT142 came out with 205's ?
If so, 30% wider is your legal limit, so 265's.
Maximum rim a 265 is legally allowed on is a 10" rim

If the TT142 only came with 185's, then those figures are reduced to 235 and 9"

OK - getting a little confused here - so you're saying that if i can find a car that has -25 offset WHEELS to start, or are figures available for the offset of the hub or something?

If its just a case of putting in suspension that sits further out than mine from factory, then that would seem to be a good option, although i think in the grand scheme of things i'm not going to find something that sticks out 75mm more than my current suspension up front, not even 62.5mm if i plan on then "increasing the track" by the maximum allowable amount of 12.5mm per side.

I'm getting the feeling that running two sets of rims, one for the pits and one for the street would be required. I'm pretty sure the Corona runs around a +20 offset - maybe +30, does this mean that if i got a rim that was negative offset, say a -45 (jsut for the example) then using the exact same width tyres i would (assuming +30 offset std) now have a tyre that stuck out 75mm more than the old one did? And i could probably get away with even less if i took a wider tyre, so if my tyre was 40mm wider i could get away with 20mm less offset?

If thats the case i'll look into these MS63 front hubs to see if they'd stick out further up front, and the MS123 hubs in back to take as much extra width as possible, then make the rest up in offset - i'm assuming of course you can get -ve offset rims, and my idea of how it all works (stated above) is anything ever remotely close to correct....

PS - Excuse me if i'm showing my ignorance here, i'm pretty good with cars, but offsets and hubs etc etc aren't something i've had to deal with before.

[CrUZida]

MS65 hubs stick out 2mm further than your stock hubs (assuming your stock hubs are the same as RT142/RA60/65 hubs).
MS123 hubs are the same as what you have (assuming your stock hubs are the same as RT142/RA65 hubs).

Stock offset on a 14x5.5 rim is +27, 15x6 rim is +20
A combination of width and offset will 'put the rims outside the guards'

And yes, a -50 offset rim will stick out 3" further than a +27 (given the same width).
The wider the rim is, the less drastic the offset will need to be.

Any dramatic changes to suspension/steering need to be approved by the DPI, and this approval requires submitting drawings and calculations proving that (for want of a better term) 'its better than factory'.

[oldcorollas]

well... if you are going to have one set of rims for the street and one for the pits, then you may as well not engineer or register the car, cos your insurance will be likely be voided anyway in the event of an accident.

surely the TT142 is nto the widest car in the world? falcadores? crowns?, soarer, supra... they are all skinnier than a TT142?

you DEFINITELY need to go and see an engineer... now...
there is a reason you can't (by law) increase track by wheels by 75mm.... a really good reason.... so please don't...


think of it this way.. if you have say.. 25mm scrub radius now.. and you make that 100mm scrub radius... you are now putting 4 times the bending load on the stub axles. you might get lucky and they designers built in a 5x idiot limit, but maybe not,... and then if you hit a pothole... the stub axles might just snap off... and then what do you do?

according to some site, Rt142 has track of 1375 front and 1350 rear
http://ourworld.compuserve.com/homep...o/homepage.htm
soarer 40 series is 1550/1530 (+175mm/+180mm)
30 series = 1520/1520 (+145/+170)
soarer 20 series is 1460/1460 (+85/+110)
11/12 series = 1440/1450 (+65/+100)
anything from soarer 20 series onwars will get you minimum+110/+135mm which should be heaps (with the +25 on rims too)

but that all depends if you can find an engineer in WA, who is willign to put their insurance on the line, to say that your transplant of soarer front and rear suspension into your corona is safe and is approvable...