Austarion

If I was to fit 9" wide rims on the rear of a JA Starion... what offset should I get so that it clears strut?

Im not too worried about the guard as I could alwys get that pumped out a bit.

wont the rim dia have a bearing on this as well?
ie where on the strut the clash will occure.
eg with my 7 inch x 17 inch BSA's, the spring plate hade to be "massaged" very slightly (after spacers).

17x9's.

The tyre will need to clear the spring.

What offset are your rims, Merlin?

Measure what you have now and how much clearance either side. ie if you have 7" rims now and there's 2" clearance inside, if you go 9" rims with the same offset then there will be only 1" clearance.
If you increase from 7" to 9" and want to keep the same clearance inside, then the offset needs to increase/decrease 1" (can't remember which).

At least that's what I think.

I was hoping I could avoid all that icky measuring stuff and hope someone here would know. :)

Alspos wrote:Measure what you have now and how much clearance either side. ie if you have 7" rims now and there's 2" clearance inside, if you go 9" rims with the same offset then there will be only 1" clearance.
If you increase from 7" to 9" and want to keep the same clearance inside, then the offset needs to increase/decrease 1" (can't remember which).

At least that's what I think.

You would need to decrease the offset. Reducing the offset pushes the rim further out.

Cookiemonster wrote:You would need to decrease the offset. Reducing the offset pushes the rim further out.

Don't decrease and reduce mean the same thing??

but yes, a negative offset is for deep dish type rims, pushes the whole wheel outwards away from the car. Maybe a 0 offset will keep it all pretty central??

Alspos wrote:Don't decrease and reduce mean the same thing??

Yes.. I was saying the same thing. :x

Alspos wrote:but yes, a negative offset is for deep dish type rims, pushes the whole wheel outwards away from the car. Maybe a 0 offset will keep it all pretty central??

How bout a 17x9" rim with a +15 offset? Will it fit? Don't make me have to crawl under the car and measure... Im sick of working on the stupid lump of metal.

I suppose you want me to crawl under my lump of metal and measure it all up for you?

cookie find the guy with the purple starion with wheels that had the mint coloured centeres, im sure he will know as hes been thru about 8 - 11" wide wheels or something IIRC

merlin wrote:I suppose you want me to crawl under my lump of metal and measure it all up for you?

That'd be great. Thanks Dave.

Yes the offset would need to be more, ie more of a rear wheel drive offset than a front drive type setup (+30mm)

The other point cookie is, where are you going to fond such a wheel aside from simmons, arrows and other custom setups?

Just to clarify what offset is and how to understand it. It's just a little confusing...

Offset is the dimension between the centerline of the wheel (halfway between the tire bead seats), and the mounting surface. Positive offset tucks the wheel closer to the car. A 10mm spacer reduces the offset by 10mm.

Cookie, I have 16 x 9's on the rear with a 40mm offset (incorrect for the Starion) and the 245/40 tyre just clears the spring playtform. I also have penty of room between the wheel/tyre and the inner guard. I have measured the maximum backspacing to be 154mm. In my opinion, a 9" wide wheel would require a +10 to +20 offset, so your +15 estimation is quite accurate and the wheel should fit fine.

However, I will need to know what size tyre you will be using to work out if it will all clear. Also, I think your coilovers might affect the clearance of the tyres if they are lower and/or wider than the standard struts.

That sounds promising NXTIME. Thanks. Yes I was looking at a 245 tyre.

The wheels im looking at ar 17x9 with a +27 offset. But I have 12mm spacers.. so this equates to +15 offset overall.

I'll do a quick measure up to make sure it all fits but it sounds like it should.