Moving front wheels outboard

[fusion]

So I am building a 76 280z.  I will be running Marugen ZG flares on all 4 corners.  I have BC coilovers.  I will be running 15" wheels.  I have measured in the back and for a 275/50r15 on a 15x8 wheel a +35mm offset fits really well.  15" wheel options aren't great, but I found a wheel that works that I really like.  So now I was looking at the front to see how a 15x8 +35 would fit.  Mocked up 225, 235 and 245 tires.  Definitely need to move the wheel outboard by about 35-50mm to sit close to flush with the flare. (Still need to get more precise measurements)

 

The rear is already 5x114.3, and the front is still stock 4x114.3.  I haven't bought them yet but wheels in question are Rays Gram Lights:

 

I am mulling my options.  I really like the wheels and would really like to make them work on the front.   

 

Since I need to convert to 5x114 anyway, I could get a pair of quality wheel adapters that go from 4x114 to 5x114.  They make them in the thickness range I need and it would be a simple install.  It would kill 2 birds with one stone and be the cheapest/easiest option.

 

I've read that as long as spacers/adapters are either hubcentric or lugcentric and are installed correctly, it's not an issue to use, even at big thicknesses.

 

Another potential option would be to install different hubs on the front.  I believe the 300zx moves the mounting surface outboard (is it like a 25mm??).  Probably wouldn't be enough, but maybe then I could run a thin spacer to make up the difference.  Much more work and expense.

 

 

Any other hubs that would work?

 

Any other ideas/comments?

 

What's the widest wheel/tire combo that generally works on the front of a 280z?

 

Thanks

[jhm]

Wheel adapter spacers can definitely be used safely; but keep in mind that they add a fair amount of stress on the wheel bearings.  

 

Have you considered the T3 bump steer spacers that push the front spindles outboard approx 1"?  I've been using them for years and really like them.

[fusion]

Got a link to those spacers?  I couldn't find them for some reason on T3 site.

 

Edit:  Are these what you are talking about?  https://technotoytuning.com/nissan/280z/evolved-roll-center-adjusters-datsun-240260280z

 

Does it move the spindle outboard at the sake of increased negative camber?  Is it possible to get back in spec with coilover adjustments?

 

 

 

 

 

Edited March 26, 2021 by fusion

[jhm]

Yes, they move the spindle further outboard, resulting in wider track width and more neg camber.  And yes, you should be able to dial "out" the neg camber if you have the right camber plates (the DP Racing plates might allow you to use them in a positive camber fashion.

 

I have the older style NCRAs, which may not even be available anymore.  These new adjustable units look pretty nice.

 

Simliar effects (minus the bump steer adjustment) can be achieved with adjustable front LCAs; but you will still have to deal with the increased neg camber.

 

Hope this helps.

Edited April 2, 2021 by jhm

[Michael]

Have a look at the "suspension" chapter of the venerable JTR V8 conversion manual, where there's a discussion on re-drilling the K-member to move the LCA outboard (and slightly upward).  There's also been discussion suggesting (sorry, the context escapes me) the benefits of a "slightly" wider track in the front than in the rear.

 

As to the 5x114.3 vs. 4x114.3 dilemma, both aesthetics and wheel selection-options suggest the benefits of swapping to 5-lug in the front, if that's already been done in the rear.  Given the cost of the Ray's wheels, the additional cost of new 5-lug hubs (around $500?) is not outlandish.

 

275's on an 8" wheel... is that advisable?

[JMortensen]

The JTR manual says up 3/4, out 1/4 inch. IME from stock on a 240, you need to raise the pivot about 7/16" to minimize bumpsteer, without moving it outwards at all. 

Making either end wider will increase grip at that end, so if you have an understeering Z (which is their natural tendency) then making the front wider would help. Almost nobody does it though. Some racers will run wheel spacers for that reason, that's about it.

[260DET]

Go with your first choice, the 4x114 to 5x114 adaptors. As you said they are available in the thicknesses you need and are a structurally sound option.