[singincanary]

Ok, so I haven't seen a dumb question here today, so I thought I'd add my own idiocy to the world.

I have a friend with a "set" of wheels for "cheap". Here's the issue that gives rise to the dumb question.

He has 3 wheels that are 17x7.5, et53 and one wheel that is 17x7.5, et48. They are matching rims though (same maker). If you run a 5mm spacer on an et53 wheel, you are effectively running et48, right? So, could you run either one 5mm spacer on the same "axle" (fronts or rears--likely rears on the Foz), or 3 5mm spacers on the other 3 wheels to make them all effectively 48mm?

I told you it was a dumb question. I personally don't see any detrimental issue with it, but something just seems "off" about doing it.

What say you guys?

 

[BAC5.2]

I don't see a reason why not.

All that truly matters, in terms of vehicle longevity, is tire diameter.

 

[singincanary]

OK, someone smarter than me agrees.

Yep, same size tire on all four same sized rims, just different offsets. I can't see a mechanical problem with that.

Next question is should I bother putting a 245 tire on them, only being 7.5" wide. Might have to go tire shopping again.

 

[BAC5.2]

It won't be optimal, but it'll work.

I'd probably stick with a 225 or 235 max.

 

[sea-scooby]

There was a local who bought 4 new wheels, ran them for a good while and when rotating them one day noticed he had one +51 wheels and three +48. Never had any issues but he did add a 3mm spacer until he could find a 4th +48 wheel.

 

[stan_t]

Weight on that corner will be a bit higher, not sure if it'd be enough to influence handling or negatively affect bearings though.

225 fits perfectly on a 7.5" wide wheel.

Stan

 

[hal0tw0]

I dont see any real detriment to doing this but just remember, adding a spacer doesnt physically change the et of the wheel...it changes the hub to wheel distance which changes the fitment of the wheel to the car.

Heres an extreeeem example just to visualize.... Take an 6" wheel (152mm) with a RWD offset of 0. You have another 6" wheel for FWD with an offset of say +76...
Adding a 76mm spacer to the FWD wheel doesnt make it 0et. Thats where you get into trouble when you see people running those bolt on wheel adapters. Im not a mechanical engineer and cant use the correct jargon to describe how dynamic loads are distributed negatively when you start adding spacers.

But like I said before....5mm isnt a big deal

 

[singincanary]

Yeah, figured 245's were too wide, but I ran them on my FSTi wheels w/o issue.

Think I'll pull the trigger if the price is low enough. Probably run the 48 on one side of the rear and a 53 with 5mm spacer on the other.

 

[funkymonkey1002]

Yeah, figured 245's were too wide, but I ran them on my FSTi wheels w/o issue.

Think I'll pull the trigger if the price is low enough. Probably run the 48 on one side of the rear and a 53 with 5mm spacer on the other.

I'd definitely keep the one with the spacer on the back, but there shouldn't be any problems. 235/50/17 is the perfect size on a 17x7.5, if you can get it to fit to the rear struts. I had 235/45/17 and now 225/50/17 and neither were quite right. If this is on a nonturbo though you might want something skinnier. I'd probably go 245/45 or 235/50 or 225/55 depending on fitment and what tire you pick out.

 

[stan_t]

Wait, I misread he initial post. You'll need 3 spacers to match the 48 offset wheel, not the other way around. So, spacers on 3 corners that have the 53ET wheels. I'd avoid using spacers and find a 4th matching wheel, spacers cost money and aren't really nessasary so I'd rather spend that money on a wheel.

Stan

 

[singincanary]

I already have spacers that I picked up when I needed to make sure my winter wheels/tires would clear the rear struts.

Lots of people, especially with the Foz's are running spacers only on the rear hubs to help with strut clearance.
I'll probably pick them up and run just one rear one with a spacer (if necessary for strut clearance) until I can find a new matched wheel. They're Prodrive's though, so tougher to find. Maybe have my buddy in the UK look for me.

 

[gdawrx]

depending on how they add the offset the spokes might look different. i.e. if they lower offset by moving the disc back, then the lower offset rim will have more dish. If they lower offset by adding material to the back of the disc, then the dish will be the same.

 

[RSwain]

Adding wheel spacers makes your lugs effectively shorter. If they are long enough for some good thread engagement, go for the spacers (just my vote).

 

[BAC5.2]

I dont see any real detriment to doing this but just remember, adding a spacer doesnt physically change the et of the wheel...it changes the hub to wheel distance which changes the fitment of the wheel to the car.

Heres an extreeeem example just to visualize.... Take an 6" wheel (152mm) with a RWD offset of 0. You have another 6" wheel for FWD with an offset of say +76...
Adding a 76mm spacer to the FWD wheel doesnt make it 0et. Thats where you get into trouble when you see people running those bolt on wheel adapters. Im not a mechanical engineer and cant use the correct jargon to describe how dynamic loads are distributed negatively when you start adding spacers.

But like I said before....5mm isnt a big deal

I don't know if you are correct...

A +53 gives 53mm from the centerline of the wheel to the hub mating surface. A +48 gives 48mm from the centerline to the hub mating surface.

Add a 5mm spacer to the +53 car, and you have 48mm from the centerline of the wheel to the new hub mating surface.

With respect to the hub face, the location of the centerline of the +48 wheel and the +53 w/ 5mm spacer wheel is exactly the same.

It's the same as shaving down the hub mating surface to increase offset. You ARE effectively changing the offset of the wheel.

In the extreme example (the 6" wheel +76 offset), if the rim is otherwise identical, then there is little difference between a 0et wheel, and a +76et wheel with 76mm of spacers. If you machined the wheel with those 76mm of spacers as a part of the wheel... you'd have a 0et wheel.

The only problem you could assume is that the spacer carries no vehicle load. So you now have a static moment on the lugs greater than a one-piece original 48mm offset wheel. Sufficiently torqued, I wouldn't expect this to cause any issue at all. There should be no relative movement between the wheel, spacer, and hub. The moment on the lugs, even in the worst case scenario, would never be sufficient to strain the stud. Just properly torque the lug nuts, and you'd never know.

GDAWRX is right though, a lot of wheels change dish to change offset. The wheels might look different. That is something to look at.

 

[hal0tw0]

I don't know if you are correct...

A +53 gives 53mm from the centerline of the wheel to the hub mating surface. A +48 gives 48mm from the centerline to the hub mating surface.

Add a 5mm spacer to the +53 car, and you have 48mm from the centerline of the wheel to the new hub mating surface.

With respect to the hub face, the location of the centerline of the +48 wheel and the +53 w/ 5mm spacer wheel is exactly the same.

It's the same as shaving down the hub mating surface to increase offset. You ARE effectively changing the offset of the wheel.

In the extreme example (the 6" wheel +76 offset), if the rim is otherwise identical, then there is little difference between a 0et wheel, and a +76et wheel with 76mm of spacers. If you machined the wheel with those 76mm of spacers as a part of the wheel... you'd have a 0et wheel.

I think your missing my point....the et of the wheel is finite. It is manufactured that way. Imagine that +76 wheel face down. Now stack on 76mm of spacers and weld them on the wheel, machine it all down to look pretty, and viola.

Edited---I started writing this thinking of the spacer/adapters as being bolted onto the cars wheel hub surface.....which would then increase the track to still make the wheel sit where it should be.....sure welding the adapters to the wheel would then make a new wheel of et0....

 

[stan_t]

You guys are both correct, but it depends on how the wheel is made. If it's as simple as extra thickness at the mating to the hub, then yes, raising the offset would be same as shaving off the extra thickness (you could shave the 48mm offset wheel to make it 53mm). But, if the difference in offset comes from offsetting the points where the spokes attach to the barrel, then running spacers will be a hack and it won't be same as running a wheel of correct offset -- lip (if there is one) would be larger, etc.

"The offset of a wheel is the distance from its hub mounting surface to the centerline of the wheel". So, yes, welding 53mm worth of spacers to the hub mating surface of an ET53 wheel would, by definition, make the wheel's offset 0. The tire would be right in the center in relation to the hub mating surface.

Which Prodrives are these anyway, GC-07s?

Stan