Hub Bore, Spacers/Adapters, Bolt patterns, Lug nuts , Aftermarket wheels GEM pre 2016

I am restoring a 2014 E6 and was impressed with this forum’s recent wheel thread. Aftermarket 16" & 17"rims are a great way to give your cart a custom look. A set of tires/wheels can be had in the $700 range. Seems simple enough with general tire & wheel diameter recommended less than 24”. But for those of us working on pre-2016 Gem models, it is more difficult to put on aftermarket wheels. I reviewed all the old posts and found some good and not so good advice on previous posts. This is my experience.
Hub Bore First, GEM vehicle wheels are not “Hub centric”, they are “Lug centric” . This means that the alignment of the spacers and wheels you install are centered by the Lug nuts, NOT the Hub in the center. This is good because the Hub center measures 57.15 mm, and the closest hub bore I could find was 57.1 mm. Next size up is 58.1 mm. With no product available, the only thing to worry about wheel bore, is using a spacer that has a center bore measurement greater than 57.15 mm. Smaller and the spacer will not go on the hub.

  1. Wheel Lug Pattern The Gem vehicle bolt pattern changed in 2016 from the “4x4” (or 101.6mm) to the 114.3 mm bolt pattern. That is great and lots of spacers are available for 2016 models. But for those of us with pre 2016, the hub is 4" x 4" which is 101.6 mm. It’s confusing when you are looking for spacers because they jump back and forth with the measuring units. (e.g. 4 4x100 means quantity four 4x100 NOT 4x4). In earlier posts there are Gem owners who use and are satisfied using a 4x100 spacer when the Gem bolt pattern is actually 4x4" or 101.6 mm. I thought myself that wasn’t much of a difference. But if you look at the picture below with a 4x100mm spacer/adapter used on a 4x4 hub, the installation rub marks don’t look good. The lug centric alignment can’t be precise. Since this is a LSV max 25 mph, it may not be an issue, but what of these GEM owners that are traveling 40 mph? I don’t feel comfortable selling a car like this.

    An alternative is to consider is “Wobble nuts” or “PCD variation lug nuts”. These are expensive but can accommodate variations in wheel patterns up to 2.4 mm. But when I searched, there are no wobble nuts that are 10 x 1.25mm in size, a necessity for GEM studs.

    2) Spacer Adapter lug bolt pattern and Spacer Size In a way you might as well use “Spacer” and “Adapter” as synonyms for Gems. Adapters change the lug nut pattern. Spacers are used to push the wheel out away from the suspension. In a perfect world all you need is one piece: a single spacer/adapter. For me I had to add an additional spacer. Most Gem forum posts suggest matching the thickness of the spacers with your new wheel offset. This is a good rule of thumb to approximate spacer needs. For example my offset is +38mm which converted to inches is around 1.5”. And that should clear my Gem suspension. The problem is that although a 4x4 to a 4x100 in a 1.5” pattern has been posted as available on Gem forum before, I was unable to find any premade spacers/adapters in a 1.5" thickness. Maybe it is the pandemic supply chain issue, but there are limited adapters available for 4x4. I could use a 4x4 to 114.3 adapter but couldn’t find a 1.5” that was not custom made with return policy. I found 1” and 2” spacers. I did find sites making custom 4x4 to 4x100 spacers that were 1.5" thick, but not ones in stock. Since I am not certain about what thickness size I would ultimately end up with, I did not want to buy a non returnable custom product. Which means I needed to purchase an available 4x4 to 4x100 adapter that was 1” and use an additional spacer that was 1/2” (12 mm) thick to make up the 1.5” space. (Thank goodness for Amazon Prime returns) I have had to return 2 sets to date.
  2. Lug nuts: Studs on Gem hub differ from studs on spacer Pre2016 Gem Hub studs are 10x1.25mm. Your spacer wheel studs can be 12x1.5mm, 12x1.25mm or 1/2"x20. In the below picture are examples of lug nut to attach spacers to Gem hub. The one on the left has been recommended by forum. I used the one on the right to attach my spacers. Another recommendation is to have the lug nut thread in with a minimum of 8 rotations. And torque GEM M10 stud to 63 ft. lbs. For spacer studs M12 to 75 ft lbs. Recommend installation by hand NOT by air gun since this is soft aluminum.

4) " Dual Bolt Pattern" or “Multi-Lug” wheels . This turns out to be an improvement innovation in aftermarket wheels. The same rim can used in twice as many applications! You need to establish what bolt pattern spacer you want first. Then choose multi-lug wheels with the correct pattern. I choose a spacer 4x100mm wheel pattern. So my 8 hole multi- lug wheels work on both 4x100mm and 4x114.3 mm. If I decide to sell my wheels I will have twice the market!

In conclusion, I’m not finished. Likely will be going with a custom 1.4-1.5" thick spacer adapter because I cannot get the proper thread contact using the additional spacer. There is a EBay seller who has 1.5" 4x4 to 4x100 spacers, but he has terrible feedback and of course no returns. So I will likely go to a reputable provider on the internet. At least all of this has given me a rough idea of a spacer thickness that works.


Great post, lots of valuable information in there. Thanks.

On a side note, you just took the lead in “longest single post” competition over @AssyRequired .

OMG!!! Dang… He raised the bar!!!

Thank you for a truly excellent post.

I used 14” Crager SS golf cart wheels purchased from Jegs. Bolted right up with no need for a spacer. Fit perfect on a 2002 two seater.

Yes the golf cart wheels are all 4x4. Easy to bolt on. (But won’t bolt on the 2016 and newer with a 114.3mm pattern) If you like the looks great, but I’m wanting the larger wheel look–

I have done a dozen custom wheels on Gems. 4x100 spacers, tighten nuts in sequence to center ang good to go. No vibration at all over 40 mph. I think you are making this way harder than you need to.

tighten nuts in sequence to center and good to go.

Doesn’t that do goofy things to the studs?
Can you tell if they are all pointing a bit into the center?

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Thanks for your Post. It’s never a bad Idea to do things the right way if you can. I have used many 4x100 spacers on the Stock Gem hubs that are 4x4 that you point out. I knew it was not perfect but never thought it was unsafe or could create a uneven ride. On my next wheel upgrade/install I’ll try out the 4x4 adaptor. Vs the 4x100 adaptor and see what I notice.
4x100 seems to be very common and available

More problems. The lowest profile 10 x 1.25mm lugnut is too tall for some 1" spacers.
The depth of lugnut hole is variable on different spacers. Several photos above there was adequate lugnut clearance on a 1" 4x100mm StanceMagic adapter. But I don’t want 4x100 and StanceMagic doesn’t make a 4x4 spacer. As you can see below I purchased another Ebay 1" thick 4x4 adapter. But the depth of the lugnut hole is too shallow to accomodate for the shortest 10 x 1.25mm lug nut I could find. (Lug nut height .75" or 19mm)

So I have offically given up on using a 1" adapter with an additional spacers. One with access to a machine shop could make this work.
I contacted Tire Shop supplies (AKA Bronson) in San Bernadino who specializes in spacers. When you provide the fact that the Gem is a 4x4 lug pattern they have a note stating that spacer lug holes need to be “as deep as possible” to accomodate for short Gem studs. It’s nice to talk to a human sometimes. That piece of information was not available with online order.
So I ordered (4) 4x4 to 4x100mm spacers/adapters, 60mm bore, 1.5" thick, with deep holes to accomodate short Gem studs and feel pretty confident right now.

From what I can tell from your description and pic- It is just the lug nut that is too thick(not the wheel stud).

What kind of tools do you have within your reach?
That looks easily solved if you want to drag it on a sander for a bit.

Better yet- put a bolt(stud) in a drill chuck, thread a lug on the stud, spin it up and drag the offending nut on an equally spinning grinder.

Repeat 15 more times.

Yes it is the lugnut that is too long. And I felt good returning the spacers back to the Ebay vendor because if you can’t get clearance for a lugnut, they are useless. M12 lugnuts can be narrower, so maybe they are useful for someone. But not for Gem owners.
AssyRequired you and I have too much time on our hands. I’m splitting hairs and you are out there customizing with a grinder in your spare time! For me the purpose of this exercise is to come up with a fail-safe list of reccomendations for others. A recipe for pre2016 Gem owners so they can just order the right stuff and bolt up without having to return a stack of spacers, lugnuts etc. Obviating the need for a grinder. It’s frustrating!

I used to ‘fix’ everything with some duct tape and baling wire but then came Harbor Freight…

Most everything can be made to work with one of these. :wink:

Thanks for taking the time to figure this problem out. “They don’t call it Hot Rodding for Nut-in”

Some times a Grinder is all you have and you have to make it work.

Sometimes you can pick up the phone and break out your credit card and that makes things work.

Looking forward to your results!

I was not aware of your intent. I wandered in here thinking this was a problem that needed a fix. By all means- carry on!

Once you get this figured out, and maybe if you want to expand it a bit more…
Since you are already using adapters/spacers to change dimensions, perhaps you can explore the concept of REALLY changing this up and going to a lug pattern that takes you into another group of wheels.

Point being - Why stick with just a 4 on 4? Are there more styling wheel options if you look at maybe a 4 x 156 like on a Polaris RZR? (If you like that look)
Just an example.

“Ask, and it will be given to you; seek, and you will find; knock, and it will be opened to you”.
Bronson does have 4x4 to 4x156 adapters. This would be great for someone with 4x156 wheels that want to use on a 4x4 Gem hub. I have provided the link. But again when ordering I would make the phone call. Make sure they are aware of the Gem vehicle hubs. So for an order such as you want,it would be:
(4) 4x4 to 4x156mm spacers/adapters, 60mm bore, (what ever thickness you need based on your wheel offset), with deep holes to accomodate short Gem studs"

Here is a more strait on picture.

Thanks for the photo! So that is a 57.15mm hub bore and looks to be a standard 60 mm spacer bore. Which means that on either side of the hub bore should be a 1.425 mm space. It certainly looks close. There is a lot of crud in that space, but the feeler gauge should be .056" throughout the circumference. My belief is since it is the wrong adapter for a 4x4 hub, you will find tight and loose areas (minus the crud). My point is why even bother putting the wrong size spacer on, when the right 4x4 spacers are available in custom sizes? But I already know your answer Michael–Because it doesn’t matter(to you) Peace

It’s nice to have choices. When I do my next Gem I might try them. Not expecting any any performance improvements but why not try them. The only downside is they appear to be 4x more expensive. Not a big deal to me but might be to others. Keep us updated.

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