4x100 to 4x114.3 Wheel adapters?

[CMG]

I'm sure this has been discussed a million times but for some reason when I search I come up empty. I'm normally kind of old school with my cars and generally I don't even use spacers unless absolutely necessary for clearance. I'm trying to find some lightweight 4x100 wheels and although there are options, it is hard to find a good size and offset. I already have tons of wheels in 5x120 and 4x114.3, and most are around 30-40 offset, so I started to think about maybe using adapters so that I can just use the wheels I have. I have lots of 4x114.3 wheel sets. If I use 20mm thick 4x114.3 to 4x100 adapters it should end up at just the right offset. Are there any real life cons to using appropriate hubcentric wheel adapters? If the hardware holding the adapter to the hub and also holding the wheel to the adapter are high grade I don't think there should be any shearing concerns, right?

[e30davie]

There are two schools of thought,

- Adapters are shit, buy the right wheels the first time
- Adapters are fine, here is a list of unscientific anecdotes with "no-issues" as proof

I personally am not the biggest fan. The engineer in me says "more points of failure that can be avoided with the right wheel choice". But i do understand the annoyance of finding wheels in 4x100. In australia at least we have loads of RWD cars with decent sized 4x114.3 (s13, ae86, ke70), all of the 4x100 cars require a much more positive offset (civics etc) than an e30.

However I often look at race class regulations often to see if things are "acceptable".

The spec e30 rules states "9.3.9.8. Wheel spacers are permitted and must be used in matching pairs on each respective axle. "

It does not specify slip on or bolt on, but i assume bolt on.

That at least should give you some confidence that the idea of spacers is acceptable.

Key points for me are:

- Checking that the "hidden" bolts are checked for tightness as often as the wheel nuts. Checking the inner bolts for tightness requires wheel removal, so i can see how their tightness might get checked rarely
-Hub concentricity on both the spacer to hub AND wheel to spacer, two areas of concern for hub concentricity, twice as many as without a spacer. (remember engineer = more points of failure)
- Correct grade of bolts. The critical bolts i think are the ones that hold the spacer onto the hub. Especially if you use more negative offset wheels, the moment on the spacer, and thus the tension requirements of the bolt is considerably higher than your regular wheel nuts. Id go 12.9 bolts and to reiterate again, these must be checked for tightness as often as wheel to spacer bolts/nuts.

Now please make way for the "I've been using bolt-on spacers for 12yrs with no issues" brigade:)

[MR E30 325is]

Totally agree with e30davie (as another engineer, mechanical and structural) above.

I would never do it personally, but the backing of spec E30 does have some value.

[CMG]

I'm definitely more of the old school train of thought, but I'm trying to be more open minded with this car (within reason). I'm sure you guys remember the thread back in the day where the guy used lug nuts as spacers, haha. I'm not an engineer or physicist but I do have some experience with both. It can get pretty complicated with the rotation and unsprung forces being added in, but the basics are that if the wheel is centered on the axis (hubcentric), and if it stays tight (correct hardware), then there is no issue. The "hidden" bolts can not back out due to spacer, but they could get loose and you wouldn't see it. IMO there would be a difference between using an adapter to 4x114.3 compared to 5x120, due to change in symmetry. I'm gonna give it a try...fingers crossed I don't come back a year from now posting about how my car did a belly flop.

[e30davie]

I always wondererd why noone has manufactured hubs to suit e30 that have a different bolt pattern. In my googling i found one or two guys who were obviously machinists, who had custom made their own.

One issue is that the holes are already quite close to the edge of the hub with 4 x 100 pattern, so you would need to increase the OD of the hub to get 4 x 114 or 5 x 120 or whatever, and then the oem disc wont fit, both cause the holes dont line up anymore (they can be re-drilled too), but the hub wont fit inside the brake disc hat.....but maybe an e36 disc could be used on a custom made e30 hub on an e30 spindle with e30 brake calipers etc.

I know alot of guys swap in e36 or later parts to to change to 5 studd, but anecdotes suggest that this "ruins the geometry", unsure how exactly, but its not surprising.

[Kershaw]

The only downside is the thickness it adds.

[CMG]

I always wondererd why noone has manufactured hubs to suit e30 that have a different bolt pattern. In my googling i found one or two guys who were obviously machinists, who had custom made their own.

One issue is that the holes are already quite close to the edge of the hub with 4 x 100 pattern, so you would need to increase the OD of the hub to get 4 x 114 or 5 x 120 or whatever, and then the oem disc wont fit, both cause the holes dont line up anymore (they can be re-drilled too), but the hub wont fit inside the brake disc hat.....but maybe an e36 disc could be used on a custom made e30 hub on an e30 spindle with e30 brake calipers etc.

I know alot of guys swap in e36 or later parts to to change to 5 stud, but anecdotes suggest that this "ruins the geometry", unsure how exactly, but its not surprising.

I already looked into doing the standard 5 lug swap using e36 m3 front and 318ti rear, and it is way too much money and effort just to have better wheel options. It definitely changes the suspension geometry, if only in ways that engineers could understand. The wheels on my car are actually not that bad, but I always have at least two sets of wheels for each car. I'm still gonna keep an eye out for the right offset and pattern set, but the 4x114.3 adapters are cheap enough to warrant a little experimenting.

[CMG]

Started looking around and there are multiple options for adapters in 15 to 25mm thickness. The issue so far is that they all have the 60 degree acorn style seating, so the hardware to mount them would be specialized slim head bolts with the right angle seating = $. Still searching.