Square Wheels!

Another weird aspect of Deloreans are the staggered wheels, i.e. 14" in the front and 15" in the rear. The initiated would tell you that the purpose for that is to supposedly provide more grip in the rear for an already rear-heavy car. While that may be true, finding a matched set for all four corners has become virtually impossible for good reason: 14" tires are all but extinct and look hopelessly dated and 15" aren't far behind. To alleviate this problem, I decided to purchase a set of rear rims and put them in the front. Going from the stock 6" wide front wheels to 8" is perfectly doable - with some modifications.

First of all, I selected a set of Toyo Proxes R1R SL 205/50R-15" ("Extreme Performance Summer" per Tire Rack) tires with a "V" speed rating. Of great significance here is that this tire dimension provides a virtual identical circumference with the stock 195/60-14" tire i.e. the speedometer is not affected. 

Stock front wheel on the left; new front wheel on the right

Same OD!

Secondly, I purchased a new set of Upper Control Arms  from DMC Houston and had them drop shipped to Reid Performance who modified the UCAs with a -3 deg camber angle. This should not only help turn-in but also provide some added fender clearance at the top of the wheel - and of course - it looks cool. In this picture you can see how four new holes for the Upper Ball Joint have been drilled further in to provide the added camber:

Modified UCA

Something I had not expected is that the new UCAs threw the toe-in out of spec but that was easily adjusted. 

Thirdly, the fender lips had to be rolled:

Fender rolling in progress

The front spoiler where it meets the front of the wheel arch also needed to be modified (basically, the plastic was shaved using a Dremel tool) for more clearance.

In the end my new 8" wheel fit like a glove - tight, yes - but no interference from tilt to tilt. And it looks pretty damn good too (at some point I need to re-spray all wheel for a uniform look):

To me it's striking how dated the rear wheels look... so now I'm thinking an identical but customer made rear rim with the diameter increased from 15 to 16" and another 25 mm negative offset ("poke"). I might out put out some feelers with some custom wheel machinists... 

Upper Control Arm bearings

The movement of the Upper Control Arms relative to the frame is to a large extent a function of the amount of torque you put on the Wishbone Pivot Bolt (#43) and Nut (#29). It's a shame considering the fine engineering modifications many of us have done to our suspension, only to have the movement hog-tied by the thru-bolts' arbitrary clamping force. Also, there seems to some confusion within the Delorean community as to what washers, and how many, go where.  

I started researching how to decouple the bolt torque from the UCA movement and found what appeared to be a very good solution from my favorite supplier McMaster-Carr:

• Thrust Bearing p/n 5909K31
• Thrust Bearing Washer p/n 5909K44

Up to this point, this is how my UCAs were arranged:

Bolt head - Large Washer - CONTROL ARM - Two snub washers - FRAME - Two snub washers - CONTROL ARM - Large Washer - Nut

So, replacing the two snub washers with one thrust bearing and two thrust bearing washers on both sides would result in the following: 

Bolt head - Large Washer - CONTROL ARM - One thrust bearing washer - One thrust bearing - One thrust bearing washer - FRAME - One thrust bearing washer - One thrust bearing - One thrust bearing washer - CONTROL ARM - Large Washer - Nut

One thrust bearing and two thrust washers

The thickness of a thrust bearing and two washers is about 0.2 millimeters more than the combined thickness of the two snub washers so the fit is pretty tight and can be a little tricky to get in there, but once it's in there it is as if it was "engineered in".

Some pictures with the thrust bearings/thrust bearing washers in place:

Thrust bearing washer/thrust bearing/thrust bearing washer. Right front wheel; left of UCA. 

Thrust bearing washer/thrust bearing/thrust bearing washer. Right front wheel; right of UCA.

Is it worth it? Hard to quantify but from my personal point of view this modification is definitely working: If you grab the bolt head with one wrench and the nut with another wrench, the Wishbone Pivot Bolt/Nut spin freely about its axis even after they have been fully torqued down. I'd say that it's a testament to its effectiveness!