The wheel and tire balancing nightmare

There’s an interaction I sometimes have with my wife. It’ll happen after I’ve cheaped out on some purchase or repair and had it go sideways on me, like buying a $75 laptop computer on Craigslist only to have the hard drive crash the next day. I’ll rail against my shortcomings, asking—largely rhetorically—“Why do I keep doing this? Why don’t I ever learn the lesson?” She’ll say, “Because you’re usually right, and you save us a lot of money.”

God, I love this woman.

There are a lot of aphorisms regarding this sort of tradeoff between cost and quality. Ben Franklin himself is quoted as saying, “The bitter taste of low quality remains long after the sweetness of a low price is forgotten.” Another is “There’s never enough time to do it right, but there’s always enough time to do it over.” These are both powerful wisdom-drenched quotes, but one of the problems I have with them is that they’re almost always uttered by someone other than the person who has to spend the time and/or foot the bill.

I am, at my heart, a pragmatist. If a “correct” solution isn’t possible, due either to exorbitantly high cost or a scope that creeps beyond my capabilities or my attention span, I’m not really interested. And if, because of that, I seek a solution elsewhere and it doesn’t go well, I may well be chastened and come away thinking, “Well that was stupid; I’ll never do that again.” This was the case when I once bought a $100 set of corroded wheels and tried refinishing them myself. Lesson learned. At least it only cost me a hundred bucks and a week of my time to learn it. But often it’s not that simple.

I’ve written numerous times about the plusses and minuses of buying used wheels and tires. On the one hand, who wants to pay list price for new wheels from a dealership when there’s a lot of money to be saved buying take-offs? The vintage BMWs that make up most of my not-a-collection are fairly robust with regard to wheel-balancing issues. Spin the wheels on the car, select the straightest two for the fronts, put the bent ones on the back, and it’s usually fine. But on the other hand, I’ve found that my newer cars with bigger, wider, heavier wheels and tires are more sensitive to wheel-vibration issues both front and rear, and when buying used wheels, it’s impractical to the point of being almost impossible to put them on a car and spin them to check for straightness before buying them. As they say, you pays your money, you takes your chances.

On the tire side, there are similar trade-offs. With 11 cars in the fleet, I need to save money wherever I can, and that has occasionally included buying used tires. When I bought the 2003 BMW E39 530i stick sport a few years back (it’s still my daily driver), it needed rear tires. I’ve long been of the opinion that if you check the standard DOT date codes on the tires, make sure they’re not too old (and yes, you can have endless debates over what’s “too old”), check the tread depth with a gauge, and verify that the sidewalls have no gouges in them and aren’t dry-rotted, you’ll probably be fine. I found two inexpensive used tires on Craigslist that matched the E39’s fronts and took them to a local tire shop to be mounted and balanced. While I was waiting, the tech came out and said that one of the tires I wanted to install was bad. I went into the back and looked at it, and he pointed out sidewall cracks that I could barely see. “That?” I questioned. “I’m not worried about that.” Three weeks later, I had a blowout on I-95, and I had to admit that it was the very tire the tech warned me about. I did learn the lesson from that and would be unlikely to buy used tires again unless they were nearly new, nearly mint, and dirt cheap. (The exception is that if I find a sidewall issue on a car I’m about to sell, I will sometimes use bestusedtires.com to source one used tire, figuring that this is better than selling a car with an obvious safety-significant tire defect.)

But that doesn’t mean that I still don’t try to save money. When I went to replace all the 235/45R17 tires on the E39, the range of choices and costs was enormous. I found a set of Achilles-brand ATR Sport tires on eBay for $245 shipped. The reviews for them on Amazon and in some of the BMW forums were excellent, and I read the usual concerns about cheap tires, but I didn’t see any specific red flags about poor quality or safety issues from this brand. Despite worrying about how stupid I was going to feel if I bought Achilles tires and they, you know, had a weakness, they’ve been great and I’d buy them again.

So, with all that in mind, I now can tell you about the wheel and tire adventure on my 1974 Lotus Europa Twin Cam Special.

Eighteen months ago, when I finally got the car running after it had sat in my garage for six years during a challenging engine rebuild, it obviously needed tires, as the ancient Dunlop Formula 70 SP Sports were good only for keeping the rims off the cement. The Lotus takes staggered-sized tires, 185/70R13s in back and 175/70R13s in front. In addition to being laughable—on modern cars, staggered tires are the width of a refrigerator in the rear and a dishwasher in the front—this created a selection problem. It’s challenging enough to find a decent tire in one of those small sizes, much less both. I looked online and was delighted to find that Achilles ATR Sports—the same tires I put on the BMW E39—were available in both sizes for just $160 shipped. Hey, the car needed everything. I was saving money wherever it seemed reasonable. I clicked and bought.

When the tires arrived, I jacked up the Lotus, spun all four of its 13-inch factory alloys on their hubs, found that none of them looked obviously bent, took them to a hole-in-the-wall shop not far from me that charges $20 a wheel for mounting and balancing. I asked the guy to find the straightest two wheels and put the 175s on those and the 185s on the other two. Since I was in the thick of resurrecting the car—getting it running, then capable of backing out of the driveway, then driving around the block—it was weeks before I was able to take it on the highway and see how the new tires behaved at speed.

When I finally did, I was immediately met with vibration issues—a steering wheel shake and a chassis vibration so strong that it felt like the fragile little fiberglass-bodied mid-engine car was going tear itself apart. At this point, I hadn’t yet sorted out the front end of the car, so the source of the problem could’ve been there, but I didn’t feel any play in the ball joints and tie rods. I spoke with my friend Lindsey, the shop foreman at The Little Foreign Car Garage (TLFCG) in Waltham, Massachusetts, who works on a variety of vintage European sports cars. He said that it was possible the vibration was a combination of mediocre-quality tires and a garden-variety wheel balancing, and he recommended I bring it in to him for a road-force balancing.

The goal of road-force balancing is to find the optimal orientation of each tire on each wheel. The roundness and balance of the wheel is first measured. Then the tire is mounted and rotated while a thick roller is pressed against it, simulating the road force. The springiness of the tire is measured along its circumference. The balancing machine then recommends an indexed rotation of the tire on the wheel to optimize the balance of the tire/wheel pair. The tire is then removed, rotated, and re-mounted in that position on the wheel. The wheel and tire are then balanced with weights.

Lindsey put the wheels on the balancing machine, and we noticed that the tread was bobbing up and down. It turned out that two of the wheels were slightly bent, but I didn’t see it spinning them in my garage, both because the bends were subtle and because they were on the inside lip of the rim. But in addition, the tires themselves appeared to have some degree of out-of-roundness. I received the appropriate amount of flack for not only buying cheap tires, but ones actually named “Achilles” (“Gee, Rob, if only you had some way of knowing that these tires would have a fatal flaw.”)

We talked about what to do. Lindsey does straighten wheels and offered to have a go at mine, but we agreed that the best strategy was probably to try road-force balancing and see what the results were, and if they weren’t good enough, then throw everything at it, meaning straighten or replace the wheels, buy a higher-quality set of tires more likely to be round, and try again.

Fortunately, the results were quite good. There was still a bit of steering wheel shimmy at about 60 mph, but it largely smoothed out at 70, and while I could still feel the chassis thrumming from the bent wheels on the back, it no longer felt like I was sitting on a washing machine stuck on the spin cycle. Considering that I still hadn’t touched the car’s front end or updated its suspension yet, I was thrilled. It was plenty good enough to allow me to drive the car to the Lotus Owner’s Gathering (LOG) event in Sturbridge, Massachusetts, in the fall of 2019.

Over last winter, I completely rebuilt the Lotus’ front end and installed a set of Spax adjustable shocks to replace the original dampers that were barely working. When I began driving the car again this past spring, I found that, while I loved having a functional and adjustable suspension, this round of work had no discernable effect on the vibration issues. I used the car all spring and summer, and last month I took it on its longest trip to date. Upon returning, I decided that, even though the steering and vibration issues weren’t showstoppers, eliminating them would give me a lot of pleasure. I set about making this a project so I could enjoy its fruits before the snow began falling in New England and the car was laid up for the winter.

I looked on The Tire Rack website and found that only one tire—the Kumho Solus TA11—was available in both of the Lotus’ staggered sizes. The prices were reasonable: $58 each for the front tires, $61 each for the rears, $211 total including shipping. I’ve had these tires on several of the vintage BMWs, and while I’m not a raving fan, Kumho is generally regarded as a first-quality manufacturer. Usually I’ll buy from The Tire Rack and then take the tires and wheels to a local shop for mounting and balancing, but in this case, I decided that the thing to do was to see if I could buy the Kumhos from a local shop that also offered road-force balancing. That way, if the tires wouldn’t balance properly because they were out of round, I’d have one vendor whose feet I could hold to the fire and return or exchange the tires if necessary.

With some web-searching, I found that a Hogan Tire shop less than five miles from my house listed the Kumhos on its website and offered road-force balancing for a very reasonable cost. I called and asked if they’d match The Tire Rack’s price. They agreed. I gave them the go-ahead to order the tires.

Having set things in motion, I put the Lotus on my mid-rise lift and carefully spun all four wheels, this time taking care to examine the inner lips. I knew that both rear wheels were bent, but to my surprise, I also found that one of the front wheels was visibly bent on the inside. I dug around and found the spare. It’s normally shoehorned under the hood (“the front trunk”—it’s a mid-engine car, remember?), but I’d removed it when I was sorting out the car to gain access to the bolts holding on the skid plate, which needed to come off to get access to the clamps holding on the coolant hoses. I mounted it on the car, spun it, and it was dead straight, as you’d expect an unused spare to be. It also was wearing a like-new 46-year-old Dunlop Formula 70 SP Sport, which made me smile.

I carefully marked the wheels as front and rear, threw them in the back of the E39, drove them down to Hogan Tire, did the face-to-face thing, explained about the Lotus’ vibration issues and how this was now the second set of tires and the third wheel balancing, and how much I’d appreciate it if they did the most careful job they could. They said they’d put their most experienced tech on it.

A few days later, I got a call from Hogan saying that the rear tires (the 185s) had come in, and they’d mounted them, but the tech advised that the rear wheels were too bent to balance correctly. I drove back down, and the tech put both wheels on the balancing machine and showed me the problem. One wheel had a minor bend, but the other looked pretty bad, much worse when spun at speed like this rather than my rotating the rear wheel by hand when it was still installed on the back of the Lotus. I loaded the two bent wheels in the trunk and asked them to give me a few days to deal with straightening them.

I drove the bent wheels back to where they’d been a year earlier at The Little Foreign Car Garage, and asked Lindsey if he could straighten them. Later that day, I received a text saying that he’d fixed one of them, but the other one was outside the envelope of what he could do. The only other wheel I had was the bent one I’d already pulled from the front and swapped out for the spare. I brought it down to TLFCG. The following day, Lindsey said he was able to straighten it to the point where it’d probably be fine.

Back to TLFCG I went to pick up the wheels, and from there, back to Hogan. The new Kumho front tires had come in, and they’d already road force-balanced them on the front wheels, which, mercifully, were straight. While I waited, they mounted and balanced the rears on the now straight(er) wheels. The cost for everything—the new Kumhos plus the road-force balancing—was a very reasonable $345. I took all five wheels and the remaining old tires home. (It’s times like these when the BMW E39’s fold-down rear seat, which makes it almost as useful as a hatchback, is extremely handy.)

I mounted all four wheels on the Lotus, which had been marooned on the mid-rise lift for five days while all this played out, then took the car for a test drive. I drove up the entrance ramp to I-95, the speed creeping up, and felt … nothing. Steering wheel vibration? Gone. Thrumming from the chassis vibration? Gone. Problem solved. This is probably one-third straight wheels, one-third round tires, and one-third careful road-force balancing. Big kudos to both my local Hogan Tire for working with me on this and to Lindsey at TLFCG.

Now, you can draw a couple of conclusions from this. One is to say that I’m an idiot, that all of this was foreseeable, that I wasted the $160 for the set of Achilles tires, $80 for the first balancing, and $211 for the first road-force balancing, and that I deserved what I got for being penny wise and pound foolish.

But I look at it another way. In retrospect, yeah, it was kind of silly saving 50 bucks and buying the Achilles instead of the Kumhos. But look, I don’t track my cars. I don’t do autocrosses. I don’t do any high-performance driving events. These days, I don’t really even try to hang the tail out around entrance ramps. In 44 years of DIY wrenching, this is the first time I’ve ever paid for road-force balancing, and only the second car I’ve ever paid to have wheels straightened on. The two 185/70 Achilles tires I removed are a size that fits my BMW 2002s and have fewer than 2000 miles on them. I’d buy another two and throw them on one of the 2002s—no wheel straightening, no road-force balancing—in a heartbeat, because one of the cars does need new tires, it’s the least expensive way to get new rubber, and my experience is that it’ll be fine. The take-away message here, at least for me, is that the Lotus—this weird light fiberglass-bodied car—is extremely sensitive to wheel and tire roundness and balancing issues in ways no other car I’ve ever owned is, and if I bought something else similar, I’d address its needs as carefully.

As far as the other take-off tires, I had Hogan mount one of the Achilles 175s on the badly bent wheel, so I have a spare of some sort. I put the other Achilles 175 on Facebook Marketplace for $20. No takers yet.

But the original never-used 45-year-old Dunlop Formula 70 SP Sport spare? I advertised it on FB Marketplace for free, and three people wanted it. The guy who picked it up said he has a mint Triumph Dolomite that he keeps a set of wheels and correct vintage tires for. He slaps them on for judged events. He was thrilled to get it.

I hope his wife, like mine, appreciates his scrappiness.

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Rob Siegel has been writing a column (The Hack Mechanic™) for BMW CCA Roundel magazine for 34 years and is the author of seven automotive books. His new book, The Lotus Chronicles: One man’s sordid tale of passion and madness resurrecting a 40-year-dead Lotus Europa Twin Cam Special, is now available on Amazon (as are his other books), or you can order personally-inscribed copies from Rob’s website, robsiegel.com.