TWMX All Access: Uni Filter

While visiting the offices at Uni Filter this week it was heartening to walk in the door and see a couple bikes proudly displayed. One was a Honda four-stroke set up with a big tank for desert use, and the other was a vintage Husqvarna MXer, complete with chrome side panels on the gas tank. That harkened back to the early 70s, when Uni’s filters were first spotted, mounted directly onto the carbs on Honda XR75s. When that recollection was mentioned that to Uni’s Vice President, Tom Gross, he chuckled and said, “When Uni Filter started back in 1971, the philosophy then was to make an air filter work that worked—to stop dirt. That’s how it began, with the universal clamp-on stuff, where the filter would just clamp onto the carburetor and eliminate the airbox. It’s funny how all these years later, we’re back to that with the XR50s. Just yank off the airbox and put a little clamp-on filter, and we’re right back to 33 years ago. That’s neat.”

Tom’s duties include a bit of everything in the family-owned business. “I wear a lot of hats. Marketing, sponsorship with all the teams and all the freestyle guys. I really enjoy that. For Supercross teams we have both Kawasaki and Team Yamaha, who we’ve been with for years. We also have some satellite teams.” Tom also works on new product development.

“Ken Mitchell, the founding father of Uni Filter started the company back in the 70s. He just passed away this past October. His son, Lanny Mitchell, is the President, and he runs the company now. Also, Allen Mitchell is running our shipping and accounting. He takes care of all the finances. He’s also one of Ken’s sons.”

While Uni does do some automotive product, Tom know where there primary focus is. “We just want to focus on the motorcycle industry. That’s our core business. But we’ve got automotive, truck, off-road, dune buggy stuff, Volkswagen stuff from back in the day…a little bit of everything. We’ve been doing automotive stuff for years, and we private-label a lot of automotive product for other people…put their name on it instead of the Uni brand and let them go ahead with the marketing.”

In the powersports world Uni not only sells aftermarket product, but they also supply OE manufacturers with filters. “You’ll find Uni Filters on certain models of Hondas and all kinds of other manufacturers. There are also a lot of the ATVs—Bombardier, Arctic Cat. We also worked for 15 years with Harley Davidson.”

Walking through the facility with Tom, he showed us the machine shop where they develop some of their own machinery (more on that later), but also their flow bench where they can test filters. This is our flow bench room. It’s a SuperFlow SF-600, so it goes up to 600 CFM. We can set it up for different flow ranges, to test automotive or motorcycle or ATV filters. It allows us to compare to stock, so we can beat it by flowing better.” They also use it for dirt testing (which is how it’s set up in the photo), to see how much dirt a particular foam sample will pass through.

When quizzed about what makes the Uni Filters unique compared to other brands, Tom replied, “On all the racing bikes, our two-stage filter comes apart. That allows you to get in there and get all the dirt out of the two layers of foam. That’s the most important part. The other bonded filters, where the two layers of foam stay together, there are little granules of rock and dirt that will stay embedded in the foam and you can’t get it out. So every time you clean it and re-oil it and use it again, a few of those particulates stay in there and you lose air flow. You can never get it back to 100 percent and you’re losing performance.”

Tom was also queried about his take on filters that are shipped with oil already applied. “We don’t offer that for retail. Some of the race teams will get filters that way, but as for offering them at retail, we don’t do that. We feel iit’s better to ship them unoiled, because you can get migration of the oil. So by the time the end user might get it, when it’s gone through a distributor and it sits in their warehouse for a while, then to a dealer where it sits again, So by the time the end user gets it, you kind of need to freshly oil the filter.”

Next, Tom showed off the giant blocks of foam that were awaiting production, and said, “It’s crazy how they make it. They pour the urethane into a big tank, which is the size of a semi-truck trailer. It foams, but to make it reticulated foam, which is breathable foam like we use, they add acetylene into a closed chamber, and once the chamber is full of acetylene, they light it and it explodes, and that blows the windows in the foam that makes it breathable foam, as opposed to furniture foam that doesn’t breathe.”

The foam “buns” are cut to size using large band saws. Tom said, “There’s no machine that will cut foam and do what we need to do, so we just engineer and make what we need in-house, and build our own machines to do what we need to do.” Their saws can easily cut quarter-inch thick sheets from the raw foam blocks, which is then die-cut to size, assembled, and packaged for shipping. There are currently over 5,000 part numbers in the Uni catalog, each one a different size and shape.

While walking through the warehouse, Tom pointed out several large bags of scrap awaiting pickup. “That’s about half a day’s worth. Most of the scrap goes to carpet padding. You know how you see it and it’s all different colors? They pick it up and take it and use it for carpet padding. The nicest stuff we use for packing material ourselves, so we get free packing material from our scraps. We’re sort of like Henry Ford and utilize every little part and pallet and bracket. It works out great.”

Looking at some of the unusual shapes of the finished filters, Tom said, “It’s funny, over the years the running joke has been that the last thing the manufacturers think about is the air box and the air filter. They say, ‘Here, make us a filter for this thing,’ and we say, why didn’t you call us before you put that shock there, or that frame rail where it is?’ They do everything else, the engine, suspension, make it go fast, and then they go, ‘Oh yeah, we need an air filter.'”

While air filter maintenance rarely ranks as anyone’s favorite maintenance chore, Tom feels they’ve gotten a bad rap. “It has that stigma, and everyone sticks with it. But there are worse things to do. Packing wheel bearings isn’t real fun either, but you don’t have to do that as often. Besides, the air filter’s the lifeline to your engine, and that’s going to make or break the whole deal.”

“One of the neat things is we came up with the maintenance kit a few years ago, which is our oil and cleaner all in one, and the two are designed to work with each other. Using those two together, really makes it a snap.”


UNI Filter
1468 S. Manhattan Avenue
Fullerton, CA 92831
(714) 535-6933