Flirting With Disaster, The Dangers of 21in Front Tire Conversions

I think I've just learned something that probably everyone that's passed journalism 101 already knows (pretty obvious who's had no formal journalistic training huh? Damn.), and it's this; when no one will talk to you about a story, it's probably a damn good story. And trust me, I couldn't get a peep from any of the players I sought out for an interview, I'd probably have better luck getting Anthony Weiner to guest lecture a photography class at the local junior college. OK, not true, that pathetic bastard would no doubt jump at the chance. But you gotta hand it to the powersports crowd, they can play it close to the vest and stay mum, good qualities in a friend and a bookie, but really frustrating when you're trying to get to the bottom of an issue.

Gotta admit, looks pretty cool

And that issue is? Nothing major, or so I thought, I just wanted to know what the tire folks thought about all those 21 inch conversions that are so smokin' in custom circles these days. Specifically the conversion of FLH model Harley's (which depending on year are typically shod with a 16" or 17" front hoop) from their stock configuration to 21" tires and rims. You see them everywhere, it has to be one of the top five trends in bagger customization, maybe top three. And in many cases, from a design aesthetic point of view, the conversions work well, giving the entire machine a more menacing and aggressive profile. I kinda like the look. Hell, there might have been a brief instant, fueled by more Jack and Coke than common sense, that I may have toyed with the notion for my beloved Paint Shaker. There was just one thing wrong, I knew better, see it's not about "the look", it's about the numbers. And the numbers don't add up.

For the sake of familiarity, we'll use Paint Shaker (my 2006 Harley FLHRCI) as a reference point (from '09 FLH's have 17" fronts). The '06 Road King slid off the factory line sporting Dunlop 402's; specifically an MT90B16 up front, and an MU85B16 bringing up the rear. As for maximum load, the rear is rated at 908lbs at 40lbs of pressure, while the front is rated at 783lbs at 40lbs of pressure. So far, so good. Until you begin to look for your 21" replacement for that MT90B16 that is. Now is when things really get dicey, staying with Dunlop (and why not, they make the best tires on the planet, and are OE fitment on most Harley's, so they know what's up) we'll search for our 21" inch front.

Can you imagine cleaning that wheel?

Uh oh. This isn't good. Try as I might, I couldn't find a 21 incher with a maximum load rating above 467lbs at 40lbs of pressure. That's a whopping 40% drop in max capacity. No matter how you slice it, that's significant, and in the wrong direction. Didn't matter what brand, the 21's just weren't up to the job. So I started reaching out to my friends in the tire business to get their take on the relative safety of converting an FLH to a 21" front end, just what did they think? Crickets was all I got. As you can imagine, after 20 plus years in the industry working at a retailer that at one point sold more motorcycle tires nationally than anyone, I knew just who to talk to, the folks with the answers. Trouble was, none of them was willing, or more to the point, able to talk "on the record" about the issue of 21" conversions. Not Dunlop, not Metzeler, not Michelin. Nobody. Nada. Nicht. Zilch. The fact is, liability and scum sucking accident attorney's have made cowards of us all. These guys couldn't talk, and I don't blame them, in their positions I wouldn't either.

Here's the deal, all of the manufacturers are paranoid beyond belief; we already know the 21's aren't load rated for the baggers they're getting thrown on, but that's not all. Check out any Harley forum, say http://www.cvoharley.com/ or http://www.hdforums.com/ and search around and you'll find horror stories of ill-handling bikes, owners one step away from a 5150 holding order, all because they fitted up a 21" tire, and they can't get their bikes to smooth out at anything above a walking pace. Think we might have screwed up the steering geometry Ace!? The cold hard facts are, Harley-Davidson and the tire companies (mostly Dunlop) spend countless hours and boat loads of dough ensuring that your bagger handles like Valentino was at the helm no matter what. Huge downpour? No big deal. Massive crosswind? Hardly even notice it. Rain grooves? Who cares. Board scraping cornering antics? Bring it on! In all but the most extreme situations, your badass bagger will be as well behaved as church deacon. That is if you leave it as God and the Motor Company intended. And yeah, the Motor Company wouldn't talk to me either.

Not gonna stop like a stock rig, no way

Start monkeying with steering geometry, things like rake and trail (I know you've seen those terms in the magazines, don't have a clue huh? Don't lie, most of us don't either) and unless you're some sort of suspension guru, and we know we're not, chances are trouble is just around the corner. Nine times out of ten, you're just gonna f##k it up. And until you get it sorted, the chances that you're gonna end up on your noodle are pretty good.......or not good, you get the idea. Oh, did I mention braking? Yeah, it just keeps getting better. No doubt in those very same magazines that bored you to tears with rants about the aforementioned "rake" and "trail", you might have run across the term "contact patch", it's where the rubber literally meets the road. Well sir, the contact patch on a 21" inch hoop is significantly smaller than its 16" and 17" cousins. Less patch, less grip, all things equal. This means when you need to get the beast whoa'd up in a hurry, you'll have reduced braking capacity because you've got fewer square inches of rubber "interfacing" with the blacktop. See how that might not be great? Hello Subaru.

So what's the deal, should we bag the idea of 21's on our baggers? And if so, what about customizing in general? It's our position at Chrome Asylum that you should be free to do whatever the hell you want to when it comes to modifying/customizing your ride. Period. My bucket list ride is a Sucker Punch Sally's bobber with no front brake, suicide shifter, and an open primary belt, hardly a model of NHTSA restraint and propriety. And I don't want some nanny fascist to tell me I can't have it. Just do your homework and keep your eyes open. But remember, with that freedom comes the responsibility to live with whatever consequences rear their homely heads because of the idiocy you inspired. In short, live with it. Own it, and don't sue! Don't sue anyone, they didn't hold a gun to your puppy's head and demand you fit up that 21. It was your call, if you get screwed up because of it, oh well, better luck after rehab. But sadly, that ain't the world we live in.

The fact is; the tire guys, HD (if I may be so bold), wheel manufacturers, OE dealers, independent shops and everyone else that could be bundled into a lawsuit are probably dealing with the fallout from 21" conversions as you read this. Do you really think they're aren't pending suits, please. Something tells me that ongoing litigation is the primary reason for the lack of conversation coming from the industry on this issue.

So if you still wanna slap that 21 incher under your bagger, it's totally up to you. Just know that you've surely compromised the handling, maximum load capacity and the braking performance of your motorcycle. A machine, it might be worth noting that's more likely to be overloaded and ridden two-up than its smaller, less touring oriented cousins. Your call, your risk. And if things turn to doo-doo, just remember who's idea it was. As for me? I think I'll chill and see what the Motor Company comes up with, at least I know it'll work.