KTM RC390 Long-Term Mod: Captured Wheel Spacer Install

Functional Axle Jewelry From Fast Frank Racing!

WRIST: Ari Henning
MSRP (2015): $5,499
MILES: 2,675
MPG: 58
MODS: Wheel spacers, axle cup, axle blocks, and rearstand spools

The stock cast-aluminum axle blocks (pictured above, left) are a loose fit on the axle and in the swingarm, so the reference marks on the blocks and swingarm are rough estimates at best. Frank’s blocks (right) are milled from billet and fit the swingarm and axle snugly. No play means accurate wheel alignment, and that means better handling, less tire wear, and longer chain and sprocket life.©Motorcyclist

The small-bike segment is growing quickly, and so are the accessory options for those small bikes. KTM's RC390 has really helped kick aftermarket interest into high gear, and one of the companies that has taken a liking to the little orange bike is Fast Frank Racing.

A while back Frank Shockley at Fast Frank Racing (fastfrankracing.com) sent me a smattering of RC accessories to try out on my long termer. Stuff like captive wheel spacers, precision axle blocks, sacrificial swingarm spools, and a rear-axle cup. I've been using his parts for months now, so I figured it was time I told the world how they work.

I wish I'd had the race-inspired captive wheel spacers installed when I took the RC390 to the track for our Small Sportbike Tire Comparison last summer, because I struggled with the stock spacers through all five wheel changes! Frank's spacers have a thin lip at one end that you push past the bearing seals so the spacers remain attached to the hub. That means you don't have to worry about them falling out and rolling away like the stock spacers tend to do. The beveled outboard edges help ease installation as well, and since the spacers are made of aluminum instead of steel, you save unsprung weight. (Six ounces, to be exact.) The kit costs $110 total ($45 for the front and $65 for the rear, which includes a replacement sprocket-carrier spacer). The spacers aren't something your friends are likely to notice, but you'll certainly appreciate them when it comes time to swap tires.

Frank’s captured wheel spacers (left) have a thin lip at one end that you push past the wheel seals The seals then keep the spacers in place so they can’t get knocked out as you’re guiding the wheel into place. The beveled edge helps ease wheel installation further. The stock steel rear-wheel spacer is pictured at right.©Motorcyclist

Another item that helps streamline wheel changes is Frank’s $30 rear-axle cup. It’s just a little machined cup that slips over the end of the axle so you have something to grasp when it comes time to remove the shaft. No hammer, drift, or bruised fingertips required. The cup is an elegant solution, and you can get it in silver or black.

And of course, none of the tire changes or other work I’ve done on the RC390 would be possible without a rearstand, which means installing swingarm spools. The thing is, most spools are secured with steel bolts, and some RC390 riders have discovered that in a crash a spool may get torn off—and the steel bolt may take a part of the swingarm with it! Frank’s spools are machined entirely from aluminum and they’re designed to sheer off in the event of a crash, thereby protecting the swingarm from damage. I haven’t tested that theory, but I have used the spools to lift the bike up on a stand for tire changes, oil changes, and other maintenance. The spools are $45 a set and they come in silver or black.

rc390 mods, sportbikes
How many times have you driven an axle out with a hammer and drift? Come on, admit it! I’ve done it a few times myself, but I won’t have to with the RC390 thanks to this axle cup. So long as you keep the axle greased, the cup allows you to pull the pin out with two fingers. It looks pretty trick, too. The only other place I’ve seen axle cups is on factory racebikes!©Motorcyclist

Lastly, I installed a set of Fast Frank axle blocks. Dropping $95 on axle blocks (in silver only) might seem superfluous unless you're familiar with the sloppy fit of the RC's stock cast blocks. Frank's replacements aren't trivial parts—they solve a real problem on the KTM, namely the inaccuracy of the hash marks on the stock axle blocks, hash marks that owners are supposed to rely on for rear-wheel alignment. Frank's blocks are precision machined so they fit snugly into swingarm the dropouts with no play. That means you can use the tick marks to accurately set your wheel alignment. If you're still rocking the stock blocks, make sure you know how to verify wheel alignment the old-fashioned way. All it takes is some string and a rear stand, and we cover the whole procedure in this MC Garage How-To pictorial.

long-term ktm rc390
©Motorcyclist
The stock cast-aluminum axle blocks (pictured above, left) are a loose fit on the axle and in the swingarm, so the reference marks on the blocks and swingarm are rough estimates at best. Frank’s blocks (right) are milled from billet and fit the swingarm and axle snugly. No play means accurate wheel alignment, and that means better handling, less tire wear, and longer chain and sprocket life.©Motorcyclist
Frank’s captured wheel spacers (left) have a thin lip at one end that you push past the wheel seals The seals then keep the spacers in place so they can’t get knocked out as you’re guiding the wheel into place. The beveled edge helps ease wheel installation further. The stock steel rear-wheel spacer is pictured at right.©Motorcyclist
rc390 mods, sportbikes
How many times have you driven an axle out with a hammer and drift? Come on, admit it! I’ve done it a few times myself, but I won’t have to with the RC390 thanks to this axle cup. So long as you keep the axle greased, the cup allows you to pull the pin out with two fingers. It looks pretty trick, too. The only other place I’ve seen axle cups is on factory racebikes!©Motorcyclist