With 13,000 miles showing on the clock of my project 2002 Triumph Bonneville, I realized it was time to spring for a new chain and sprockets. On the advice of a mechanic buddy, I contacted Drive Systems USA, which specializes in custom chain/sprocket kits, and after an enlightening conversation with President and headmaster Brian Lewis, opted to downsize from the OEM 525 chain to a smaller 520 set up, which is a fairly popular conversion. So why would I go from a larger chain to a smaller one? Basically, to save weight. Chains and sprockets are unsprung weight, so the lighter they are, the less they’ll impact handling. They are also a rotating mass, so it takes more torque to move heavy chains and sprockets than it does light ones. By swapping my OEM, heavier steel sprockets for a lighter chain and lighter sprockets, I should (in theory) see a slight increase in acceleration and some improvement in handling and braking. Plus, I had to admit, those black anodized Superlite sprockets from Drive Systems USA looked pretty bitchin', too.
Reducing the size of the chain normally affects its strength as well as its longevity, but a top-shelf chain like the RK XW-ring chain has a tensile strength of around 8,800 lbs, (compared to a standard 525 RK’s 7,700) so I doubt I'll run into problems. In the second place, Drive Systems USA reckons their 520 kits are good for around 15,000 miles anyway, which compares favorably with the OEM stuff.
As the chain and sprockets were being swapped onto the Bonneville by mechanic Chris Vandervoort at CycleTune PDX, we took photos of the process and asked him some chain questions along the way.
AC: So what makes a good chain?
CV: "Tensile strength; how it's made and how it goes together. The tensile strength between X Rings and O Rings can look the same, but the X Ring chains are great because they hold lube in better. O Rings are a good choice but you have to really keep the maintenance up. I talk to a lot of customers looking for new chains, and tell them, if you spend more on a chain -- say a good DID X Ring or RK X Ring chain -- you're typically gonna do a lot less maintenance because it holds the grease better."
You also have to make sure it matches; you can't just say, "Oh I want that O ring chain... you have to look too to see if it's rated for your particular bike. If you cheap out for a low-quality, low tensile-strength chain, it'll keep stretching and stretching until you're always *** with it, and now you're getting just 4000 miles of life because you didn't adjust it right."
" Every chain is different, but the OE stuff is pretty good; we see original chains getting 15-20K miles. But that's normally dealing with 525 or 530 sizes, which tends to extends life. With this 520 kit, we've shortened our chain's life span a bit, but it's also less weight, and we now have more gearing choices, and more availability of chains and sprockets in a 520 size. "
As Chris proceeded to remove the mufflers and front sprocket covers to make room for the new components, we kept pestering him.
AC: So what about the maintenance? Chains require more attention, don't they?
" Many people don't realize that the chain comes prelubed out of the box, so no further lubing is required at the install. In, fact the first thing you should do is wipe down the new chain really well as you remove it from the packaging; it's packed with so much lube already that any more would be complete overkill, and in fact, would fling right off anyway.
I know guys that install the new chain, lube the snot out of and then go for ride. When they come back they wonder why all that new lube is all over his rear tire. "
AC: What if you want to change the components?:
CV: A general rule of thumb is to replace the chain and sprockets all together as a unit; unless you're really diligent about doing maintenance, and only if you can keep the chain running straight and lubed on a consistent basis.
AC: What about gearing changes?
CV: If you wanna do gearing changes it's best to do it in the first 500 miles; figure it out and then leave it on there. You can go back and forth but then you are going to affect your chain and gearing set (you may cut the life as much as 1000 miles) if you keep going up and down a tooth.
"Front sprockets are typically the worst because they hardly ever get checked: most are hidden by covers and stuff. (Bonnie's front sprocket, below): See how pointy that sprocket is? That's the original front. It shouldn't look like that. At some point somebody probably put on a new chain and rear sprocket and never changed the front. And probably killed the chain. "
Moving rearward on the bike, Chris then spun off the rear wheel axle bolt, clipped the old chain....
..and then slid out the rear wheel.
Once the wheel is off, pop off the thrashed old sprocket and slide on the new rear sprocket. This Superlite feels waaay lighter than the stocker.
The front sprocket goes on now as well; make sure you've torqued everything to spec. And don't forget the Loctite.
And long last, it's time to slip on the new chain over the fresh sprockets.
Back out the rear adjuster bolts until the chain is the correct tension. Chris makes sure things measure up the right way, with his trusty caliper.
Finish things off with a pull of the torque wrench on the rear axle bolts. Double check your work, then go for a ride.
With the new sprockets and chain installed on the Bonneville, I found a definite increase in pep over the stock setup (though it was more of a subtle boost rather than a substantial leap in performance). There's not much of a difference in handling, but the Triumph pulls a shade better now in stock gearing (18 tooth front /43 tooth rear) and I may just opt for the forum-recommended change to a 19-tooth front sprocket for better power up top and a more relaxed cruising character. Stay tuned.
Huntington Beach, CA 92649