There’s a quiet revolution taking place in the Pro ranks of ATV motocross. No one really wants to talk about it, but most of the top riders have started using Hinson’s BTL clutch over the last two years. The Team Yoshimura riders were using it first, so they didn’t want to talk about it. Other teams have sponsorship conflicts, so they don’t want to talk about it. Even they guys at Hinson don’t want too much publicity because it cannibalizes their sales of conventional clutches, which is the company’s bread and butter.
But the word has leaked out and now most of the top riders have turned to the “slipper” clutch. We wanted to find out for ourselves what everyone wasn’t talking about.
WHAT IT ISN’T
There’s some confusion about what the BTL does and doesn’t do. It is not an automatic clutch. The Rev-Lok and Rekluse clutches are very different products designed to prevent stalling. The BTL is similar to the French STM clutch, which was developed for MotoGP and then became popular in SuperMoto racing. It’s designed to limit engine braking, hence the name Back Torque Limiter. Hinson produces the clutch under license from the European designer. That’s why the profit margin isn’t great, but according to Wayne Hinson, it’s such a good product he wanted to bring it to the market.
The BTL works exactly like a conventional clutch when the motor is accelerating. It even uses the stock basket and plates. But when the inner basket starts driving the outer basket–in other words, when engine braking is taking place–then a mechanism relieves the grip on the clutch plates and you have controlled clutch slippage. A washer-type spring controls how much engine braking you get.
Installation is no more difficult than that of a conventional clutch. You can certainly use your original basket and plates, but Hinson would be delighted to sell you the entire package.
WHAT IT IS
The BTL’s effect is subtle. If you ride normally, you might not even notice. The clutch feels absolutely normal and you can certainly stall the bike, as always. But if you start to modify your riding style to take advantage of the effect, you’ll see the advantage. It’s all about braking bumps and how your ATV acts when it hits them. Normally, too much rear brake makes the rear end kick, so a good rider tries to moderate his rear-wheel braking when he hits bumps without even thinking about it–less braking before the bump, more afterward. But even when he releases the brake completely, the motor still does its part. With the BTL, a rider can downshift early without worrying about how the machine will act in bad breaking bumps.
On rough tracks, that’s a huge advantage–much bigger than you would think. Glen Helen has an enormous downhill that’s difficult for all riders, from beginners to Pros. The effect of the BTL is obvious there. On the other hand, if the track is smooth and tight, there might not be any advantage at all.
That explains why the product has taken over the Pro motocross ranks so completely. Those guys never have the luxury of a smooth track. There are no real disadvantages, unless you need to bump-start your bike in a tall gear. Chances are that you can still do it, but it might just slip. But reliability is excellent; Hinson has never had a failure at the Pro level.
WHO NEEDS ONE?
Cross country racers are less likely to use the BLT. It could certainly help on some of their courses, but many of them are currently experimenting with automatic clutches, as they consider that a bigger problem.
We think that the BLT is a prefect example of a great product for racers that might not trickle down to the rest of the world. The advantages of smoothing out braking bumps are huge when shaving off a half second a lap can mean the difference between winning and not making the podium. But if you don’t race, the BLT’s MSRP of $1150 is a lot of money to spend for the quiet satisfaction of riding slightly better. It’s all about priorities. If you’re interested, call Hinson at (909) 946-2942 or shop on-line at www.hinsonracing.com.