Bonneville America Forums Forums Technical Forums Performance Mods Steering Damper - Anybody?

Anyone fitted a steering damper to an America/Speedy? A good/bad mod? What say you, Gents....

Also, if any have them, howzem BP aluminum radiator conversions working out?

Useless mod to be sure. If you can cause a tankslapper on one of our bikes you fell off a mile back.

howzem huh?

Tankslapper? Not sure what that is...so nix the damper anyhow.

Bonneville Performance sells an aluminum twin vertical radiator conversion that clips to the downtubes and replaces the black center radiator. Seen one here somewhere....

Roadworthy has 'em on his bike. (coolers, not damper)
BTW, loose steering head bearings can cause a tankslapper!! Axe me hows i know...

Dan, a tankslapper happens normally at high speed when the front wheel leaves the ground and comes back down in a different direction from the track of the bike. As it recovers it slaps like a pendulum past center to the other side. Once this starts, well, its ends badly.

Dampers act like a shock absorber kinda like a storm door closer, so the bars don't start a radical shake. Once a slapper starts at high speed, nearly 100% of the time the ride is over. Youtube tankslapper and you will see some very good examples.

A short trail causes it like on trail bikes, sport bikes, and side car equipped bikes. Our bikes have a long trail and a little power. I don't know of any at speed over-driving out of turns or over a small rise where our front ends are lifting.

Watch the radical direction changes on Moto-GP or AMA Superbike. You will see on rises and sharp turns when they hit the throttle hard after the apex the front end lifts up. If when the front is up, if they quickly try to adjust the direction, the potential for a slapper is there. The damper helps to retard that effect.

In short, don't do wheelies at 60mph with your America and all will be fine.

I could be wrong, but unless the front tire changes direction a slapper will not start. Downhill, straight line, level straight line, what would be the difference on the front end stresses? Bad head bearings or a bad tire, once the slapper starts at speed it stops at a lower speed. Very controllable unless you accelerated through the defect to the point of no return.

The harmonic imbalance IMHO can only happen with the weight removed from the front wheel and the tire gets cocked. When it touches back down it starts the radical correction.

Very rough roads, wheelies gone bad, airborne over a storm drain etc. But again the trail on our bikes is pretty long. Sport bikes are much more subject to it. That is why most have a damper already.

Those same coolers (or very close) are sold for HD and one has a temp gauge in the top of it.

Thanks Ron, et al, for the good info.

Inline Radiators: Work good? Better than stock? leaks, etc? They do look cool, RW....

My oil temp runs right around 200. I shot it with an infrared thermometer and it read 190-195 at the top fitting and around 140-145 at the bottom fitting. It's never had a leak. And thanks, I think they are one of the coolest things on the bike!

30 years ago I had a 70 MPH tank slap & get off on a single cylinder 500, with a 27.7 degree rake and a 4.7 inch trail. Horsepower was 28.5. The road surface was a closely spaced series of one inch deep holes, probably created by snow plowing.

Do we need steering dampers with our fairly long rake? Probably not, but I don't believe they're a bad idea either. I've never ridden with one on. I wonder how they act with slow speed manuevering?

I think we are at 33 degree rakes and over 6 inches in trail. That is a lot. Plus the America has beach bars so a huge fulcrum advantage to control the front end.

Bucky at low speed normal negotiation the damper slides. Violent compression is when resistance occurs.

It would work fine.