
Having been involved in the Hack project mentioned by Mike above and adding on to what Trapper said, I'll follow up a bit.
We restored an Oooooold velorex sidehack and adapted it to his 2007 Ultra. Our friend Jim, for whom we built the hack, has relayed his thoughts after having it a while.
Importantly, his biggest response has been that it has been the most liberating feeling, being able to keep riding and never having to dread falling when stopping. He has been riding over fifty years and riding is huge part of his existence and his connection to his circle of friends. He is 70 years old, a small fellow and fairly frail, with some health issues. After a parking lot drop in May and breaking ribs, he had to cope with the fact that he would have to hang it up. The hack has been his salvation (his words) so, yes, if it's either three wheels or four, three wheels is awesome!
He has put over 3000 miles on it since he got it July 4. He said the only issue he has is with the upper-body strength that is required. With all these miles, obviously, he's been gaining on it! On group rides (recently to the Texas hill country) he knows fully that he is slower in the curves so he and the trikes (older riders also) will ride "sweep" and we all catch up at a fuel stop.
Consider that there are special triple-trees available to alter the steering geometry and reduce the need for muscle; these are pricey, though and also make the bike a dedicated three-wheeler. Don't install if you might ever take the hack off.
The factory triglides already have the setup, I think. If considering shopping for a sidehack, I would offer these suggestions;
- Craigslist is a likely source
- avoid fabrication projects, either get an HD sidecar or
- get a sidecar that already has the PROPER mounts for YOUR bike
- Buying a complete bike and hack is likely a better deal than a hack alone, (then sell the bike)
- The factory hacks are easy to spot as the hack wheel has no suspension, but the BODY of the hack is mounted on leaf springs.