I know, shock right! I've tried the search function but there are so many thread about various shakes, rattles and rolls on Harleys it's impossible to find anything relevant.

I have an issue with my 2010 FXDC. First off I'm a big bastard, 6'6" and 25 stone so consider the bike is pretty well loaded with me on it.

When I hit a pothole or similar sharp suspension shock, or if I'm cornering enthusiastically and hit a bump compressing the suspension further, I get a sharp vibration which feels like it's coming from underneath me. My first thought was maybe it was the belt hitting the guard but I've ruled that out. Belt is correctly tensioned also.

Having previously shimmed the front motor mount I was intending to fit a Predator motor mount anyway so I did which made no difference by itself. I have aligned the front and rear motor mounts since which did make some difference but the issue is still there.

I'm thinking a rear stabiliser like True Track or Sputhe is my next step but it's a fair bit of wedge to lay out on a gamble. Anyone had the same issue, perhaps when riding two up, and managed to solve it?

Thanks in advance..

 

Weighing 350 and hitting pot holes isn't going to do your bike, it's suspension, the wheels, nor your spine any favors.
Only thing I can think of would be to look for shocks/forks that offer longer travel that's progressive. Oh yeah, I'd lose the laced wheels too.

 

 

Thanks for your responses. Avoiding potholes is damn near impossible on UK roads!

Sorry, should have said, running 12.5" Progressive 412 shocks and progressive fork springs.

There is no evidence of the tyres rubbing on anything. The shocks are pretty firm, I'm confident they are not bottoming out.

As for laced wheels, spoke tension is OK all round. My '03 and '07 Dynas also had spokes and no issue like this.

 

What do you have your shocks at, i.e. 1 click is softest and 5 clicks most firm. Check on the right hand side of the bike and see if your fender is bottoming out onto the swing arm. Most forward part of the fender by the passenger peg. you may have to trim that fender if your are hitting the swing arm or buy stiffer rear shocks ($$). I have Prog. 412 HD

 

For your size and weight I would go to 13” or taller rear shock, get ohlins or similar not progressive, some thing that is tuned to your weight...

 

The recommendations for heavier shocks with more travel is right on.. The vibes are coming from when the shocks are closer to botting out or even bottomed out.. The angle of the shocks are so great they actually mess with the function of the rubber isolators. I spent some time trying to develop a better rear isolator and found that when the isolator is at its limits the whole bike vibrates more when the shocks are compressed. All dynas do it. Find a big dip and ride through it, you'll notice it.

 

Thanks for all your responses.

4 out of 5. On 5 they might as well be rigid. I've just gone out and put them up to 5 for today to see if that stops the issue. If it does it will confirm it's a suspension travel issue instead of lateral movement I suppose.

The fender is not hitting the swingarm. I have had that issue before on a previous bike with 11.5" shocks.

Can't stretch to Ohlins right now although they are fantastic units, used them several times and have an Ohlins shock in my Stratoliner.

I messaged Hagon this morning enquiring about shock length and weight. I have their Nitro shocks on my XJR and am pretty impressed with them for the cost.

I know the Progressive 412s are cheap and cheerful but I've not had this issue before on my last two Dynas with the same shocks..

 

Hmm, I think you guys may be on the money. On setting 5 I struggled to get the vibration to occur but it still did it over sharp impacts like pot holes. Ride was stiff as hell though lol.

A brother has 13.5" 440s on his Dyna. I won't have a chance for a couple of weeks but I think I'll borrow his shocks one afternoon and put them on my bike to make sure..

Thanks for your help