Seems I've come across a problem with my new 416's I installed on my 89 flhtp, problem is no matter what I set the air pressure to the shocks bottom out mostly in town or on dips on the hiway. I weigh 210 and wife is about 150. I've tried 25 lb's and bottoms real bad and on the hiway today I had to put 60 to keep it from bottoming and it did pretty good but once we hit town it was brutal. Any suggestions or experiences with these particular shocks? Is it possible I have defective shocks. My stock shocks were 13" and I ordered 12.5 " shocks.

 

Lynn,

You are travelling down a well trodden path. I have owned my 1990 FLHS from new and have only last winter finally cured the problem. Read my thread on Suspension THUMP. Most of all you need decent shocks like I used.

 

Thanks for the reply Graham, I just finished reading through your post and all the modifications you completed and sounds like your wifes butt is much more happy. I was hoping your results were achieved from air shocks but seems more it is the newer swingarm and new shocks. I did get one idea though when I noticed where the bottom eye of the shock is attached to the swingarm, on my swingarm there is a lowere hole ( below the axle ) and an upper threaded hole ( above the axle ) and because I didn't buy this bike new I don't know much about its history, is it perhaps possible I'm suppose to have the bottom eye going to the higher hole? The old shock was a 13" which I beleive is stock size and the newer shock is 12.6.

 

Lynn,

Because I have been trying to work out how to cure the bottoming-out problem for some while I decided to start at the bottom and work up! As wide a tyre as I can get in, plus the late stiffer swingarm (which needed a later wheel and brake) as well as the shocks.

It sounds like the lower shock hole on your swingarm is added later, I certainly have never come across one. I recommend using the stock upper hole, which at a guess will lift the rear of your bike at least 1 1/2". It may not cure your bottoming, but is a good start.

I like air shocks, or I should say I like the idea of them. I replaced my stock shocks with Fournales brand (French), which use far higher air pressures than Harley ones. They were better, especially solo, but still didn't cure the problem 2-up.

There is a grave risk of trying several different shocks and not finding any of them just right. While there are plenty of HDFers who are happy with brand X, there are enough of them who have tried many alternatives and still not been happy that I decided to take a short cut to the top of the heap, save myself some time and probably much cash!

 

The mount on top of the swing arm is where the shock should be mounted. I am pretty sure the stock length should be 13.5 inches. That would put you with a half an inch shorter shock in the low side of the swing arm, which will cause the bottoming out.

I use the 416 on my 06 UC and have a much better ride than stock. I went with the air shock so I could bump it up when pulling a trailer. I am running 250 and momma is 135.

 

Just did a double check and sure enough the bottom hole is actually a very manufactured looking nut welded on that someone actually had welded on to lower the bike. Would you beleive they used two different threaded bolt threads and of course neither will fit in the upper holes.

 

How much air are you running with?

 

Got some bolts and moved the shocks up and all is well I have about 24 psi in them and hit as bumpy a road as possible and no bottoming out. I've yet to try with the wife on the back but I'm sure it will be good. I also noticed a much better ride in the corners with the bike lifted more level.

 

I run about 25 - 30 depending on solo or two up, but tend to maintain around 25.

 

Lynn,

That sounds hopeful! Let us know how you both get on.