fellas,

need the help of all the gurus on the forum. got me an '06 superglide with stock suspension. i want to put some lower rear shocks on without adjusting or lowering anything on the front. from what i was told, the stock shocks are 13.5 inches bolt to bolt. went to the dealerand had mine measured (bought the bike used and the person who had it before me was a shorty too and i wasn't sure if they had already been changed) and they measured 12.5" bolt to bolt but he said that because they were already adjusted to the lowest setting. i wasn;t really confident that he knew what he was talking about. anyway, i'm eitherconsidering the harley low rider rear shock kit or something from progressive. thedescription in the hd catalog doesn't give the length of the shock but says it will lower theseat height 1". I like the progressive 412's but they only come in 11" or 12" for that bike. I'm not sure of the 11's are too low and I don't think the 12's will make much of a difference. the 418's come in 11.5" but they are not my style. and the 440's? has they are selling the for $670, that's ridiculous.... anyway, need some advice thanks.

 

Stock Superglide shocks are 12.6" eye to eye. The discontinued FXDX had 13.5" rear, but no other late model dyna had anything longer than 12.6". That would mean the lowering kit will get you down to 11.6 if it's lowered 1" from stock.

 

Leave it alone and enjoy the ride, spend the 600 bucks on something worthwhile or give it to me if you have money burning a hole in your pocket.

 

Your stock shocks are 12 5/8" as glide05 said. Low Rider shocks are 12". If you decide on 12" shocks, get the Progressives rather than the Low Rider ones.
Keep in mind that the shocks are at about a 45° angle, so the amount of lowering is not the same as the difference in length.

 

since they are at an angle, wouldn't the seat height be lowered by an amount less than the difference in the length of the shocks?

 

Not hijacking the thread, but I've done the progressive 418 rear shocks on my FXDCI-06 (superglide) a while ago.

They are 11,5" long compared to the stock ones that are supposed to be 12,6".

Because they are at a 45 degree angel, I´m not sure about the real height in lowering.

So, now I'm ready to do the progressive front lowering kit. Already ordered one.

Here´s my question.
There is a choice of going 1" or 2" lower with the progressives front lowering kit (use on or 2 lowering damp springs).
To keep the original geometry of the bike, I´m supposed to lower 1", right?

/Dan

 

Assuming the angle is 45deg, which seems like a reasonable guess, if the shock is shorter by 1", then the seat height will be lowered by 0.707".

If the lowering kit describes lowering the seat height by 1", then the shocks are indeed shorter by 1.414 times that (once again, assuming the 45 deg angle is accurate)

Dan B - I would not lower the front anymore than you are lowering the back, this will shorten the "trail" which could negatively affect front end stability.

 

Thank you, glide05!

/Dan

 

why spend the$ to lower the front when could just slide your front tubes up? just a thought.

 

That's what I was originallythinking also, sin of 45° is 0.707, etc. But I laid it out in a CAD program and there's more to it than that. Since the shock mounting points are fixed and the swingarm rotates in an arc around the pivot shaft and the rear axle is behind the lower shock mounting point, the amount of lowering is actually quite a lot more than the difference in length of the shocks. If youreplacea 12.625" shock with a 12" shock and assumethat the 12.625" shock isat 45°,that the swingarm is parallel to the ground and that the lower shock mounting point is 12" from the swingarm pivot shaft, you would have to raise the swing arm approximately 0.89" at the lower shock mounting point toget 12" between upper and lower shock mounting points. Again assuming that the rear axle is 4" behind the lower shock mounting point, the axle would raise 1.18", which would be the amount of lowering at the rear of the bike. I realize that these assumptions are not accurate, but they're probably close enough to say that Harley is right when they say a 12"Low Rider shock will lower your bike about 1" if you have stock 12.625" shocks.