Burly Stilletto 13" shocks or ?

[Andy56]

I have made the following measurements with a rider weight of 165lbs

No preload
bottom collar to slider 58mm fully extended
bottom collar to slider 40mm stood up
bottom collar to slider 30mm sitting on bike

6 turns of preload
bottom collar to slider 58mm fully extended
bottom collar to slider 51mm stood up
bottom collar to slider 41mm sitting on bike

7 1/2 turns of preload
bottom collar to slider 58mm fully extended
bottom collar to slider 53mm stood up
bottom collar to slider 43mm sitting on bike

Sitting on the bike wrong as feet were on the floor so bike would sag just a little bit more.

Reading around I have found that the default spring most companies use covers a range of rider weight from 165 to 190lbs. It looks like these springs will not do that.

I am going to declare the standard springs useless on the 430-4063 shock on a Superlow for all but a light solo rider and nothing else.

[Tomcatt]

Originally Posted by Andy56

...I am going to declare the standard springs useless on the 430-4063 shock on a Superlow for all but a light solo rider and nothing else...

Originally Posted by Andy56

7 1/2 turns of preload
bottom collar to slider 58mm fully extended
bottom collar to slider 53mm stood up
bottom collar to slider 43mm sitting on bike

Have you rode the bike with 7 1/2 turns of preload? With your limited travel it would seem you need that much if not slightly more.

Your examples are a bit obtuse but I'm assuming "bottom collar to slider 58mm fully extended" vs "bottom collar to slider 43mm sitting on bike" means the shocks are compressed 15mm with you sitting on the bike? 58-43=15?
Your "7 1/2 turns" numbers indicate your spring rate is right where it should be in the context of only 40, maybe 45mm shock shaft travel.

[Andy56]

Sorry it is a bit vague.
https://www.progressivesuspension.co...0-series_6.jpg
The bumper is covered by the bottom turns of the black spring which I have so I measured from the top of the bottom collar to the bottom of the fat bit inside the spring or to the top of the exposed thin rod.

The shock absorber is supposed to have 51mm of travel but I take what you are saying that probably doesn't take into account the bumper.

The 7 1/2 turns is the full extent of the preload. I admit this is the first time I have actually done this with any accuracy. I randomly had the shocks set with 3 turns of preload so no I haven't ridden it like this and unfortunately it is below freezing here at present.

The problem I see is if I put anything extra on the bike there is no more preload and if a "standard" heavier rider has the same bike the spring doesn't look like it will support his weight. I want to be wrong!

[Tomcatt]

Originally Posted by Andy56

The problem I see is if I put anything extra on the bike there is no more preload and if a "standard" heavier rider has the same bike the spring doesn't look like it will support his weight. I want to be wrong!

Unfortunately you may not be wrong. I would try riding the bike with your "maxed out" 7 1/2 turns of preload. See how it rides. The numbers you posted tend to indicate the springs may be close to the right rate but Progressive blew their installed height. Only a ride will tell.

The bigger issue is that the shocks just don't have much travel, at best you won't have a very good ride quality except on very smooth roads.

You also have their Heavy Duty springs?

[Andy56]

I do and there is an overlap in the rates. It will be worthwhile doing the test again with them on.

How people get on with slammed suspension goodness only knows especially with general road conditions. Yep more travel please but that would entail the front being done as well to keep the steering geometry as it is.

[Tomcatt]

Originally Posted by Andy56

...Yep more travel please but that would entail the front being done as well to keep the steering geometry as it is...

I replaced the OE 11 3/4" shocks with longer travel 13 1/4" shocks on my '17 1200C. No steering geometry issues, just a MUCH better ride.

[Andy56]

You don't get issues as such but you get a steering that is a bit quicker on the turn in and a bit quicker getting upright. There might be just a little change in stability on the straights.

Perhaps going to a 12.5" shock would be very beneficial. From progressive it would give 29mm of extra travel or 3.13" vs 2.02" with what I have.

Now it might be the Progressive philosophy on spring choice is not correct and I need to look at a different manufacturer.

[Tomcatt]

Originally Posted by Andy56

You don't get issues as such but you get a steering that is a bit quicker on the turn in and a bit quicker getting upright. There might be just a little change in stability on the straights.

In theory, yes. In practice, not really. You have enough rake and trail you don't notice the (relatively minor) change. Your ride height only changes about half the amount you lengthen your shocks because with longer travel you run more sag.

Originally Posted by Andy56

Perhaps going to a 12.5" shock would be very beneficial. From progressive it would give 29mm of extra travel or 3.13" vs 2.02" with what I have.

Now it might be the Progressive philosophy on spring choice is not correct and I need to look at a different manufacturer.

More travel is good. Even on Progressive shocks...

There are lower belt run issues when you go with shocks near 14".

Johns' Burly Progressive shocks are really looking pretty good but we need to see where his sag numbers fall.

[John Harper]

Okay, had some time to install shocks today, no issues at all, easy peasy. The red spring matches well with timing cover and Sportster logo on tank! Viewed from the rear, they really stand out and might actually provide improved visibility, at least at stop lights during daylight. So, perhaps a safety benefit as well.




Sag was about an inch, according to my buddy, although he just eyeballed it, but no more than one third. I'll try to get a more exact measure this week, but my BPS (butt position sensor) seemed to confirm. I'm only on the base preload, so if it's more than recommended I can try to compensate.

Looks like we're getting one of our very rare days of rain Sunday, so no chance to ride until next weekend.

John

[Tomcatt]

Originally Posted by John Harper

Looks like we're getting one of our very rare days of rain Sunday, so no chance to ride until next weekend.

John

Let us know what you think after a ride. I'm NOT a fan of Progressive Suspensions' stuff but these spec out well. Only some ride time will tell.