Mounting bags IFS/ IRS- how to handle the arc?

[Coach529]

Ok so new to bagging and still working on this IRS project.

What is the secret to mounting bags in a IFS IRS situation where travel is an arc.

Currently by lower cup and upper plate are aligned at air out, and parallel. Looks great at air out, but I am not please with it at ride height.



The bag is rolling over the bag cup on the back side and I think it will cause issues.



Is there a rule of thumb I am missing regarding placement of the cup and upper mount, and angles?

Looks like I have a couple options. Move the top place out a bit, and/ or take some angle out of the cup.

Any thoughts??

[Coach529]

[youngrodder]

No expert...It almost looks like the top of your bag needs to be inverted toward the frame rail more. In other words if you look at the 2nd pic you attached the bottom of the bag is out further than the top of the bag. This would keep the bag from rolling over. I think you either need to move the top in or move the bottom of the bag mount out towards the spindle.

Marc

[Advanced Design]

Same here I am no expert and someone with more knowledge hopefully will jump in.

Thinking logically...I hope...the mounting surface of the upper and lower plates should be parallel to each other at ride height. Thinking this just based on this picture of a front on bags and movement through arc. And flat to the earth may not be the best angle for both...maybe 30 degrees...

Coach, just thinking aloud here... I will step aside for smarter folks.

[Coach529]

To be honest I am a but stumped.

Fought it most of the evening. Moved the top plate out and then took about 1/2 the angle out of the cup. Pretty much same results. Looked great aired out, but the bag looked really stressed at ride height and above. Finally went back to straight cup and aligned the cup and top plate while at ride height. Looks great at ride height and above. Not so pretty aired out.

Current set up is bag cup and top plate are parallel at ride height.

Aired out



Ride Height



Max Height

[Coach529]

If I cut the top of the cup down an inch it will be the same diameter as the bag bottom. Then there is nothing that can really hurt the bag when aired out.

[Coach529]

Something I just thought of. If I increased the diameter of the top of the bag cup, say to 8" it would support the bag at air out. The it could not roll down......

Hmmmmmm

[Coach529]

[Advanced Design]

So the bag is the bump stop? The bags in the bottom picture look ok aired out. What's different?

[Coach529]

Originally Posted by Advanced Design

So the bag is the bump stop? The bags in the bottom picture look ok aired out. What's different?

The biggest difference I can see is the bag is supported underneath.

[Coach529]

I came to the conclusion that a lot of my problem was that the bag was not supported underneath.

I did a temp install last night and felt a lot better about it.

['68 Newtricks]

I would say try to mimic the picture in post #2. The upper bag mount has more angle on it and is NOT right above the lower mount. Seems your IRS mounts are a little closer to that design. Also looks like your front LCR rides at a much steeper angle while air out than all the other pictures.

Just coming in with fresh eyes, but I've never had a bag suspension. :/

['68 Newtricks]

nice
can you offset the lower mount more towards the spindle? Might get even better, dunno

[PGSigns]

I think this is a place where a shock wave would be a better solution. Not all suspension systems lend them selves to the swap in of an air bag for the spring. They were never designed for the amount of travel the air bag can run them through. You need to look at what the limits of the usable travel that the system you have really is capable of and design around those limits. As short as the arc is to use that type of bag is going to have some short limits.
Jimmy

[SCOTI]

If it was mine, my priority would be to set it up so the bag is as close to upright as possible @ ride height where it is most important & will spend the most time.

[Longhornss]

All of you pictures in post #5 tell me you lower bag mount needs to be moved closer to the outside of the control arm, as new tricks and youngrodder suggest.

[Coach529]

Originally Posted by Longhornss

All of you pictures in post #5 tell me you lower bag mount needs to be moved closer to the outside of the control arm, as new tricks and youngrodder suggest.

I agree, but my concern with moving the bottom bag cup towards the wheel will only make the angle of the bag more severe at max height.

I feel the set up is adequate at air out and ride height which is where the bag will spend 95% of it's time.

[Coach529]

Originally Posted by SCOTI

If it was mine, my priority would be to set it up so the bag is as close to upright as possible @ ride height where it is most important & will spend the most time.

I think that is the what I have now. Thanks!!