dust boots on rallycross car suspension

I'm currently changing from my standard-style springs/strut to a coilover-type setup with 2.5" ID springs (using Bilstein HD shocks). This presents the issue that my Bilstein dustboots won't fit inside (they are almost 3" diameter).

Now after 2 seasons of the current setup, there was no shortage of dirt inside the dustboot anyhow, but the two seals (one on the shock collar and the other one on the insert itself) clearly caught everything and there are zero marks of any kind on the piston.

So what say you? improv something (I've heard some steering rack boots can be used)? Go without? Go with the over-spring dust boot things that some baja guys use?

I only ask because I notice that a lot of gravel-spec coilovers don't have dustboots, and just looking at pics of stage car suspensions, most of them have the pistons totally exposed.

Thoughts?

I have seen people make "coil bags". just a durable fabric that velcros to its self around the outside of the spring. Don't know how well it would keep dust out but it is somthing.

found a link.

Anything available from the offroad 4WD world?

I wouldn't worry about it. Modern seals act as very good wipers of dust. Off road guys aren't protecting from dust so much as potential rock strikes on the shaft.

I wouldn't worry about it. I had the factory dust boots on my Bilsteins but they never kept much out. I never bothered to put them back on.

Was just gonna mention spring bags. In the offroad world they use shock dust boots which are like big steering rack boots that cover the shock piston. My coilovers came with these as well.

irish44j wrote: the two seals (one on the shock collar and the other one on the insert itself) clearly caught everything and there are zero marks of any kind on the piston.

This says it all. Unless the damper is in a position to take a direct hit from a rock, you're probably fine- in fact, not trapping the dirt in a boot may be better.

¯\_(ツ)_/¯ wrote: ...in fact, not trapping the dirt in a boot may be better.

My thought as well. Consider that moto dirt bikes don't use boots anymore and neither do mtn bike suspension forks, although they were quite common in the early days when consumers thought them necessary. But as mentioned, they did a better job of trapping and holding dirt on the seals. Inverted forks have guards to protect the stanchions from rock hits and roost damage, but not from dust.

Shock boots are usually left loosely fitting at the bottom (on a traditional upright shock) for this reason, so that dirt can fall out rather than getting trapped inside.

GameboyRMH wrote: Shock boots are usually left loosely fitting at the bottom (on a traditional upright shock) for this reason, so that dirt can fall out rather than getting trapped inside.

Considering the amount of dust I've shaken out of some shock boots during suspension swaps, I'd beg to differ.

My opinion is that dust boots trap more than they keep out.

From what I've seen they don't really seem to make a difference, but that's in a car that only drives on relatively clean surfaces.