Coilovers and bumpstops

[blubottlemax]

Has anyone tried trimming the bumpstops on there coilovers? I just recieved my TEIN HA coilovers, and I noticed the bumpstops seem pretty long, 1 3/4 in, but they have grooves in them, like you might be able to trim them. I know KYB sells shorter bumpstops that can be trimmed down, I'm just wondering if TEIN made them that long for a reason, ie bottoming out the internals of the strut, or if I can trim them down for a little more strut travel. Heres a picture of the rear bumpstop.
http://images.cardomain.com/member_images/2/web/302000-302999/302013_22_full.jpg

[sykikchimp]

the best thing to do is put them on the car they way it is. strap a zip-tie around the piston rod shaft, and trim it short. Go drive around. If the zip tie is sitting at the bottom of the bumpstop when you come back, then trim a bit off, and retest.

[Halz]

Unless you lower the car 'too much', there should be enough stroke in the strut without doing anything to the bumpstop.. unless Tein just haphazardly slapped together a set of coilovers for this car.

The reason the bumpstop gets progressively thicker/thinner is to give a... progressive.. change in the effective 'spring rate'. The rate would increase from just the spring's rate, say, 450lbs/in.. to maybe 550lbs/in.. then to 850lbs/in, then 1350lbs/in.
If you trimmed the bumpstops, if/when the car encountered the bumpstop, the rate would jump from 450lbs/in to 850lbs/in, etc. With such a high, sudden change in spring rate, it would be easier to lose control of the car when its at the limit.

..but sure, you're trimming the bumpstop in hopes to never encounter the bumpstop.

In order the make the call whether or not to trim, the car should be run as hard as possible.. and then some. On a track, of course! Then check to see how close you had come to the bumpstops.