What is the purpose for trimming the bump stops? I would think that since you are lower (more likely to bottom out) that you wouldn't want to trim so they can absorb more of the shock? Does it just allow the struts more travel or something?
For coilovers, you have to trim them because the wide part won't fit in the new springs. I have no idea why people trim them for lowering springs though.
I bought new ones for my coilovers that are about 3" tall and they made a world of difference on my ride!
The only reason I can think of to trim them would be to slightly increase the amount of available travel but I think sacrificing half an inch of travel for the cushioning that the bump stop provides is probably well worth it!
Well, I bought some H&R springs and the documentation said to trim the bump stop an inch. I may just not do it since its such a mild drop.
My sportlines said to trim it an inch as well... i didn't... and every time I hit the bumpstops it rattled my teeth SO HARD.... so the next time they were apart, I trimmed them... was fine since that point.... drove like stock, but lower and sportier
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you trim the bump stops because they get into the working range of the spring, and when you hit the bump stops the car will bounce because the bump stops are kind of like a very stiff spring when compressed. then the struts that you spent all the time to dial in to the H&R spring rates see a huge jump in spring rate and are not set to handle it so the car will bounce. in autox terms that is not good because it upsets the car too much throwing the weight around. = push then snap over-steer at times
see ya!
novaracer wrote:you trim the bump stops because they get into the working range of the spring, and when you hit the bump stops the car will bounce because the bump stops are kind of like a very stiff spring when compressed. then the struts that you spent all the time to dial in to the H&R spring rates see a huge jump in spring rate and are not set to handle it so the car will bounce. in autox terms that is not good because it upsets the car too much throwing the weight around. = push then snap over-steer at times
YES, trim them!
-da chinchilla
<img src="http://registry.gmenthusiast.com/images/jiggamon/avatar15569_2.gif">
Here's my next dumb question, are there bump stops in the rear? I haven't pulled the rear suspension apart yet since i'm support the back end of the vehicle by the axle
.
I'm assuming the bump stops in the front are located inside the dust boot.
bump stops all around. stock ones arent really that hard but can alter handling if reached.
aftermarket bumpstops i garuntee one can break a window with em if thrown hard enough.
i believe both are in the dust boots.
yupe both are inside the dust boots. I trimmed mine about an inch, got rid of the first "bump". I don't think I've ever hit them. I just did it because Eibach recommended it, Just took their word for it that they knew what they were talking about.
Quote:
Here's my next dumb question, are there bump stops in the rear? I haven't pulled the rear suspension apart yet since i'm support the back end of the vehicle by the axle .
by the axel?? noooo please not there. if you let the axel move free you'll be allot happier
Well, I'm in the process of chaning out my transmission and I jacked the rear up by the axle to get the car level. Waiting on some coolant lines so I can finish off the transmission. I went ahead and cut off the first "bump" on my front bump stops. AGX's are in! Wahoo! never thought this day would come...
Wow talk about bringing back a old post from the dead. I think this needs more discussion on my end. I have read all the search's I can find.
I have installed brand new mounts, AGx's and the pro-kit. I didnt cut the bump stops. My cousin (4th year mechanic) said not to b/c they will prevent you from bottoming out harder pending you hit something hard enough. So we didnt cut them. Could this be the cause of a harsh ride. I dont think I have bottomed out yet or hit the bump stops. How can you tell? Here is a quote from what wild weasel said.
Wild Weasel QUOTE:
"For coilovers, you have to trim them because the wide part won't fit in the new springs. I have no idea why people trim them for lowering springs though.
I bought new ones for my coilovers that are about 3" tall and they made a world of difference on my ride!
The only reason I can think of to trim them would be to slightly increase the amount of available travel but I think sacrificing half an inch of travel for the cushioning that the bump stop provides is probably well worth it!"
Can anyone elaborate?
Regards,
if your bottoming out you would know. adjusting your struts will make a difference
The directions say to trim them because they don't need to absorb as much energy when you bottom out. The new springs, with a higher spring rate, will absorb more energy as they approach bottoming out. So to prevent hitting them prematurely, and thus effecting handling, you trim them.
I personally didn't trim because I don't push my suspension that hard. If I AutoX or something regularly, I would have trimmed them.
Any questions?
Well Im juyst a daily driver. No auto-x for me or heading out to the drag strip. So should I be ok. I think the roughest thing I will be going over is rail road tracks.
Regards,
J
Looking at Lenko's post, it looks like that extra bit of travel may be necessary depending on your setup. He has Sportlines though which is about as low as you can go.
I wouldn't cut them unless you find you need to. As I said... they'll give you extra travel. If you're bottoming out a lot, trim them down and you should bottom out less but harder when you do. If trimming them down means you drastically reduce them frequency of bottoming out then it's definitely worth while.
Well I went and talked with my cousin about it again who did the install. He said not to trim them unless I need to. As far as I know I havent bottomed out yet so maybe I might not need to as you said wild weasel. I'm not sure I will need that extra bit of travel as of this momment.
But like you said. If you do trim them and you do bottom out you will bottom out harder which could potentially cause more damage to the strut itself long term. The bump stop is there to absorb if you bottom out. Which is Just what my cousin said. So I think I'm just going to leave it for now. I'm going to play around with the settings for a while and see how that goes.
I talked with KYB about the cutting the bump stop and they said you dont have to pending they are installed on stock springs. But they refered me to eibach to debate the issue.
The technicial at eibach I talked to said about the same thing but he kind of contradicted himself. He said to trim them if your on stock struts. I said that I wasnt. He said all there products are tested on stock OEM valved struts which I found to be interesting. So the valving of a stock strut will be completely different from my AGX's since I can play with the valving and they could be stiffer right off the bat. But he said since it Isnt OEM I might not have to.
So there you have it. I think I'm going to leave the bump stops for now and see how things go and just play with the settings. just as wild weasel said if you do bottom out with trimmed bump stops you will bottom out harder. I dont auto-x or drag so, I'm just driving everyday and have to watch the road.
trimming bumpstops doesn't cause the car to bottom out harder. The springs are stiffer and more of the motion is absorbed into the spring. The stiffer springs wont compress as readily, but you are cutting strut travel down quite a bit. So the stops should be trimmed to account for the strut travel you lose by lowering. Well I have always trimmed them, and never had a bottoming out issue. Every car I have done an install on has had them cut and they all ride well.
Do what you want. If you are not comfortable with cutting them, well...don't.
You can always cut the stop, and if it is a problem, just put that cut off piece back on. I've done some experiementing with GC coilovers and bumpstops. I cut the three ribs apart (created 3 pieces) and experimented with what worked best. One allowed the car to lower a bit further at shows, but when driving it sucked!! So I sliced them vertically and removed them to drop the car down as far as it would go, and when I raised it back up after the show, just snapped them back on the strut shaft.
Sorry I rambled on.
-da chinchilla
<img src="http://registry.gmenthusiast.com/images/jiggamon/avatar15569_2.gif">
trimming bumpstops doesn't cause the car to bottom out harder I understand that. I was just stating that with trimmed bump stops that when you do bottom out. It will hit harder in the strut internals. I also do understand that with a lowering spring you do shorten strut travel by 1.4" (pro-kit) so you need to compensate some how by by cutting the bump stop.
As I said above I'm going to try it for a while and see how everything goes and rides. But if I dont cut them and everything is fine then it's fine. If I start to have issues I'll cut them the 25mm that they recommend. So far it has been ok.
As above you can see my responses I got from eibach and KYB.
Regards,
J
It's cool. i wasn't criticizing, just stating my experience.
Enjoy being lowered.
-da chinchilla
<img src="http://registry.gmenthusiast.com/images/jiggamon/avatar15569_2.gif">
I think I'll give it a try for a while without cutting them. I dont know why this seems to be such a hot debate. I know the instructions say to but Im getting such mixed reviews from my cousin (Mechanic) and people here. See this is the first time I have wrode and driven a lowered vehicle. I saved my money and did it right the first time and want to do everything I can to not void warranty on either product. (AGX struts and Prokit and all new mounts)
I talked to one of my friends last night who is riding on sportlines and koni reds and he didnt cut his. So for example sake there is another example.
I know the ride is stiffer b/c of the springs and probably the increased valving of the struts but as far as I know I havent bottomed out yet. I have been very carefull. So maybe or maybe not that extra inch of shaft travel may come into play when I hit something really hard. But i'll just have to wait and see I guess. But if I dont need to trim I wont.
As wild weasel said about lenko's setup. "it looks like that extra bit of travel may be necessary depending on your setup but may be needed on a lower setup like lenko's sportlines."
How much of a difference could it really make?
Regards,
J
NeoJuice wrote:How much of a difference could it really make?
Ask any hot-rodder or anyone who has built a custom suspension how much of a difference an inch (25.4mm) could make. Suspension geometries are very tricky, and being off by a little bit can be the difference between a good handling car and one that just plain sucks.
As far as bumpstops go on a daily driver...probably won't notice too much difference unless the roads are very bad and you dont avoid the bumps.
-da chinchilla
<img src="http://registry.gmenthusiast.com/images/jiggamon/avatar15569_2.gif">
I didn't cut my bumpstops at first (even though it was suggested by the manufacturer)... and I was hitting them.. I was pissed because I had to pull it all apart again to cut them.
So, your choice... do as most people on here and the manufacturer recommend and cut them.... or listen to your brother and don't.
Just keep in mind... if you have to pull it apart later on, it's a pain in the ass!
Is there anyway to do it without taking everything out? Like jacking up the car, taking the wheel off and just sliding the shield up and trimming it with a real sharp blade?
Has anyone tried this?
Lenko wild weasel said your running sportlines but your profile says pro-kit. Which one is it?
Regards,
J
If you have air tools, It's quicker to take it apart than it is to trim them on the car.
My H-techs said to trim them a bit. But if GM decided that this was was enough suspension travel, then I will not contest GM on that.
But I can surely see if you have a huge drop like the Sportlines to cut the bumpstops.
But if you use Suspension Techniques, H-techs, or even maybe Pro-kit there should not be a reason, unless if your commute is rock climbing.
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