Are bumpstops necessary....Help please
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Are bumpstops necessary....Help please Hey guys, are bumpstops necessary? Opinions please. I've got my 17X11 ZR1's w/ BFG KD's ready to go on today. I've done a lot of research and I'm ready to shave the bumpstop down as close as possible to the bolts, or just cut that badboy. Ive got the +50mm offset and I know for a fact that I'll be cutting or removing the bumpstops, BFH ing, rolling the lips and adjusting my panhard rod for sure. I just don't want the bumpstops digging into my rims and messing then up or cuttng the tire. It's pretty flat here in South Carolina where I am and I don't plan on going airborn at any time and I take railroad tracks very carefully. I'm lowered w/ prokit and my FLP's will scrape if I'm not careful, so I'm used to driving cautiously when needed. Please let me know what your opinions are on bumpstop removal vs trimming. Those who think it is okay to remove them....will it affect the car's performance at all..i.e. cornering or acceleration (I personally do not think so). Someone school me please. Thanks. 
Just cut them completely off.... removed mine a long time ago. Your shocks will keep it from bottoming out so you wont have any issues unless you jump something dukes of hazard style. 
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That's what I was thinking also. I figure, if I'm in a condition where my car bottoms out that badly, then I probably have a lot more to worry about. I think I'll grind them down as far as I can go first, just to see, but then cut them off. Those 315 KD's are HUGE. Okay, so that's #2 on my problem list....bumpstops/ addressed. #1 BFH, #3 Rolling Fender Lips, and #4 adjusting panhard rod. These things are going to be a major PITA to get on, but I keep smiling everytime I look at them, so I know it'll look tight when all is said and done. Thanks for the help guys, and if anyone else agrees or disagrees, please post. I'm always open to hear ALL varying opinions.
With a 50 mm the bump stops can be shaved down to the bolts and you will have clearence. Only time they cause an issues is trying to pick the car up by the body and not the rear end. As for the BFH mod, gonna have to do a lil beating to get good clearence. Shouldn't have to roll the fenders with a 50, they should be ok. Good luck with it.
Ive got 50mm 17x11 boyd coddingtons and will be removing my bumpstops as well. Right now Ive got some spacers on it. Ill probably have to BFH it a bit and I should be good to go after that.
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Thanks John02SS. Yeah, I know I'll have to jack the car from the rear from now on. I do have the +50mm offset, but I'm still a little nervous because these tires are some BIG ****'s. I just can't wait to get off work and start working on these things today. The anticipation is killing me, and it will probably go like most aftermarket installs go for me. I'll end up cussin' and screaming and hating my car, then when it's all said and done, I'll be in love again. I just feel like it is gonna be some WORK getting these tires in. I knew that from the start, but I'm glad I got them, because I've wanted to do this for years. I've always loved the G-Force KD's from the first time I saw them. They look very aggressive. Anyway, wish me luck.
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Verdad Gallardo The front inner corners will probably be the only place you will need the BFH. Just be careful not to hit your fender I had to beat some in the top center portion to clear my 19X10s and grazed the fender a bit 
If you have rubbing issues here... use a grinder instead. Those ribs dont beat in well at all. When its all said and done spraypaint it black and the carnage will be hidden pretty well.
I had to beat some in the top center portion to clear my 19X10s and grazed the fender a bit If you have rubbing issues here... use a grinder instead. Those ribs dont beat in well at all. When its all said and done spraypaint it black and the carnage will be hidden pretty well. 
Originally Posted by silver02Z
My tires rubbed worse over bumps when I removed my bump stops. Put them back on and problem solved...I guess the suspension travels more when they're gone..
Not quite sure how that can happen, after all, you are removing an obstruction, not adding one, unless you bottom your car out on a daily basis, in that case your bumpstops...the actual rubber part, not the tab they are bolted to...should be mush by now.
Either way Carlos, I PM'ed you.
No worries taking the bumpstops out, mine are out, the mounting tab is shaved back and now I can lift the car on a normal lift without any hangups....literally.
And the hammer thing....****...no biggie dude, a 3 pounder should do it
Took me all of 5 mins per side...it's kinda fun actually, just be careful not to hit the fender when you reach back for a swing
Manny
Originally Posted by Comin' Thunder
That's what I was thinking also. I figure, if I'm in a condition where my car bottoms out that badly, then I probably have a lot more to worry about. I think I'll grind them down as far as I can go first, just to see, but then cut them off. Those 315 KD's are HUGE. Okay, so that's #2 on my problem list....bumpstops/ addressed. #1 BFH, #3 Rolling Fender Lips, and #4 adjusting panhard rod. These things are going to be a major PITA to get on, but I keep smiling everytime I look at them, so I know it'll look tight when all is said and done. Thanks for the help guys, and if anyone else agrees or disagrees, please post. I'm always open to hear ALL varying opinions.
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Hey guys, thanks for all the advice. I wish my digital camera weren't broken, because I'd have all types of pics up. I will get some up when I get a new camera though. I didn't get to try putting them on today, because I ran around all afternoon here in Charleston South Carolina, trying to find a competent "professional" tire mounting joint. You will not believe how many of these established, BIG businesses were scared to touch my 315/35/17's and 17X11 inch rims. I was PISSED. I had one place tell me that they didn't put tires on aftermarket rims????WTF They are ZR-1's
I tried 5 places today before I finally found a place called Tire Kingdom who would do the job. They did a nice job putting the tires on the rims and balancing them. The other places looked a me like I had two freakin' heads when I rolled the tire in. I was dumbfounded and amazed as I watched their techs confidence decline rapidly when they saw the rim and tire. Another guy told me that they would try, but if they scratch the rim up all they could do is say sorry. 
Are you kidding me? These rims are brand new. Okay, enough of my rant.....it was a frustrating day. I'll give it a go tomorrow. The shop that did mount my tires on the rim did have to turn away a guy with a viper who wanted 345's put on. They couldn't balance the rims for anything....just too big.
I tried 5 places today before I finally found a place called Tire Kingdom who would do the job. They did a nice job putting the tires on the rims and balancing them. The other places looked a me like I had two freakin' heads when I rolled the tire in. I was dumbfounded and amazed as I watched their techs confidence decline rapidly when they saw the rim and tire. Another guy told me that they would try, but if they scratch the rim up all they could do is say sorry.
Are you kidding me? These rims are brand new. Okay, enough of my rant.....it was a frustrating day. I'll give it a go tomorrow. The shop that did mount my tires on the rim did have to turn away a guy with a viper who wanted 345's put on. They couldn't balance the rims for anything....just too big. 
They prevent the rear axle from moving upwards too far. Removing the bumpstop could cause premature shock failure, and damage to the exhaust system.
Pretty rare for GM to put pointless parts on their cars . . . .
Pretty rare for GM to put pointless parts on their cars . . . .
Originally Posted by Xsta Z 28
They prevent the rear axle from moving upwards too far. Removing the bumpstop could cause premature shock failure, and damage to the exhaust system.
Pretty rare for GM to put pointless parts on their cars . . . .
Pretty rare for GM to put pointless parts on their cars . . . .
Very true, but ONLY if you take your car flying over the hills of San Francisco on a daily basis. During normal driving the bumpstop never ever touches the rear axle, it's only a precautionary part. Once the bumpstop does hit the axle, it's pretty much toast and worthless and needs to be replaced. As long as you don't drive like Steve McQueen, driving without bumpstops is just fine. Besides, he's putting on 315's, and with tires that wide, which protrude that far into the fender well, the stock bumpstops are not located close enough to the axle to engage it early enough to prevent damage to the fender well with those big tires mounted. That's the reason why WS6's and SS's come with a relocated bumpstop that's closer to the axle. For that same reason, SLP sells "jounce bumpers" which are basically just spacers that go between the mounting tab and the actual bumpstop to relocate the bumpstop further down closer to the axle which is where it needs to be to do it's job correctly with SS wheels or WS6 wheels mounted on a TA or Z28, or a 6 banger for that matter.
Manny
When I get to the stage where I'm ready to mount my wheels, I'm going to take my car to a shop and have them weld in brackets that will move the bump stops an inch inboard. Believe me, it was a hard decision, but whenever I thought about whether I'd rather have a $350 tire or a $5 piece of rubber eat metal any time I should happen to hit a nasty bump...well, I'm sure you can guess the rest.
Originally Posted by MannyZ28
. . . During normal driving the bumpstop never ever touches the rear axle, it's only a precautionary part. Once the bumpstop does hit the axle, it's pretty much toast and worthless and needs to be replaced. . . .
The bumpstop DOES contact the rear axle , and probably more often than you care to think, and the thing does not disintegrate upon contact . . . 
Plus if you lower your car, well the MORE important it becomes . . . I would NEVER completely remove the bumpstop, if you find it necessary; trim it, move it, but DO NOT remove it . . . Yes it is pain to deal with if you have your large wheels mounted with the axle hanging, but how many garage mechs use a lift to install wheels?
The Bump stop is there for a reason. The guys saying the shocks will stop it from going to far? True to an extent. But if the compress to much and too far they will blow or cause damage to them. The spring will compress completely and that is the only thing that will stop travel other than the shock bottoming out when the Bump Stop is removed.
Why would they be bad after one contact? They are made of durable rubber for long use and damage prevention.
Also if you do remove them you increase the travel the wheel can go inside the wheel wel and may cause the tire to rub more or on the top of the wheel well. Also think of the articulation of the rear. Since it is a solid piece if you hit a low spot on one side it will raise that side up high and cause excessive angle and cut into the outside of the tire on the wheels well.
Why would they be bad after one contact? They are made of durable rubber for long use and damage prevention.
Also if you do remove them you increase the travel the wheel can go inside the wheel wel and may cause the tire to rub more or on the top of the wheel well. Also think of the articulation of the rear. Since it is a solid piece if you hit a low spot on one side it will raise that side up high and cause excessive angle and cut into the outside of the tire on the wheels well.
I agree with Xsta Z 28 & JGKadell. Take a look at your axle just below the bump stop when you take your wheels off. I'm willing to bet you'll see a mark there from it hitting.
I cut mine as close to the mounting tabs as possible when I put my 325's on.
I cut mine as close to the mounting tabs as possible when I put my 325's on.
While my car is not lowered with lowering springs, it is a inch lower than any other Z28 I have seen around...god knows why, but it is. I bought the car new, it came that way. When I put the 11's on, it was 5 years old, the bumpstops never touched the axle, I don't know how you guys drive to have your axle rubbing your bumpstop on a regular basis. Either way, consider my car lowered, and I have went over 30000 miles on 11's and NEVER had a problem! I never had any excess rubbing going on after the bumpstop was removed.....and as a matter of fact it was my dealer who suggested and removed them for me!
But as mentioned before by some other people, each car is different, so I'll leave it at that, my car, despite being lower with stock components, seems to be very 11" wheel friendly.
But as mentioned before by some other people, each car is different, so I'll leave it at that, my car, despite being lower with stock components, seems to be very 11" wheel friendly.