BMX - loose handlebars

alright, so i tighten my stem with my handlebars at a 90 degree angle to the floor. After a few bunnyhops, i notice that the handlebar slowly moves back, to the point where it almost hits my knees (then wont go any further back). What ive noticed about the handlebars is that at the part where the stem locks onto it, it's kinda squeezed into an odd shape. Is it time for new handlebars? new stem? or is there something i can do?

i already tried cutting an old tube out and wrapping it around the handlebars, but even with the stem fully tightened, it moves alot

btw, the parts i described are the stock GT stem and stock GT handlebars.

I have had this problem before. The reason mine ovaled/bent in is because the inside had bad rust, causing it to bend when i tightened the stem. Over tightening could cause it too, with or without rust. I reccomend buying new handlebars.

how would i know if im over tightening?
i dont have a torque wrench, and they dont really make them for the allen bolt styles, do they?

I had the same problem. The bike shop took the paint off my handelbars, then it never happened again. Take a flathead screwdriver, and put cuts in your stem going diagonally. Alot of them, some deep. Then if they still move, get new handelbars.

is there another thing i can do besides that?
like maybe some sort of material that could be stuffed in there to keep it nice and snug.

I think anything extra you put in there is just gonna act as a bearing and make it slip more

Is your stem really smooth inside? Are your handelbars really smooth where they meet the stem? Or are they rough to keep them from moving.

yeah, mine were completely smooth a while back. I actually bought it used, then tried DJ. that's how I learned abotu the slipping bars. bad results, lol. just buy a new set, and wipe the inside of your stem out. the bits of metal that had worn off my bars made a kind of sludge in there. make sure it's gone.

there's some metal stuff inside the stem, and the handlebar part is pretty smooth too.

the handelbar part shouldnt be that smooth.

The handle bars should have a cross-thatch section, or a section where it has grooves for the stem to tighten down on to.

nope. i guess it's time for me to install my new handlebars once i get a new stem, unless someone has another solution for me.

try rubber. like cut some rubberbands and wrap em around the inside. just a temporary fix though. wont last more than a week or two depending on how hard you ride

hmm, rubber bands sounds good.
i was sitting here thinking of how to fix it, and how well would cement work? or super glue?

Super glue? No
Cement? wtf
Caulk? Maybe
Hot glue? Maybe
They'd end up wearing out fast though.

I had the same problem. The bike shop took the paint off my handelbars, then it never happened again. Take a flathead screwdriver, and put cuts in your stem going diagonally. Alot of them, some deep. Then if they still move, get new handelbars.

still this

WOAH! No glue ever lol. And cement? You nuts? Thats as bad as me using a hammer on my bike >.< Possibly worse.
Get some rough ass sand paper and sand your stem and bars untill its really rough. That should buy you some time.

alright, i will start sanding the handlebars, do i sand the inside of the stem too?

and also, im looking to buy a new stem right now, are all stems supposed to have the grooves to match the handlebar? or is it just the cheap stems that are smooth on the inside?

I only suggest sanding because it should be kinda rough on your handlebars where the stem grabs it. Not sure about inside my stem, dont have allen keys on me right now to check...pretty sure mine hase diagonal "cuts" in it.

Here is what me and my buds did when we were too broke to buy new parts:

Get a coke can and cut out a square as wide as the stem. Then fold this square once, making a rectangle. Install it between the stem and handle bars...and if that doesn't solve the issue, then repeat this for the opposing side of the stem/bars.

***I am not responsible for any damages to you or your property***

Might buy you some time or even solve the issue. I did this on a bike when i rode hard and all it required was an adjustment every month or so.

sounds cool, im gonna try it.
thanks

Alright, i tried the soda can trick, but handlebar still moved after a few bunnyhops.
I think it's because the part where the stem locks onto is squeezed smaller from over tightening or something.

Your first problem is that you're putting your bars perpendicular to the ground, rather than parallel with your forks and steerer.

the starting angle has nothing to do with it. I align my bars by using the ground, not my fork and they're fine. just buy new bars.

That's the angle he's riding his bars at, not simply the starting angle, if I'm reading it correctly.

well, my forks are kinda slanted forward.
so if i readjust them to be straight with the forks, it should be fine?

don't think so. seriously, if the base of the bars are smaller than they were originally, you really need to buy new ones.

just buy some mother freaking badger bars
like 70 bucks
and theyl last forever

i already have another one that i tried to install right now, but here's the problem...
The stem looks like it may be a bit ovaled or something, because when i put the new handlebars against the stem, it doesnt fit up against it tightly. There is a small space, so i didnt install them yet..
I guess it's time for a new stem too.

Here's my stem question, does the type of headset you use determine what kind of stem is compatable?
because ive noticed that the older bikes like mine, have another shinny shaft thing that locks onto the stem, instead of like the newer bikes, which directly lock onto the steerer tube of the fork itself.

you are using the old style system. Your stem is actually a "gooseneck" and it holds it self in place by the wedge system you've probably seen. The headset and steerer tube are threaded so you can only use that old-style system. Or just buy a new bike.

i see...
how much could i sell my gt for?
thinking about parting it out then selling it on ebay.