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Alright, I haven't owned a bike in 20 years and am doing my best here. The handlebars turn the wheel, but it still slides around when met with any resistance at all.

I have tightened as best I can all 3 bolts in the stem? Idk what else I would call it. 2 side bolts and a center bolt.

Please help?

enter image description here This is the bike I have, I hope this helps Max4out Fat Tire Mountain Bike 21... https://www.amazon.com/dp/B07Z37H8ML

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    A picture of the stem area would help tell what headset type you have.
    – Robert
    Jul 3 at 18:11
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    That's not good - if you feel any uncertainty at all in fixing this then consider searching your area for a bike cooperative who can assist. Having the steering loose could have significant consequences, specially if you have to brake hard. Was it always like this or did you buy it new?
    – Criggie
    Jul 4 at 0:05
  • You added a link to the specific bike in a comment below. You should add that to the question as well since there is no guarantee people will read all the comments. For information this seems to be a mail order bike that has the usual partial self-assembly required. There is a video on the link that shows how the stem should be adjusted around 40 seconds in. I can't tell what might be wrong but seeing the specific design might help someone else identify the problem.
    – Eric Nolan
    Jul 4 at 13:44
  • It looks like a modern threadless stem with some pinch bolts and a top cap, but the frame at the back is weird. I'm not sure if this is just a bad `shop or if the bike really looks like this. Can you please confirm? A photo of your own bike in this area, more from the side would help a lot.
    – Criggie
    Jul 4 at 21:18

1 Answer 1

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Make sure you adjust the center bolt on top first while the 2 stem bolts on the side are still loose. Only tighten it a little, until there is no more headset play. That preloads the bearings, and then the 2 stem bolts lock everything in place. Do not tighten the stem bolts first. That will make the center bolt unable to preload the bearings.

See this video:

Altough, I'm wondering if your stem has the same diameter as the fork it's clamped on. If the stem has a larger diameter, it is not compatible with the fork, and would slide around no matter how much you tighten it, making the handlebars turn without the wheel.

There are these standards for threadless stems:

3.2.2 Threadless stems

TABLE 3
Steering column outer diameter (and inner diameter for the attachment on the stem Standard Name
measurement units: mm (inches)
25.4 (1") One inch standard
28.6 ("1 1/8") 1-1/8 inch standard
31.8 (1 1/4") 1-1/4 inch standard
38.1 (1 1/2") 1-1/2 inch standard

Table from: https://bike.bikegremlin.com/3729/bicycle-stem-size-standards/#1.2

Edit: Another scenario that came to my mind where the handlebars could be sliding around is if the steerer column / steerer tube of the fork is cracked, bent or damaged. The stem could be cracked or damaged as well, causing this. I would remove the stem and inspect for any damage. This video shows how to remove and reinstall the stem:

Be careful about problems on the front end side of the bike. Any damage to the stem or fork is also a huge safety risk. As the frontend is responsible for steering and keeping balance, it can easily cause a bad crash.

Easiest is to take the bike to a local bike shop and they should diagnose it pretty quickly.

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    Of course there are several other configurations for the fasteners. The one pictured is probably the most common on newer bikes. Jul 3 at 18:28
  • @DanielRHicks Yes, indeed. If it's a quill stem I'd suspect it had rusted and is not tightening properly. Maybe...
    – Robert
    Jul 3 at 18:33
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    This is the bike I have, I hope this helps Max4out Fat Tire Mountain Bike 21... amazon.com/dp/B07Z37H8ML
    – Robert P
    Jul 3 at 19:02
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    I’d rather write “adjust the center bolt”. Tightening it like it’s holding something is surefire way to destroy bearings.
    – ojs
    Jul 4 at 13:05
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    @ojs good observation, i edited
    – Robert
    Jul 4 at 15:06

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