Are you also wondering what causes tight spots on a BMX chain?
Yes, I know.
This can be very frustrating. That’s why I created this article to clarify things for you.
Usually, any of the following five scenarios can cause uneven chain tension:
- Bent sprocket
- Misaligned sprocket
- Stretched chain
- Off-center freewheel or rear cog
- Improper chain tension
It’s a pretty common hiccup, but don’t worry – I’ve got your back.
But first: What is a tight spot on your BMX chain?
Your chain feels tighter at a specific point in the rotation.
This inconsistency can mess with your ride, making it less smooth, and, what’s even worse, it causes wear and tear, particularly on your front sprocket.
This post covers:
- Common causes of tight spots on a BMX chain
- Diagnosing tight spots on a BMX chain
- How to prevent/fix tight spots on a BMX chain
- Conclusion: Enjoy smooth BMX chain rolling!
Common Causes Of Tight Spots On A BMX Chain
1. Bent Sprocket
Your sprocket’s the big guy up front that the chain wraps around.
If it’s bent or not perfectly round, your chain’s gonna have a bad time.
Maybe you took a hard landing or had a gnarly crash – that can tweak the sprocket.
A bent or out-of-shape sprocket can happen more easily with sprockets without the guard. (See pros and cons of a BMX sprocket guard.)
When it’s out of shape, the chain tension changes as you pedal, leading to those pesky tight spots.
2. Misaligned Sprocket
The chainring’s gotta sit just right on the crank spindle.
If it’s off-center or tilted, your chain won’t run straight.
This misalignment means the chain tightens and loosens as you pedal.
To align your sprocket, use the thin spacers that come with cranks and insert them on the inside of the sprocket (you add spacers first, then come the sprocket and crank arm).
3. Worn Or Stretched Chain
Chains don’t last forever.
With all our grinding, jumping, and riding, they stretch out or get stiff links.
A stretched or damaged chain won’t mesh well with the sprocket and cog, causing uneven tension.
Regular check-ups can help spot these issues early.
Also, a stretched chain will damage our front and rear sprocket teeth – and that’s no good.
It’s better (and cheaper) to replace the chain than to replace the front sprocket and rear cog (or entire hub).
4. Off-Center Freewheel Or Rear Cog
The back end’s gotta be in sync, too.
The chain tension will fluctuate if your freewheel or rear cog isn’t centered right.
This one’s less common but still worth a look if you’re having issues.
For instance, you miss the ledge/rail and hit it with your rear peg and this can quite easily move your rear wheel, so it’s not centered anymore.
5. Improper Chain Tension
Too tight, and your chain will strain; too loose, and it’s flopping around.
You want that Goldilocks tension – just right.
When you press on the chain, aim for about a half-inch of vertical movement. That sweet spot keeps everything running smoothly.
However, I run my chain slightly tighter, mainly because I want my bike to be as silent as possible during landings.
One of the worst sounds is a chain hitting your frame!
Diagnosing Tight Spots On A BMX Chain
Here’s how you can check for tight spots and fix them up:
- Visual inspection: Flip your bike upside down or pop it on a stand. Spin the pedals and watch the chain. Look for any wobbles in the sprocket or chainring. If something’s off, you’ll see and feel it.
- Feel the tension: Slowly pedal and feel for any resistance. If it gets harder to pedal at certain points, you’ve found a tight spot. Mark that spot so you can focus on it.
- Check the chain: Look for stiff links or signs of wear. If a link doesn’t bend smoothly, it’s time to replace the chain. (A chain checker tool can help you measure stretch.)
- Inspect the sprocket: Check for bends or warps. If it’s not true, you’ll need to straighten or replace it. Sometimes, loosening the chainring bolts and realigning it can solve the problem.
- Align the rear wheel: Make sure your rear wheel’s sitting straight in the dropouts. An off-center wheel messes with chain tension. Adjust it until it’s centered.
- Set the right chain tension: Adjust the rear wheel to get that half-inch of slack in the chain. Too tight or too loose, and you’re asking for trouble.
How To Prevent/Fix Tight Spots On A BMX Chain
You know what they say – prevention’s better than cure.
Here are my top tips to keep your ride smooth:
- Regular check-ups: Give your bike a once-over after heavy sessions. Look for any signs of wear or misalignment.
- Keep it clean: Dirt and grime are your chain’s enemies. Clean and lube it up regularly to keep it running smooth.
- Quality parts: Invest in good components. They last longer and perform better, saving you headaches down the road.
- Proper installation: When swapping parts, make sure everything’s installed right. A poorly installed part can cause all sorts of issues.
You don’t have to inspect and maintain your sprocket after every session.
But doing it weekly or bi-weekly is recommended.
Note: Usually, I ride my sprocket until I can no longer use it. That said, I won’t try to fix it if it’s bent; I’ll replace it instead.
Conclusion: Enjoy Smooth BMX Chain Rolling!
Tight spots on your BMX chain can be a pain, but with a bit of know-how, you can tackle them head-on.
Keep an eye on your chain and sprockets, maintain proper tension, and don’t skimp on quality parts. (You can always find good deals online.)
Your bike will thank you, and your rides will be smoother and more enjoyable.
Don’t let those tight spots on your BMX chain stop you from having an epic session!
Further reading:
- BMX chain alignment (make it straight!)
- Bent BMX sprocket (worth fixing?)
- BMX sprocket maintenance (6 tips!)
- Best BMX sprockets
- What BMX sprocket size is best?
- Best BMX chains
