Help me fix my dirt...
 

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[Closed] Help me fix my dirt jump bike

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I am not a dirt jumper. But I have a Specialized P.1 that I got cheap and would like to ride at pump tracks to get better at that and maybe learn to manual on it. The drivetrain is obviously simple but rather worn (feels notchy and has slipped when riding) so I am going to replace chainring/chain/freewheel. So I need:

Chainring: fixes with a single bolt to the crank arm, current one is 25T but always seemed low. OK to go to 28T do you think? Want something blue to keep it matchy matchy!
Chain: Simple I will replace like for like with KMC Z510-HX
Freewheel: No idea how to get the current one off (see picture below) or what I need to replace it - advice needed!

Also where best to buy this stuff

Freewheel


 
Posted : 07/06/2021 11:35 am
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Is the slipping from the freehub? Hub looks pretty cheap and nasty with loose balls in the freehub which are visible as the shield is hanging loose further out on the axle.

I'd strip the freehub and check the nick of the pawls and the ratchet ring as well as all the bearings. Spares unlikely to be available for a basic hub like that, so more than likely be a case of replacing the hub if it's damaged.


 
Posted : 07/06/2021 2:56 pm
 5lab
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singlespeed stuff lasts forever - I would also suggest it might be the freehub skipping - and if it feels knotchy when peddling it might just be that your chain is too tight.


 
Posted : 07/06/2021 3:36 pm
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singlespeed stuff lasts forever

Have you ever had a BMX or dj bike?

Those cup and cone, single speed cassette hubs really are the worst of all worlds. I'd be looking for a suitable rear wheel for sale if you need one. If it's in decent condition service as normal.

As said, a tight chain can causing creaking and slipping so get the chain and sprocket fitted first. Then shop for a rear wheel if you need one.


 
Posted : 07/06/2021 3:46 pm
 5lab
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Have you ever had a BMX or dj bike?

yes, sorry I meant that the chain, chainring and sproket tend to last forever. Adjusted right, I'd be surprised if they were causing issues.

Hubs on the other hand tend to be garbage


 
Posted : 07/06/2021 4:46 pm
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There is quite a lot of wear on teeth of chainring and freewheel so going to replace the parts whatever but agree the hub does look to be garbage! Any ideas what tools I need to strip it? All looks a bit different from the mountain bike parts I am very familiar with.

Looks like I might need some sort of circular notched tool to fit the bit that says 'Lock' on it.


 
Posted : 07/06/2021 4:56 pm
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Looks like I might need some sort of circular notched tool to fit the bit that says ‘Lock’ on it.

Or a nice flat screwdriver, hammer and a steady hand.


 
Posted : 07/06/2021 6:30 pm
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Hmm, I suppose so. I have been looking for the tool and found two and four notch option but no sixes so it may well be the approach I have to use or I could take it to an LBS :-O


 
Posted : 08/06/2021 9:30 am
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You can use a fixed gear lockring wrench on there if it's not made out of monkey metal (which it may be!):

https://www.parktool.com/product/fixed-gear-lockring-wrench-hcw-17


 
Posted : 08/06/2021 9:39 am
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Is it definitely a freehub design? A lot of those bikes have single speed freewheel hubs so you could just replace the freewheel sprocket + engagement apparatus in one go. That would be nice.

Having said that, it does look like a mini cassette carrier from your picture. Which is weird and annoying.

It also looks like the sprocket might be too small for the lockring. Which means the chain could skip under load. I'd definitely try a bigger sprocket.

You might find a suitable tool here: https://www.parktool.com/blog/repair-help/bottom-bracket-tool-selection-threaded-and-thread-together


 
Posted : 08/06/2021 10:07 am
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It's a single speed driver. They tend to be specific to the hub so you need to know the hub to be able to replace it


 
Posted : 08/06/2021 6:42 pm
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