servicing hubs.

[Willam]

My cranks have been slipping when I put pressure on them, at lights etc tried changing cassette and chain, still same problem...could the star ratchets in the freehub cause this kind of issue?

I can clean them out or replace them, tho the replacement cost is £30 so want to e sure it's worth replacing them first.

When would you replace rather than clean?

 

[gbb]

Can you get access to the pawls inside your freehub ?
If you can, then I'd clean then depending on type, give it some light grease or oil and see what happens. A clean and re lube is a reasonable option, they can stick.
Chainrings ok ?, sounds like you've covered everything else.

It is a problem that can go away, for some reason a freehub on a previous Bianchi slipped for a couple weeks when reasonably new. I was deciding what to do..and it stopped playing up, never to return.

 

[lpretro1]

Chainrings should be chief suspect

 

[Willam]

Chainrings should be chief suspect

How you mean? the chainring loose?

 

[lpretro1]

No - worn - fitting a new chain often shows this problem up for the same reason it is a bad idea to fit a new chain on an old cassette - the teeth wear and then do not mesh with the new chain

 

[Willam]

No - worn - fitting a new chain often shows this problem up for the same reason it is a bad idea to fit a new chain on an old cassette - the teeth wear and then do not mesh with the new chain

I said I replaced both at the same time, chain and cassette...I thought you were meaning the chainrings at the front, not the cassette/cogs.

 

[Cubist]

Remove the free hub body and look at the ratchet pawls. They may be gummed up with old grease and dirt, in which case they can be cleaned up and put back together with a sparing amount of grease. The pawls may be chipped or worn, or the spring or springs may be broken, depending on the design of the hub. Some lower end Shimano MTB hubs are not serviceable, but may respond to flushing with GT85 squirted into the space between the free hub and the main hub body via the red plastic straw.

 

[Willam]

Remove the free hub body and look at the ratchet pawls. They may be gummed up with old grease and dirt, in which case they can be cleaned up and put back together with a sparing amount of grease. The pawls may be chipped or worn, or the spring or springs may be broken, depending on the design of the hub. Some lower end Shimano MTB hubs are not serviceable, but may respond to flushing with GT85 squirted into the space between the free hub and the main hub body via the red plastic straw.

It's a DT Swiss hub, I've ordered a service pack, came today so changing the ratchets and springs...hope that does the trick.

 

[Globalti]

The service pack is a waste of money. It's the chainrings; the new chain no longer fits the worn teeth and is skipping under load. You should have changed the entire transmission.

 

[fossyant]

How worn are the chain rings.

 

[Andywinds]

I had these symptoms on my MTB, it turned out that a few teeth on the front small chainring were worn so under force my pedals would slip.

 

[Willam]

He did mean the chainrings. How are they looking?

Oh right, the whole crank is only 14 months old, but I'll also check it.

 

[Willam]

The service pack is a waste of money. It's the chainrings; the new chain no longer fits the worn teeth and is skipping under load. You should have changed the entire transmission.

Well the problem was happening before the new chain went on, not sure many Change the whole transmission with a chain and cassette everytime...fair enought if that's what's causing the problem but I'll need to confirm it first before changing the chainrings that are only 14 months old.

 

[Globalti]

Stand on a pedal while holding the brakes and leaning on a wall and see what happens.

 

[fossyant]

Post some pictures of the chain rings. - make sure they are clean so we can see the profile. How far can you tug the chain away from the larger chain ring - a photo would help.

Freehubs usually completely slip and then grab, i.e. you'll be pedalling thin air first. They rarely slip a little at a time as once engaged the pawls dont miss until you freewheel if they are sticky.