Slight grinding from cassette/rear hub

[EasyPeez]

Hi,

In the last few days I've noticed a slight grinding sound coming from my rear wheel. At first I thought it was the rotor catching on the brake pads, but adjusting them didn't help, so I whipped the pads out for a check and realised the sound was still there with no brake pads in. So then I wondered if it was the rear hub. With the wheel off I broddled about with some pipe cleaner through the middle of it and gave the spindle a clean and a squirt of GT85, but still the noise persists. Having now realised that it only happens when the rear wheel is freewheeling I think the cause is light friction between the hub and the cassette. The fact that the grinding occurs when turning the cassette backwards and holding the wheel in place seems to confirm this. I tried a bit of precision applied GT85 where the cassette meets the hub to no avail.

As I say, the noise is fairly faint and whatever the issue is it doesn't affect the movement of the wheel or performance of the bike at all. But it is a bit annoying for an OCD perfectionist like me!

One thing that has just sprung to mind is that I took it into the LBS for a new chain recently and noticed when it came out that the plastic disc between the spokes and cassette had been removed. I know lots of bikes don't have these anyway (not sure what the point of them is? Prevent spokes going into cassette if one breaks perhaps?) so didn't think anything of it. But could this be what's causing the issue? Should they have replaced it?

Any advice much appreciated. 10sp Tiagra cassette and Fulcrum Racing Sport wheels if that helps.

Thanks, Andy.

 

[Turbo Rider]

Could be a faulty / warn out freehub but could just be a dirty one...could try taking the cassette off, degreasing the freehub, re greasing, sticking the cassette back on...might work...if not, probably need a new freehub, else it might stop engaging and then you might find yourself stranded one day...LBS should be able to remove the cassette and inspect it for you...if it is a degrease and regrease then it should cost around £5. Anything else might be more...if it is to do with the freehub...

 

[EasyPeez]

Could be a faulty / warn out freehub but could just be a dirty one

Thanks for the advice.
Given the bike's only done just shy of 550 miles I'd hope it's not worn out?! I guess it could have developed a fault
If it's dirty is the only way to clean it to take the cassette off? Again, given the low mileage and my meticulous cleaning regime, and the fact that (until I got caught out last night) the bike's only been ridden in the dry I'm a bit bemused as to how dirt could have found it's way in there so soon.

 

[Turbo Rider]

I think so, but I'm not completely sure - someone will no doubt be along to correct me if I'm wrong, but to get to the part that needs a clean, I think the cassette has to come off...if it needs a clean, that is...from what you say about the conditions you ride in though, it's probably less likely to be dirt than a fault.

I've had two issues myself over the winter.

The first was when I couldn't freewheel, which meant I couldn't back pedal, which is annoying for me, because I do it frequently...especially when stopped at lights and trying to get a nice position to take off from. That resulted in a simple clean and I had no tools at the time, so it was a drop off at the LBS and they cleaned it up for £6.

The second was when the freehub got dirt or grit in it and stopped the pawls (little springy things which grab the cassette...I think) from engaging with the cassette, meaning I was spinning with no movement. This was the worst of the 2 as it left me stranded in the middle of a 12 mile commute.

Definitely sounds like a freehub thing to me, as you seem to have isolated the sound to it, but others may have other suggestions. Wait to see if anyone chips in with an alternative, but I'd probably start with a degrease and regrease to begin with, if you have the tools and the time, just to pre-empt any of the problems I've had.

 

[EasyPeez]

I think so, but I'm not completely sure - someone will no doubt be along to correct me if I'm wrong, but to get to the part that needs a clean, I think the cassette has to come off...if it needs a clean, that is...from what you say about the conditions you ride in though, it's probably less likely to be dirt than a fault.

I've had two issues myself over the winter.

The first was when I couldn't freewheel, which meant I couldn't back pedal, which is annoying for me, because I do it frequently...especially when stopped at lights and trying to get a nice position to take off from. That resulted in a simple clean and I had no tools at the time, so it was a drop off at the LBS and they cleaned it up for £6.

The second was when the freehub got dirt or grit in it and stopped the pawls (little springy things which grab the cassette...I think) from engaging with the cassette, meaning I was spinning with no movement. This was the worst of the 2 as it left me stranded in the middle of a 12 mile commute.

Definitely sounds like a freehub thing to me, as you seem to have isolated the sound to it, but others may have other suggestions. Wait to see if anyone chips in with an alternative, but I'd probably start with a degrease and regrease to begin with, if you have the tools and the time, just to pre-empt any of the problems I've had.

I don't have the tools or time to take off my cassette this weekend. It also doesn't help that the shop I bought the bike from is 50 miles away, so not too convenient if/when any faults crop up as they would be happy (read obliged!) to sort them out for free, but a round trip of 80 miles in the car plus a parking ticket makes that a very expensive 'free'!
Better take it into my LBS for a quick look over after Bank hols. Thanks again for your advice.

@Yellow Saddle - sorry to bother you but as you've given me some sound maintenance advice in the past just wondered if I could trouble you for a second opinion on the above.
Edit: I should probably have described the sounds not as a grating but more as a light scraping - the sound you'd expect to hear if 2 bits of metal were coming into light contact as they rotated past one another.

 

[Tojo]

I've found this a lot on various different wheels lately, and it seems always to stem from the freehub side wheel bearings, I have had a few bikes in and they have had water/dirt ingress past the seal and the ball bearings were rusted and pitted, take the axle out, clean and re-grease and replace the freehub side bearings if they are pitted, you will probably find that the opp freehub side bearings are good and just re use them....Hope this is all the problem is as it's a quick cheap fix, also as Turbo Rider mentioned earlier might as well, clean, de and re-grease the freehub while its apart...

 

[S.Giles]

...I took it into the LBS for a new chain recently and noticed when it came out that the plastic disc between the spokes and cassette had been removed. I know lots of bikes don't have these anyway (not sure what the point of them is? Prevent spokes going into cassette if one breaks perhaps?) so didn't think anything of it. Should they have replaced it?

It's an absurd bicycle fashionista/weight weenie thing to absolutely hate those disks. Don't ask me why. I've tried to get to the bottom of it on this forum with no luck. They shouldn't have removed it without asking you first, but I guess they knew better than the bicycle's manufacturer! If the chain ever slips off the large rear cog, your spokes will be damaged, possibly beyond repair. Not to worry though, I'm sure your LBS will give you a new wheel free of charge!

 

[Yellow Saddle]

I don't have the tools or time to take off my cassette this weekend. It also doesn't help that the shop I bought the bike from is 50 miles away, so not too convenient if/when any faults crop up as they would be happy (read obliged!) to sort them out for free, but a round trip of 80 miles in the car plus a parking ticket makes that a very expensive 'free'!
Better take it into my LBS for a quick look over after Bank hols. Thanks again for your advice.

@Yellow Saddle - sorry to bother you but as you've given me some sound maintenance advice in the past just wondered if I could trouble you for a second opinion on the above.
Edit: I should probably have described the sounds not as a grating but more as a light scraping - the sound you'd expect to hear if 2 bits of metal were coming into light contact as they rotated past one another.

The good news is that to check if it is the freehub, you don't have to remove the cassette. There's nothing extra you can inspect with it off. Nor is there anything that can grind if the cassette is installed badly. It is almost impossible to bodge the installation. I think your original chain of thought is correct - that the noise only appears when the freehub is free-ing (i.e. no pedaling, just coasting), means that there is something inside that's touching and scraping. It has nothing to do with the removal of the plastic spoke protector unless the bike shop cut it out with a shears or side-cutter and let a piece jam behind the freehub. Have a look. I stayed out of the discussion since I don't know what GT85 is nor do I know what type of freehub is installed on the wheel you mentioned. Cheaper freehubs are very noisy sometimes. Some of them kick up quite a racket. You can demonstrate this by putting the bike on a workstand, pedal fast and then stop the crank and turn it backwards. The noise then increases noticeably. There is usually nothing to do other than wait until the freehub fails and you have good reason to replace it and hope the new one is a better one from the batch.

I say ride it as is and phone your shop where it was purchased and tell them you will bring it in when it is convenient for you.

 

[Tojo]

Recently, I had a mates bike ( new Giant Defy 3 with about 500miles on it) in just to tweak the gears and I noticed a bit of a click as I spun the rear wheel so took it out and to get to the root of the problem I ended up stripping the rear hub only to find the offending article was a plastic tab from the spoke protector which must have just been thrown on and had managed to get past the seal, unseating it slightly and allowing water in......

 

[accountantpete]

You don't mean the clicking sound of the pawls do you?

Some retailers smear liberal quantities of grease into the hub where it contacts the pawls so make them quiet like Shimano. When the grease wears out/is thrown away from the area, the hubs starts to click like any normal Campagnolo rear hub.

 

[Tojo]

No, if you read what I said I found one of the plastic tabs from the spoke protector in amongst the bearings on the free hub side.

 

[Cyclopathic]

Could be that the cones have been slightly over tightened.

 

[Yellow Saddle]

Could be that the cones have been slightly over tightened.

That was eliminated by the clue that the grinding only happens when freewheeling. The bearings on the cones always work when the wheel turns and will thus always grind, if it were them.

 

[accountantpete]

No, if you read what I said I found one of the plastic tabs from the spoke protector in amongst the bearings on the free hub side.

I was replying to the op

 

[Tojo]

I was replying to the op

Ok sorry, I just took it that you were replying to the message directly before...