Scary rear wheel noise

[kik3sir]

Hello,

My rear wheel does a very loud sound (almost as if I have a expensive carbon wheelset with a very loud hub, which is not the case) when going downhill at 35/40kph +

Sound appears only when i'm not pedalling, it stops instantly when i start pedalling.

I can trigger the sound when pedalling backwards, (pedalling backwards doesn't feel smooth at all when that's the case)

I've had this issue last october, then I stopped cycling, started again in february and problem was gone for some reason, but now it's back

Wheelset is Mavic ksyrium pro exalith (alloy)

Do you guys have any idea what may be the problem here ? thanks a lot!

[pushpush]

what kind of hub?

Pull the freehub and check that your ratchets/pawls are all undamaged and properly lubricated.

If a ratchet DT style hub, adding a little grease could be your solve.

[kik3sir]

what kind of hub?

Pull the freehub and check that your ratchets/pawls are all undamaged and properly lubricated.

If a ratchet DT style hub, adding a little grease could be your solve.

Thank you for your input.

The freewheel is "steel FTS-L" from Mavic. I hope that's what you asked as I'm very clueless about how a rear wheel works.

On the following link there is a exploded view drawing of the wheel (click on rear under Ksyrium Pro Exalith as by default it shows the front wheel)

https://technicalmanual.mavic.com/tech- ... ronu=23676

I will take everything appart and let you know, I hope I can notice if something is damaged as i've never taken appart a rear wheel.

[Mr.Gib]

If those are the older Mavic hubs with two pawls, then the fix is just to lube the axle where it contacts the freehub. Some of those hubs have a bushing instead of a bearing that can get dry and squeal. I have fixed this problem by dripping chain lube behind the cassette. Sometimes you can get the lube to where it's needed without taking anything apart.

[Sjoerd]

It's because of wear of the white plastic ring on the back of the body, a very common thing with the Mavic FTSL body's unfortunately. They refer to it as the Mavic squeal of death Search around on the internet and there's lots of info to be found.

This can only be fixed by buying a new cassette body and eventually the same thing will happen to that one. A couple of years back I bought conversion sets from E-Bay, sold by a guy named the hub doctor. Maybe he is still around? You can use your existing body with his kit.

[Steve Curtis]

It's the old Mavic death scream. The main bush around the inside of the freehub is worn so it can vibrate, causing the noise.
See hub dr for parts or just buy a new freehub.

[kik3sir]

It's because of wear of the white plastic ring on the back of the body, a very common thing with the Mavic FTSL body's unfortunately. They refer to it as the Mavic squeal of death Search around on the internet and there's lots of info to be found.

This can only be fixed by buying a new cassette body and eventually the same thing will happen to that one. A couple of years back I bought conversion sets from E-Bay, sold by a guy named the hub doctor. Maybe he is still around? You can use your existing body with his kit.

It's because of wear of the white plastic ring on the back of the body, a very common thing with the Mavic FTSL body's unfortunately. They refer to it as the Mavic squeal of death Search around on the internet and there's lots of info to be found.

This can only be fixed by buying a new cassette body and eventually the same thing will happen to that one. A couple of years back I bought conversion sets from E-Bay, sold by a guy named the hub doctor. Maybe he is still around? You can use your existing body with his kit.

It's the old Mavic death scream. The main bush around the inside of the freehub is worn so it can vibrate, causing the noise.
See hub dr for parts or just buy a new freehub.

Thank you guys that's very helpful !! And somewhat reassuring that's its a well known issue that is relatively well documented online.

Tomorrow I plan a mega ride, i've seen online people that rode for months with this issue, do you guys think there is any safety concerns ? (if so, would it be when the noise occur, or at any moment in ride?) cheers!!

[goodboyr]

If it gets really bad, there's sufficient friction that at higher coasting speeds the chain can wrap around and that can lock up the drivetrain which is a safety issue. It's really a super easy and quick job to pull it apart, clean it and relube. And yes, I believe hub doctor stuff is still available on eBay. Works great.

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[kik3sir]

If it gets really bad, there's sufficient friction that at higher coasting speeds the chain can wrap around and that can lock up the drivetrain which is a safety issue. It's really a super easy and quick job to pull it apart, clean it and relube. And yes, I believe hub doctor stuff is still available on eBay. Works great.

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Ok thanks for your very helpful comment.

It's just that I don't have all the tools right now and tomorrow is a good opportunity to ride in great weather (first of the kind in 2024) before a 50mph wind week. Now at least I have all the infos to make my own decision.

[Steve Curtis]

It's very easy to remove the freehub and service it. If you have a ride coming up, it takes 10 mins to remove,clean and re grease it.
It will help, short term but it will need to be replaced.

[kik3sir]

It's very easy to remove the freehub and service it. If you have a ride coming up, it takes 10 mins to remove,clean and re grease it.
It will help, short term but it will need to be replaced.

I did the ride and it was fine, happened a little bit but that was very minor, even though there was 2300m of elevation. Road surface seem to have a big impact as it never happened on a smooth road at high speed, but happened on some very cracked roads at 30kph.

I'm the champ of failing bike maintenance operations and really did not want to risk that superb day before weather turns very bad, that was one of the best ride of my life tbh.

I'll defo fix the issue this weekend! thanks a lot everyone!!

[TobinHatesYou]

Post a video.

[naylor343]

Common issue with Mavic. Lubricate the white plastic ring. Do a YouTube search, lots of how to videos.

[ParisCarbon]

I often solved it using a light smear of finish line mineral oil on the white teflon seal on the back of the freehub.. it shut it up (for a little while anyways) I got that fix off the net years ago...

[goodboyr]

Why not just follow the mavic maintenance manual and do it right?

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