How long should rear hub bearings last?

[Newbie321]

So for the second time maybe third time in as many years I've had to replace my rear hub bearings.

What would be an average/good amount before of time/riding before they need to be replaced? Having to replace them yearly seems a bit excessive. Could it be a bad/cheap hub and need to upgrade (it's a bontrager line comp 30 wheelset). Or just bad riding, casing to many jumps or hitting rocks square on?

[michaelbiker]

Hard to say - how much mileage are you riding? Do you ride in wet, muddy conditions? How often do you wash your bike? Bearings die from corrosion, so if water can get passed the seals then they will likely need to be replaced more regularly. Also living and riding near the sea. My front wheel bearings on my gravel bike needed to be replaced after 4000km. The rear bearings after 7000km.  Most likely because I was doing a lot of wet weather riding and needed to wash my bike more often. The bearings were also not the best quality with likely crappier seals than the more expensive ones. 

[Jimmy 2.0]

nothing wrong with the hub. quality of bearings, how they are installed, grease used, conditions you ride in, how often you ride, how you ride your bike, how you look after your bike and so on. i have some clients that will get 2 years out of a set of wheel bearings then i get clients 100kg plus that will have to get theirs replaced twice a year. if you're doing the more rough stuff then your bikes maintenance will be higher

Edited September 2, 2025 by Jimmy 2.0

[Headshot]

A poorly manufactured hub with poor tolerances will wear out bearings prematurely IMO. This is more critical with a rear hub. We have a DT wheelset that has not needed new bearings in 10 years or more. Cheaper hubs that rely on threaded end nuts to keep the freehub/axle in place require checking and maybe some Loctite to keep everything tight. Also check your axle is tightened properly on a  regular basis.

[JoeMerida]

Water is a bearing's worst enemy. 

[DieselnDust]

Everything is covered from conditions to maintenance to tolerances

for where and bb bearings I try and source SKF, FAG, NSK or NTN bearings because the popular brand dispensed at the bike shops are just utter shyte

[Newbie321]

I cycle about 5000 km a year in CPT. Wash the bike once a week and not to afraid of mud and water but don't go looking for it. The big reason I ask is it's only the hubs with this bike, the BB and pivot bearings are still going strong after 2/3 years

Edited September 2, 2025 by Newbie321

[nick_the_wheelbuilder]

Some hubs simply chow bearings.
Slightly poor tolerances and incorrect preload will wear bearings out.

Often there's nothing you can do about it.

If your bearings last a year, that's considered acceptable.

I rode a set of Hope Pro4 hubs for over 15 000km before any bearings needed changing, and then it wasn't even all of them... 

[DieselnDust]

2 hours ago, Newbie321 said:

I cycle about 5000 km a year in CPT. Wash the bike once a week and not to afraid of mud and water but don't go looking for it. The big reason I ask is it's only the hubs with this bike, the BB and pivot bearings are still going strong after 2/3 years

What hubs are they? Brand? Model?

There are several bad actors in this space. Some are just poor designs and no amount of polishing will get those turds to last. Making a hub is not as easy as turning a billet of aluminium on a lathe and maching on a mill. Having bearings seats actually round and concentric is an engineering challenge especially after spokes are tensioned to carbon rims that are not necessarily uniform in the spoke bed. There's so many dimensions that can run out once a wheel is assembled.  hub design tolerance that does not account for this is going to fail and many do because of this failure 

[Newbie321]

44 minutes ago, DieselnDust said:

What hubs are they? Brand? Model?

There are several bad actors in this space. Some are just poor designs and no amount of polishing will get those turds to last. Making a hub is not as easy as turning a billet of aluminium on a lathe and maching on a mill. Having bearings seats actually round and concentric is an engineering challenge especially after spokes are tensioned to carbon rims that are not necessarily uniform in the spoke bed. There's so many dimensions that can run out once a wheel is assembled.  hub design tolerance that does not account for this is going to fail and many do because of this failure 

Bontrager comp 30. 

But seems a year is good enough.  Thanks all

[DieselnDust]

Bontrager Comp 30 rear hub reviews

 

 

 

 

 

 

 

 

 

Reviews for the Bontrager Line Comp 30 rear hub generally praise its balance of performance and value, especially the quick-engaging Rapid Drive 108 hub

. However, some riders have noted issues with hub durability, particularly with the bearings and the potential for contaminants to enter the freehub mechanism. 

 

Performance

• High engagement: The hub's Rapid Drive mechanism features 108 points of engagement, resulting in a snappy 3.3 degrees of crank rotation before power is transferred. This is a standout feature for a wheelset in its price range and is beneficial for technical climbing and maneuvering.
• Good value: Most reviewers consider the Line Comp 30 wheelset an excellent value, particularly for riders who purchase a Trek bike with the wheelset already installed. Some reviews note that for a relatively small cost, the hub can be upgraded to the full 108-point engagement, making it an even better deal. 

 

Service and durability

• Easy maintenance: The freehub mechanism is designed for simple, tool-free disassembly, making cleaning and re-lubricating the pawls and springs a straightforward process.
• Pawl and spring issues: Some users report that the freehub is susceptible to dirt and grime, which can cause the bearings to feel gritty or lead to pawl and spring problems over time.
• Catastrophic failure: A more severe but less common issue reported on forums is the complete failure of the ratchet mechanism, where the "ratchet part is bonded (glued) into the hub" and the bond lets go. In such a scenario, the pedals will spin without the wheel engaging, requiring a hub replacement.
• Bearing durability: Several riders have noted that the bearings are a weak point, with some experiencing premature wear even under dry riding conditions. However, the bearings are relatively easy to replace when they wear out.
• End cap loosening: On some wheels, the freehub body or end caps may come loose over time, causing lateral play. This is a common issue for many hubs but is generally easy to fix by re-tightening the components. 

 

Who is it for?

The Bontrager Line Comp 30 rear hub is a suitable option for:

• Value-focused riders: Those who want high engagement performance without the premium price tag of boutique hubs.
• Trek bike owners: Riders who get the wheelset as original equipment on a mid-range Trek mountain bike, as it offers a solid performance base that can be upgraded with a pawl kit.
• Mechanically inclined cyclists: The hub's easy serviceability is a plus for riders who don't mind performing more frequent hub maintenance to ensure longevity. 

 

Considerations

• Maintenance frequency: To prevent premature wear, riders should be prepared to perform basic freehub cleaning and lubrication more frequently than on some higher-end, better-sealed hubs.
• Heavy-duty use: For aggressive trail or enduro riding, the hub may not be as bombproof as higher-end, more expensive options, particularly regarding the bearing seals and the potential for complete failure. 

[Alouette3]

When you replace the next set of bearings, pop the seals open and pack some waterproof grease in there. I've found most bearings to have very poor or inconsistent lubrication.

[Mook]

I buy bearings from reputable suppliers like BMG, Bearings International, etc. All bearings have their part numbers pressed into the plastic covers or etched onto the bearing housing. Take your old bearings or the part numbers to these guys and they can sort you out with Timken, SKF, NTN, etc. 

I have found that your popular sizes are cheaper at the pro's than what you would pay at your LBS, or the large online retailers we are familiar with.

Wheelbearings work hardest of all bearings on your bike. Best is to get proper components from bearing specialists. I have successfully done the @Alouette3 trick, but it is risky if you damage the seal or you don't seat it properly when replacing. I would do this on good quality bearings, but not your typical wang-chung brands.

[Alouette3]

The problem isn't reseating the seal, it's taking them off without damaging the lip or deforming the steel ring in the seal. Be gentle.

Been using Everon waterproof grease for many, many years.

Currently running a cheap set of bearings from my local bearing suppliers in my frame, I re greased when I bought them. They are still running well after 3 seasons, the stock, full compliment bearing set only lasted 1.5 seasons. I am beyond surprise they still going.

[droo]

12 hours ago, Newbie321 said:

Bontrager comp 30. 

But seems a year is good enough.  Thanks all

Bearings are standard sizes in those hubs - go to a bearing shop and get proper German / Japanese bearings and you should have a much better time.

And service your freehub regularly - if that's where the contaminants are getting in, keeping it clean will go a long way.

[JoeMerida]

Once a year is not acceptable. For the Average 100Km/week Rider.

Edited September 3, 2025 by JoeMerida