Mountain Bike Reviews Forum banner
Cancel
Create thread New Forums

Grease into the bottom bracket bearings?

Jump to Latest
41 - 60 of 63 Posts
#41 ·
speedygz said:
If you're chewing out bearings on a regular basis ie yearly or less, I'd suggest you have bigger problems than the viscosity & volume of the grease being used. Cr@p engineering/manufacture & garbage bearings would be top of my list.
Click to expand...
Banshee frame and everything is in perfect alignment. Comes with F.A.G bearings in the suspension pivots. They are the highest quality bearings I've ever used and have good seals. It doesn't matter how high quality the bearings are if the original grease isn't up to the task or if the design doesn't keep water away from the seal face. Both frames were bought used. One of them was like new and the pivots were perfect, after 500 miles of riding they started getting gritty when I inspected them. After I cleaned and regressed those same bearings they've been perfectly smooth for over 1,500 miles so far and it's been through quite a bit of wet fine silty mud at the downhill park. That's after I "damaged the seals with a pick." The second Banshee frame had about 800 miles on it as reported by original owner. The nice F.A.G bearings were gritty from water ingress.

A lot of hubs like on my road bike have end caps that provide some sort of labyrinth. I could practically take the seals off those bearings with how the end caps protect them from water and dirt but not have any issue. My new Onyx hub on the mtb doesn't have any special protection to keep water away from the bearing seal. If the seals don't adequately protect the bearing, you need a grease that will and there are zero draw backs to doing so unless you carelessly screw up the seal.
 
#42 ·
adriano said:
I had a closer look at my bearings. They seem to have a plastic inlay that is sealed in one side and filled with grease on the other. Is that a sign of decent quality?
Click to expand...
Plastic bearing cages are used in cheaper bearings and can scrub a lot of grease off of the balls in operation with the snug fit. Better quality bearings use metal cages.
 
Discussion starter · #43 · (Edited)
I have seen this tool at my LBS and I thought it's amazing. In 5 seconds the guy pulled out a stuck bearing that I had tried to remove for a whole day. It's pretty expensive but my time is valuable as well! Also, it seems to be able to grab the outer races of the bearing, which means that it would not (perhaps) destroy them in the process
 
Discussion starter · #45 ·
#46 ·
adriano said:
Well, the whole set costs € 854.80 (that's almost a grand), so it may take more than a heartbeat. But if they sell the BB30 adapters separately, it may be around $200. See: CYCLUS TOOLS universal ball bearing extractor set | incl. exchange weight and case (ra-co.com)
Click to expand...
Yeah that's pretty expensive. It's just a blind bearing puller which you can find much cheaper than that.

Personally I've just been using bolts/all thread and the correct size sockets to make my own bearing presses and removal. Some configurations require a blind puller though.
 
#48 ·
I picked up a blind puller from Amazon for a much more reasonable price.
Of course, I've only had to use a punch so far so the set is collecting dust.

One of these days I'll try it

Sent from my SM-G960U using Tapatalk
 
#49 · (Edited)
Unlike bicycle bearings, I haven't had any issues with modern car bearings despite the fact they deal with drastically higher rpms and loads. Current car from 2007 is still rolling on the original bearings after 250,000 miles with no hint of play or grit.
Click to expand...
Another mechanical/marketing mystery... How can an upper-end MTB cost as much or even more than a dirt bike? A dirt bike is far more durable and has far more precision parts (typically made in Japan not China). For example, a 2021 T2 Yeti 165 goes for $8300, while a 2021 Yamaha YZ125 goes for $6599.
 
#50 ·
adriano said:
I have seen this tool at my LBS and I thought it's amazing. In 5 seconds the guy pulled out a stuck bearing that I had tried to remove for a whole day. It's pretty expensive but my time is valuable as well! Also, it seems to be able to grab the outer races of the bearing, which means that it would not (perhaps) destroy them in the process
Click to expand...
This tool is great for removal but it can also damage the bearing as the pull is from the inner race, so if you want to clean and re-pack a bearing this is not a good option.
unless you have a BB which was designed to facilitate bearing removal it will be very difficult to remove a bearing the correct way: by pulling/tapping on the outer race. The expanding collet type tools may work but there is still a risk the seals are damaged or the entire PF BB is knocked out of the frame.

my recommendation is not to remove bearings for re-packing as the removal process will likely do more harm than the new grease does good. If you want to repack bearings do it in-situ and only remove the outer seal. I'm still intrigued as to how this can be done with no damage to the seal! A pick or any metal object will surely damage the seal.
 
Discussion starter · #52 ·
Cleared2land said:
That video you posted shows it grabbing only the inner race. I don see how that could grab the outer race.
Click to expand...
I may be totally wrong, but they market adapters for every bearing size, and I was under the impression that the retractable pronges that pop out laterally will fit to the external bearing diameter. I will however ask the company about that and report.
 
Discussion starter · #53 ·
Fajita Dave said:
Yeah that's pretty expensive. It's just a blind bearing puller which you can find much cheaper than that.
Click to expand...
I am not familiar with the term "blind bearing puller" but what I find nice about the cyclus tool is the spring mechanism that extends lateral grabbers. This is essential, since it allows for the tool to invade the dead space behind the bearing, which is inaccessible to rigid tools because they would be blocked by the contralateral bearing. I haven't seen any other tools that do that.
 
#54 ·
adriano said:
I am not familiar with the term "blind bearing puller" but what I find nice about the cyclus tool is the spring mechanism that extends lateral grabbers. This is essential, since it allows for the tool to invade the dead space behind the bearing, which is inaccessible to rigid tools because they would be blocked by the contralateral bearing. I haven't seen any other tools that do that.
Click to expand...
The tool you posted, while nice, does the same thing a blind puller does. Blind puller uses a wedge mechanism to expand "fingers" with a ridge behind the inner race. As I stated earlier, it is simply impossible to pull most bicycle bearings from the outer race, they're seated into some kind of shell where you cannot access the outer race. Only time I've been able to pull bearings from the race without putting force on the bearings was on transmission where the bearing is tight on a shaft but just pulls out of shell.
 
#55 ·
Taroroot said:
The tool you posted, while nice, does the same thing a blind puller does. Blind puller uses a wedge mechanism to expand "fingers" with a ridge behind the inner race. As I stated earlier, it is simply impossible to pull most bicycle bearings from the outer race, they're seated into some kind of shell where you cannot access the outer race. Only time I've been able to pull bearings from the race without putting force on the bearings was on transmission where the bearing is tight on a shaft but just pulls out of shell.
Click to expand...
And that's why you replace them, as more than likely you've damaged the races by loading them the wrong way.
 
Discussion starter · #60 ·
I see many people saying "I have the same bearings since xy years and have no problems". Guys, this is not a meaningful metric. Some of us ride 1000km/yr, others do 1000km/month. Some of us ride comfortable dirt roads, others ride muddy steep downhill trails with bumps and jumps. Some of us weigh 60kg, others 100kg. It's not surprising that some have frequent bearing problems whereas others don't.
 
41 - 60 of 63 Posts
About this Discussion
62 Replies
18 Participants
Last post:
speedygz
Mountain Bike Reviews Forum
posts
16M
members
534K
Since
1990
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
General Discussion Downhill - Freeride California - Norcal Shocks and Suspension Passion