Bottom Bracket MTB how long should it last

[Sidmouth]

I replace my MTB GXP in November, or 2000KM ago, now the drive side is a bit crunchy and needs replacing,ditto as the one before it, is this normal wear , I am 96KG

[rouxtjie]

GXP....there is your problem. They are just kuk, I have tried everything to get longer life out of my GXP bb's...grease once a week, stand the bike upside down after a wash for hours, drill drainage hole in frame...best was 1100km out of a bb, worst was 470km...all logged in sporttracks. They are just hondnaai

 

Here is the good news...you can motivate buying a new crank

 

Switched to shimano BB's...havent been able to kill one yet.

Edited March 4, 2014 by rouxtjie

[Mojoman]

GXP....there is your problem. They are just kuk, I have tried everything to get longer life out of my GXP bb's...grease once a week, stand the bike upside down after a wash for hours, drill drainage hole in frame...best was 1100km out of a bb, worst was 470km...all logged in sporttracks. They are just hondnaai

 

Here is the good news...you can motivate buying a new crank

 

Switched to shimano BB's...havent been able to kill one yet.

Had this on my previous bike, and it is indeed a marvel of crappy engineering!

[GoLefty!!]

I replace my MTB GXP in November, or 2000KM ago, now the drive side is a bit crunchy and needs replacing,ditto as the one before it, is this normal wear , I am 96KG

 

I have never worn out a quality BB.

I use Shimano, Campagnolo and Chris King.

GXP is rubbish

The new Red XX and XX1 BB's are an improvement

[HowardSteele]

I have had bb's last for years and I've had one pack up after 6 months, The shimano screw in cup bb's certainly outlasted the one piece sealed octolink bb's...indecently its almost always the drive side I have 4 replaced bb's lying around and all the left side bearings still good. The heavier you are and if you do single track certainly is a factor.... my ridding buddy is over 100kg and he goes through bb's faster than me.The bb that collapsed on me was when I was doing single track 4-5 times a week.

Edited March 4, 2014 by howardsteele

[rouxtjie]

I have had bb's last for years and I've had one pack up after 6 months...indecently its almost always the drive side I have 4 replaced bb's lying around and all the left side bearings still good. The heavier you are and if you do single track certainly is a factor my ridding buddy is over 100kg and he goes through bb's faster than me.The bb that collapsed on me was when I was doing single track 4-5 times a week.

 

Why the connection between bb failure and singletrack?

[droo]

The problem with the GXP design is that all the side load is taken up by the left side bearing - the right bearing only takes normal forces. The left bearing is usually the first to go on Shimano BBs too, I'm guessing because of the amount of flex that happens during transfer of power from the non-drive crank to the chainrings.

 

IMO BB bearings should be preloaded angular contact bearings, in a similar configuration to the old cup and cone style. But then I'm not the one making the most money from replacing them...

 

As GoLefty says - get a Shimano crankset and a King BB. End of problems, although it'll take you a few years to make up the cost vs replacing the GXP one at short intervals.

[Skylark]

Don't throw away BB just yet, or crank for that matter - knock out old BB bearings and get enduro GXP replacement BB bearings!

Rushsports has them or maybe your LBS

[Sidmouth]

Ok great to get to know I am not alone in replacing this crap GXP bearing after 1000KM, just picked one up from my LBS R475.00 opened it up hoping to feel the smooth rotation only to discover the drive side has a pitted feeling, I will have to take it back, looks like they are crap even in the box?

[Eldron]

In related news - when fitting Shimano BBs DO NOT tighten the non drive side cap too tight. It should be hand tight and not even hard hand tight - two finger hand tight should do it.

 

I use index finger and thumb to tighten them - my Shimano BBs have lasted even longer since easing up...

[Madala]

For Shimano about 20 000km, 2yrs or the first wash with a high pressure hose. Whichever comes first!

 

The reason that the left side bearing fails first is that the right side bearing is protected to some extent by the chain-rings and does not get a direct hit from the pressure washing.

[braailegend]

I have Saint BB's on my bikes, still going strong, and I weigh 105kg and ride on the rougher side of trails, but not full on DH. As for weight, have no Idea what they weigh.

[kosmonooit]

Isn't GXP a format? you get plenty of brands.

 

And you can just replace the bearings, not the shells every time.

[Sidmouth]

For Shimano about 20 000km, 2yrs or the first wash with a high pressure hose. Whichever comes first!

 

The reason that the left side bearing fails first is that the right side bearing is protected to some extent by the chain-rings and does not get a direct hit from the pressure washing.

well both time my drive side has done not the other side, no high pressure water either, I believe the drive side on a GXP is 22mm and the non drive side 24mm, Shimano as 24 mm both sides, making sram and Shimano no compatible

[droo]

Don't throw away BB just yet, or crank for that matter - knock out old BB bearings and get enduro GXP replacement BB bearings!

Rushsports has them or maybe your LBS

 

Shimano yes, GXP no. Unfortunately.

 

In related news - when fitting Shimano BBs DO NOT tighten the non drive side cap too tight. It should be hand tight and not even hard hand tight - two finger hand tight should do it.

 

I use index finger and thumb to tighten them - my Shimano BBs have lasted even longer since easing up...

 

Yep, that preload thingy's just there to pull the left crank onto the spline. The recommended 1 - 2 Nm isn't very tight at all.

[Skylark]

Droo but whats this..... http://www.endurofor....com/id228.html

Edited March 4, 2014 by Skylark