UKC

I was hoping some of the wise cyclists on here may have some experience and be able to offer advice on a problem I have with the Trek Madone bottom bracket.

The bike is a 2012 model Madone 5.2 bought in June 2012. Within two months of purchase the shop had replaced the bottom bracket twice. In 2013, I replaced the bracket at least three times. It always failed on the non drive side. Also, this bike is very rarely rode in wet conditions. It is stored from October to April/May time and the bearings always fail after the few times it has got wet.

I took the bike to Majorca at the beginning of April this year. On the first outing I rode the bike on damp roads, it wasn't raining but the roads were damp from rain earlier in the day. The bearing failed within 3 days. I replaced the bearing and went out the next day, again it had rained in the morning and although the roads were dry I rode through some sections were water was running off the hillside and across the road. The bearing failed after only 90km.

At this point I took the bike back to the dealer. Trek advised them to fit a V2 bottom bracket bearing, which they did. It lasted approx. 30 days, covering 1000km. Then it rained!!! Within 2 days the bearing was dry and grating.

Again the bike was returned to the dealer who sent the frame off to Trek, they have now rebuilt the bottom bracket with new bearings.

Is this story familiar and if so have you any advice.

Thanks

Alan

In reply to alan1961:

Is this a Press-fit or Hollowtech bottom bracket?

In reply to alan1961:

3 things...

1. How are you cleaning the bike? using a pressure washer or even a powerful hose isn't a good idea... even worse is to use things like muc-off if you don't completely dry and re oil your bearings (a very difficult and tedious thing to do)

2. It sounds like the bottom bracket shell isn't faced properly - go back to where you bought it and get them to sort it out or get it done yourself

3. What make is the BB? I know others with SRAM External BBs that have had similar experiences - in most cases the facing of the frame was the problem

In reply to Bob:

The original is pressed in using your fingers the V2 is an interference fit on the frame. I my humble opinion a very poor design.

In reply to alan1961:

I have a 2012 Madone 5.9 and they are press fit bearings. Mine were pretty grindy when I replaced them a few weeks ago. They'd been replaced by the previous owner and I could see why he'd supplied a Park Tools bearing tool and a pair of bearings with the bike.
I've just pushed in some Enduro bearings and will keep doing so each time they feel nasty. With the Hollotech2 crankset it's pretty quick to replace them.
It's a bit of a cheap and nasty way to build a bike TBH

In reply to balmybaldwin:

1. I never pressure wash any of my bikes. I normally wash down with clean water and a brush. I try to keep water away from the bottom bracket and wheel hubs.

2. The dealer replaced the first two bottom brackets and installed the V2 bottom bracket last month.

3. As the bearings are a push fit no other system fits.

In reply to woolsack:

I'd resigned myself to doing just that last year, but with the bearing failing earlier this year after just 90km. I felt this wasn't good enough.

In reply to alan1961:
Did you get a good look at the bearing that failed or did the dealer squirrel it away?
Next set of bearings I put in will be SKF if I can get them. I'll get them from the bearing supplier that we use at work

This problem shouldn't be happening. If the bearings are getting water and grit ingress then the bearing seals are clearly not up to the job. I don't know what sort of quality Trek supply as new?

In reply to alan1961:

Press-fit bottom brackets are a solution to a manufacturer's problem that is sold as a solution to a rider's problem.

The manufacturer's problem is that it costs time and therefore money to thread and face the bottom bracket shell. The rider's problem is that the bottom bracket area isn't stiff enough. (aye, right)

In reply to Bob:

Reading up on some of the forum posts the V2 oversized bearings are just a bodge to increase the interference fit into what seems to be worn away carbon fibre. Nice.

In reply to woolsack:

When I've taken the bottom bracket apart, the chain wheel side bearing is always clean and in good condition. The other side looks like it's been in there 10 years. The bearing that lasted 90km in Majorca had seized solid by time I got back to the UK

In reply to alan1961:


It surely can't be that difficult to arrange an effective crap and crud seal on that in this day and age

In reply to Bob:

I don't have much experience with new top-line carbon frames. Is the bottom bracket shell alu or is it just carbon? I doubt threads in epoxy would be very strong, so if you want to save the tiny weight of an alu shell press-fit would be the only option.

Seems to me though that if they can make threaded external bearing BBs sealed they should be able to do the same with press-fit ones.

In reply to Bob_the_Builder:

It's not weight, it's the cost of threading and fitting the BB shell. I'm not sure if it's Alu or steel TBH.

Sealed bearings aren't actually sealed, the bearings are just better protected than with cup and cone style systems.

Press-fit BBs are the Emperor's new clothes: "Can sir feel the extra stiffness?" "Can you?" "Ooh sir, can you?". Might the extra amount of carbon fibre laid down around the bottom bracket to accommodate the press-fit system have something to do with the perceived increase in stiffness?

In reply to alan1961:


Good (an amazing number of people don't realise this is a problem)


This isn't about fitting, this is about whether the BB shell has been faced properly in the first place to enable the bearings to be fitted correctly. (i.e. are the ends square? even the slightest bit out, and the bearings will be heavily worn very quickly)


Yes, but what make? (are they just shoving the cheapest SRAM ones in or are you putting exotic Ceramic Hope bearings in?) The reason I ask is I have seen masses of problems with SRAM low end bearings.

In reply to woolsack:

You would have thought a builder as large as Trek would have done this!

In reply to balmybaldwin:

2. The bearings on a push fit i.e. can only be as square as the housing allows. The V2 interference bearings have to be press fitted. As three sets of bearings have been fitted by a Trek main dealer you would expect them to be fitted square.

3. The recommended bearings are Shimano, which is what I've always used.

In reply to alan1961:

The accuracy of the bearing alignment pretty much depends on the mandrel that Trek would have used to create the bottom bracket bearing bores. The carbon would have been laid up around the mandrel which would be removed once the carbon has cured. From what I can see, there is no machining of the bearing bores, these are as moulded.
This has all the hallmarks of design by accountants, never the best engineering IMHO

When I had the bearings out of mine I wasn't overly impressed with the fit of the bearings. Mine are not the oversized outer race V2 type

The bearings should be sealed enough to prevent water ingress. That isn't difficult.

In reply to alan1961:

You've been very patient, considering.

I'd have returned the bike for a full refund long ago, as clearly not fit for purpose!

In reply to alan1961:

reading this thread is giving me the fear about my new bike and it's press fit BB