press in bottom brackets and mountain biking

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press in bottom brackets and mountain biking

Postby Gordo » Wed May 23, 2012 3:43 pm

i'm talkin about all these suckers

The elements are pretty extreme where i ride. Coz there is just so much mud and water at times i generally find myself doing a major clean after every ride. One of the probs i have is water/mud getting into the bottom bracket area and horrible clunking noises developing. This problem can be fixed pretty easy. Coz the BB's threaded type, i just take them out (unscrew), clean and regrease everything, and off i go.

Here's the prob. Im thinking of buying a XTC 29er. It's on special. Test rode in the wet a few weeks ago. It rode well. At the end of the ride though i noticed that familiar clunking in the bb. So i think, well, i'd rip that sucker out, clean and regrease. But its bb91 standard. How do i get that thing out. I need more than a wrench. I need rather expensive tools. Once u knock the pressed in bottom bracket out it seems u more or less have to toss it, its not recommended that it be reinstalled which seems rather wasteful. Also it cant be good pressing stuff in and out of your frame all the time either. The only thing i can realistically do is take the cranks out and regrease that, else i would say i'm off to the mechanic.

I would like to buy the XTC since its rather cheap. But i'm not very tolerant of clunking noises and things that arnt easily servicable. Am even thinking of going with the Santa Cruz Highball who dont do press in stuff for the reasons above.

But I would be interested to hear other opinions/experiences from people (Giant owners or otherwise) with press in bb in their moutain bike. maybe its just no big deal??????....anyone :?
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Re: press in bottom brackets and mountain biking

Postby Mulger bill » Wed May 23, 2012 8:30 pm

No problem with the unit in my TranceX to date but a little prayer to the patron saint of creaks is said before riding.
I do my best to avoid riding in wet and sloppy conditions, it does horrible trail damage.
...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.
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Re: press in bottom brackets and mountain biking

Postby trailgumby » Wed May 23, 2012 8:44 pm

+1. Unless you're in the wet tropics, riding wet trails in Oz is regarded as seriously uncool, due in no small part to the massive increase (200+ times?) it causes compared to dry conditions.

Graunchy bottom brackets are the least of my worries. Brakes and transmission get absolutely flogged. Wet tree roots and timber trail structures get ice-slippery.

Erm... pass. :|

If you must, there are BB30-to-external BB threaded adapters out there.
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Re: press in bottom brackets and mountain biking

Postby Mulger bill » Wed May 23, 2012 9:16 pm

trailgumby wrote:If you must, there are BB30-to-external BB threaded adapters out there.


Yeah, but we're talking PF90 or whatever it's called. The "cups" are all plastic and press directly into a large diameter and ~90mm wide BB shell. Somehow, methinks an adapter will be a big engineering task. If someone manages it, I'll be an early adopter, not a fan of the disposableness of the concept.
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Re: press in bottom brackets and mountain biking

Postby Nobody » Wed May 23, 2012 10:31 pm

Mulger bill wrote:
trailgumby wrote:If you must, there are BB30-to-external BB threaded adapters out there.


Yeah, but we're talking PF90 or whatever it's called. The "cups" are all plastic and press directly into a large diameter and ~90mm wide BB shell. Somehow, methinks an adapter will be a big engineering task. If someone manages it, I'll be an early adopter, not a fan of the disposableness of the concept.
We're talking about an adaptor from BB30 shell to take standard Shimano external BB cups.
http://www.chainreactioncycles.com/Mode ... pgod6BLy3Q
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Re: press in bottom brackets and mountain biking

Postby Mulger bill » Wed May 23, 2012 10:46 pm

Gumby was Nobody but the OP was talking BB90. Here's one...
Image
It's a straight press fit (no circlips) into a monster shell...
Image
Image
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Re: press in bottom brackets and mountain biking

Postby Nobody » Wed May 23, 2012 10:50 pm

Yeah, you can have all those freak press fit monstrosities. If I die before owning one, it will be too soon. [Can feel the retro grouch coming out. :oops:]

According to the FSA guide, BB90 is a Trek standard.
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Re: press in bottom brackets and mountain biking

Postby toolonglegs » Thu May 24, 2012 12:39 am

My CX bike has press fit... mechanic stuffed up putting them in and damaged the inner spacer, but as they are shimano press fit the inner spacer is the same as XT... easy fix.
They are not a very tight press fit as they are plastic sleeve... they seem to have a fair bit of friction.
OP, yes XT type screw in ones are easy in and out and as they seem to need replacing so often i agree the new systems are a pita!, but if you have a bit of mechanical skills you will realize they are easily and safely installed with a block of wood and a soft faced hammer... ditto for removing.
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Re: press in bottom brackets and mountain biking

Postby trailgumby » Thu May 24, 2012 9:06 am

My bad: With a plastic sleeve I'd be less concerned about the potential for damaging the BB than with BB30.
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Re: press in bottom brackets and mountain biking

Postby silentbutdeadly » Thu May 24, 2012 10:16 am

I've exactly the bike that Gordo is looking at. In his situation I'd be more concerned with the suspension pivot bearings than the BB.

I recently had mine in pieces for a complete suspension service so I decided to inspect the bearings whicle the forks and shock were away. The Shimano BB was fine...it is actually reasonably well sealed for a bike bearing. But some of the pivot bearings were cactus...I've put no more than 750km into this bike and it doesn't rain here. Two outer bearings under the shock were crunchy and one of the main pivot bearings beside the seat tube was rusted to the point of scoring the pivot shaft. A couple of careful hours with an Enduro bearing kit, a socket set, a DIY bearing press, lanolin grease and Dryglide spray lube and we are back to sweetness. But it was a bit of a fraught process at times because of the heavily sculpted rear triangle...I've put my name down for the Giant Maestro Bearing Press Kit at a certain Oz shoppe to try and make things a little easer

The BB itself is no biggie. In fact it is the easiest thing in the world to sort. My LBS has the correct bopping out and putting back tools that I can use - and the replacement Shimano BB itself is not expensive. One can go with Enduro, Chris King, Hope or another bling BB if you prefer. The key is to remember to grease up the cup before you fit it and the crankset shaft as well. I suspect that I'll end up tooling up to do the job myself in the longer run - even though the bopping out tool is expensive.... a bearing press is easy to go to school on as a shed build (but is also not that expensive to buy either).

http://www.starbike.com/p/Shimano-TL-BB ... ol-3736-en
http://www.starbike.com/p/Shimano-TL-BB ... ol-3735-en

Honestly...if you want a complicated bike like a full sus MTB and you want to ride it in challenging locations then be prepared to commit to a complicated & expensive service schedule in order to keep it running properly. There's nothing intrinsically wrong with press fit BB but they do require a different set of compromises to screw in outboard BB which in themselves require a different set of compromises to the old cartridge BB. And you can't manage the compromises then be prepared for some hurt..
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Re: press in bottom brackets and mountain biking

Postby Gordo » Thu May 24, 2012 4:58 pm

trailgumby wrote:+1. Unless you're in the wet tropics, riding wet trails in Oz is regarded as seriously uncool, due in no small part to the massive increase (200+ times?) it causes compared to dry conditions.


i saw ur post in a previous thread about this. fair point. i gave it due consideration too. i have thought about it

i'm way south. like as far as u can go south almost. ur pretty much guaranteed to get wet in tassie. i dont know how long the trails dry out here but it cant be that long. around the mountain in hobart there are parts i have thought, yeah, i shouldnt ride that maybe. though it seems to hold pretty well. Then there are the bog holes that u just avoid. Then there are the more rocky solid fire trails that hold fine and no-one seems to ride and i dont see what damage i'm doing, especially when climbing. Its very varied. But guaranteed u are going to get wet and water is going to make its way into moving parts and u are going have to clean ur bike here i think. The bike will take a hit.
Last edited by Gordo on Thu May 24, 2012 6:02 pm, edited 1 time in total.
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Re: press in bottom brackets and mountain biking

Postby Gordo » Thu May 24, 2012 5:45 pm

silentbutdeadly wrote:I've exactly the bike that Gordo is looking at. In his situation I'd be more concerned with the suspension pivot bearings than the BB.


FS = more maintenace, yeah, i know. Leaning towards hardtail for ease of servicability and the alloy XTC is at a nice price. Anthems are all out of warehouse stock till 2013. Would like to go carbon XTC but same deal as anthems. Ok, i could go Anthem composite...but...unlikely. If money was no object i'd be on an epic 29er but thats 5 grand of bike if u factor in decent wheel purchase.

I recently had mine in pieces for a complete suspension service so I decided to inspect the bearings whicle the forks and shock were away. The Shimano BB was fine...it is actually reasonably well sealed for a bike bearing. But some of the pivot bearings were cactus...I've put no more than 750km into this bike and it doesn't rain here.


it rains here though...alot. And that xtc test bike was making a clunk clunk clunk noise from the bb after not much riding. made me nervous. I dont want to spend an extra 400 on tools when a little wrench does the job at the minute in no time (EDIT: just looked at above links and those tools look rather cheap compared with the prices i've seen. hmmm).. And all that pressing in and out of bearings cant be good. For me, at the moment, BB30 looks like a dog of a design. BB91 is a little diff with the plastic nylon cups, maybe thats better, i dunno. Id like someone to say yeah, its all good, just get the bike. But i read this on the santa cruz website and they have me suckered in:

Q.Why does the Highball use a standard thread-in bottom bracket, when many of your competitors use press-in style (BB30, Pressfit 30, BB90, BB92, BB86)

A.It is true that there are some slight weight savings available with the various pressfit bb designs (exact weight savings obviously vary depending on system, frame manufacturing techniques, and crank model), but we don't feel this small savings make up for the inconveniences. We are still able to make a frame that is lighter than most of our competitors (2.45 lbs), while still using a heavier bb system. There are a number of disadvantages that exist with press fit systems:

1) Special installation and removal tools are required for these parts, including a headset press. This is not convenient for most home mechanics, and they are quite expensive. Traditional external BB's can be installed or removed with a simple $10 hand tool.
2) "Permanently installed cups". Shimano doesn't recommend removing and re-installing their press in bb cups (as they may become damaged), so moving parts from bike to bike is no longer an option. http://techdocs.shimano.com/media/techd ... 625426.pdf
3) Creaking or shifting bb's can be common with these systems. Since the bearing is pressed into a cup, which is then pressed into the frame- it can be hard to get all of the press fits snug- without being too tight on the bearing or too loose in the frame.
4) Reasonable tube sizes. One of the most commonly claimed advantages of a larger bb shell is the larger diameter downtube that goes with it. This may be an advantage on road bikes, where tubes can be increadibly thin and large for optimal stiffness. On a mountain bike, this area of the frame sees a lot of abuse from rocks and crashing, and needs to have a certain amount of wall thickness to survive actual use. Using what we consider a "safe" wall thickness and carbon layup, and a fairly typical tube diameter, we get an exceedingly stiff, light, durable product. If we used a larger downtube, we would either have a heavier frame (same wall thickness but larger diameter), or a less durable product (thinner walls and larger diameter).
5) Chain clearance. Take a look at some of our competitors frames with press in bb shells. The down tube comes so close to the chainrings that many frames have chainsuck guards on the downtube! In our mind, the chain should be able to fall off on a mountain bike and not get jammed between your crank and thin-walled carbon downtube.
6) Backwards compatibility: Many of our customers purchase a frame and build it up with their choice of parts, or parts from an old bike. By using a standard bb, we are compatible with everything without requiring confusing adaptors.
7) Chainguide compatibility: While it may seem strange to talk about putting chainguides on a hardtail, it is becoming more common now with 10 speed drivetrains. Thread in bb's mean the frame is compatible with bb mount chainguides. We like versatility....


:?: :?
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Re: press in bottom brackets and mountain biking

Postby Nobody » Thu May 24, 2012 8:05 pm

Gordo wrote:But i read this on the santa cruz website and they have me suckered in:
Thanks for posting. :)
I like bike companies that can give clear reasoning on the choices they make.
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Re: press in bottom brackets and mountain biking

Postby trailgumby » Fri May 25, 2012 4:35 pm

Gordo wrote:
trailgumby wrote:+1. Unless you're in the wet tropics, riding wet trails in Oz is regarded as seriously uncool, due in no small part to the massive increase (200+ times?) it causes compared to dry conditions.


i saw ur post in a previous thread about this. fair point. i gave it due consideration too. i have thought about it

i'm way south. like as far as u can go south almost. ur pretty much guaranteed to get wet in tassie. i dont know how long the trails dry out here but it cant be that long. around the mountain in hobart there are parts i have thought, yeah, i shouldnt ride that maybe. though it seems to hold pretty well. Then there are the bog holes that u just avoid. Then there are the more rocky solid fire trails that hold fine and no-one seems to ride and i dont see what damage i'm doing, especially when climbing. Its very varied. But guaranteed u are going to get wet and water is going to make its way into moving parts and u are going have to clean ur bike here i think. The bike will take a hit.


To be fair to you, I should apologise for over-generalising. Tassie would be the other high rainfall area exception I would make besides the wet tropics. If you don't ride when wet there, you wouldn't get to ride.

While that in itself is not a justification from an environmental point of view, the high rainfall happily means a different plant ecosystem and consequently a different soil type, which is deeper, more fertile and less erodible (sp?). I would still encourage you to stay away from areas that don't drain well or where the trails run down the fall line, which you seem to be doing.

Fire roads are interesting. Given that they are usually open to large 4WD vehicles and AWD fire trucks, unless they are specifically closed to bikes by land managers they would seem to be fair game regardless of weather. You could host a major event on most of them and not do as much damage as a single pass by a NPWS 4WD or a Rural Fire Service truck.

While I sometimes go stir crazy and have to get on the dirt or go mad, of late I'm finding the horrible crunchy grinding noises my favourite dually makes after 40km of wet fire trails just get unbearable, so rather than love it to death I've been taking the hardtail commuter out on wet weekends and have been staying on the road.
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Re: press in bottom brackets and mountain biking

Postby Nobody » Fri May 25, 2012 6:15 pm

trailgumby wrote:While I sometimes go stir crazy and have to get on the dirt or go mad, of late I'm finding the horrible crunchy grinding noises my favourite dually makes after 40km of wet fire trails just get unbearable, so rather than love it to death I've been taking the hardtail commuter out on wet weekends and have been staying on the road.
Ah, the problem with expensive lounge chairs. :P
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Re: press in bottom brackets and mountain biking

Postby Jean » Sun May 27, 2012 11:28 am

Nobody wrote:
Gordo wrote:But i read this on the santa cruz website and they have me suckered in:
Thanks for posting. :)
I like bike companies that can give clear reasoning on the choices they make.


Yeah I get the warm and fuzzies about Santa Cruz bikes. I'm giving some thought to getting a SC Superlight once my current 29er hard tail project is completed.

Sorry, OT
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Re: press in bottom brackets and mountain biking

Postby Gordo » Sun May 27, 2012 3:39 pm

i would love to have a santa cruz. Just poking around on their website they seem to have considered servicing and maintenance side of things rather well, and not completely given to all this weight weenie clap trap. Some nice diagrams for servicing their bikes. grease ports and what not. just wish they were a little cheaper
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Re: press in bottom brackets and mountain biking

Postby Bentnose » Sat Jun 02, 2012 10:31 am

I'll be buying a new cx bike later this year and will be crossing any bike off the potential list that has a press fit bottom bracket. I know a couple of people who have had to warranty MTB frames as the press fit bearings eventually wouldn't sit tight in the frame. I have an external bearing removal tool and can easily do it myself, I have no wish to have to buy new tools or take my bike to a bike shop, hopefully it's just a fad like biopace.
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Re: press in bottom brackets and mountain biking

Postby silentbutdeadly » Mon Jun 04, 2012 10:13 am

Bentnose wrote:I'll be buying a new cx bike later this year and will be crossing any bike off the potential list that has a press fit bottom bracket. ...hopefully it's just a fad like biopace.


Not a chance. It makes bike frames cheaper to make, faster to assemble and it can be done via automation...therefore more potential for margin at the factory door. Given those circumstances...
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press in bottom brackets and mountain biking

Postby toolonglegs » Mon Jun 04, 2012 3:01 pm

I couldn't find many cx bikes without press fit bearings :-| ... I was looking at race only ones but they were nearly all press fit of some type.
But as my cx bike does about 15-20 hours maximum riding during a winter race season i don't have to worry to much about bearing problems! .
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Re: press in bottom brackets and mountain biking

Postby Gordo » Mon Jun 04, 2012 6:10 pm

did note here the following when i was digging around for 2013 stuff:

And finally, it seems like there’s not much new to report in bottom-bracket-standard land. BB30 and especially PF30 remain popular, but companies on all sides are still struggling with short bearing life and creaking due to alignment issues and difficulty maintaining tolerances.


one of the shops i went to said they've been having heaps of problems. sounds like they need to tweak things a bit at the least. I'll prob buy a bike with press fit bearings due to the fact that there aint much choice...stearing clear of bb30 though.

Oh, and just on 2013 stuff, looks like Giant are out putting a trance 29er through its paces (see adam craigs bike at 4:51). Ok, maybe we'll have to wait for 2014 for that one. But no doubt for 2013 Specialized will come up with a billion and one proprietary bs designs to put on their bikes in an attempt to try and dissuade me from buying their stuff.
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Re: press in bottom brackets and mountain biking

Postby Bentnose » Wed Jun 06, 2012 6:15 am

Ok, we have BB30, BB90 and Specialised have the OSBB or is it PF30? Whey do we need to steer clear of BB30 over the other ones and are there others I've missed, are they all compatable with the same BB shell? Are any of them any good at all, I'd say probably not?
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Re: press in bottom brackets and mountain biking

Postby silentbutdeadly » Wed Jun 06, 2012 11:07 am

Bentnose wrote:Ok, we have BB30, BB90 and Specialised have the OSBB or is it PF30? Whey do we need to steer clear of BB30 over the other ones and are there others I've missed, are they all compatable with the same BB shell? Are any of them any good at all, I'd say probably not?


You needn't steer clear of any particular pressfit BB system...they are all much the same in design and construction. Big difference is that some press directly into the frame itself while others are pressed into plastic cups that are pressed in the frame. Cannondale and Specialized use BB30 bearings pressed directly into some frames while other makers use a Press Fit BB30 system which has the same BB30 bearings inside a plastic cup that's pressed into the frame...BB86 is the same setup (bearing in plastic cup) that you'll often see in road bikes.

In the end...it's quite simple. The press-fit systems require the exposure of the bearing to the environment so unless the bearing is well made and well sealed then it will get killed quite quickly with mis-use. Second compromise is that (unlike external cup and internal cartridge systems) they require very high precision in order to function correctly - so punters who think they can be 'just bopped out' of an alloy BB shell with a hammer and dowel without risk are deluded. If you have a bike with a press fit BB system then you'll either need to buy the correct BB press tooling in order to service them yourself...or get the LBS to do it. And you'll probably need to do it every year depending on your local ride conditions...
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press in bottom brackets and mountain biking

Postby toolonglegs » Wed Jun 06, 2012 3:48 pm

The good thing about bb30 is you can readily get adapter sleeves.
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Re: press in bottom brackets and mountain biking

Postby Gordo » Wed Jun 06, 2012 6:26 pm

Bentnose wrote:Ok, we have BB30, BB90 and Specialised have the OSBB or is it PF30? Whey do we need to steer clear of BB30 over the other ones and are there others I've missed, are they all compatable with the same BB shell? Are any of them any good at all, I'd say probably not?


see the youtube vid in my first post regarding all the diff standards.

why steer clear of bb 30. ughhh, just my preference at the minute. i just dont like the idea of wedging stuff directly into the bb. seems to need very tight tolerances. With pf 30 and bb 86/91 (shimano stuff), they use the plastic sleeve which seems a little better. Perphaps not so fine tolerances needed. I dont know if im right or not. but maybe outa supersititon i'd ping for those anyway (lesser evil im thinking). Or if i get the cash i'll just go buy santa cruz.
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