Author Topic: Outboard Bottom brackets - durability  (Read 1775 times)

psmiffy

  • Newbie
  • *
  • Posts: 4
Outboard Bottom brackets - durability
« on: August 12, 2015, 02:11:34 PM »
Im putting together a spec for my new tourer - 26" wheels 3x10 derailler geared - Sherpa Mk3


Outboard bottom brackets - having read around them I get conflicting messages about how often they need maintenance/bearing changes - old school - even octolink v1 - was fit and forget for a tour(s)- 20k km was not uncommon for me- I dont like the idea of having to do BB maintenance on tour (<10k km) - so at the moment looking at deore chainset (or better if I can find it) with square taper BB

  • what sort of km do you expect from an outboard bottom bracket between maintenance?
  • I assume that an old school BB will actually fit in a Sherpa BB shell!
  • If new school is more durable than im led to believe then what outboard BB would be best/most durable for a sherpa?

What Im trying to achieve is something like this (unfortunately stolen from me)
« Last Edit: August 12, 2015, 02:15:52 PM by psmiffy »

jags

  • Guest
Re: Outboard Bottom brackets - durability
« Reply #1 on: August 12, 2015, 02:58:30 PM »
as long as the BB shell is faced u will get years of happy miles and there a snap to replace.i had them on the sherpa never a problem.
but when i had them on my look road bike i went through 3 sets of them (dura ace) all because the shell wasn't faced lesson learned.


jags.

Danneaux

  • Administrator
  • Hero Member
  • *****
  • Posts: 7163
  • reisen statt rasen
Re: Outboard Bottom brackets - durability
« Reply #2 on: August 12, 2015, 03:54:00 PM »
Hi Miffy, and welcome to the Thorn Cycling Forum!

I deliberately chose Outboard/external-bearing (I'll use the terms interchangeably)  BBs for my original Sherpa and again on my later Nomad. I'm a bit pressed for time, so will answer in bullet points...

External-bearing BBs use seals (shields, in most cases rather than the more robust seals typical of Conrad-type cartridge bearings). What this means is they really require no maintenance. You use them and use them up, then replace. It is possible to pry off the shields and inject some grease -- you can even knock out the bearings and press in replacements -- but as a rule, they are maintenance-free.

Many external-bearing BB's use less than full bearing complements, so there are fewer ball bearings to share the load. To compound this, the balls are typically smaller in size. Sometimes, they aren't greased very well. These can all lead to a shorter bearing life, particularly if all are present.

In my experience, "most" OBBs are "good enough" for general use and good service life provided they are not installed with excessive preload on the bearings(!). When installing the OBB, the left side has a little plastic preload adjuster that can  easily be turned tightly, placing a lateral load on the bearings, causing them to wear quickly. The adjusting nut should be installed with only enough tension to take up or prevent any excessive play. A lot of people with failed OBBs cranked this adjuster down and paid for their mistake in a short service life.

OBBs seem to do fine for the majority of people when installed correctly. They need to have parallel BB faces, so a refacing might be in order, and they need to be installed without excessive preload. Do those, and a reasonable service life can be expected. If they are poorly adjusted at installation, see a lot of high-torque use, dunking, or the bike lays on its side a lot in heavy weather, they tend not to last as long as their more conventional brethren.

As a general rule, Internal-bearing bottom brackets seem to last longer in severe or touring service because the bearings are generally larger in diameter and/or more numerous, and the seals are a bit better, being shielded by the edge of the BB shell in part.

That said, after two Shimanos that failed for me, I bought a Phil Wood OBB and have been very happy. It has so far proven to be very durable (as have their IBB cartridges on my bikes) and I expect a long service life from it. It is well sealed, filled with premium grease, the bearings are supported by robust stainless cups, and the bearings themselves are objectively better.

Hope this helps.

Best,

Dan.

bikerwaser

  • Jr. Member
  • **
  • Posts: 94
Re: Outboard Bottom brackets - durability
« Reply #3 on: August 12, 2015, 07:16:58 PM »
Check this link to CTC forum for "external" bottom brackets :

http://forum.ctc.org.uk/viewtopic.php?f=5&t=52346

As you can see it's currently running at 48% of people only getting less than 3000 miles on them.

this obviously depends on the make/quality of bottom bracket you buy. Myself and a friend have used the Sh!tmano BB51 BB's and only got averages of just over 1000 miles ( which is in line with the survey ).
Both our bikes have been faced professionally.
BB51's don't use Stainless Steel bearings, which in my opinion is ridiculous considering how much battering the BB gets from rain, mud and crud.

After several Sh!tmano BB51's with low mileage i've swapped to a Hope BB and all is fine. I've clocked about 10,000 miles on it so far and it's as good as the day it was fitted. Guess what ...... Stainless Steel bearings. What an idea . Duhhhh !

I hear people saying that the BB51 is only 10 but it's no good for a tour of more than 1000 miles . My brake blocks last longer than that.  Not only that , i don't want to carry tools to service my BB on tour.

The Hope BB cost 7 times the price but has given me almost 10 times the mileage maintenance free.

"Hope" this helps !

Biker Waser


psmiffy

  • Newbie
  • *
  • Posts: 4
Re: Outboard Bottom brackets - durability
« Reply #4 on: August 12, 2015, 09:27:15 PM »
Check this link to CTC forum for "external" bottom brackets :

http://forum.ctc.org.uk/viewtopic.php?f=5&t=52346

As you can see it's currently running at 48% of people only getting less than 3000 miles on them.


Yup ive seen that thread and another one on CC - partly why I was asking - been on my mind that if I get another bike together the idea of actually contemplating having the means to do a BB service/replacement mid-tour is so wrong



I hear people saying that the BB51 is only 10 but it's no good for a tour of more than 1000 miles . My brake blocks last longer than that.  Not only that , i don't want to carry tools to service my BB on tour.

The Hope BB cost 7 times the price but has given me almost 10 times the mileage maintenance free.

"Hope" this helps !


Answer seems to be to Hope for the best or Wood something else do just as well

or maybe just go old school  :)

psmiffy



jags

  • Guest
Re: Outboard Bottom brackets - durability
« Reply #5 on: August 12, 2015, 10:08:10 PM »
Nah go with the more modern gear you wont have any problems . ;)

mickeg

  • Hero Member
  • *****
  • Posts: 1209
Re: Outboard Bottom brackets - durability
« Reply #6 on: August 12, 2015, 10:28:04 PM »
I have only used square taper or the older cup and cone style myself. 

I went on a group tour a couple years ago with 15 other riders.  One had external bearings that went out, he had to have the bike manufacturer send (under warranty) a set of bearings to a bike shop on our itinerary to get it replaced.  The only other mechanical failure besides flat tires on the whole trip was one front derailleur spring broke.

Whatever your decision, good luck in your travels.

If I was doing an expedition, I would consider hunting for an old cup and cone style one.  Then if I needed to clean it out with cooking oil, I could.  I did find one used in a parts bin at a bike shop but the bearing surfaces of the spindle were pitted.

Andre Jute

  • Hero Member
  • *****
  • Posts: 2893
    • Andre Jute
Re: Outboard Bottom brackets - durability
« Reply #7 on: August 12, 2015, 11:08:12 PM »
I think the best compromise for someone like a tourer, to whom a bike he can depend on is so important, is the sealed standard, internal bottom bearing. It may not have a lot of sex appeal, butit rarely breaks and then causes a delay that is generally not very long because it is such a ubiquitous components, available in every third-world town bigger than a brothel and a bar.

Square taper goes without saying...

jags

  • Guest
Re: Outboard Bottom brackets - durability
« Reply #8 on: August 12, 2015, 11:22:22 PM »
what is concider the best  square taper BB and crankset,any links.

jags

psmiffy

  • Newbie
  • *
  • Posts: 4
Re: Outboard Bottom brackets - durability
« Reply #9 on: August 12, 2015, 11:31:56 PM »
what is concider the best  square taper BB and crankset,any links.

jags

I asked that question of google several months ago and went through all the usual suspects Middleburn et.al but they had all gone over to the dark side  :D

John Saxby

  • Hero Member
  • *****
  • Posts: 1247
Re: Outboard Bottom brackets - durability
« Reply #10 on: August 13, 2015, 12:13:36 AM »
Quote
the best square taper BB

Not a direct answer to your question, Anto, but:

> Shim UN 54 or 55 works well for Thorn requirements -- I have a UN55 in my Raven, 118mm length to mate with a Stronglight crankset from Spa cycles (the latter a bargain at 20 quid.)  The Shim has worked fine so far. Reports of their lifespans run from 2,000 kms to 10,000 kms and up. It could be a false economy, but if it lasts a few years, I'll be OK with that.

> Phil Wood or SKF seem to be very good indeed, priced around USD 150 (plus shipping to wherever, local taxes, etc.) I thought about the SKF, with its 10-year guarantee and my fondness for German engineering, but thought:  one of these will likely outlast my knees and other motive forces for the bike.  My Scottish ancestors frowned at this, and without bothering with any consultation/negotiation with me, ordered the Shim.

Danneaux

  • Administrator
  • Hero Member
  • *****
  • Posts: 7163
  • reisen statt rasen
Re: Outboard Bottom brackets - durability
« Reply #11 on: August 13, 2015, 02:13:15 AM »
Quote
what is concider the best  square taper BB and crankset,any links.
I've had good luck with three Phil Wood internal units currently on my bikes; there's been others in the past. One has well over 32,000mi/51,500km, another more than 28,000mi/45,000km and the third well into the mid-20,000mi/40,000km range. Still smooth -- smoother than when first installed, due to run-in and seal wear. No rust, either.

I'm hoping current production is still as good; it has been a good while since I had need to purchase one.

Phil retaining rings are available in stainless or aluminum and allow for lateral chainline adjustment of several millimeters.

If you ever decide to go with a Phil internal unit, they have various cartridge jacket options. Two of my older ones are stainless steel, the third/newest is aluminum. I understand there is also a lighter carbon jacket available. Phil now also offer o-ringed dust seals for the retaining rings. Despite their apparent appeal, I have so far declined to fit them, fearing they might trap any water that did enter, causing internal rust to form in the BB shell. Nice idea, and I'm mightily attracted, but still have that little niggle of doubt that keeps me from going further toward getting one.

Older Tange cartridge BBs served me well also with well over 22,000mi/35,400km. In earlier days, Shimano's premium sealed cartridge BBs were produced by Tange under contract. Hot tip: If you need minor chainline adjustment, Phil retaining rings will fit many other cartridge BBs, but require their own uniquely sized and shaped ring-wrench to install and remove.

Hope and SKS are other premium brands of internal cartridge BBs with well-deserved, excellent reputations.

I'm hoping the OBB Phil unit will last a good long time. Photos and further discussion of these issues here:
http://thorncyclesforum.co.uk/index.php?topic=4523.msg43173#msg43173
http://thorncyclesforum.co.uk/index.php?topic=4523.msg43281#msg43281
http://thorncyclesforum.co.uk/index.php?topic=4523.msg43285#msg43285

Best,

Dan. (...who shares a surname but no other connection with the Phil brand except as a happy customer)
« Last Edit: August 13, 2015, 03:05:38 AM by Danneaux »

leftpoole

  • Hero Member
  • *****
  • Posts: 533
Re: Outboard Bottom brackets - durability
« Reply #12 on: August 13, 2015, 09:12:46 AM »
I think the best compromise for someone like a tourer, to whom a bike he can depend on is so important, is the sealed standard, internal bottom bearing. It may not have a lot of sex appeal, butit rarely breaks and then causes a delay that is generally not very long because it is such a ubiquitous components, available in every third-world town bigger than a brothel and a bar.

Square taper goes without saying...

Hello!
How big is a Brothel as I cannot find one anywhere   ;D ;D ;D
Best regards,
John

il padrone

  • Hero Member
  • *****
  • Posts: 1208
Re: Outboard Bottom brackets - durability
« Reply #13 on: August 13, 2015, 12:32:36 PM »
Shimano UN72 was installed on the frame that my son now rides in ~1995. It was only just replaced a few months ago, and I would guess it had a service distance of some 50-80,000 kms.

No longer available but the UN73 was its replacement.
« Last Edit: August 13, 2015, 12:34:57 PM by il padrone »

Andre Jute

  • Hero Member
  • *****
  • Posts: 2893
    • Andre Jute
Re: Outboard Bottom brackets - durability
« Reply #14 on: August 13, 2015, 09:59:52 PM »
what is concider the best  square taper BB and crankset,any links.

Quite a few other people's branded and boutique-priced bottom brackets are made in what used to be Czechoslovakia by Kinex. The same factory also makes own-brand Kinex bottom brackets, which are widely fitted as OEM equipment by upmarket bike makers and custom builders. They're amazingly cheap for the quality, perhaps because there's no big advertising to carry. The square-taper Stronglight BB is exactly the same as the Kinex, and made for Stronglight by Kinex.

SJS had some Kinex BB the last time I looked, and at very attractive prices too.

As for the best crankset, I think it is hard to beat the Japanese forger (no, not that kind, the engineering stamping kind) Sugino's restrained, classy Cospea. This crankset is generally only available in Japanese boutiques but some crept into the Sugino-supplied compact sets that Stronglight called Impact, which is usually a Sugino XD-2 when you open the box. My Cospea came from Stronglight. The XD-2 strikes me as a lot of bang for the buck, especially if you buy it for twenty quid or so from Spa, as their house brand, instead of a hundred-quid, and often then some, housebrand flogged by someone with pretensions to grandeur.

Of course, if I didn't have to meet so many other criteria (sorry!) which can only be satisfied by modern cranked (sorry!) cranks, I wouldn't fit anything other than the 50.4mm PCD Stronglight T49 (left) or the TA Cycletourist (right). These are the only "classic" cranks; you can get a modern version from Velo Orange, but, besides it having very badly specified chainrings, I wouldn't be seen dead with gear specified by someone so ignorant as to make a copy of Stronglight's T49 and then say it was inspired by TA!