Bikeguide.org - Bike maintenance for BMX'ers
The Street => The Bike Shop => Topic started by: nailbomb on April 08, 2012, 09:51:31 PM
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Hi Everyone,
Yesterday mid way through a dirt session at my local spot, my bike made a loud cracking sound originating from the BB area, my bb has been making creaking a couple of days ago.
I'm running a two week old Eclat Spanish BB, prior to this, i have never had any issues with my BB prematurely 'shittin the bed', i couldn't think of what i did wrong installation wise.
I then took my entire Cranks/BB off and saw that the seals on my bearings are all knackered. I then measured the tube spacer (48mm), both bearings (18mm) and my bb length is 68mm.
This comes to my question, why did they provide a tube spacer that isn't long enough for a standard BB Length? my conclusion is that I actually had to install a 2mm thick crank spacer inbetween my tube spacer and bearing on the inside of the frame?
I reckon what caused the seals to be knackered was cause there's a 2mm space in the BB shell that was allowing the tube spacer to be moving around?
Who else have encountered a similar problem? pretty bummed cause i waited ages for the eclat bb to be delivered to me and i have to the same again...:)
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there's a pretty big lack of standards in bmx. i ran into the same problem on my old FBM frame but i just stuck an extra 5mm non drive side spindle spacer inside with the tube spacer
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yeah man, true that, wished i had actually double checked on the measurements!
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I don't think that would cause your bearings to fail quite that fast. I've heard of lots of people not running the tube spacer at all and being fine.
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I don't run the tube spacer every one I've ever installed has always been a few mm too long
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pretty sure the tube spacer has nothing to do with how good your bearings work,always thought is was to protect the middle of your spindle from rust. Like how the inside of your frame will rust a little and obviously moisture could get to the spindle and rust it making it near impossible to get the spindle back out. happened to my buddy once with profiles and had to drill the spindle out but he also never took care of the bike and left it outside im sure.
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pretty sure the tube spacer has nothing to do with how good your bearings work,always thought is was to protect the middle of your spindle from rust. Like how the inside of your frame will rust a little and obviously moisture could get to the spindle and rust it making it near impossible to get the spindle back out. happened to my buddy once with profiles and had to drill the spindle out but he also never took care of the bike and left it outside im sure.
It is to keep the bearings straight in the bottom bracket. Otherwise they can be over tightened and "cave in", putting more pressure on the bearings.
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pretty sure the tube spacer has nothing to do with how good your bearings work,always thought is was to protect the middle of your spindle from rust. Like how the inside of your frame will rust a little and obviously moisture could get to the spindle and rust it making it near impossible to get the spindle back out. happened to my buddy once with profiles and had to drill the spindle out but he also never took care of the bike and left it outside im sure.
hahahahhahah lol it's to actually allow your cranks to be tighten enough and the inner races of the bearings have something to press on with, to ensure your bearings won't get crushed radially/axially....:dunno:
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usually when i build up a new frame, whether it's spanish or not i measure the BB and the stack height of the tube spacer plus both bearings. i think for each the last 3 frames i've had (older t-1 moody/hickerson, fbm capone, 2007ish s&m dirtbike) i've used a 2mm spacer along with the tube spacer.
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I don't think that would cause your bearings to fail quite that fast. I've heard of lots of people not running the tube spacer at all and being fine.
yeah, well some people just spin the boltaround with a tiny little allen while others might try cranking it down with an impact wrench
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there's a pretty big lack of standards in bmx.
DING DING DING
Of the standards we do have a large percent of them go ignored by companies unfortunately. In the end this mainly hurts the end user as we're the ones who get to try to figure out solutions or buy different parts in order to ride.
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Unless its been changed, the bearing seat depth is called out at 10mm, if I remember correctly. So taking that into account, the spacer is the correct width. Are your bearings flush with the shell or are they sitting below the face by 1mm?
What did you use to install the bearings?
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It is to keep the bearings straight in the bottom bracket. Otherwise they can be over tightened and "cave in", putting more pressure on the bearings.
hahahahhahah lol it's to actually allow your cranks to be tighten enough and the inner races of the bearings have something to press on with, to ensure your bearings won't get crushed radially/axially....:dunno:
I'm an idiot. honestly never cared what it was for,just knew it was some what important.
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Unless its been changed, the bearing seat depth is called out at 10mm, if I remember correctly. So taking that into account, the spacer is the correct width. Are your bearings flush with the shell or are they sitting below the face by 1mm?
What did you use to install the bearings?
TOUCHE! exactly what i thought as well, i had the assumption that once i tighten the cranks down, the bearings would be pushed in to accomodate the 'extra' 1mm on each side but that's not the case thou.
I agree with the lack of standards in bmx, funny how when i got a new spanish bb set from a local company last night, the tube spacer is 50mm compared to eclat's 48mm....
I've ridden and work on bikes for ages now but encountering a problem with bb lengths and bearings are definately a first to me, thought i had all of these settled when the euro bb got phased out eventually but nooooo... hahahaha :confused:
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DING DING DING
Of the standards we do have a large percent of them go ignored by companies unfortunately. In the end this mainly hurts the end user as we're the ones who get to try to figure out solutions or buy different parts in order to ride.
exactly! like how my profile hub required two shims instead of one hahaha
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"BMX standards" is like an oxymoron... each standard is created by whatever company created whatever design first, and then a bunch of companies take it and mess with it.
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if the tube spaces isnt long enough, you just have to put an extra thin spacer or two between the bearings with it. its a bit fiddly, you can either tape it to the tube spacer or put one bearing into the frame, put your crank axle a little way into the bb, then put the spacer and tube on, then put the second bearing in.
you can get away with not running the tube if you have powerbites or other pinchbolt cranks, but you probably should if you can
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yeap, did exactly that with the new bb but instead i installed a 1mm thick spacer in the frame cause the tube spacer is at 50mm and bearings are 18mm for both, my frame bb length is 68mm, so my non drive side bearing sticks out a lil (not even noticeable), tighten them up as tight as i could and it still spins really smoothly, my previous problem was definately a tube spacer issue, glad everything is sorted now!
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Better to have too much spacer than not enough.
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you can get away with not running the tube if you have powerbites or other pinchbolt cranks, but you probably should if you can
Sprocket can come loose doing that
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Same question just came up on a different forum and a Google search brought me back here. What's weird is that Profile's website now has a tube spacer for Spanish listed as
1.985" (which converts to 50.419mm) rather than the typical 48mm tube spacer for a 68mm bb shell.
http://www.profileracing.com/estore/product.php?productId=63 (http://www.profileracing.com/estore/product.php?productId=63)
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Oh profile is being so profile. You know them...
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I got MID 68 and the same frame next season with 73mm. Bigger tyres, wider bb could help to move chainstays another 2.5mm each side. Same story with Spanish? Anyway I saw also custom Spanish bb that was CNC deeper by mistake or so (I had to cut 48mm to 46mm). You can always throw inside a 1-2mm washers to avoid preload/sideload on bearings and give them support.
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I hate tube spacers, they never fit nicely. Be glad it was too short, and not too long. I have had problems with BBs for like 10 years and the biggest annoyance is having too long tube spacers, had to go to a machine shop to get it cut nicely.
After all my troubles I have collected an impressive amounts of tube spacers that I can chose from when buying a new frame.
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After all my troubles I have collected an impressive amounts of tube spacers that I can chose from when buying a new frame.
haha likewise
someone should make an adjustable length bb spacer, kind of like the colony adjustable headset one
(http://rainbowcycleworx.com/wp-content/uploads/2014/06/40a44721669b40eb99ff0e993c2dc1bc.jpg)
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someone should make an adjustable length bb spacer, kind of like the colony adjustable headset one
someone should make an adjustable length bb shell on the frame, kind of like... bla bla blah
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someone should make an adjustable length bb spacer, kind of like the colony adjustable headset one
someone should make an adjustable length bb shell on the frame, kind of like... bla bla blah
(http://i3.kym-cdn.com/entries/icons/original/000/000/045/n725075089_288918_2774.jpg)
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#1
I hate tube spacers, they never fit nicely. Be glad it was too short, and not too long. I have had problems with BBs for like 10 years and the biggest annoyance is having too long tube spacers, had to go to a machine shop to get it cut nicely.
#2Better to have too much spacer than not enough.
Somehow Im always in the team "#2", using spanish bearings with alloy cups inside mid bb shell since few years (looking like smaller version of Us bb). Cause I only had extra Spanish bearing and cup to fit MID when Mid exploded in the middle of the night. Then never replaced back to proper Mid bearing. Then recetly cracked the 19mm bb axle in the middle of the night. Too far away from my garage but somehow had access to extra 19mm axle. But one small spacer lost when the axle exploded. Removed most of spacers from old rusty axle. Then put on the new axle. And still missing one after instalation. So having 5 of 6 needed spacers inside BB, all making rattling noise and bearings still slowing down. And not having any will or power or tools to remove again whole set and no missing last 1mm spacer. Dude, that night I would love your adjustable BB lenght spacer.
(http://scontent-a-vie.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/10891606_10204321559137188_2898950336726114364_n.jpg?oh=006ed470b9118875108414305e38f260&oe=552F10FF)
actual BB is MID 73mm + sticking out cups to Spanish making it somwhow something close to Spanish 77mm?
(http://scontent-a-vie.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/10891508_10204321573817555_6337235027563463523_n.jpg?oh=232198d0bbb07c3fb25d3406a3a17c94&oe=55278029)
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ok yeah i get what you mean, sorry bit of a misunderstanding.
if the tube spacer is aluminium, you can cut it down and file it flat pretty easily.
and yeah its super annoying when you dont have enough spacers in the bb, and have to take the bearing back out to add more. if theres not enough in there, there might as well be none at all for the good that theyll do
id also recommend harvesting bbs out of old frames that other riders dont want anymore (people throw away perfectly good bbs and spacers all the time because they can be bothered to remove it from their old frame.
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ok yeah i get what you mean, sorry bit of a misunderstanding.
No, I really meant adjustable shell. HA HA HA.
If adjustable spacer can be done, adjustable shell probably too. It is not a rocket science.
WTF LOL :)
Both of them - adjustable spacer and adjustable shell make no sense. too complicated, too heavy, too expensive. A right spacer and couple of small washers if needed are good enough.
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ok wow, nah bit of a step up from an adjustable spacer to an adjustable bb shell. if this shit was actually standardised, then bbs could include 1 tube spacer which was the correct length and thered be no fucking about
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I think he was being sarcastic, in a weird not standard British way.
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yeah i dont get polish sarcasm, im confused haha