Category: Misc

We Need To Torque About Bolts

(from left to right) US 1/4″, large-head 6mm, regular (hollow) 6mm, and a crank bolt for comparison…

Read: A Rough Guide To Making Your Bolts Last Years Rather Than Months.  Excuse the appalling pun I chose for the main title… it makes more sense if you say it in an Estuary English accent.

Rusty, rounded-out allen heads, dirty, greasy, snapped bolts and stripped threads; when most people think of working on their bike in any form they tend to cognitively leap to these nightmare scenarios before thinking twice about the whole affair and kicking their tool box back into the dark, spider-infested abyss.  Being the ragtag bunch we are, a lot of riders don’t really think about bolts much further than a. getting a new component and b. tightly bolting it as quickly as possible to your bike so you can get out and ride but hold up there, slugger, your bolts are the only things holding the lumps of metal you call a bike together.  Furthermore they’re the only thing stopping you landing on your teeth.  Bolts deserve our uninhibited love and respect.  So how can you bolt parts onto your bike in a fashion that prevents the bolts from turning terracotta in 6 months time and binding with the strength of a thousand pickle jars?

The answers to all bolt related problems are simple enough, I’ll try and keep it snappy as I’m very aware of the fact I’m trying to make an article about fucking bolts interesting.

So before we start, what tools are you using? And how are you using them?  Rusty tools are something you should avoid like the plague, because rust spreads like such.  Rust will transfer from your tools to any exposed metal on your bolts so always keep your tool clean, dry and rust-free.  A bit of WD-40 and some wire wool is good for getting rid of superficial amounts of rust if it does build up however.  Next up, it’s always good practice to have a good amount of leverage in your tools for the job at hand.  Sure, trying to undo your rusty-ass cranks with a tiny 3 inch long allen wrench by stamping on it might indeed work… but it could easily enough put you in hospital.  A shorter allen key will almost certainly be a cheaper allen key with sharper edges- stick with something either a little longer or use something with a proper handle ie. a multitool.  Lastly, is that allen key seated properly before you turn it?  You sure?  Wiggle it a little, push it down and repeat until you’re absolutely certain.  Rounded bolt heads are literally the worst.  While we’re on the subject of rounding things off, are you still doing up your wheels with a spanner head when there’s a socket or ring spanner to hand?  Stop dat.  A spanner head only has 2 points of contact where a ring spanner or socket have 6, spreading the load more efficiently.  Your wheel nuts will last much longer.

A US Imperial 1/4″ stem bolt (left) and a ‘large-head’ 6mm stem bolt (shown right) look very similar side-by-side but use two different sized allen wrenches and two different thread pitches. They do not fit the same stem.

90% of bike mechanics is cleaning shit no one thought to clean; and this is no different.  Let’s focus on the stem for now as it’s the component with highest concentration of bolts and it’s the easiest to fuck up.  First step is to take a 6mm allen key (or a 1/4″ if your stem is American- there is a difference) and unbolt your bars.  If you’re installing new bars then it’s never a bad idea to use some glass/sand paper to sand any paint off the knurling if it hasn’t been masked off during powdercoating.  If it’s an old stem, it’s probably absolutely filthy under the stem plate, body, and bar clamping area so grab a whole load of loo roll/ paper towels and clean all that stuff away.  Do the same with the steerer tube/clamping area.  Spray some WD-40 or some degreaser to help clean stubborn dirt away if need be.  Just like your Mum told you when using the toilet for the first time, ‘Keep wiping until there’s nothing left on the paper.’  Repeat this process with the bolts and threads until everything is dry and clean.  You can just use a parts washer if you’re a flash cunt.  It’s very important to clean any dirt away, any debris left in between two parts acts as a lubricant allowing your bars and/or steerer to slip.

Now everything is dirt free you can inspect the parts for wear and damage.  If your stem plate and body have significant scratches gorged into the clamp area from slipping, this could prematurely damage any new bars you put on them and may have reduced clamping power due to having uneven clamping surfaces.  By all means, use damaged parts at your own risk if you have no other option but if they continue to slip, I highly recommend replacing.  The same goes for your bars, if they’ve been slipping about to the point the knurling on the clamp area has been ground smooth, it might just be time for some new ones.  It’s always worth checking the holes in your stem face plate for burrs caused by over-tightening (more on that later)  These burrs will make putting the bolts through them and installing your bars an extra hassle as the bolt threads will ‘catch’ on the faceplate.  This can be remedied slightly by filing them with a round file.  Prolonged over-tightening of those bolts will warp the faceplate creating further burrs and warping until it eventually fails and takes your face with it…

Lets say everything is gravy with your bars and stem, before you go and bolt them back on, pop a little of that thin ‘3-in-1’ type oil onto your bolt threads to keep them from oxidising over long periods of time and making it a pain to undo them again.  Grease of varying kinds works well too but takes longer to clean when it becomes dirty.

This paragraph will seem to many like I’m stating the obvious, but you don’t know until you know… and plenty don’t.  Most stems will have four stem plate bolts and they’ll have one of a few ways of fastening them.  The most common and traditional way is to tighten the four bolts incrementally and evenly in an ‘X’ pattern, another is occasionally used on top load stems and involves tightening two shorter front bolts fully against the stem so the plate and body are touching before tightening the two rear bolts to tighten everything in place.  Sometimes the plate will be on a hinge, sometimes in two pieces, this changes stem-to-stem so it’s always best to check with the shop from where you bought it or the manufacturer website if completely unsure.

Over-tightening is something we’ve all been guilty of at one point or another, particularly when it comes to stems, and yet is probably the easiest way to kill a part.  I understand the reasoning behind it, it’s the logical thing to do in most people’s heads; if your stem’s slipping wrench the shit out of the bolts with a long ass allen key to clamp it tighter! The only thing you’ll find is it puts totally unnecessary amounts of stress on your parts (sometimes to the point the pinch bolts at the back cause the two sides of the stem to touch, or the bars and steerer get crushed out of shape) and still your stem will slip about like a greased up pig in a Vaseline factory.

Example of a large torque wrench- 12-60Nm

 

In MTB and road cycling, manufacturers often print torque settings onto their parts so you know exactly how tight to do up each bolt.  Contrasted against BMX, most people couldn’t tell you what a torque wrench even was…  mainly because they cost a small fortune and are far from essential.  Even I don’t own one of my own.  A torque wrench is essentially a standard ratchet wrench with a built in mechanism that clicks when you reach a desired tightness in a nut or bolt to indicate when to stop.  Getting your hands on a torque wrench and working with one for a while can teach you to gauge what kind force to put into bolts just by feeling them.  In this section I’ll approximate and describe to the best of my ability what each kind of bolt requires in the way of force, as well as the rest of the bolts on your bike as a comparison.

  • Wheel bolt/nut- 55 N m+ (Pretty much as hard as you can tighten it without shitting/ hurting yourself, you don’t want a saggy chain every time you do an ice pick do you?)
  • Crank bolt- 40-50 N m (Pretty damn tight, not putting your entire weight into it, but most of it- stopping when you feel a lot of resistance)
  • Pedal spindle- 30-35 N m (You don’t want to be using a ton of force- stop when you begin to feel increasing resistance in the pedal spanner)
  • Pivotal seat- 25-30 N m (Pretty much the same as above- just with an allen key, so there’s less leverage involved)
  • 1/4″ and large-head 6mm stem bolts– 20-27 N m (Tighten until you feel the threads slow you down, then tighten by an extra 1/8th of a turn or so.  You should feel like you’d be able push the bolt round a fair bit more if you put some elbow grease into it… don’t though.)
  • Standard 6mm stem bolt– 15- 19 N m (Simply tighten until you start feeling resistance, then stop.  It’s best to stick to the lower end of the Nm scale if your bolts are also hollow)
  • Seat clamp- 7-15 N m (lightly tighten until you feel the bolt becoming a little harder to turn but not fully resisting- you can test by trying to turn the seatpost)
  • Brake hardware- 3-6 N m (brake hardware uses smaller bolts and needs less in the way of torque, just enough to stop the bolt moving when the calipers are pivoting)

The overwhelming voice in some people’s heads will scream, ‘It’s not tight enough! Tighten it more! Tighter is safer!’ but it’s hardly ever the case.  Your first port-of-call should always be to clean the affected component before you try torquing your bolts any tighter than you already have.  Bike mechanics often work under the cautionary mantra of ‘try the least dramatic fix first’ even if that fix is simply to break out some clean toilet roll and give everything a good ol’ scrub.

*EDIT* A very good point was made in the fb comments section about what happens to bolts once you over-tighten them;

“One thing (worth) mentioning is that if you over-torque a bolt chances are that not only did you overload it – essentially weakening the bolt and/or part, but you can also end up with LESS clamping (power) since the bolt will have stretched past its yield limit and the more you turn the bolt the more it will stretch until it snaps.” -Jimmy Röstlund

BMX And Unplanned Obsolescence

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One thing that has always fascinated me about BMX or more specifically; the economy of BMX- is the current lack and decreasing amount of what is commonly known in ‘the real world’ as planned obsolescence.  Planned obsolescence, for anyone unfamiliar with the term, is the reason you buy a new phone every year, a new games console every 2 years, a new TV every 3 years, a new fridge every 4 years, etc; instead of every 10 years- for ALL of them.  It’s not that companies can’t produce a games console that wouldn’t overheat and melt the solder, or a phone that doesn’t bend in your pocket or smash when you drop it, it’s that it doesn’t make them anywhere near as much money if they make a product that lasts a decade rather than last two years- even if they charged double for it.  800 quid per person every ten years? Or 400 quid every two years? (equating to 2000 per person every decade) It’s a very easy business decision.  The downside is that we are polluting the very planet we are stuck on with our broken junk, merely in the quest for profit.  Thanks to everyone who participates in making BMX what it is, we truely have something we can be proud of; our own little world where planned obsolescence is kept to a bare minimum. Continue reading

Headsets Revisited- A Decade On

 

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When S&M unveiled the first BMX frame to feature an integrated headset over 10 years ago, it was met with puzzled looks and optimism alike; would it be that much easier to install? Would it be expensive to convert from Aheadsets to integrated? Where did this revolutionary design come from?  Let’s have a quick recap… Continue reading

Skapegoat Bob Bars And The Case For Bike Fitting

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I’ve been holding off writing anything about Skapegoat’s Bob Scerbo bars for a little while, not least for their rich yet turbulent history that has already been well documented (let’s break it down briefly for anyone who’s not up to speed; GT made them originally, Bob had his Animal signature bars made in their image, Animal made them bigger for the masses, Bob didn’t like that, 7.8″ versions stopped being made, everyone missed them, a few imitations and variations got made, Bob didn’t like that either so he had some made by S&M under his Skapegoat brand) but because I knew a follow up to the original DIG Bob bar article would surely surface sooner or later.  In said ‘Opinionated‘ article, Brian Tunney brings up some interesting points about bar sizes and angles and speculates as to why some people may or may not still be into these iconic street-specific bars.  While there are things in his article I may disagree with to a small degree, the discussion about bar sizes and angles is a subject often avoided that I and many others take a great amount of interest in. Continue reading

The Union’s Evolutions Of The BMX Fork

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The Union posted an awesome article on the evolution of the BMX fork featuring a plethora of examples of some of the defining designs of the old-to-mid school era.  Some of the more wild examples include Kasta’s Uniblade fork, Hutch Trickstar forks and the S&M Ditchforks shown below with peg and AD990 mounts.  I’ve totally still got a pair of those Terrible One forks in my shed…

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Chrome Ain’t Cool

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Chromium plating (usually known simply as ‘chrome’) has been a staple finish for BMX bikes and parts pretty much since the sport’s inception when I was little more than a glint in the milkman’s eye.  Everybody from yours truly to your little brother has run chrome plated parts; rims being the steady favourite for generations (you can’t deny that it’s a classic look) partly due to being a harder wearing brake surface than anodizing.  While it’s nice to have nice things, the horrible truth is that although chrome plating has aesthetic advantages, it has a far darker side behind the scenes.

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The biggest structural flaw with chrome plated parts is in the structural steel components like frames, bars, and cranks and is caused by something called ‘sacrificial metals’.  When electroplating a steel component, it is first negatively charged by an electrical source before being immersed in a chromic acid bath with a sacrificial zinc or carbon anode; of which is positively charged.  The anode is (in layman’s terms) used to prevent the iron in your part from losing it’s electrons thus attracting oxygen molecules and turning into a lump of rust in the acid/electrolyte bath. The anode loses the electrons instead and it oxidises in place of the iron; this is a good example of a ‘sacrificial metal’.  This technique is also used on cheap zinc-covered town-bike spokes, roofing and even for ship hulls.

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Unfortunately there is a bad example too.  If the necessary pre-treatments of stripping, cleaning, sanding, polishing, multiple layers of copper and nickel plating etc, etc aren’t done properly then there will be flaws in the chrome when it comes to chrome plating eg. porous texture, poor adhesion, perforations etc.  While I use the word ‘flaws’, don’t think of them as cute, minor little flaws like a bubble in your grips or a small buckle in your rim; these are disastrous flaws that, if unchecked over long periods, can and may well maim you.  Chrome plating keeps water away from the iron contained in the tubes of (let’s say for argument’s sake) your bars and preventing them from rusting as a barrier layer but the problem is that iron is anodic to the nickel in the same way that zinc is anodic to iron.  The slightest perforation in the plating (of which can easily be caused by manufacturing or rider error; defective chrome plating, grinding, crashing, even simple installation can damage the plating if you’re not careful- chromium is plated by the millionth of an inch) not only makes the tubing vulnerable to rust but because iron is anodic to the plating itself, the rusting is actually accelerated by the chrome plating that’s supposed to be protecting it- the steel literally sacrifices itself for the chrome.  This is why you’ll see old American cars with rusted out bumpers with the chrome peeling away where the steel has corroded underneath to the point where it’s barely there any more.  This site is a good place for more information about chrome plating as a finish.

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It doesn’t end there though, while searching for distribution info on the FlyBikes website last week, I stumbled across an interesting section on their frequently-asked-questions portion of the page;

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While the structural (and weight) disadvantages of chrome has been more or less clear to me for years and usually steered me away from actually spending money on it, I had no clue of the environmental or the human cost of a mere finish.

Spotting that Flybikes FAQ explaining their wholly righteous reason for not offering chrome colour options prompted me to do some good old Google trawling on the negative health affects of chromium plating; there was a lot of material.  This report by the Centre of Disease Control and Prevention was the most reliable literature I could find on the subject; being the CDCP is a government agency and the fact that the US chrome plating industry is pretty damn big so they probably know what they are talking about.

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There are two different types of decorative chrome plating, trivalent and hexavalent; the stuff that made Erin Brockovich a household name.  Unfortunately I can’t tell the difference scientifically because I only have a very limited understanding of these things but trivalent is basically ‘modern’ chrome, it has more of a nickel tint whereas hexavalent is the classic ‘old school’ stuff; harder wearing, blue-r tint but heavily regulated by the state and for good reason, hexavalent chromium is hugely toxic.  It’s trivalent counter part is not quite as harmful, has less stringent exhaust regulations and is easier to waste treat; spilling a small beaker of it’s hexavalent counterpart on your garage floor has the potential to poison any nearby wells and land you in some deep trouble.

chrome-plating-process

The gases emitted by the chromic acid are the super dangerous part about hexavalent chromium, without adequate fume-extraction or personal protective equipment, a chrome worker is subject to some horrific illnesses including but probably not limited to; cancers of the lung, trachea, and bronchus, contact dermatitis, skin ulcers, irritation and ulceration of the inner nasal lining (nasal mucosa) as well as perforation of the nasal septum- a symptom commonly associated with prolonged cocaine abuse.  The CDCP findings also report of kidney damage, liver damage, pulmonary congestion and edema, epigastric pain, erosion and discolouration of teeth, and even perforated ear drums.  In the case of the nasal ailments, on average the symptoms start manifesting within the first month of employment with a chrome plating shop.

This passage from the CDCP report was stood out to me as the most troubling though;

..11 male employees in an Ohio electroplating facility reported that most men had worked in the “hard-chrome” area* for the majority of their employment (average duration: 7.5 years; range: 3–16 years). Four of the 11 workers had a perforated nasal septum. Nine of the 11 men had hand scars resulting from past chrome ulcerations. Other effects found during the investigation included nose bleeds, “runny nose,” and nasal ulcerations..

*Hard-chrome is often known as ‘engineering chrome’ and is used for lubricity or oil retention in things like car engine parts and gun barrels.  Although essentially the same as it’s decorative counterpart, it’s applied in thousandths of an inch rather than millionths like decorative chrome.

So what can be done?  It depends on how much you like your chrome bike I guess, you could hassle your favourite companies via social media into telling you whether they’re using hexavalent or trivalent chrome (to the untrained eye it’s hard to tell the difference) and only buy trivalent if like me, your conscience is getting the better of you.  You could even boycott using chrome parts altogether until there’s better identification of whether they’re using trivalent or not, there are plenty of adequate alternatives including fine polishing, anodising and even certain types of chrome-look paint that look great, come in more colour options, weigh less, are less harmful to the environment and are better suited to people who live in wetter climates.  If you already have chrome parts, you can take better care of them by spraying something like J P Weigle’s Frame Saver into the inside of the tubes and generally keeping the outside of them clean with soapy water… and by not grinding.  The choice is yours at the end of the day; vote with your wallet.

 

Slacking Off- A Brief Study In Freecoaster Slack

Occasionally with a ‘job’ like this, I’ll be lucky enough to be sent parts to test by companies going through research and development stages of making new BMX components, my main qualification to do so is being able to throw a bike around while still being able to analyse a broken one better than simply saying ‘I fell and it broked!’
Then one day someone will pull a cruel joke and send you not one, but two types of freecoaster to test knowing full well how you feel about that kind of heresy and witchcraft… but with me being ever curious about new technologies emerging and not wanting to be left behind, I gladly accepted the task.
Trying out both clutch and pawl type freecoasters, I figured out that while the pawl type was the easiest to use, the clutch type was best for adjustability and thus, reliability (in the respect it won’t engage and throw you on your arse as easily when rolling backwards) due to being able to remove/ add slack spacers at will. This is something that can’t be done with a pawl type coaster without using a different clutch-disk or slack cam ring- depending on which brand you ride.  This is not to say that you are completely out of options when it comes to slack adjustability though; the following factors can also play a part in the time it takes your hub to engage;

Gearing.

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A higher gear ratio where a larger sprocket, or a smaller driver, is used so higher top speeds can be reached does so because a larger sprocket like a 27T-9T ratio for example, pulls more chain links over the driver with each pedal stroke than a smaller 25T sprocket pulls over a 9T driver; it works the same way that a single point on the outer edge of a vinyl record will move faster than a point in the middle despite it having the same number of revolutions per minute- except there’s a chain wrapped around it.  What this also does is reduce the time it takes for your rear hub to engage as chain gets pulled over your driver at a faster rate when your gear ratio is higher.  In the days of cassette hubs and freewheels (if you’ve been riding as long as some) this wasn’t so much of an issue but with freecoasters and fakie tricks coming back into popularity, it’s something that is of much greater importance.  If you’ve got steady legs and a desire to bomb it around at mach 10 then you could probably get away with something like 27 or 26T-9t but if you like a bit of room for error when moving your feet around while coasting backwards then maybe stick to a lower 25T-9T, no one likes a bruised arse.

Crank Arm Length.

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While 175mm tends to be the standard go-to length for BMX cranks they can usually range from around 165mm to 180mm depending on your height, riding style or personal preference so for arguments sake we’re just going to talk about the two extremes of long (eg. 180mm) and short (165mm).  If you imagine the crank in it’s engaged and disengaged position as well as the distance between the pedal spindles as a kind of triangle (as illustrated in the shoddy MSpaint diagram above) you can see that the red lines represent the set freecoaster slack angle but you can see that the slack effectively widens as the cranks get longer.  It’s worth noting that the difference is negligible but noticeable if you go between 165mm and 180mm cranks although virtually non-existent if you were running 175mm cranks to begin with, but you know, every little counts sometimes…

Chain Tension.

It’s pretty much common knowledge that freecoaster driver bearings really do not like tight chains but a loose chain can also artificially increase your freecoaster slack angle as well as help your bearings last longer.  Before your hub even starts to engage your legs have to make the chain tension enough to pull the chain over the driver to begin with so the slacker the chain; the slacker the angle, obvious enough.  But that also increases the likelihood of your bike sounding like a rusty bag of nails inside a biscuit tin so exercise restraint with that one kids.

While I’m sure all of the above is quite obvious to some older riders including the Bikeguide police, and I’m sure it’ll get picked apart in some way or another but the main point I want to make is that it’s not something that gets talked about a whole lot, especially to younger riders, despite being a big issue in BMX today. That said, if there are any points I’ve missed feel free to hit me up at oberzine@hotmail.com.

The Inaccuracy Of Tyre Labelling/ The Birth Of The 21″ Wheel

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The term ’20 inch bike’ gets thrown around a lot, usually by douchebag pseudo-journalists like me trying to contextualise their gonzo style drivel about dudes riding or making little 20 inch kids stunt bikes… see, i’m at it again. Cruising on the interwebiverse one day I came across this photo on 22 inch BMX‘s Facebook/Instagram/whatever of Kye Forte’s ride;

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The striking thing about it is the addition of 22 inch forks and front wheel whilst the rear wheel remains 20 inch… yet, somehow, it doesn’t look too odd at all.  While one could argue all day about the benefits or hindrances this set up might provide(a big one being head angle, but I’ll get to that shortly) one thought awoke and wouldn’t slumber; what even makes it a 22 inch wheel? What, for that matter, makes a 20 inch wheel a 20 inch wheel?! Continue reading

Can You Dig It’s Brutally Honest Certified Helmet Buyers Guide

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It’s the elephant in the room again… Jon at Can You Dig It posted this highly amusing review of all the CPSC/CE certified helmets he could get his shovel wielding hands on.  He gives each of them a fair trial before listing the positives and the negatives of which if we’re honest, we’re all more concerned about here.  He even picks a clear winner, we won’t reveal it here but I can tell you it’s (thankfully) not the ugly luminous green/black one that looks straight out of Starship Troopers.

Are Bikes As Good As They Will Ever Get?

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Probably the most time saving invention to be applied to BMX’s; the press-fit Mid BB

Fourteen years have flown by since I first walked into a bike shop as a twelve year old, decided that mountain biking was far too expensive a pursuit for my budget and rather than dispiritedly retreating out the shop door back in front of the TV, I opted for a BMX bike.  For a young boy I think it was the most logical of choices, primarily for steering away from my previous life as a reclusive Playstation enthusiast but also the kind of bike I chose to do it on.  BMX caught my eye that day with its sheer stripped back simplicity that no other cycling sub-culture had bred before.

Continue reading