What is loctite? Is there more than one kind? Apparently I NEED it for my new dirt bike?
So I just got a cheap chinese dirtbike and was told I need to LOCTITE everything. If you LOCTITE something does that make it impossible to undo if you need to? What kind of LOCKTITE would you recomend using on the bolts of a dirtbike? THANKS!!! Best Answer - Chosen by Voters ---------------------------------------------- Has anyone explained WHY you were told that about your new Chinese bike? You can look around and see only Rare mention of "Loctiting Everything" on the japanese Dirtbikes. It's Not because the Chinese Vibrate more than the japanese. Loctite does NOT keep Bolts/Nuts Tight. It merely keeps them from falling off when they come loose,,,and any parts they're holding coming adrift. Fastener Tension is what keeps things tight. Pretty Much the same as a "Spring Tension" Effect. When you Torque a Fastener to correct specs,,, the shank STRETCHES and holds the tension in a spring-like effect. Too Loose,,,and ya dont have enough tension to hold the load. Too TIGHT and you've exceeded the Yield Strength of the Fastener,,,,you've "sprung the spring",,,Over Stretched it. Old Saying,,"Over Torqued Bolt is a Half Broken Bolt" There's all sorts of GRADES of fasteners. Higher Grades have both Higher Yield Strength AND typically a "high modulus of elasticity"---they are SPRINGIER. LOW Grade Bolts are Soft,Weak,Spongy,and with Low Yield strength. When you Torque them to "Correct Specs",,,they Stretch too. But when You LOAD them,,,that exceeds their elasticity. The Result is that the fastener PERMANENTLY Stretches. A Bolt becomes actually LONGER. A "Longer Bolt" gives exact same effect as a LOOSE BOLT which is not tightened down all the way. Dynamic Loading/Movement,etc will eventually LENGTHEN,,,Not "loosen",,the fastener to the point where it Becomes Loose. Then Vibrations will cause nuts to back off,fall off,,screws & bolts to vibrate out of their hole and so on. Loctite can be BAD NEWS on Low Grade hardware. Exagerated example: Say you have a Bolt that has a 1" Clamped Length when installed and torqued. And it Stretches in service to 1 1/8".(Gross exageration) But OBVIOUSLY it's then Wobbling Loose,,right? It's no longer even bottomed out on the parts,,not even "touching". So what does that Normally Require? RE-Tightening,obviously. (In Reality,,it NEEDS a Better Grade Bolt) So You have a Low Grade Bolt,,,loosened from Over Stretching,,,, and a SEMI-SEIZED Thread from Loctite. The LOCTITE itself introduces a False Torque during Re-Torque operation. It RAISES the Break-Out Torque just to MOVE it. That gets Added to the Total Torque. So you either : a)See 15ft Lbs on your Torque Wrench,,,while Clamping Force is only equivalent of 10FT lbs. Because 5ft lbs goes Just to TURN the Fastener or b)You Torque the Threads and Shank of the fastener sytem without applying ANY clamping force or c)You try to REMOVE the fastener which has been Over stretched beyond it's yield strength,,,and the Torque demand of the Loctite allows you the Break the Fastener becomes it comes loose. Now,,,did you see me say ANYWHERE that "Locktite is BAD??" Or,,,"DO NOT USE Locktite"?? No,,it's a fine product and does an incredibly dependable job in it's intended & appropriate applications. People bet their Lives on it,,,and the safety/security of Zillion Dollar Equipment. But you have to Focus on the Key Words>>"Intended & Appropriate Applications" There's LOTS more to the matter than knowing what each Color of Loctite Does. The explanation of THAT simple aspect is written right on the product's instructions. ......................................… The Best,,,and generally the ONLY advantage that Loctite can offer any unit assembled with Low Grade Hardware is to prevent a part from falling off. It will Retain a Loose Bolt or Nut. That SOUNDS like,,,"Well thats what it's supposed to do" And that's correct. But ,,THEN What? What Loctite DOES NOT DO is prevent parts from coming loose due to Fastener Stretch/Yield. Nothing about Loctite improves the metallurgy of the fasteners involved. It ONLY increases Torque Requirement to prevent vibrations from spinning a nut off,etc. Consider what happens NEXT,,,when you get tired of your exhaust flopping around,,,Handlebars slipping,,,footpegs wobbling around,,etc. And all your "safely Loctited" nuts/bolts are Still Present on the Now Loose hardware. Tighten them Up? Good Luck. It was "half Broken" when originally installed,, Yielded it's clamp length till it got LOOSE,,, Now You wanna Torque it AGAIN,,,,but with the addition of the Loctite Breakout Torque Requirement? I'll say it again,,,NOTHING Wrong with Using Locktite. At least it "FEELS GOOD" that you've done SOMETHING. But whoever told you to use Loctite SPEFICALLY BECAUSE You're bike is CHINESE does NOT Understand the phenomenon of those machines having Nuts & Bolts which continually come loose and fall off. The "Falling Off" aint the Problem. That's only the RESULT of the Problem,,which is FAILED Fasteners. Preventing the things from Falling Off is Not a Bad Thing,, But it ONLY is addressing a SYMPTOM of a more serious and potentially dangerous problem. Loctite use has the distinct potential to cause Further Probs when you try to Tighten stuff. And most likely will help the fasteners reach Failure sooner. Only REAL FIX is to REPLACE the Fasteners with Hi Grade Hardware. Nuts,Bolts,AND flat washers & lockwashers as well. Spongy ,Soft-surfaced washers don't help matters. I realize that Replacement is Both tedious And an expense. But it's a Genuine Fix,,,not just Feel-Better-About-It Patch. A Rational Approach would be to initially replace Critical App/Safety Related hardware,,,such as Brake Mounting stuff,,Handlebar Clamp bolts,etc. WAY more of a nuisance to use than Loctite,,,but a Much Better alternative is to use a couple wraps of Teflon Tape. It forms a Pseudo-"Nyloc Nut" by introducing enough Thread Interference to impede vibration spin-off. Teflon Tape also has the xtra benefit which Loctite Doesn't of prevent Thread Galling,,,,and Torque Binding between the threads. Especially on Low Quality Tapped Blind Holes where you DONT wanna break a bolt off in the hole. When Threads engage each other and begin to take a load,,, The FRICTION between the 2 sets of Threads begin to "bite into each other". On Soft,Mis Formed,or otherwise Low Quality Fasteners,,,any Further Torque simply Twists the fasteners shank. That Creates a False Torque because Thread Bind Stops the advance of correct Stretch. The Nut quits jacking up the bolt Tighter and Stretching it to correct tension,,,,Because the Threads Freeze. So any further Torque just TWIST the Shank,,,NOT the Thread. A Few Heat Cycles or Load Cycles Relaxes the Thread Friction>>>result is a Loose Bolt. Teflon Tape as a thread Locking Agent prevents Thread Binding to a high degree,,,and ensures far more accurate actual Torque. It's a Tedious Nuisance to use it,,,,even with a BUNCH of practice. And hardware never gets "handy" and finger-spinnable when disassembling. Anyway..... Nothing "Wrong" with Loctite. But it DOES warrant a Bit more thought & consideration of the task at hand. One should be fully aware of what they're dealing with,,what they're trying to accomplish,,,and what the outcome of any effort will be. As well as being aware of alternatives & their Pros & Cons. The Observation of Chinese Machines "needing Loctite" is NOT as obvious as it seems. The Problem is Low Grade Fasteners. Which need occasional tightening. In light of that condition & its requirement,,,Loctite and it's properties may not be the ideal choice. Doing Something is not necessarily Always better than doing nothing. Sometimes there can be ,,"Worse than doing nothing". Like adding torque demands to already weak fasteners,,,especially when they're expected to need frequent tightening. ......................................… ****Been there,, Done that,,,exact same situation. Anybody who worked on japanese bikes in early '60's recalls the japanese Standard Torque Specs. "Tighten it till it gets loose again,,then back off half a turn" 6mm bolts got broken off without even realizing they were getting tight,,,especially if they were old. 8mm bolts could be broken off at will. Or,,the threads pulled outa the nut. American 1/4"(6mm equiv) Grade 5 from Cars,Harleys,or Brit Bikes took a Lot of effort to strip or break. Ya could stretch them till they were Distinctly narrow in the middle. A Grade 8 was extremely difficult to break. A Grade 8 3/8" SAE bolt(8mm equiv) would Damage TOOLS before it would break. Finally the japanese upgraded their hardware. The Chinese will too eventually. I have a hunch they're at LEAST as serious about developing their Bike Industry as the japanese were in 1960. The parallel of each country's introduction to American mkt is remarkable. The japanese had just about every aspect of their machines Nailed. Except material quality was marginal in many aspects. The Chinese,,in my opinion,,are very much the same right now. Good designs,lots of features,great prices,styling,everything. But they're using cheesey quality materials in areas that blight the whole bike's overall value and appeal. In 60's,,,it took a LONG time for People to FINALLY say,,"The japanese Build GOOD bikes". I think the Chinese CAN turn that corner Real Quick with some minimum & low cost Upgrades. We'll likely just wake up one day and see "World Class" Chinese Bikes with quality equal to anyone's. If they dont shoot theirself in the foot first,,from crap like skimping $20 per bike on nuts & bolts. That's Critical,,but it's also the kind of nuisance which makes potential Dealers reluctant to wanna fooll with them. And for the Chinese to ultimately get solid established,,they GOTTA build better Dealer /Parts/Service network than they have so far. Anyway,,enough babbling outa me. Good Luck with it. ------- From: http://answers.yahoo.com/question/index?qid=20070720122316AA3mxRj -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bu...@googlegroups.com. 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