ghosts_cloak Posted May 28, 2006 Report Share Posted May 28, 2006 Hey guys! I have my new Hope stem now Being the non mechanically minded person I am, how tight is 5NM for the handlebar screws? I just did them up fairly tight with the allen key long ways (so I couldnt put down much torque) and it seemed fine, but I thought Id make sure on here?Also it says to grease the threads... now I dont have any grease but I could put some finish line chain lube on instead?Cheers!Garethps: It rides excellent now, much better control! Felt like Felix hopping on upturned crates on the beams (nice and smooth, for me!) Quote Link to comment Share on other sites More sharing options...
ScotchDave Posted May 28, 2006 Report Share Posted May 28, 2006 You can put the lube on as a short term solution I think, but grease is much better. Well, the equation for torque is: Torque=ForceXRadius. In other words 5=ForceXRadius measure the length of the allen key and calculate the force you need to use. To put it into perpsective under gravity a one kg bag of sugar produces a force of roughly 10 Newtons (9.81....Newtons if we're being pedantic). Radius is measures in metres so if it's a 10 cm alen key: T=Fr 5=FX0.1 F=5/0.1=50Newtons, about the force to lift 5 bags of sugar. Quote Link to comment Share on other sites More sharing options...
ghosts_cloak Posted May 28, 2006 Author Report Share Posted May 28, 2006 (edited) You can put the lube on as a short term solution I think, but grease is much better. Well, the equation for torque is: Torque=ForceXRadius. In other words 5=ForceXRadius measure the length of the allen key and calculate the force you need to use. To put it into perpsective under gravity a one kg bag of sugar produces a force of roughly 10 Newtons (9.81....Newtons if we're being pedantic). Radius is measures in metres so if it's a 10 cm alen key: T=Fr 5=FX0.1 F=5/0.1=50Newtons, about the force to lift 5 bags of sugar. Hey Hehe nice reply! Right up my street so to speak, Im a second year physics undergraduate, currently studying for exams! I didnt think of actually working it out, I was more looking for a "pinch it up, and then an extra quarter turn" or something, but I can see what your getting at!I will stick some lube on in the short term then and when I get chance Ill get some grease.Thanks, Gareth Edited May 28, 2006 by ghosts_cloak Quote Link to comment Share on other sites More sharing options...
Has anyone seen my shoe? Posted May 28, 2006 Report Share Posted May 28, 2006 (edited) Bout as tight as a lady leprechaun.Seriously though I dont know, bit dogey guessing though Edited May 28, 2006 by Has anyone seen my shoe? Quote Link to comment Share on other sites More sharing options...
Krisboats Posted May 28, 2006 Report Share Posted May 28, 2006 I just do mine up as tight as i can physically get them. Always have done it like that and i always will. Quote Link to comment Share on other sites More sharing options...
Janson Posted May 28, 2006 Report Share Posted May 28, 2006 remember though, that 5Nm gives a higher clamping force if the threads are greased/lubed. because less force is used to overcome friction, and more to tighten the bolt itself... Quote Link to comment Share on other sites More sharing options...
Walleee Posted May 28, 2006 Report Share Posted May 28, 2006 Hehe nice reply! Right up my street so to speak, Im a second year physics undergraduate, currently studying for exams! I didnt think of actually working it out, I was more looking for a "pinch it up, and then an extra quarter turn" or something, but I can see what your getting at!A 2nd year physics undergrad should know that there isnt really anyway of translating 5nm into a force applied by one's arm.Just tighten it up nice n tight, hope are good quality, you wont rip the threads out unless your the incredible hulk.remember though, that 5Nm gives a higher clamping force if the threads are greased/lubed. because less force is used to overcome friction, and more to tighten the bolt itself...Surley that would only be the case if the threads were so fuct as to require a force close to, or above 5Nm? If it only takes for example, 2nm to move alubed nut on a thread, and 3 to move an unlubed, ultimatley the 5nm is still going to hold the bolt on the same, lubed or unlubed........It would just make it harder to screw on in the first place, and you might think that it's holding when it's not, but that would be if the thread were totally jacked..... Quote Link to comment Share on other sites More sharing options...
Janson Posted May 28, 2006 Report Share Posted May 28, 2006 It makes quite a big difference in clamping force actually.It's not that relevant on bikes, but more of a big deal in airplanes for example.A lubed thread generally speaking gives a higher clamping force than an unlubed one, both tightened to the same torque. Quote Link to comment Share on other sites More sharing options...
sexymike Posted May 28, 2006 Report Share Posted May 28, 2006 A 2nd year physics undergrad should know that there isnt really anyway of translating 5nm into a force applied by one's arm.Just tighten it up nice n tight, hope are good quality, you wont rip the threads out unless your the incredible hulk.Surley that would only be the case if the threads were so fuct as to require a force close to, or above 5Nm? If it only takes for example, 2nm to move alubed nut on a thread, and 3 to move an unlubed, ultimatley the 5nm is still going to hold the bolt on the same, lubed or unlubed........It would just make it harder to screw on in the first place, and you might think that it's holding when it's not, but that would be if the thread were totally jacked.....:S:Sthey are poo, thats the worst bit about them!u need Stainles steel bolts, 50 p each but well worth it Quote Link to comment Share on other sites More sharing options...
Connor Posted May 28, 2006 Report Share Posted May 28, 2006 (edited) common sence to know how far to tighten somthing u just no by how hard it gets to turn Edited May 28, 2006 by Snowy Quote Link to comment Share on other sites More sharing options...
ghosts_cloak Posted May 28, 2006 Author Report Share Posted May 28, 2006 (edited) A 2nd year physics undergrad should know that there isnt really anyway of translating 5nm into a force applied by one's arm.I dont quite follow your argument there Im afraid, I was looking for a rough estimate such as: 1) Screw it up real tight, tight as you can!2) Just pinch them up!3) Tight as you can with two fingers Etc.. Yes lots of variables but you can get a rough idea!Good point about the grease /oil, they did kind of screw in "in steps" rather than a smooth motion so its hard to tell just how tight they are, Ill sort it now as its such a nice evening Thanks for the replies guys, even if we didnt establish a definative "tightness".Gareth Excellent, thats the kind of thing I was looking for Gareth Edited May 28, 2006 by ghosts_cloak Quote Link to comment Share on other sites More sharing options...
dave33 Posted May 29, 2006 Report Share Posted May 29, 2006 5Nm isnt very tight at all small 5mm hand allen key shoul be good Quote Link to comment Share on other sites More sharing options...
Simpson Posted May 29, 2006 Report Share Posted May 29, 2006 about 2 grunts thats how i measure tightness!!!! LMAO Quote Link to comment Share on other sites More sharing options...
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