|Tightening & loosening stem bolts||superdog|
Nov 2, 2003 2:10 PM
|The Deda Newton stem comes with specific instructions for tightening the four clamp bolts. My question concerns loosening the bolts to remove the handlemars or to make adjustments.
I would assume that when loosening the bolts, you should follow the same procedure as tighting, except in reverse order. Is this the case?
The reason I am asking is because one of my bolt holes was stripped and I'm trying to figure out how it happened. I tightened using a Park Tool torque wrench and did not exceed the recommended torque. However, when I went in for a bike fitting, the guy made an adjustment to my bars. He whipped out an allen wrench and had loosened one of the bottom bolts completely before I had a chance to stop him. I heard a sharp "creak" sound as he was loosening the first bolt. When he went to loosen the other bottom bolt, it just spun around without coming out.
I don't know if he broke it or if it was already stripped, but I'm not very happy about it. I'm not going to make a big deal out of it, I mainly want to be more educated about the maintenance aspect so this does not happen again.
|Probably good practice, but shouldn't be critical||Kerry Irons|
Nov 2, 2003 6:06 PM
|It is probably best practice to partially loosen each bolt in turn, but if fully loosening one bolt caused another one to strip or break, then you were really close to the edge in the first place. Do you know that the bolt was stripped, and not broken? It makes more sense if it was broken, since loosening one bolt would put a twisting torque on the other bolt. Still, this all suggests that things were near the breaking point - better to have it happen in the shop than on the road.|
|lube the bolts...||C-40|
Nov 3, 2003 6:29 AM
|One of the important but overlooked requirements is to lubricate the bolts before tightening. A lubricated bolt should not make a creaking sound when it is tightened or loosened.
If should require about twice the specified torque to strip a properly made thread. Check to be sure that you are reading your torque wrench correctly and not confusing english and metric units. Personally, I never use a torque wrench on small bolts, just a 4-5-6 Y-style wrench and common sense.
Loosening only one bolt should not cause a problem with the others. If the thread stripped after loosening, the stripping occurred when it was tightened and only became apparent when loosened. It was overtightened, unlubed or perhaps improperly tapped when manufactured.