Oh. So it gives a wrench a higher rating? Sounds like witchcraft.This any good?
Very interesting. This is the sort of thing I print off and nail to my garage wall for future reference. That said, is it not rather a profound pain in the gonads to continually bugger around with metre long bars and various weights etc? Also some of those torque wrenches do look rather smart. For instance I am tempted to dive for the credit card and nab one of these. I reckon I would mount it on my living room mantlepiece.248 Nm is 248N on the end of a bar a metre long. 248N is (in round numbers) a 25kg weight on the end of a metre long bar (or 50kg on a half metre long bar, or 183 lbft in "old money", which, again, is 183lb on the end of a foot long bar or 92 lb on a 2 foot long bar... and so on. I've never cashed-out on a big torque wrench for wheel bearing jobs, because it's just so easy to stand on a bar of the correct length to apply the right torque. The bar just needs to be more or less horizontal when you finish tightening.
LOL! Yes, I like shiny tools as much as the next guy - especially Snap-On! However, I'm not a man of substantial means, and I think the response needs to be proportionate to the task. With something like a modern wheel bearing, the massive torque is to make sure the bearing races are pressed tightly together. But the manufacturer (of both the car and the bearing) doesn't know exactly how much friction there is going to be between the bearing inner races and the stub axle, or the nut and the threads, or the underside of the nut and the washer (or whatever it bears against). Accordingly, he just vastly over-specifies the thread size and calls up a mahoosive torque which is bound to give "plenty" of clamping load in the bearing inner races. The bearing manufacturer, in turn, will size everything so that it will work fine with "a lot" of torque applied to the nut.Very interesting. This is the sort of thing I print off and nail to my garage wall for future reference. That said, is it not rather a profound pain in the gonads to continually bugger around with metre long bars and various weights etc? Also some of those torque wrenches do look rather smart. For instance I am tempted to dive for the credit card and nab one of these. I reckon I would mount it on my living room mantlepiece.
LOL! Yes, I like shiny tools as much as the next guy - especially Snap-On! However, I'm not a man of substantial means, and I think the response needs to be proportionate to the task. With something like a modern wheel bearing, the massive torque is to make sure the bearing races are pressed tightly together. But the manufacturer (of both the car and the bearing) doesn't know exactly how much friction there is going to be between the bearing inner races and the stub axle, or the nut and the threads, or the underside of the nut and the washer (or whatever it bears against). Accordingly, he just vastly over-specifies the thread size and calls up a mahoosive torque which is bound to give "plenty" of clamping load in the bearing inner races. The bearing manufacturer, in turn, will size everything so that it will work fine with "a lot" of torque applied to the nut.
My breaker bar is about 0.6m long, and I weigh about 110kg, so I could apply 650Nm if I stood on the end of it. For 250Nm, I'd just stand on the bar with one foot, so that the middle of my foot was about 9" from the centre of the hub nut, with the bar roughly horizontal when the nut stops turning.
One thing I should add, however, is that I do possess two smaller torque wrenches! A 50% overload on a wheel bearing won't bother it, but some of the bearing caps on my cams only want 7Nm. Here. I can't do my "weight x distance" thing, because the bar would need to move horizontally, for a start, but also because +/- 50% would either strip them or leave them dangerously loose. So I'm a big fan of torque wrenches for smaller fasteners!