Click type torque wrench
So I picked up a 3/8" click type torque wrench from harbor freight last night so I could actually adjust my compression plug and stem to correct tensions and quit trying to guess. Got home, opened it up, read my FSA compression plug instructions said 53-80 lbs for the expander assembly and 45 lbs for the top cap. I set the wrench to 70lbs and started torque away on the expander. It was getting real tight then snap the 5mm allen head broke on the bolt. So I needed to get to the store and buy a new hopefully stronger bolt, but I live car free. So I grabbed a 12" clamp, slapped it on the bottom of the work crown and the top of the fork and clamped it down tight enough to be comfortable, and started tightening up the stem bolts. I've read general rule on those is 35-45 lbs, so I set it to 30 lbs just to start and before I got any click on the wrench the stem was almost closed shut and was making me feel uncomfortable (I'd hate to crack a steer tube on a brand new $350 fork.)
I took the wrench and adjusted it to 20lbs and put a 15mm socket on there to test it against my back wheel nuts. It tightened them a bit more then clicked over, which suggests it worked but I was a bit surprised by how much pressure it seemed to take since I'm a reasonably strong guy, in shape, work out, yada yada. Rode to the store and got a new allen for the compression plug and tried again. Set the wrench down to 50 lbs this time and started torque. Before it clicked it certainly seemed like the expander was too tight to move any further so I just stopped. Went to put the top cap on, set the wrench to 30 lbs and the headset started to bind before it clicked. So I dropped it down to 15 lbs and it still didn't click. At 10 lbs I got it to click on the stem bolts, but again the stem is almost closed, brand new FSA vision tech stem. Is my wrench not calibrated correctly? Do I just need to break it in more? Am I just being too worried after a faulty bolt snapped? |
That should be inch-pounds.
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Are you sure that the torque wrench in-lb. and not ft.- lb.
Thats 53-80 in-lb. |
I agree 55-80 Ftlbs sounds like alot of a headset. You better double check you information. You need to get a 1/4drive inch pound wrench too.
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The bolt wasn't faulty, your intrepretation of the torque spec was. The difference between ft-lbs and in-lbs, not surprisingly, is a factor of 12. Typically, the only torque specs for bike components given in ft-lbs are bottom bracket cups and crank fixing bolts. Almost everthing else is in in-lbs.
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50 Foot Pounds is a lot for pedals -- no wonder the bolt snapped. Unfortunately, the lesson here is if you have no knowledge of mechanics, you're better off leaving things to a bike shop. You would have been better off using a standard allen wrench. The hazard of using the wrong tool is you can do some serious damage.
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Pff, imperial.
When are you guys gonna ditch that crazy system you persist with and get with the metric program? The Poms have seen the light... |
Is not going to happen maybe ever :)
As for the OP and his tool, well thats one of the reason I dont have a torque wrench. Been doing it by feel since I remember because with some stuff even with the torque wrench it is a lot of torque the one specified by the manufacturers. For example the famous 5 in/lb in stems... thats a huge amount or torque :) I say, get carbon paste, use that and tight the stuff by feel, with the carbon paste you dont need to be worried about applying too little torque. Because just with a fraction of the torque the parts wont go nowhere. |
I don't get it... The compression plug only needs to be tight enough that it doesn't slide up when you set the headset preload, and the top cap bolt should be torqued to whatever amount gives you good headset adjustment. I'm not an expert, but I don't think any of these are best adjusted to a set torque number... Would anybody concur/correct me?
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Originally Posted by milkbaby
(Post 14819136)
I don't get it... The compression plug only needs to be tight enough that it doesn't slide up when you set the headset preload, and the top cap bolt should be torqued to whatever amount gives you good headset adjustment. I'm not an expert, but I don't think any of these are best adjusted to a set torque number... Would anybody concur/correct me?
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Originally Posted by Kimmo
(Post 14816972)
Pff, imperial.
When are you guys gonna ditch that crazy system you persist with and get with the metric program? The Poms have seen the light... |
Originally Posted by Kimmo
(Post 14816972)
Pff, imperial.
When are you guys gonna ditch that crazy system you persist with and get with the metric program? The Poms have seen the light... :rolleyes: |
Originally Posted by bikepro
(Post 14816910)
50 Foot Pounds is a lot for pedals -- no wonder the bolt snapped. Unfortunately, the lesson here is if you have no knowledge of mechanics, you're better off leaving things to a bike shop. You would have been better off using a standard allen wrench. The hazard of using the wrong tool is you can do some serious damage.
I really hope the countless oil changes I've done, and replacing of both disc and drum brakes haven't caused all those friends and parents cars to explode or crash. I should have left that all up to a shop too. Now that I think about it nobody who doesn't charge an arm and a leg for basic labor should work on anything. I'll make sure to call a plumber out for $200 next time the toilet clogs. Thank you for the incite bikepro. Lives have been saved >.> [/end pointless rant]
Originally Posted by milkbaby
(Post 14819136)
I don't get it... The compression plug only needs to be tight enough that it doesn't slide up when you set the headset preload, and the top cap bolt should be torqued to whatever amount gives you good headset adjustment. I'm not an expert, but I don't think any of these are best adjusted to a set torque number... Would anybody concur/correct me?
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Originally Posted by bikepro
(Post 14816910)
50 Foot Pounds is a lot for pedals -- no wonder the bolt snapped. Unfortunately, the lesson here is if you have no knowledge of mechanics, you're better off leaving things to a bike shop. You would have been better off using a standard allen wrench. The hazard of using the wrong tool is you can do some serious damage.
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The size drive of a torque wrench has no bearing whatsoever on the amount of torque applied. The torque is measure at the end of the lever through the center of the device being turned. But in general the finer the torque measurement, the smaller the drive. Easier to make a 1/4 to tighter standards and to maintain the tolerances also larger drives will handle the torque being applied as well as the attachments. Using a drive size changer is not acceptable either as any flex between the components will distort the torque readings. The best small value torque wrench to use is a dial. Do not confuse that with a beam type torque wrench which has the pointer moving across the scale. Also click type, or the technical term micrometer torque wrench are designed to be best used by a typical repeating torque value and can lose calibration when adjusted often. Also never leave the click type set to a value other than zero as this causes undue wear on the mechanism as well. This is the torque wrench I have used for many years. http://www.amazon.com/Torque-3002LDI.../dp/B000I1WPFE
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Originally Posted by bikepro
(Post 14816910)
50 Foot Pounds is a lot for pedals -- no wonder the bolt snapped. Unfortunately, the lesson here is if you have no knowledge of mechanics, you're better off leaving things to a bike shop. You would have been better off using a standard allen wrench. The hazard of using the wrong tool is you can do some serious damage.
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I'm still trying to understand what happened here LOL.
Were you using the wrong ft-lbs, in-lb or none of this LOL. The numbers dont seem to match up to me but I am confused on what you were using or doing anyway. But for me bike stuff I like using nm measurments for torque on bike parts because most parts are all small about the only thing that is actually that tight were you really need force is the BB. |
Like the OP, I too bought the same click-type torque wrench from the said store, though I got the ¼" type (can't beat $9.99 with coupon). I also almost got fooled by the in-lb Imperial measurement by the wrench. I know that I need to tighten my top cap no more than 5 N-m, and in one of those hasty decisions I arrived at a conversion of 60 in-lb (12 x 5). Bad calculation. Good thing I verified what I did by re-checking my conversion, and found out that it should only be 44 in-lb. Thankfully the mistake only happened 10 minutes after everything was realized.
To the OP, your mention of just 'lbs' isn't complete. Verify if what you're referring to is ft-lbs or in-lbs then make the precise conversion. I agree with the other posters. You shouldn't be referring ft-lbs when tightening anything on your bike, as this is motor vehicle territory (think wheel lug nuts). |
This is the best Torque wrench I bought for bike specific use Wiha # 2852 new model # is 28554 with #28581 bit holder and #28582 Socket holder
TorqueVario®-S Torque screwdriver 0.2 to 0.8 Nmhttp://www.jtgraphics.net/images/bik...wiha_28554.jpg |
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