| Author | Message | ||
     Duphuckincati |
So the rear caliper bolts are accessed in such a way that an extension is needed to go all the way across the back of the bike (through the rear wheel and disc) if you're using a torque wrench. Unless I'm missing a trick or a certain tool. My question is since I'm using a deep allen socket and three misc. sized extension for a total of one foot from bolt to head of click-type torque wrench, and the specs call for 18-20ft.lbs, what do I set my wrench to because of the one foot length? | ||
| Nillaice |
as long as you aren'nt increasing teh leverage of the torque wrench (using a crows foot) it will not change the applied torque. (if you use a deep-well socket vs a shallow socket it doesnt matter) with teh long extensions, make sure to apply counter torque to teh torque wrench head. (keep it still) | ||
| Bextreme04 |
there is actually a deflection in the extensions for each joint and inch of extension due to torsional flex in the steel and the joints... however you should still have an accurate reading from the torque wrench as long as you don't change the angle too much and you don't use a universal joint | ||
| Nillaice |
torsional flex. wow-zers torsional flex should be neglegible, but if you've got a sizeable legnth, you might wanna take that into consideration and add some more umph. also dry vs wet threads will have an effect on the torque. | ||
| Nillaice |
or you could just give it a good tug on the allen wrench, stop over-thinking it | ||
| Bextreme04 |
lol.. he asked  bottom line is never use a universal joint to torque and you should be fine.. all the other losses would only matter on an extremely high precision application anyways... so like the man says.. quit overthinking it! | ||
| Jdugger |
Duph, You don't need to pull the rear caliper except to service it. If simply removing the wheel, put blue masking tape on the back of it and pull upwards and with a slight twist and the rear wheel will come out without dropping the caliper. I have mine more or less permanently safety-wired in. | ||
| Court |
Pretty good READ.
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| Zac4mac |
Torsional flex would only be an issue if you're measuring degrees of rotation like stretch bolts use. It won't affect the torque - what is measured at the wrench-head will be felt by the bolt, regardless of stretch in between. Good call on NO U-joints or crows-feet. Don't use a "cheater bar" either. I love Physics. Z | ||
| Duphuckincati |
Thanks for the replies. I use never-seize and did notice the flexing to a minor degree so just went with 22lbs figuring that the specs call for 18-22 so it should have been in there anyway. And I use a small glop of goop on the bolt heads as backup against loosening. I'll try the don't remove method again next time. I'll be unbolting it anyway to replace the brake pads soon though. | ||
| Jdugger |
If you use anti-seize use the lower range of the torque spec. If you are worried about it, I'd use one of two procedures: 1. Loctite Blue and 18 ftlb 2. Clean threads, 20ft lb, and safety wire. The swing arm is cast Aluminum. To be honest, it's barely real metal, and you WILL strip the threads if you use 22 ftlb on lubricated threads one day. It's not a huge deal if you do -- you can just put a timesert or whatever in there, but it's a PITA and will cost you an hour or two when it happens. Mine became M8, then M10, then timeserts a fair while ago... | ||
| Duphuckincati |
Great info. It was the aluminum factor that had me wanting to be careful and the fact that it's the brake and if the bolts were to back out the disc is right there. Thanks. | ||
| 1_mike |
To clarify one statement.. You CAN...use crows feet "without" changing the wrench's value... That is, if you orient the crowsfoot at a 90degree angle from the length of the wrench. This does NOT alter the torque put on the fastener. It may not always work to reach the fastener, but it will work to not change the final torque. Jdugger's last comments look pretty close. Mike |
