beware of over-torquing

[TSB67]

Check out this page from Carroll Smith's "Screw to Win" (aka nuts, bolts, fasteners and plumbing handbook).

http://books.google.com/books?id=A81HmmRCN7YC&lpg=PA48&ots=ZwiGDHAARz&dq=safety%20wire%20does%20not%20keep%20things%20tight&pg=PA48#v=onepage&q&f=false

[ohiomike]

I'm doubtful that aluminum fixtures can stretch a grade8 fastener to the breaking point, more than likely you'd pull the threads from the caliper before the bolt stretched to where it would shear - think most OE bolts are a grade 5? I may be wrong but they seemed softer than the 8's I upraded to back then

::edit:: Now that I think about it, did it shear at the head of the bolt? Or somewhere on the shank? It would make sense it could break at the head if over-torqued enough times but you're racing the bike right? Thats quite a bit of extra force against those bolts, may need to upgrade them all

Good point. It makes me wonder how much the number of threads and their pitch might add to the strength of the threads holding, even in aluminum. I'm sure the grade of aluminum they use is a much higher grade, don't you? I mean, for example, billet aluminum is stronger than some other aluminums. Another point of interest-oxidation. If the calipers are a true aluminum and the bolts are steel, then oxidation (of some sort) will occur and that can cause problems with the metals (degradation) as well.

[serpentracer]

I'd go to the local Fastenal branch or another specialty fastener warehouse. Glad it was a farily painless surgery to extract the broken bolt. My '97 YZF1000R had 5mm hex driven socket-head capscrews for the rotors and calipers and needed torqued about 20 ft-lbs, the hex bit loved to roll inside of those bolts.........but I replaced them with torx driven grade 8's as I took them in and out quite a bit for brake jobs -- think I gave a tick over $30 for all new hardware for both fronts and rear setups, but the torx bolts will allow for some major overtorque if you're not careful ;)

these places are construction stuff. been there and they don't sell anything metric etc.

it's just lags n shit for construction use.

knowing how to use a torque wrench properly is key too. you can't run a nut/bolt down like a wild man waiting for it to click. you should do it slowly. slower than you do with a normal wrench. and lubing the threads will give you a more accurate setting too.

I've had most of the bolts on my R6 off more than a dozen times and re-torqued to factory specs without any problems. (my caliper bolts are 29 ft/lbs). of course I don't have a walmart or autoparts store torque wrench either.

spend the money on a good brand. (not sears). this is the one I have and that's a pretty decent price for a good torque wrench.

http://www.thetoolwarehouse.net/p-2678-k-d-tools-85052.aspx

Edited April 26, 2011 by serpentracer

[redkow97]

P.S. Safety wire isn't meant to hold things tight as much as it is a visual verification that something was properly torqued. While it may keep things from falling out, if a fastener has already loosened to the point that .025 wire is holding it in, the joint is compromised.

if you want to borrow my wiring jig, I can bring it to Nelson. the new caliper bolts should be the last thing I have to drill.

then silicone on the caliper pad-pins, and i'm WERA legal (i hope)

[Helmutt]

Good point. It makes me wonder how much the number of threads and their pitch might add to the strength of the threads holding, even in aluminum. I'm sure the grade of aluminum they use is a much higher grade, don't you? I mean, for example, billet aluminum is stronger than some other aluminums. Another point of interest-oxidation. If the calipers are a true aluminum and the bolts are steel, then oxidation (of some sort) will occur and that can cause problems with the metals (degradation) as well.

Typically, a finer threaded fastener will withstand more torque since there are more threads per inch displacing the force agasint each thread.

But on the bikes I've owned, most metric rotor and caliper bolts are "fairly" coarse threaded ( 1.25 or 1.50 TPI ) where as a 2.0 would tolerate more pressure -- But, like you said......contact between ferrous and non-ferrous metals WILL result in some sort of corrosion I would think -- Or maybe not, assuming that thread lock would HELP eliminate possible corrosion though......I can always tell when I pull my rotors whether or not I forgot to threadlock the bolts - usually have a coating of chalky corrosion that squeak and squeel and fight to be removed;)

Then again, maybe corroded bolts is BETTER than threadlock?? Hahaha :D:D

[redkow97]

my 3/8 drive torque wrench (which is what I was using) is the old-school style with 2 bars, and the analog reading.

They're not terribly precise, but they also never go out of calibration...

My 1/2 drive (only really used for axles) is from harbor freight, so I know it's not perfect, but for axles, I'm okay with "close enough." They're being safety wired anyway, and the front is held in place with pinch bolts. The rear is wired, and captive with the chain-tensioners, which are also wired.

[serpentracer]

Fastenal sells all sorts of metric hardware.

weird. I went to the one closest to me with bolt in hand and the guy said they don't sell anything like that.

I needed a M10 or something like that. I forget exactly.

[mello dude]

Lowes has a pretty good supply of metric hardware too. Grade 8.8 and 12.8 - Its usually the first place I check before mother honda.

[rubbersidedown]

That's funny. He must be from another planet.

http://www.fastenal.com/web/search/products/fasteners/sockets/socket-cap-screws/_/N-judql8Zgj4wbsZjubkf6&Nty=0

I believe that Fastenal stores are independently owned. I've been to some that stock lots of stuff and others that did not. This would explain the "Metric" stock issue.

McMaster Carr is great but I prefer Fastenal and Grainger since they are everywhere.

[serpentracer]

That's funny. He must be from another planet.

http://www.fastenal.com/web/search/products/fasteners/sockets/socket-cap-screws/_/N-judql8Zgj4wbsZjubkf6&Nty=0

maybe they only have it online?

I think I'll pay another visit to that place just to see. it was over a year ago

[serpentracer]

I believe that Fastenal stores are independently owned. I've been to some that stock lots of stuff and others that did not. This would explain the "Metric" stock issue.

McMaster Carr is great but I prefer Fastenal and Grainger since they are everywhere.

I had a grainger catalog and spent the better part of a day looking through it lol

[ohiomike]

Each store sells what goes in their area. If it is a slow mover, it's not on the shelf. Where I came from I worked with fastenal all the time. They didn't carry any hardened bolts other than generic sizes, and nothing in metric to speak of. But that stuff never moved. I went in looking for bolts for my old jap bikes. Had to shop elsewhere because they would not sell anything more than large quantities when they had to special order.

Online might be different. And if you order online why is it you cannot have it shipped to your place instead of having it shipped to their store?

[Helmutt]

If you order online and pay via creditcard, they can direct ship anything you buy - almost my favorite way to shop if I'm not in a hurry

[TSB67]

and lubing the threads will give you a more accurate setting too.

Don't lube the threads. Unless otherwise specified (some head bolts,etc.), given torque values assume clean, DRY threads. By lubing the threads, you are effectively overtorquing the fastener.

I am told anti-seize is OK, but I have never verified this.

Among many other things, I was irritated to find someone greased the threads of my front axle bolt (and probably gorilla torqued it on top of that judging from the rest of the front end). Perhaps "Apply a thin layer of grease to front axle surface" was misunderstood.