Mechanics Quick Question Thread [Ask Questions Here]

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Mechanics Quick Question Thread [Ask Questions Here]
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flag gabriel-mission9
Posted: Jan 11, 2021 at 14:21 Quote
Re: torque specs. This has always bothered me as a system. Wet/Dry/Threadlocked etc in theory would require a differen't torque spec to achieve the same clamping force. I get that torque specs are kinda the only system that works. But I still think it's a shit system.

I once had a handlebar that had maximum torque ratings for stem bolts printed on the bar. I always thought this was ridiculous as the bar manufacturer had absolutely no idea what stem/bolts were going to be used.

Standard mtb industry nonsense....
flag Thepureface
Posted: Jan 11, 2021 at 14:26 Quote
Thank you both. I will make sure to leave no thread dry!

I haven’t had any problems but thought I would ask- last thing you want is something to come loose when ripping downhill
flag R-M-R
Posted: Jan 11, 2021 at 14:31 Quote
gabriel-mission9 wrote:
I once had a handlebar that had maximum torque ratings for stem bolts printed on the bar. I always thought this was ridiculous as the bar manufacturer had absolutely no idea what stem/bolts were going to be used.

The difference in hoop stress from, for example, a stem with greased, fine pitch threads vs. dry, coarse pitch threads - let's use uncoated aluminum fasteners to really max out the friction - could be [commence dodgy mental math and vaguely remembered coefficients of friction] maybe four-fold. Granted, most stem fasteners are pretty similar, but that's quite the range.

Now let's throw in a factor of two on the range of clamp widths, highly variable clamp surface areas, and maybe a stress riser on the edge of the face plate from poor forging. Maybe a factor of two on rider forces, too.

I wouldn't be surprised if the range of maximum forces at the edge of stem face plates could vary by a factor of ten!
flag ducklord
Posted: Jan 11, 2021 at 17:17 Quote
I have a 300x3.25 spring. Can I put a 400x3.5 on my 2013 Fox DHX RC2?
flag R-M-R
Posted: Jan 11, 2021 at 17:32 Quote
ducklord wrote:
I have a 300x3.25 spring. Can I put a 400x3.5 on my 2013 Fox DHX RC2?

You can if your shock body has an extra ¼" of threads beyond the preload collar.
flag ducklord
Posted: Jan 11, 2021 at 19:08 Quote
R-M-R wrote:
ducklord wrote:
I have a 300x3.25 spring. Can I put a 400x3.5 on my 2013 Fox DHX RC2?

You can if your shock body has an extra ¼" of threads beyond the preload collar.
Ok. I have almost an inch so Il get the 3.5
flag YVRRider
Posted: Jan 11, 2021 at 20:22 Quote
Has anyone done a cable replacement for the front derailleur on a 2020 Giant Revolt Advanced?

I would like to know if the cable housing runs from the head tube to the derailleur? At the derailleur end there appears to be a thin cable housing, which is too thin to allow the new cable to be attached to the old, in order to pull it through.
flag el-booto
Posted: Jan 12, 2021 at 0:13 Quote
ducklord wrote:
I have a 300x3.25 spring. Can I put a 400x3.5 on my 2013 Fox DHX RC2?

You'll have to measure the freestanding length and compare it to the existing one. Everyone specs their springs differently
flag tannerzinck
O+
Posted: Jan 12, 2021 at 0:27 Quote
Anyone have any experience using a super deluxe with the bearing eyelet on a bike that uses m10 shock hardware? Seems like rockshox only sells bearings for m8 hardware for them, but someone must make a bearing that would take m10 hardware.
flag radatabs
Posted: Jan 12, 2021 at 1:32 Quote
Quick one here, carbon seatpost in a Titanium frame. Grease, carbon paste or dry and see how it goes?

My initial plan was just to go dry and if there is any slipping use the carbon paste?
flag riish
Posted: Jan 12, 2021 at 3:09 Quote
Carbon paste, I would say.
flag riish
Posted: Jan 12, 2021 at 3:18 Quote
Speaking of threadlocker vs grease for threads - would you ever use copper paste spray or a similar anti-seize on bolts instead of grease?
I use it quite often working on cars, mostly on stuff that gets really hot. Would it be useful applied to threads instead of grease, as it's less of a lubricant?
flag radatabs
Posted: Jan 12, 2021 at 4:43 Quote
riish wrote:
Speaking of threadlocker vs grease for threads - would you ever use copper paste spray or a similar anti-seize on bolts instead of grease?
I use it quite often working on cars, mostly on stuff that gets really hot. Would it be useful applied to threads instead of grease, as it's less of a lubricant?

I used to use it all the time when I lived with my parents as my dad has a massive jar never did any harm and just as effective as grease Salute
flag Aptlynamed
Posted: Jan 12, 2021 at 5:40 Quote
radatabs wrote:
riish wrote:
Speaking of threadlocker vs grease for threads - would you ever use copper paste spray or a similar anti-seize on bolts instead of grease?
I use it quite often working on cars, mostly on stuff that gets really hot. Would it be useful applied to threads instead of grease, as it's less of a lubricant?

I used to use it all the time when I lived with my parents as my dad has a massive jar never did any harm and just as effective as grease Salute

It can damage rubber though, so don't let it touch o-rings, and seals. Also you probably don't want it near bearings, because of the metal particles that are in it.
flag gabriel-mission9
Posted: Jan 12, 2021 at 7:16 Quote
riish wrote:
Speaking of threadlocker vs grease for threads - would you ever use copper paste spray or a similar anti-seize on bolts instead of grease?
I use it quite often working on cars, mostly on stuff that gets really hot. Would it be useful applied to threads instead of grease, as it's less of a lubricant?

Yeah, if you have it anti-seize is better than grease for threads that are just plain metal on metal and it's not going to get on anything other than metal.

Grease is fine though, unless you plan on not servicing your bike for millions of years, with the added bonus that you can just slather it on liberally and not worry about it attacking any of the softer bits of your bike. As you say, applications that get hot (like engines) is where anti-seize really out performs grease.

Over the course of a year you won't notice any difference between grease and anti-seize on a bicycle. But yeah, anti-seize is better in theory.

 


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