Maintenance of m/c’s vs bicycles

[Clancy]

So I was working on my motorcycle, an older BMW, when it occurred to me that in 40+ years of working on m/c’’s, I’ve never greased nuts/bolts to keep them from seizing. The only exception are the spark plugs that get anti-seize. As long as the m/c hasn’t been abused and left in the weather, never a problem.

Yet I grease virtually every fastener on a bicycle.

Why the difference?

[speedevil]

Because MC fasteners require tightening to a higher torque value - ostensibly to stay tight with the vibration that is ever-present. I use blue loctite on a lot of MC fasteners.

Bicycles in general are more fragile, as are their fasteners, so the difference between break-loose torque and tighten-to-spec torque isn't as easily absorbed.

[Hellgate]

Because you sweat all over a bicycle and sweat is corrosive.

That said, depending on the motorcycle parts I may use Loctite. Some parts I safety wire, old racer's habit.

As far a bicycle being more fragile that's not an accurate statement and I'll leave it at that.

[Mr B]

The rider’s weight and physical force is more likely to induce creaks on a bicycle, less so on a motorbike.

[Skenry]

I anti-seize almost everything on my motorcycle. Just pulled all the head and transmission case bolts on my Royal Enfield about a week ago.

[Clancy]

So far, explanations don’t seem to align.

I don’t sweat all over an entire bicycle.

Many fasteners on a m/c are tightened to no more than on a bicycle.

Not sure about the creaking comment. But bottle cage bolts are greased and not to prevent squeaking.

The only explanation I can come up with is that often bicycles are left outside and perhaps lubing fasteners became the norm to keep from rusting? But then again, so are m/c’s.

I’ve restored a number of old BMWs and again, never coated the threads of any fasteners except spark plugs and very specific applications such as using a specified grease for transmission splines. No doubt it’s a good idea, can’t hurt, but is not a common practice as it is with bikes.

[unterhausen]

It may be because bike fasteners are generally smaller. I have had fasteners seize up on a bike over the length of a week when I didn't grease them, so it's worth it to me.

[Black Dog]

It may be because bike fasteners are generally smaller. I have had fasteners seize up on a bike over the length of a week when I didn't grease them, so it's worth it to me.

Smaller fasteners is the big issue.

[.RJ]

It may be because bike fasteners are generally smaller. I have had fasteners seize up on a bike over the length of a week when I didn't grease them, so it's worth it to me.

OE Motorcycle fasteners are generally much higher quality, too. Bicycles are hardly the pinnacle of manufacturing.

Past that, an old motorcycle is a simple machine, just more parts.... its taken me a year or so of small projects to catch up on many years of deferred maintenance on my 1975 Honda.

[unterhausen]

That's true about quality of bike fasteners. I often wonder how much making a fastener out of cheese really saves the manufacturer. I suppose it adds up, but just as one example, the bolts that come with a lot of water bottle cages remind me of the fake lugnuts on plastic hubcaps more than they remind me of a bolt. Similarly, the bolts on a lot of production stems seem like they should be a little better.

[ridethecliche]

Torque spec for parts often changes with application of grease or thread treatment.

So if oem manufacturers for bikes default to grease, that's what one should do.

For MC's most of the time there's some sort of loctite compound on things depending on the importance but mostly because of vibrations. Vibrations on an MC are far more significant than on a bike.

The issue with bikes, such as with cranks etc, is that torque is applied unevenly when riding and that back and forth motion can work things loose.

[gemship]

So I was working on my motorcycle, an older BMW, when it occurred to me that in 40+ years of working on m/c’’s, I’ve never greased nuts/bolts to keep them from seizing. The only exception are the spark plugs that get anti-seize. As long as the m/c hasn’t been abused and left in the weather, never a problem.

Yet I grease virtually every fastener on a bicycle.

Why the difference?

I have no idea why you do what you do and I have never owned an old BMW motorcycle. However I will say that I do grease the threads of axle nuts on my GSXR1000. Those nuts have a very high torque spec and I feel that greasing them helps when servicing. however I don't grease the threads of that bikes sparkplugs...should I? I will be greasing the threads on the axle nut of the rear wheel of my KTM Superduke GT. It's a 60mm nut that took a five foot long steel pipe cheater bar put over a two foot long 3/4 drive breaker bar attached to a 60mm socket (and or in inch conversion 2-3/8) to break free. the torque spec is something ridiculous and your dam right I will grease the threads.

I think greasing fasteners or using loctite on some really depends on torque specs, application and or the use of lock washers. So on the motorcycles I like to tighten sensibly as not to strip the head of fasteners or tip of tools when dealing with the small torx/allen head style bolts holding the front brake rotors. I also dab a bit of loctite on those bolts. When I loosen them it's gingerly and if needed I will use a bit of heat to soften the old loctite. This needs to be done (rotor removal) when I go to change the tires.

[Rusty Luggs]

It is hardly universal to apply anti-seize to spark plugs. Some plug manufacturers specifically recommend NOT using anti-seize, many others warn that torque spec for plugs is for dry threads and that if anti-seize is used, torque should be reduced by 20-30% to avoid over tightening.

Torque specs, in general, however, are usually for lubricated threads, as resulting bolt tension values are more consistent with a lubricated thread. Dry threads would need to be torqued to a higher value to achieve the desired tension.

loctite is generally considered to act as a lubricant at assembly, just like grease or anti-seize. Good practice is to lubricate threads at assembly. Nothing special about motorcycles or higher torque fasteners that negates that.

[benb]

The engineering in a motorcycle is on a different planet from even the most expensive bikes.

I've never seen a bike come with a service manual that was anywhere close to what say a Honda factory service manual looks like. Shimano does a good job but their still not at the level of motorcycle manuals.

If you go read the service manual for a motorcycle nearly every fastener on the whole bike is specified:

- Part # for the fastener
- Torque spec for the fastener
- Part # for the tool to use on the fastener if necessary
- What chemical treatment to put on that fastener if necessary (Grease, Anti-Seize, different colors of loc-tite, do not apply anything, etc..)
- Service interval/replacement interval for the fastener.

E.x. We fret about disc brakes here, I remember my Honda requiring Red Loc-Tite on the caliper mounting bolts and specifying that the fasteners had to be replaced any time the caliper was removed/replaced. They left nothing to chance when it came to the safety of the brakes.

My other experience was that threads, fasteners, etc.. were almost uniformly higher quality. You didn't have stuff like paint overspray in threads, you didn't have stuff like bolts or threads that weren't quite right like I see in almost every stem for example. You didn't hear about people having to do stuff like facing BB threads, etc.. stuff went in with your fingers even big fasteners and then you just tightened it down.

The only bike I have seen that was in the ballpark of a motorcycle was my Serotta... all the machining was much better than any other bike I've owned. I remember being shocked the BB would hand thread in all the way.

[benb]

I have no idea why you do what you do and I have never owned an old BMW motorcycle. However I will say that I do grease the threads of axle nuts on my GSXR1000. Those nuts have a very high torque spec and I feel that greasing them helps when servicing. however I don't grease the threads of that bikes sparkplugs...should I? I will be greasing the threads on the axle nut of the rear wheel of my KTM Superduke GT. It's a 60mm nut that took a five foot long steel pipe cheater bar put over a two foot long 3/4 drive breaker bar attached to a 60mm socket (and or in inch conversion 2-3/8) to break free. the torque spec is something ridiculous and your dam right I will grease the threads.

I think greasing fasteners or using loctite on some really depends on torque specs, application and or the use of lock washers. So on the motorcycles I like to tighten sensibly as not to strip the head of fasteners or tip of tools when dealing with the small torx/allen head style bolts holding the front brake rotors. I also dab a bit of loctite on those bolts. When I loosen them it's gingerly and if needed I will use a bit of heat to soften the old loctite. This needs to be done (rotor removal) when I go to change the tires.

Do you have the service manual? Do what it says.

Almost guaranteed Suzuki has everything specified in the manual with huge warnings that not doing it correctly may result in injury/death and that it should only be done by a qualified mechanic. (I owned a Suzuki and this was in there for mine.)

When I used to go to the track we had a brake related fatality after the rider didn't put the brakes back together exactly as they were supposed to. (Ducati)

Guaranteed the front axle has very specific instructions too. There's no way you should be tightening the brakes or axles without a torque wrench. Brake bolts likely say Red Loctite due to heat.