An old trick remembered

[Andyb1]

I am getting my Sherpa ready for going to India in January and while I won’t be carrying much weight I really don’t like how the rear rack is fixed by fully threaded screws rather than shanked bolts (loading a straight shank in shear is so much stronger than loading a threaded screw where the sharp threads act as stress raisers).  So just in case a screw snaps I want to have a couple of M5 x 30 spares - and an easy way to carry them is to fit them in two of the water bottle braze-ons where much shorter screws are usually used.  OK - if I need to use them I will have to carry the bottle and cage in a pannier, but better that than having a flapping pannier frame.

There must be other little ‘tricks’ that people use?  Spoke is seat tubes etc etc?

[Danneaux]

Spoke holder in the seat tube? Here's one I made for my Sherpa back in 2011...
https://thorncyclesforum.co.uk/index.php?topic=3896.msg18563#msg18563

I did the same for my Nomad in 2012...
https://thorncyclesforum.co.uk/index.php?topic=4523.msg39423#msg39423
https://thorncyclesforum.co.uk/index.php?topic=4523.msg39429#msg39429

It has been nice to always have the spokes with me, carried rattle-free and secure within the seatpost.

Best, Dan.

[mickeg]

I have used a wine cork in seatpost to hold spare spokes, but the wine cork dried out and shrunk, thus I had to wrap some electrical tape around it to make it fit tighter.

I have put spare bolts in unused places, my Nomad Mk II has bolt holes on the fork for a bottle generator mount.  I think my Sherpa does to, but it is in storage, I can't check it right now.  But a 30mm spare is something I carry in my tool bag, not threaded into the bike somewhere due to the length.  For example, one of my spares threaded into the bike somewhere is a shoe cleat bolt, much shorter.

But if you really wanted to make the bolt stronger, use a stronger steel bolt, which unfortunately might be more prone to rust.

Or, re-thread it to M6 if it is of that big a concern.

If a bolt breaks off, how are you going to get it out of the frame or fork.  Where I can with an M5 bolt, I thread a pan head type bolt into the frame from the inside, then use a nylock nut on the outside to hold my rack on.  If the bolt broke, then I still have the pan head side of the bolt on the inside of the frame.  Unfortunately this will not work on the drive side for the lower rack mount on a Sherpa, as the bolt head could interfere with shifting the chain to or from the outermost sprocket.

[PH]

EDIT - Beaten to the first point by mickeg!

On the subject of through fitting - Where possible, I use a longer screw from the opposite side, creating a threaded stud.  Then hold the attachment on with a Nyloc nut, or a shakeproof washer and a dome nut if I want a neater finish.  The advantage is that if it were to sheer, I'd still have a screw head to remove it.
And onto screw heads - Thorn used to use hex heads in all their builds, unless requested otherwise.  The inconvenience of carrying a small spanner is nothing compared to the inconvenience of a rounded Alen head!  If I was doing any remote touring, I'd do the same. otherwise I settle for a half measure and use Torx screws. 
A small length of steel cable and a couple of electrical chocolate box connectors can bodge most cable issues and take no room in the spares kit.  And don't forget a couple of chain links, for any bike you can't shorten the chain, I know it's obvious but... 
I've never carried spare spokes, but then I don't ride anywhere remote and I've never had an issue that made the wheel unrideable.
India is close to the top of my bucket list, have a great trip.

[Andyb1]

Like  mickeg and PH, I have the lower pannier screws* fitted with their threads pointing outwards and use a nyloc to clamp the pannier in place.  A flatish domed headed screw on the RHS gives adequate chain clearance and is stainless and greased when fitted, so should not corrode (but stainless is more prone to fatigue…).
If a screw did shear it would do so at the frame / pannier interface so I hope I could unscrew the sheared part through the frame.

I am taking a spare Q/R chain link plus a couple of spare links from a new chain.  If a chain does break I think it will probably be the Q/R link or one of the wider links that fails, the narrower chain links look strong.  The issue then of course is if the RD is damaged.

I always take about 4m of thin rope - used in the past as washing line and to tie the bike on a taxi roofrack - but also there incase a pannier starts to loosen off.

* Being pedantic, ‘bolts’ have a parallel unthreaded shank while ‘screws’ are threaded all along their length.
 

[PH]

* Being pedantic, ‘bolts’ have a parallel unthreaded shank while ‘screws’ are threaded all along their length.

We may have done this one before - but bolts and screws are most often defined by their intended purpose, that purpose does make an unthreaded shank on a bolt likely, but it isn't a requirement.  If you have any doubt, just google fully threaded bolt, or you could ask multiple engineers for multiple answers. The most likely time it becomes relevant is if you're relying on the specification, they're tested differently.

[Andyb1]

Yes, there are various definitions of what constitutes a bolt or screw but the definition I used is relevant to this application.

[mickeg]

...
* Being pedantic, ‘bolts’ have a parallel unthreaded shank while ‘screws’ are threaded all along their length.

My dad taught me that screws go into wood, bolts go into metal.  Whether he was right or wrong, I will continue to carry on the family tradition.

For my last tour, I fitted a suspension stem and suspension seatpost to my bike.  I was hitting the bumps faster than usual because of the softer ride.  It started to concern me that by doing that, I might be putting more stress on my rack bolts.  Which I completely forgot when I got home, until this thread came along.

[hendrich]

I use higher quality stainless screws (that is what McMaster-Carr calls them). I like to have easy access to the hex head, and as said, the lower rear rack lacks space for an inner head. I have cut a slot in the ends of the screws. In case of breakage, I can use a screwdriver to remove the broken piece. All the screws I have are fully threaded...good above advice regarding an unthreaded shank being stronger. However, in 30 years of heavily loaded touring, I have never had a screw shear off. Nevertheless, I carry a small plastic bottle in the tool kit with a carefully selected assortment of metal bits. Extra spokes in the handlebars. There are tool kits these days that plug into the handlebar end, but the assortment seems restrictive.

[JohnR]

However, in 30 years of heavily loaded touring, I have never had a screw shear off.

I would note that a joint held together by a screw/bolt under tension has a higher shear load capability than the screw/bolt itself due to the friction between the parts in the joint. Large steel structures are often held together using high strength friction-grip bolts. If a bolt supporting the rack is loose then it's more likely to break.