Cargo Bikes

Spokes measured 2.27mm on my vernier guage. On the chart, 2.3mm was nearest and 27 worked out as 92kgf. Don't know the rim make so can't look up/ask the correct tension

but I don't know how well that works if you've oiled the threads to help the wheel build in the first place.

The idea of spoke prep or boiled linseed oil is that it's a lubricant during the build, then locks everything in place some time later. You'll get many opinions about whether that's a good thing or not.

Did you prestress the wheel? It sounds like spoke windup to me (with a bit of under-tensioning thrown in), though odd it should happen just to the drive-side on a equally tensioned wheel.

I think your rim will be a Ryde Andra if it’s stock.

Afaik 2.3mm is 13g, and I agree with Jon - it sounds like spoke wind up / false tension so your wheels are at much lower tensions once they’ve settled themselves. Have had it happen to me before (with front and rear wheels) built with 13g and 14g spokes -in combo with not being mindful enough of removing wind up during tensioning

Well, i stressed the spokes & did a bit of leaning on the rims, though there wasn't much tweaking needed after doing so.

Think I'll run it as is (just re-tensioned & trued up the wheel) for a week or so & keep my eye on the spoke tension. Also, I'll take an 11g spoke key with me. If it all stays true I'll try some this thread-lock & keep fingers crossed

OK, any idea what the suggested tension should be?

Just looked up the rim & looks like 1400N which google tells me is 142kgf. Think I need to up the tension!

Cheers all for help

I've never bothered with anything threadlocking - I just dip the ends of the spokes in gear oil and dip a cotton bud in the oil to lubricate the eyelets, all to prevent excess wind-up and nipple binding. OTOH I've mostly built front wheels; if I were building rear wheels that were heavily dished and/or for touring, I'm heavy enough that threadlocking the NDS would probably be a good idea.

Yeah, I only tend to use thread lock if a wheel is heavily dished and one side is going to end up under tensioned (and then only on the under tensioned side).

I can’t decide exactly what angle to come at this, but 92kg (920N) force doesn’t sound like a lot. So assuming you laced the wheel 3-cross, at some point you’ll have two roughly parallel spokes vertically sharing the load. Pretty sure that means 180kg completely unloads the lower spokes. Let’s say you and some cargo onboard come to 120kg, it doesn’t take much of a bump in the road to completely unload the spokes and they start to come undone.

It’s not that simple because the tensile spoke loading and the hoop stress in the wheel is far more complicated than I’ve made it out to be, but I think it’s not far off in numbers.

Well tomorrow I'm going to up the tension to more like 135kgf. We'll see...

FYI, it is 2x lacing (large hub), bare bike ir 49kg, I'm 70kg, cargo box is roughly 15kg plus whatever I'm schlepping!

Lots of good wheel science here!

I've only ever had to threadlock (green /light duty) a few wheels, had mad unequal ness, non drive side had so little tension that they were bound to rattle loose.
All otter wheels the nipples and any washers are stored in plastic pots with oil in them, as others have said, massively sorts out spoke wind up and other things. Never heard of the linseed oil method.

Like the dt squorx nipples (brass versions) which come with a mild thread lock in them

Box progress. It’s slow progress but it’s still progress!

Panels drilled for fixings and mounted up. Stainless button heads on the sides and countersunk underneath. Did a test fit on the bike and cut the slot in the back panel to clear the random fixing on the steerer tube. All looks good so far.

I’m going to cut some handles into the side panels, mounting holes in the base, then a few coats of yacht varnish and it’ll be ready to use. I don’t think it needs the upper crossmembers so I think I’ll take them out and see how it fares.

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Looks great! What framebag is that btw?

The framebag is custom-made by me ;)
More pics here.

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I don't think thicker spokes impart greater strength to a wheel because of their tensile limit. I think it is because they are less elastic and provide greater lateral (mostly) stability.

looks pretty cool. have you thought about a/some drain holes? If water gets in, how does it get out?

I did think about it, but every hole in the base is a potential hole for toys to fall out! If it gets water in it, it’ll just run out the sides or ends. It’s not going to be sealed up.

I got a couple more hours on it today. Cut some handles at the centre of balance for decoration easy lifting. Bench seat is cut and fitted. Again, all on T-slot nuts so it can adjust and it’s locked in place with a bolt at the top.

Weight at this point is 15kg on the scales. I’ll take the front and rear crossmembers out when I dismantle it for varnishing.

There’s easily enough space for 3 kids in there and it struck me I can easily fit a second rear-facing seat in the front as it’s already tilted at the right angle.

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Looking great, and love the adjustable element. With the internal metal frame do you even need the back panel if you have the seat panel?

Just thinking weight saving

It doesn’t really need the panel or the rear frame from a structural perspective if the seat is in place, but it stops things coming out the back!

It’s a good point though. It’s a handy looking spot behind the seat for lock and chain, but I could cut that bit out and angle the back of the box if I don’t use it. Would probably take 1.5kg out the weight by doing that. It’s a question of if it’s worth the effort and whether I’ll notice 1.5kg on a total bike weight around 40kg!

Storage, what's everyone doing ? Definitely going to get a cargo bike this year as baby 2 is on the way in May. Bullitt is top the list but whatever I get it will have to be kept in the front garden. I'm not overly worried about security but more concerned with how it'll deteriorate being outside all of the time? How good are the covers? Any sort of bike cover I've used in the past has been more trouble than its worth.

Appreciate anyone's experience on this because I'll probably go for a cheaper option of family cargo if its just going to wreck it keeping it outside.

I've had a number of people suggest Oxford motorbike covers to me. Jamie and SBC Cycles said it should find over a Bullitt too.

yeah fair point. I'm trying to forward plan for when I finally am able to get myself a Bullitt and want to maximise storage and convenience whilst being as efficient on the weight side as possible.

will definitely be asking for your updates on. performance!

Hi, did you get this completed, interested to see the results and get a real world review.

For an occasional shopping trip and having a spare bike already I can see the use if it works out.

I partially stored a motorbike under an Oxford cover when I lived with my parents (it went in the garage sometimes but my dad needed the garage for woodwork quite a lot) and I was always thinking "Does this cover actually do any good?".

I imagine they are fine for bikes that only get used in the dry but it seemed like if you put it on a wet bike, it just kept it wet and therefor it got rusty.

My Omnium was stored outside for the first 3 years, under a roof but otherwise exposed. It rains a fair bit in Denmark so it did get surface corrosion on a few bit but I wouldn't say it's wrecked. Just be on top of the maintenance and don't forget the grease where required.