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by nsew
30 Jul 2021, 7:08am
Forum: Bikes & Bits – Technical section
Topic: New seven speed 700mm back wheel needed
Replies: 21
Views: 599

Re: New seven speed 700mm back wheel needed

nsew wrote: 29 Jul 2021, 9:15pm Cut 5mm off and re-space the dropouts to 130mm - builds a 20% stronger wheel than 126mm.
Correction - dish is reduced by half the overall mm increase. So increasing the OLN by 4mm gives a 2mm reduction in dish. Each mm is ~ 5%, therefore a 10% stronger wheel.
by nsew
29 Jul 2021, 9:15pm
Forum: Bikes & Bits – Technical section
Topic: New seven speed 700mm back wheel needed
Replies: 21
Views: 599

Re: New seven speed 700mm back wheel needed

Bice wrote: 27 Jul 2021, 11:10pm Maybe a realistic middle course with this is: find a new 32H rim and just reuse the Tiagra hub that I have already got and build up a wheel with the spokes I have, using the decent ones on the drive side. That reuses the old stuff without throwing things away and will result in a half-decent wheel.
You’ll need to find a rim with the correct (or near enough) ERD for those spoke lengths AND re-space the Tiagra hub back to 130mm (or the wheel is too weak) AND re-space the dropouts (or jam it in there). As you’ve discovered, cheaper rims don’t always match the manufacturers ERD. Other options

Visit the bike workshops / markets (Brick Lane), scour eBay and hope to find a decent replacement. Problem is decent used bike stuff is in very short supply / heavy demand.

Build a complete new wheel using the 7sp STX hub. Cut 9mm off the axle and QR. SRAM are still producing decent 7sp cassettes and will likely continue to now Shimano have quit. Cut 5mm off and re-space the dropouts to 130mm - builds a 20% stronger wheel than 126mm.

Re-spacing the dropouts to 130mm can be done with a threaded bolt and two nuts. Stretch to 140mm and see where they rest, my guess is you’ll need to stretch to at least 150mm to rest at 130mm. Who knows with a triple stay mixte.
by nsew
28 Jul 2021, 7:14am
Forum: Cycle Camping sub-forum
Topic: Pertex Quantum, condensation and a sleeping bag
Replies: 38
Views: 705

Re: Pertex Quantum, condensation and a sleeping bag

That’s a fine bag that will serve you well. After that trip it should be hung in a warm dry area of the house for a few days, the warmer the better. Rustle it up as you pass to open up and loft the down. If you have older synthetic bags they loose their insulating properties after ~ 5 years. Down when cared for will keep insulating forever.

https://www.phdesigns.co.uk/down-and-sy ... n-compared

https://www.phdesigns.co.uk/getting-the ... eeping-bag

https://www.phdesigns.co.uk/the-truth-a ... eping-bags
by nsew
27 Jul 2021, 5:18pm
Forum: Bikes & Bits – Technical section
Topic: New seven speed 700mm back wheel needed
Replies: 21
Views: 599

Re: New seven speed 700mm back wheel needed

Each mm in reduced dish gives a ~ 5% stronger wheel (on paper). I suspect the percentage is higher in real terms. By reducing the dish 4mm on a 7sp 135OLD 26” wheel you get a 90/100 spoke tension balance from 70/100. (3mm 85/100). Extracting a spacer from the DS and adding it and 2mm to the NDS requires minimal effort for a fairly substantial result.

That’s a desirable result for a touring bike carrying a load over a long distance.

This a 700C errand / day bike (though I quite like it and used to live just down the road from where it was built) with a bent rim (horrible to build with) and a 126OLD. One option is to pick up a decent used wheel and re-set the rear to 130OLD or even 128. I’d do that with my hands or use a cheap headset cup press - whack it out to about 150mm and see what that gets you. As mentioned strap up or clamp the stays before the bridges beforehand. I’m not surprised that wheel doesn’t want to know, the tensions must be in the region of 25/100. If going the re-build route I bet that STX hub would chop up to 126mm. Chop everything, the axle, quick release, rubber boot and do the 1.5mm DS spacer switch like before.
by nsew
27 Jul 2021, 2:02pm
Forum: Cycle Camping sub-forum
Topic: Bivvi bags - advice please
Replies: 126
Views: 8040

Re: Bivvi bags - advice please

mattheus wrote: 27 Jul 2021, 10:52am
nsew wrote: 25 Jul 2021, 8:36pm Those Thermarest compressible pillows are super comfortable.
Interesting that it's the biggest packed-down item in that photo!

(I don't seem to sleep any worse without a pillow - that's with head on a mat or soft ground. )
I’m not sure what size that is but the small packs down quite well and is put to good use in several travel situations - it serves as a luxurious pillow for the night / campsite resting and makes a cafe / rest / break stop very comfortable on what is often a hard surface. To summarize; provides many hours of use each day, ultra comfortable & virtually indestructible. Not a bad 200g carry.
by nsew
25 Jul 2021, 9:33pm
Forum: Cycle Camping sub-forum
Topic: Hubba Hubba NX broken strut
Replies: 14
Views: 539

Re: Hubba Hubba NX broken strut

Our situation is further made worse by ‘substantial origin’ of materials in a product. For example, Hilleberg fabrics, poles, fittings are South Korean in origin and consequently cost more to import from the EU. Same applies to products we export to the EU. A remarkable loose loose deal.
by nsew
25 Jul 2021, 8:55pm
Forum: Cycle Camping sub-forum
Topic: Pertex Quantum, condensation and a sleeping bag
Replies: 38
Views: 705

Re: Pertex Quantum, condensation and a sleeping bag

The bag is certainly too warm for a high summer journey. Rather than abandon I’d just post it home and pick up a cheap circa +10deg bag. I used to leave in early March with a warm bag that would have to be fully unzipped and used as a half blanket for the warmer months. Even then it would accumulate so much perspiration / moisture the down clogged up. To remedy I purchased a +4 deg bag at half the weight and bulk and layered up when temps dropped. Small tent isn’t optimal either in humid conditions. Plenty of variable weather conditions while travelling so the ability to layer up or down is essential.
by nsew
25 Jul 2021, 8:36pm
Forum: Cycle Camping sub-forum
Topic: Bivvi bags - advice please
Replies: 126
Views: 8040

Re: Bivvi bags - advice please

Nice pack. Simplicity is so appealing in the outdoors. I think the new Neo Air Venture is a bit warmer. Those Thermarest compressible pillows are super comfortable.
by nsew
25 Jul 2021, 8:25pm
Forum: Cycle Camping sub-forum
Topic: Hubba Hubba NX broken strut
Replies: 14
Views: 539

Re: Hubba Hubba NX broken strut

Are you rubbing it in, Willem? Looks like a cracking store but they no longer ship to GB.
by nsew
25 Jul 2021, 8:15pm
Forum: Cycle Camping sub-forum
Topic: New tent?
Replies: 57
Views: 2085

Re: New tent?

It’s revealing that one hour sleep guy tentatively wishes he’d brought his Wild Country Helm 2 mentioned earlier in the thread. A tent that’s almost a third of the price of the Hubba Hubba NX. Two crossed poles and 4000mm HH floor & fly makes for a stable and reliable tent in poor weather. It’s better to have and not need than to need and not have.
by nsew
25 Jul 2021, 7:17pm
Forum: Cycle Camping sub-forum
Topic: New tent?
Replies: 57
Views: 2085

Re: New tent?

This guy’s just passed as a Mountain Leader, was expecting poor weather and is surprised the wind blew one of two directions in a valley.

https://youtu.be/HGTa88ujTok 7.40min

This guy has a career in comedy waiting

https://youtu.be/HL_SHc397Lg 3.30min

This guy slept for an hour and can’t recommend the tent highly enough.

https://youtu.be/AesHJNxhuKE 9.00min
by nsew
23 Jul 2021, 7:55pm
Forum: Cycle Camping sub-forum
Topic: Pertex Quantum, condensation and a sleeping bag
Replies: 38
Views: 705

Re: Pertex Quantum, condensation and a sleeping bag

I have this in my camping notes. Found on the web a few years back and appears to be a reply to someone having similar issues.


- Dewpoint isn't a physical location. It's a temperature.

All natural air has water vapor in it. This isn't visible steam/mist, but rather lone H20 molecules sneaking invisibly between the rest of the air. The warmer the air, the more molecules can squeeze in. This is that 'humidity %' thing the weather man talks about. 80% humidity means the air has 80% of the max amount of water vapor it can invisibly hold, for that given temperature.

So what happens when it gets to 100%? Well, notionally, H20 molecules bump into each other so much they collect into suspended droplets of liquid, aka mist/steam. For boring physics reasons, this actually heats the air up again, and the droplets immediately evaporate. This is why mist doesn't just randomly appear on its own whenever water is around. Instead, it appears when temperature drops. Cooling the air robs away this heat energy as well as reducing its capacity to hold water vapor, effectively increasing that "relative" % humidity despite no H20 being added. Do it enough and water droplets condense out and stay there. Critically, the higher the starting humidity, the less you need to cool it for droplets to condense out.

This action presents in heaps of different ways, prime example being when hot water vapor shoots out a boiling kettle (or even your breath) and hits cold morning air, you get a plume of mixed, still humid, but much cooler steam. All are cases of comparatively 'warm' air, being cooled to the point that the air can't hold the vapor it has (saturation), and it forms droplets.

The temperature at which this occurs? That is the Dew point. But what does this have to do with your bag and tent?

Well, if the skin of your tent cools enough that its inner surface is below dew point for the (comparably) warmer, humid air pocket on the inside, you get some condensation on the inside of the skin, where the air touching it cools and condenses water droplets. If your tent skin was, say, goretex, some of that water vapor can escape first, reducing inner humidity, meaning the temperature would need to drop further to make those droplets form. Or, you could ventilate, allowing dry outside air to mix and reduce the humidity (and thus dew point) inside , even though it's still just as cold.

Of course, if the air outside already has a lot of water vapor (say, near the ocean....) then this doesn't work so effectively. And if it's humid and cold enough, maybe the outer skin of your tent, the grass, and indeed everything able to radiate its heat away to the sky, will cool below the dew point, and you get droplets of (wait for it..) dew! And if all the atmosphere outside drops below dew point, you'll get water droplets all throughout the air and on everything, aka fog.

Get the picture? It all comes down to how cold a given lump of air is, and how much water vapor is in it (aka relative humidity)

Now, sleeping bags:

The air contained in your sleeping gear has a given humidity (usually higher, being close to the body). The thing is, it starts to immediately cool as it moves away from your skin. Now if it's 38C inside your sleeping bag/doona/jacket/thermal cocoon, but say, 0 C outside, and the dew point for the relatively humid air in your insulation, is say, 5C...well, you have a problem. Because somewhere in your gear, between 38C and 0C, the air cools to the point that water droplets will form (typically near the outer shell).

This is what I think is happening to you.

This phenomenon used to slowly freeze early antarctic explorers' sleeping bags solid over the weeks. It happens to me a lot, when I hike in the snow. I get it because the temp drops low enough outside, for the bag's own temperature to drop below dew point even in 'dryer' air. You're getting it because the humidity/dew point where you hiked is already quite high. Same thing though. Looking at BoM observations for Kangaroo Island, I'm seeing a lot of high relative humidity conditions with ambient overnight temperatures approaching or dipping below the dew point. Meaning the air you're sleeping in, thats filling your sleeping bag, is already close to saturation, and the heat from your body isn't enough to counteract overnight temperature drop with the extra humidity you're producing. You've essentially got fog forming inside your down.

Fixing this isn't simple. But some of these might help:

-Dont use a bivvy bag. It might keep the odd tent wall drip off, but the big issue here likely isn't water from the outside getting on your bag, its from the inside. Even breathable shells will just impede vapor escape even more. The skin of the bivvy will reach dew point just the same, and you'll get water droplets all over the inside, leaving you with wet bivvy and bag.

-Similar for water repellent treatment.

-Use a THINNER bag. Similarly, wear less layers inside the bag, it sounds like you're not layering effectively anyway. Yes, I know, it sounds counter intuitive, using less to stay warmer. But the thicker the bag, the more likely the dew point is reached inside the insulation. A thinner bag hopefully means all the insulation stays warm enough that the water vapor escaping doesn't cool mid-down, and the bag stays dry. It's balancing act but you should be able to tune it, especially if your'e in fairly warm coast conditions.

-Close the tent doors and vents. Again, I know, counter intuitive. Idea here is if the ambient humidity is already high, you can't reduce it with venting anyway, so instead, trap heat in. If you're lucky and you can boost the ambient temperature above dew point, the problem goes away. You will get EPIC wall condensation where the tent skin is cold though, so just gonna have to wake up now and then to mop it down (or use a fine bug mesh inner to divert drops from your bag)
by nsew
23 Jul 2021, 1:46pm
Forum: Cycle Camping sub-forum
Topic: Pertex Quantum, condensation and a sleeping bag
Replies: 38
Views: 705

Re: Pertex Quantum, condensation and a sleeping bag

horizon wrote: 23 Jul 2021, 10:51am
nsew wrote: 23 Jul 2021, 7:39am It may be a combination of the sleeping bag being too warm for the conditions (excess heat) and the inner tent not being sufficiently breathable. It’s important that inner tents are highly breathable otherwise they form an impenetrable barrier for vapour to escape.
I'm less concerned, ironically, at this point about the condensation generally, rather the fact that it seems to take a particular liking to the shell of the sleeping bag. No, the inner tent isn't sufficiently ventilated (I don't always open the mesh vent) but that also implies that the bag isn't too warm (it's about right in fact).

A couple of extra points: I can generally wipe away the condensation and the bag dries very quickly in the morning, even inside the tent. I don't get the impression that the moisture is soaking in. So the bit I am still unsure about is whether the bag (by virtue of its hydrophobic shell) is actually attracting condensation or is, conversely, dealing very effectively with it or a combination of the two.

My next port of call is to comprehensively deal with problem of the condensation but I did want to reassure mysef that I wasn't ruining my sleeping bag in the meantime.
It’s July, the sleeping bag weighs in at 1.3kg with a comfort range of -2deg to -7deg. Rab describe the bag as being “perfect for the likes of cold bivis and Scottish winter”. It may be 8deg outside but inside your tent its several degrees warmer especially so as you’ll be generating so much heat from that bag. If on top of that the inner doesn’t breathe well (cheap fabric?) you’ve created a highly uncomfortable moisture heavy environment.
by nsew
23 Jul 2021, 7:39am
Forum: Cycle Camping sub-forum
Topic: Pertex Quantum, condensation and a sleeping bag
Replies: 38
Views: 705

Re: Pertex Quantum, condensation and a sleeping bag

It may be a combination of the sleeping bag being too warm for the conditions (excess heat) and the inner tent not being sufficiently breathable. It’s important that inner tents are highly breathable otherwise they form an impenetrable barrier for vapour to escape.
by nsew
22 Jul 2021, 10:14am
Forum: Cycle Camping sub-forum
Topic: New tent?
Replies: 57
Views: 2085

Re: New tent?

Hubba Hubba NX

Fabric:
Flysheet: 20D Nylon ripstop with Durashield coating (1200mm HH)
Groundsheet: 30D Nylon ripstop

That’s a 1 season tent - dry season and “please God I hope this wind lets up”. Pitch on wet cold ground and you’ll think it’s leaking. It’s not (yet), it’s the condensation seeping through under your mat. Think puddles. Clearly the tent needs the footprint (pay up) which I believe is 70denier 2000mm HH. The bare minimum 1200mm HH fly will induce prayers in a sustained heavy downpour. Fabrics and coatings deteriorate over time with use and exposure. There’s very little room for deterioration in that tent.