As Zippy's link reveals, there is a lack of consensus on how, or under what conditions this happens, if at all.

How and under what conditions certainly but in the main the link does seem to back the theory up ... you'll have the perfect testing ground out there

Any recommendations for Insurance?

Looking at about £50 with Snowcard.

I've had water freeze to the point that it won't come out of the bottles in 'good Scottish winter' conditions in around 2 hours with bottles in the outside mesh pockets of a rucksack. I'd guess this is similar to what would happen to standard bottles in regular cages. and it was around -10c rather than -30c!

can you find a way to fit a camelback under clothes to keep it liquid? Or stuff flexible bottle up your jumper? once its frozen you don't want to have to thaw it with body heat as it will take you a lot of extra calories to get it back to liquid.

How about one of these?http://shop.camelbak.com/mens-racebak/d/1016

Ben98 wrote:How about one of these?http://shop.camelbak.com/mens-racebak/d/1016

The review on that is funny - 1 star. Best uses - Fuel for a fire. Well, at least if all else fails, you could set light to it to melt the snow/ ice

edit: this looks marginally better, but no reviews (at least not on camelback website) http://shop.camelbak.com/menspowderbak/d/1196_c_141

It was the concept not the product

It's a bit excessive to buy just for this but a Solomon race vest may work ok under warmer layers. Space for a 2 liter bladder and 2 x 500 ml bottles at the front plus lots of other pockets and compartments that you could keep other stuff that likes to be warm in. Batteries for example.

Not convinced tbh but worth a thought. I have one in size small that I can lend if anyone is thinking that way...

johnnystorm wrote:Any recommendations for Insurance?

Looking at about £50 with Snowcard.

Balls! I forgot about insurance, I'll have a look today for some

I've used Dogtag before, they seemed pretty good and not put of by extreme stuff or competitions.

dogtag was expensive as you need to add extreme and winter options to the package taking it to £95ish. I've e-mailed snowcard for a quote as they only do the usual cycling options but yet to receive a reply

voodoo_simon wrote:dogtag was expensive as you need to add extreme and winter options to the package taking it to £95ish. I've e-mailed snowcard for a quote as they only do the usual cycling options but yet to receive a reply

Tracks, trails and competition are mentioned...

On the water front could you not just get a couple of whitby warmers and slim them in next to bottles etc. 12hrs+ of good heat next to a bottle fairly well enclosed would be helpful I'd have thought.

What's the consensus on using hydraulic brakes in -20 temps?

I know that braking probably isn't going to be a great requirement, but seeing as my XTR brakes are nearly a pound less than my BB7's, I'd rather save the weight I was there is a critical reason not to

http://forums.mtbr.com/brake-time/hydra ... 60351.html

Suggests my Dot 4 Avids won't freeze (something else will conk out I guess!) and that Mineral is good to -30 or more.

I expect the worst issues will be with old fluid that's had time to absorb moisture as that *will* freeze. If fresh they should be OK I guess. While BB7s are popular with the outback crowd I expect there is more likelihood of freezing through moistures issues with cables than with hydro fluid. So long as they don't freeze on all should be good. A couple of feet down in the powder should stop us!

johnnystorm wrote:

voodoo_simon wrote:dogtag was expensive as you need to add extreme and winter options to the package taking it to £95ish. I've e-mailed snowcard for a quote as they only do the usual cycling options but yet to receive a reply

Tracks, trails and competition are mentioned...

Snowcard replied to my email, basically they said they couldn't insure me and to try the BMC or dogtag instead

Ian, I'm using BB7 for the trip. The bike spec was custom and I err'ed on the side of caution

Thankfully I've never ridden a bike in -30 but I'd guess that caliper seals rather than fluid would be the biggest concern ... The seals rely on their ability to deform and then return to retract the piston/pads. I've no idea what happens to their properties at minus stupid degrees but you can't help think there must be some change, after all they're only made of rubber.

I'd rather use hydraulics in those conditions than cables. Reason being snow and ice has buggered about with my cable brakes (freezing cables etc.), whereas hydraulics I've never had problems with.
Although, I've not done more than -5 I don't think...

Be interesting to look into, like it's been mentioned the fluid temperatures are well known, and you can make rubber work at those temperatures (there's some rally tyres at silly £ that are optimum tackyness for adhesion on ice at -20 degrees!!!)

As long as there is no water (or damp air) in the system - they should be fine. Remember people use normal cars in those temps which have the same seal material and dot fluid as your mtb brakes.

Re water - I've used my camelbak on ski holidays at -25 and as long as you keep the tube inside it works in a normal rucksack. I guess you get enough heat coming through your jacket to keep it liquid and thats for downhill skiing so on a bike it should be fine??

and you can make rubber work at those temperatures (there's some rally tyres at silly £ that are optimum tackyness for adhesion on ice at -20 degrees!!!)

You can but did anyone tell Shimano it might be something required of their brake seals?

I admit, I was going off on a bit of a tangent with cold weather and rubber!

Cover them (brake seals) in silicone grease to keep the water out*


*suggest you research this before you follow my hair brained ideas! Someone on internet must have put them in the freezer....

Zippy wrote:Someone on internet must have put them in the freezer....

That someone could just end up being me...

Also, while we're on the whole freezing thing - this being quite a fundamental aspect of the race - any thoughts on food?
What foods (other than ice cream) can you eat directly out of the freezer?

I've got some high 5 gels and energy bars I'm going to try in the freezer. I'm hoping that the thin coating of chocolate on them will melt quickly. I might break a few up into bite size bits I can let warm up as I eat them.

9-bars are in my list to try, as are small pieces of fudge, jelly babies and all-butter short bread.

Ian wrote:9-bars are in my list to try, as are small pieces of fudge, jelly babies and all-butter short bread.

9 bars are nice but the seeds will drive you nuts as they jam in any gap in your teeth!

I was going to carry some Wayferer boil in the bag food as these can be eaten cold should your stove pack in. Not going to bother with freeze dried food. Also, usual jelly babies (coincidently, they're 150 years old this year), nuts and raisins etc in my feed bag