Posts by Charlie

Dynafit Broad Peak Carbon Ski Pole 2013

broadPeakPoleOverview

I’ve been toying with the idea of carbon poles for a while. With a gift card generously donated by Evo to the NSAS raffle burning a hole in my desk drawer, I finally gave in.

My original preference would’ve been the BD poles, on reputation alone, but they weren’t in stock for the season.  A friend uses the Dynafit poles with gusto, adding a plus to the Dynafit column. This thread, however,  makes me more than a little concerned for durability.

On to the real thing. With the usual concerns about extracting uncertainties from two measurements, the poles themselves weigh 180.9±2.4 g. The baskets are 13.5±0.4 g. In combination, they’re 194.4±2.4 grams. Dynafit’s claimed weight is 190 grams.

broadPeakPoleLatchView

The Dynafit pole lowers aren’t round, they’re D-shaped, with notches cut in them to physically block the pole from slipping. The engineering and build quality feels very fine; time will tell if the complicated linkage will hold up to years of use. I’m rather partial to the BD flicklock system (why did BD move to something with more moving parts?!), but this system seems reasonable. Dynafit has a two-year warranty on the poles.

Review/more photos below the bump.

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Ski Density

A thread over on Wildsnow got me digging back into the Off Piste data set. While in the past, I’d looked at weight per unit length vs girth, it’s also possible to plot against surface area (or surface density).

opSkiArea

The ski surface area is computed with a formula which is both atrocious and practical. If M is a ski’s mass, S is the width of the ski shovel, W is the waist, T is the tail, and L is the length of a ski, then the density D plotted on the horizontal axis is

D= \frac{M}{( S + 2 W + T) \times L / 4}

Be certain that you’ve used the right units (grams and centimeters, even for the width dimensions).

This treats the ski as two trapezoids, joined at the waist. This will tend to over-estimate the area of a ski, and hence underestimate its density. Relative comparisons of skis should be more accurate than the absolute density determined by this method. With densities determined this way, it would appear that anything in the 0.7-0.8 g/cm^2 realm is light by modern standards.

The Dynafit Cho Oyu’s claimed weight/dimensions would put it at 0.60 in these units (note that the pintail will pull the “trapezoidal density” down. Prototype skis from Ski Lab would land in the 0.64 realm.

Outdoor Research Stormtracker Glove 2012/13

I have a pair of OR Stormtrackers from 2010/11 that I really love – they’re my favorite glove ever. The softshell material keeps hands warm, but not too warm, in most temperatures we encounter in the Cascades. The Windstopper keeps things dry, at least until the DWR wears out. The old pair is now worn out/holey after two hard years of use, so it’s time for something new.  What better to replace Stormtrackers than Stormtrackers? Found a minor winter/spring sale and bought a pair.

stormtracker_glove_overview

This year’s pair is red, which is nifty. The fit at the wrist isn’t as close as before, but the zipper closure does a better job of sealing at the wrist. Not sure which I’ll prefer. Dexterity is comparable. After some break-in, it may be equivalent.

What about weight? With the usual caveats regarding assessing uncertainty from two measurements, I measure 63.1±1.5 grams per glove, for size XL, or 126.1 g for the pair. The packaging claims 168 g/pair in size L, but the current OR website claims 116 g/pair for size L.

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Vertfest

Vertfest is fast approaching, and plot-planning precedes performance, or something like that. Vertfest is an annual ski-mountaineering race held at Alpental and other venues. Alpental is closest to home, and most consistent. The race is split into roughly two divisions: a recreational route that goes to the top of the mountain and back down, and a race route that makes a second lap up and down a nearby knoll.  Am I fast enough to avoid the cut on the race route? Don’t know – experiment is the arbiter of truth.

But first, an overview:

vertfestOverview

Age is largely irrelevant. Gender doesn’t matter much either. Savvy skills are the way to go fast.

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Elan Alaska Pro 170 cm

A friend with a taste for lightweight skis brought these by for mounting. Apparently they’re a rarity here in the US. Before getting to the measurements, let me extend a hearty congratulations to Elan. Look at this excerpt from the Elan page:

ElanAlaskaProClaims

There’s an errorbar on their mass! Alas, they don’t have masses for each size, but a huzzah nonetheless!

ElanAlaskaProSecondSki

These skis are 1162 and 1145 g.  So, the pair weighed (with the usual calibration and 2-point concerns) in at 1153±15 grams. This is easily consistent with their stated uncertainty. Thank you, Elan!

As this is a very light ski, I measured the widths as well.

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SRAM Apex Brakeset 2012

I’d been interested in improved braking and modest weight savings for my newly rebuilt bike. The SRAM Apex brakes fit that bill. The new brakes saved 49 grams over the old stock brakes, originally from a ~2001 Trek 1000. At less than 1 gram saved per dollar, that’s not a lot.

Braking performance was noticeably improved. Whether it’s from the shoe-based pad design, or from different pad material, I’m not certain. The flex of the calipers is comparable to the previous brakes, so I don’t think it’s due to different caliper design.  I have a couple hundred miles on them now, in mostly dry and some wet conditions. Dry and wet braking meets or exceeds expectations.

Masses checked out nicely. SRAM claimed 308 g for the set (and still does for 2013 — unchanged?). At 152.8 g for the rear brake and 155.9 g for the front, I find 308.7 grams for the brakeset – easily within the 1-gram uncertainty implied from the quoted number’s significant digits.

sramApexFrontBrake sramApexRearBrake

Goode 95 172 cm Skis

A friend brought a beater pair of Goode 95s by for a mount on the mill. The skis themselves are in great shape, but they’re on their third or fourth mount. Skis have six inserts/ski for tele, and we added eight inserts/ski for La Sportiva bindings. Skis have had other holes filled (or not) with JB Weld.

Skis are stiff, minimal camber. The contact points are quite close to the ends of the ski. Looks like a very traditional design, and may be less forgiving of technical error than some modern skis.  Torsional stiffness is excellent; I’d expect it to hold an edge well.

goode95

 

For these skis, after calibration and unbiasing, I measure 1256 ± 40 grams . Individually, they weighed in at 1279 and 1234 g.  While these skis are holey, I’d be surprised if all 45 grams of difference between the skis is due to their post-sale history. 45 grams is a lot – almost two ounces. But, without a pristine pair, we cannot be sure.

New skis would be somewhat lighter, perhaps 20-30 g. Each ski has 17g+  of inserts alone.

Swix RC140 Skate Poles (170 cm)

swixRC140Overview

Got schooled by the kind and knowledgeable folks at Marmot Mountain on the ins and outs of skate poles. Considering my budget, the mid-grade Swix poles seemed to strike the right balance. These are the ones with the blue hatching. Definitely found the middle ground in stiffness in the Swix line, but seemingly stiffer than the full-carbon Yoko pole of the same size.

Poles weighed in at 261.6 and 263.3 g, so 262.5 ± 1.5 grams (with usual caveats about measuring errorbars off two points). Couldn’t find a Swix spec for the poles’ mass.

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Fischer CRS Skate Vasa 192 cm

 

fischerCRSSkateFull

 

The skate gear continues. As a review goes, I’m still calibrating myself as much as the skis for skate gear. No flaws, binding mount went smoothly, skis go fast.

If you’re looking at the photos, the 2000/2006 g calibration factor applies to this scale. One ski weighed in at 700 g, the other at 708 g. With the usual caveats (2 measurements is a poor way to sample a distribution),  this comes to 704±7 grams for each ski. I can’t find a spec from Fischer for the 192 cm ski.

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