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Krok

4-bar, Ver. A 4-bar, Ver. B Speleo
4-bar, Ver. A 4-bar, Ver. B Speleo
 
5-bar, Ver. A 5-bar, Ver. B 5-bar, Ver. C
5-bar, Ver. A 5-bar, Ver. B 5-bar, Ver. C

Overview


4-bar, Version A
(#1104)

Front View Rear View Side View
Front View Rear View Side View

Technical Details

I acquired my 4-bar Version A rack from PetrenkoWorld (now Gear4Rocks) in 2007. Gear4Rocks is the same company as Krok, the only difference is that the Krok trademark sells gear only inside the Ukraine, and the Gear4Rocks trademark was created to spread Ukrainian gear around the world.

Version A rack is 240 mm. tall, 70 mm. wide, 18 mm. thick, and weighs 521 g.

The frame is 7.9 mm. steel with 26 mm. internal spacing between the two legs. The first and third bars are 50 mm. long and made from 18 mm. o.d., 4.1 mm. steel tubing. They do not open. The second bar is 50 mm. long with an 18 mm. diameter. It has the end cut away so that it opens freely (i.e., no "click" closure). The bottom bar is an inverted 70 by 18 mm. hyperbar; like the third bar, it opens freely. Allowing 35 mm. for the rope leaves 87 mm. for spreading the bars.

Each leg of the frame has a hex nut backed by a nylon lock nut. The threads protruding above the lock nut are covered by plastic tubing. A steel sleeve pressed onto the frame near the U-bend keeps the bars from moving too far downward.

All steel parts except the nuts have a black oxide finish.

There are no markings on this rack.

Comments

The plastic sleeves are inadequate. The frame should have been threaded to the proper length or else metal sleeves should have been provided. This deficiency was corrected in later versions.

The steel bars make this a rather heavy rack for its size (more than a pound).

Oxide finishes do not completely protect steel, and this rack will rust if stored wet.


4-bar, Version B
(#1331)

Front View Rear View Side View
Front View Rear View Side View

Technical Details

I acquired this rack from Gear4Rocks in 2012.

Version B rack is 202 mm. tall, 71 mm. wide, 18 mm. thick, and weighs 535 g. The frame is made from 8.0 mm. steel bent into a U, with an internal width of 26 mm.

There are four solid steel brake bars. The bars are 18 mm. in diameter. The top three are 50 mm. long and the bottom is 71 mm. long with an inverted hyperbar. The second and fourth bars have their end cut away so that they opens freely (i.e., no "click" closure).

The bars are held on by tall threaded posts that double as rope guides for locking off. A steel sleeve pressed onto the frame near the U-bend keeps the bars from moving too far downward.

All parts are zinc plated.

There are no markings on this rack.

Comments

Notice that the frame is now shorter than it was with the previous version or with the corresponding 5-bar rack. Allowing 35 mm. for the rope leaves 39 mm. for spreading the bars, but four bars do not provide as much friction as I prefer.

The solid steel bars bring the weight of this rack to more than a pound. In my opinion, this is far too heavy for a device of this size and limited friction capability.

The down-pointing hyperbar is useless except for tying off, and then it is unnecessary. I see no value to having a hyperbar here. A better choice would have been to provide a standard up-pointing hyperbar on a fixed top bar.


Speleo
(#1333)

Front View Rear View Side View
Front View Rear View Side View

Technical Details

I acquired this rack from Gear4Rocks in 2012.

The Speleo is 203 mm. tall, 70 mm. wide, 20 mm. thick, and weighs 467 g. The frame is made from 8.0 mm. steel bent into a U, with an internal width of 25 mm.

There are four hollow steel brake bars. The bars are 20 mm. in diameter and have 3.7 mm. thick walls. The top three are 50 mm. long and the bottom is 70 mm. long with an inverted hyperbar. The second and fourth bars have their end cut away so that they opens freely (i.e., no "click" closure).

The bars are held on by tall threaded posts that double as rope guides for locking off. A steel sleeve pressed onto the frame near the U-bend keeps the bars from moving too far downward. All parts are zinc plated.

There are no markings on this rack.

Comments

The hollow bars provide a weight savings compared to the other Krok four-bar racks, but this is partially offset by the increased bar diameter.

The down-pointing hyperbar is useless except for tying off, and then it is unnecessary. I see no value to having a hyperbar here. A better choice would have been to provide a standard up-pointing hyperbar on a fixed top bar.


5-bar, Version A
(#1105)

Front View Rear View Side View
Front View Rear View Side View

Technical Details

I acquired my 4-bar from PetrenkoWorld (now Gear4Rocks) in 2007.

My Krok 5-bar, Version A rack is 240 mm. tall, 70 mm. wide, 18 mm. thick, and weighs 587 g. The frame is made from 7.9 mm. steel bent into a U, with an internal width of 26 mm.

There are five brake bars. The bars are 18 mm. in diameter. The top four are 50 mm. long and the bottom one is 70 mm. long. Allowing 35 mm. for the rope leaves 66 mm. for spreading the bars.

The bars are retained by hex and lock nuts, and plastic sleeves are provided to cover the exposed threads above the nuts. A steel sleeve pressed onto the frame near the U-bend keeps the bars from moving too far downward. All steel parts except the nuts are zinc plated.

There are no markings on this rack.

Comments

The 5-bar uses the same frame and bars as the 4-bar, but adds a fifth bar at the top, so that the first and third bars are solid, pivoting bars, while the second and fourth are solid. Having the odd-numbered bars pivot on a U-frame rack is an unusual choice, but it works.

The plastic sleeves are inadequate. The frame should have been threaded to the proper length or else metal sleeves should have been provided. This deficiency was corrected in later versions.


5-bar, Version B
(#1351)

Front View Rear View Side View
Front View Rear View Side View

Technical Details

I acquired this rack from Gear4Rocks in 2012.

Version B is 243 mm. tall, 70 mm. wide, 19 mm. thick, and weighs 643 g. The frame is made from 7.9 mm. steel bent into a U, with an internal width of 25 mm., and oxide finished.

There are five oxide-finished steel brake bars. The top and third bars are 18 mm. in diameter, the others are 19 mm. The top four bars are 51 mm. long, while the bottom one is 71 mm. and has an inverted hyperbar. The odd-numbered bars are solid and pivot on the frame, and the even-numbered bars are hollow with 3.8 mm. walls. Allowing 35 mm. for the rope leaves 60 mm. for spreading the bars.

The bars are held on by tall, threaded, zinc plated posts that double as rope guides for locking off. A zinc plated steel sleeve pressed onto the frame near the U-bend keeps the bars from moving too far downward.

There are no markings on this rack.

Comments

Because of the multiplicative effect adding a bar has on friction (recall the snubbing equation ΔT=e-μθ), the fifth bar considerably improves the performance of this rack compared to the four-bar models.

The down-pointing hyperbar is useless except for tying off, and then it is unnecessary. I see no value to having a hyperbar here. A better choice would have been to provide a standard up-pointing hyperbar on a fixed top bar.

Oxide finishes do not completely protect steel, and this rack will rust if stored wet.


5-bar, Version C
(#1332)

Front View Rear View Side View
Front View Rear View Side View

Technical Details

I acquired this rack from Gear4Rocks in 2012.

Version C is 240 mm. tall, 70 mm. wide, 19 mm. thick, and weighs 607 g. The frame is made from 7.9 mm. steel bent into a U, with an internal width of 26 mm.

There are five 18 mm. in diameter steel brake bars. The top four bars are 50 mm. long and hollow with 3.8 mm. walls. The bottom bar is 70 mm. long, solid, and has an inverted hyperbar. Allowing 35 mm. for the rope leaves 60 mm. for spreading the bars.

The bars are held on by tall threaded posts that double as rope guides for locking off. A steel sleeve pressed onto the frame near the U-bend keeps the bars from moving too far downward.

All parts are zinc plated.

There are no markings on this rack.

Comments

The zinc plating will help prevent rusting, but the rack should be dried prior to storage.

The down-pointing hyperbar is useless except for tying off, and then it is unnecessary. I see no value to having a hyperbar here. A better choice would have been to provide a standard up-pointing hyperbar on a fixed top bar.