O-frame & U-frame Racks

The rack is an excellent device. One of its best features is that one can add or remove brake bars from service while on rappel. O- and U-frame (i.e., closed-frame) racks sacrifice this utility in favor of added strength. For general use, the extra strength probably isn't needed, so I stick with J-frame racks.

The Howell-N-Mann Titan racks are an interesting variation. Made from certified titanium and featuring an O-frame, they are incredibly strong, but again, the ability to swap out a single bar is lost.

The last two columns in the table are the internal width and available length. These are arguably the most important dimensions for determining how well a rack functions, as opposed to how bulky it is for transport. I defined and measured the entries in these columns as follows:

• Internal Width: This is the internal distance between the two sides of the frame. I suggest using this dimension as an aid to deciding whether the rack can handle single or double rope of the size you are interested in. Most racks will function fine if this dimension is slightly smaller than double the rope diameter (say, a millimeter or two), while a large excess in this dimension doesn't add much except making the bars heavier. This does help with heat dissipation, to a point, but a 50 mm. wide rack intended for short drops on a single rope wouldn't be justified. As an example, I usually rappel on 9 mm. or 11 mm. line, and occassionally on doubled rope. A 22 to 25 mm. frame internal width is close to ideal for my needs.
• Available length for bar motion: A longer rack allows one to spread the bars out more, giving a greater control range. This is more important for lighter rappellers who, all other things being equal (and they never are), should use longer racks. In order to have a basis for comparison, I assumed that the rappeller was using four bars and that the combined space in the top three bar pairs (1-2, 2-3 and 3-4) was 35 mm., a reasonable number for 11 mm. rope. This is different than the assumption I made for J-frame racks, where I assumed five bars would be in use. I measured the total bar motion and subtracted that figure to get the numbers given here. People rappelling on six bars may wish to subtract 25 mm. from the figures given for six-bar racks. A few of the smaller racks are rigged differently, so I marked this column as "NA" for "not applicable." I entered 0 mm. for racks with fixed bars or combined bar spacings less than the 35 mm. (alt., 25 mm.) standard, effectively saying that these are constant-friction devices. The dimensions are for the racks, bars and spaces shown in the pictures on this web site. Naturally, if you change to different-size bars and/or spacers, the available length decreaseses by the increase in bar diameters and/or spacer lengths.

ID	Device	Description	Acquired	Weight	Height	Width	Thickness	Std. volume	Int. Width	Avail. Length
931	ASR NFPA	9.5 mm. SS frame, 1 long & 5 standard solid unfinished bars, lock & cap nuts	Roy Schrader, 2003	943	315	111	25	891	37	75
389	Bassett Metal Studios Mini	8 m SS frame, 1 hyperbar & 3 standard hollow SS bars, cap nuts	John E. Weinel, Inc., 1994	348	225	63	19	269	16	72
549	Bassett Metal Studios Pico-Rack	6.4 mm. SS frame, 2 16.5 & 1 14 mm. hollow SS unnotched bars, lock nuts. PED	Bassett Metal Studios, 1997	150	119	41	18	88	19	NA
527	Bassett Metal Studios, Version A	9.5 mm. SS frame, 1 dual hyperbar & 5 std hollow SS bars, lock nuts	Inner Mountain Outfitters, 1997	824	310	120	24	893	33	94
1006	Bassett Metal Studios, Version B	9.5 mm. SS frame, 2 dual hyperbar & 2 std hollow SS bars, lock nuts	Barry Duncan, 2005	702	255	120	22	658	34	97
928	Behto	7.9 mm. steel frame, 2 20 mm. hollow painted steel bars, 1 std Al bar, 1 Al hyperbar.	John E. Weinel, Inc., 2003	376	223	62	20	278	26	72
901	CMI Firefly Personal Escape Rack	6.6 mm. SS frame, 2 19.2 & 1 16.1 mm. anodized Al unnotched bars, lock nuts, PED	Karst Sports, 2001	145	125	41	19	98	20	NA
991	CMI Hyper Rack Extreme	7.9 mm. SS frame, 2 22 mm. solid hyper & 2 19 mm. solid soft anodized Al bars, lock & cap nuts	Barry Duncan, 2005	431	211	89	23	423	28	53
508	CMI Microrack	7.9 mm. SS frame, 2 22 mm. & 2 19 mm. solid unfinished Al bars, lock & cap nuts	Karst Sports, 1995	340	208	51	22	233	18	85
509	CMI Rescue Rack	9.5 mm. SS frame, 1 long solid 25 mm. Al & 6 sttamped steel bars, lock & cap nuts	Karst Sports, 1995	1015	410	102	28	1171	34	144
390	Goldlock Curlew	7.9 mm. SS frame, 4 solid soft anodized bars, lock nuts	Al Fincham, 1981	317	166	64	20	212	37	22
391	Howell-N-Mann Mini	6.5 mm. Ti frame, 1 dual Ti/Alhyperbar and 2 Ti/Al bars, screw gate, prototype #0001	Howell-N-Man, 1993	184	195	74	19	274	24	0
392	Howell-N-Mann Mt. Sira	9.5 mm. Ti frame, Dual Ti/Al hyperbar, 2 short & 1 longer Ti/Al bars, lock nuts	Ed Sira, 1994	281	213	62	20	264	21	73
393	Howell-N-Mann Titan I	9.5 mm. Ti O-Frame, 1 dual Ti/Al hyperbar & 2 standard bars, screw gate	Howell-N-Man, 1993	457	210	105	22	485	43	5
394	Howell-N-Mann Titan II	9.5 mm. Ti O-Frame, 1 dual Ti/Al hyperbar & 4 standard bars, screw gate	Howell-N-Man, 1993	334	282	105	22	651	43	24
395	Kong-Bonaiti	7 mm. SS frame, 2 22 mm. & 2 20 mm. solid unfinished Al bars, machined & pinned posts	Speleoshoppe, 1982	287	205	48	22	216	27	51
396	Kong Rackong #808PRB	7 mm. SS frame, 1 22 mm. single hyperbar, 1 22 mm. & 3 20 mm. std. bars, all bars solid anodized Al, machined & pinned posts	Amplatz Sport, 2009	329	205	82	22	368	27	52
1104	Krok 4-bar	7.9 mm. steel frame, 18 mm. bars (2 hollow, 1 solid & 1 inverted hyperbar), oxide finished, jam & lock nuts, plastic cover	Petrenko World, 2007	521	240	70	18	303	26	87
1105	Krok 5-bar	7.9 mm. steel frame, 18 mm. bars (2 hollow, 2 solid & 1 inverted hyperbar), zinc plated, jam & lock nuts, plastic cover	Petrenko World, 2007	587	240	70	18	297	26	66
1057	Mio Mechanical MIO-R	9.5 mm.SS rods on cast Al body, 4 solid 25.4 mm. Al bars, lever actuated brake cam, overspeed control	CWC Supply, 2007	2160	358	157	85	4797	29	29
1066	Mio Mechanical MIO-R2	9.5 mm. SS rods on cast Al body, 4 solid 25.5 Al bars, lever actuated brake cam	CWC Supply, 2007	1397	299	142	81	853	29	23
1064	Mio Mechanical RR-1A	9.5 mm. SS frame, 4 solid unfinished Al bars (hyperbar, short, long & short)	CWC Supply, 2007	853	287	114	25	853	36	107
1065	Mio Mechanical RR-2A	9.5 mm. SS frame,1 solid Al hyperbar and 5 short solid Al bars	CWC Supply, 2007	979	290	115	25	853	36	62
1070	Mio Mechanical RR-3S	9.5 mm. SS frame,1 SS tube hyperbar, 5 short SS tube bars, 1 center swivel tie-in bar	CWC Supply, 2007	1394	350	114	26	853	36	80
397	Pathfinder Sports	9.7 mm. SS frame, 2 solid & 4 hollow unfinished Al bars, 2 set screw spacers, hex & lock nuts	Pathfinder Sports, 1979	778	306	63	26	501	35	109
597	PFH Rap-Rak	7.9 mm. SS O frame, 3 hollow SS bars	Inner Mountain Outfitters, 2001	236	165	52	19	165	29	29
598	PFH Rap-Rak	7.9 mm. SS O frame, 4 hollow SS bars, lock-off tab	Inner Mountain Outfitters, 2001	309	225	52	19	226	29	23
599	PFH Rap-Rak	7.9 mm. SS O frame, 6 hollow SS bars, lock-off tab	Inner Mountain Outfitters, 2001	412	281	52	19	282	29	41
525	R.E.D.E. Rack	9.5 mm. SS frame, 4 solid soft anodized & 1 long hollow bar /w rubber ends, springs, nonbraking bar, lock & cap nuts	Desert Rock Sports, 1997	780	262	242	32	2029	33	20
398	Rescue Systems Inc.	9.5 mm. SS frame, 1 long & 5 standard solid unfinished bars, lock & cap nuts	John E. Weinel, Inc., 1989	957	330	111	25	916	36	96
1179	Rescue Tech Rigger Rescue Rack	9.5 mm. SS frame, 1 long & 5 standard solid unfinished bars, lock & cap nuts	Thomas Costello, 2008	987	355	111	26	1005	35	124
517	Roloff Rack, Version A	8.4 mm. SS frame, 3 10 mm. welded steel & 2 16 mm. pivoting Al solid bars, noncommercial	Ed Sira, 1995	254	180	62	17	190	32	0
545	Roloff Rack, Version B	8.4 mm. SS frame, 3 10 mm. welded steel & 2 16 mm. pivoting SS hollow bars, noncommercial	NSS Auction, 1998	196	220	50	16	176	26	0
396	SBCI, Version A	7.3 mm. SS frame, 2 22 mm. & 2 19 mm. solid grooved unfinished Al bars, machined & pinned posts	John E. Weinel, Inc., 1990	301	207	50	23	238	28	51
912	SBCI (?), Version B	7.3 mm. SS frame, 2 22 mm. & 2 19 mm. solid unfinished Al bars, machined & pinned posts	Jason Brown, 2002	295	204	50	22	226	28	50
399	Single Rope Technique DR3	7.9 mm. SS frame, 3 solid soft anodized bars, machined & pinned posts	Single Rope Technique, 1989	307	167	58	22	213	34	0
400	Single Rope Technique DR5	7.9 mm. SS frame, 5 solid soft anodized bars, machined & pinned posts	Single Rope Technique, 1989	494	257	57	22	322	34	70
1187	SMC NFPA 14400	9.5 mm. SS frame, 2 SS single hyperbars & 2 SS bars, hex & cap nuts	On Rope 1, 2009	755	241	92	25	561	32	63
1188	SMC NFPA 14600	9.5 mm. SS frame, 1 SS single hyperbar & 5 Al bars, hex & cap nuts	On Rope 1, 2009	845	356	93	27	874	32	153
401	Speleoshoppe SupeRack	9.5 mm. SS frame, 4 25 mm. solid square bars, spacers, hex & cap nuts	Jennifer Kerrigan, 1982	822	323	73	25	589	39	149
402	Storrick Monster Rack, Version A	11.3 mm. SS frame, 3 25 mm. & 3 19 mm. solid square bars, spacers, hex nut & machined posts, noncommercial	Robert W. Storrick, 1975	1179	354	88	28	872	51	75
403	Storrick Monster Rack, Version B	11.3 mm. SS frame, 3 25 mm., 3 19 mm. solid square bars, 1 round hollow bar, spacers, hex nut & machined posts, noncommercial	Robert W. Storrick, 1975	1249	354	88	28	872	50	50
1161	Unknown "S," Version A	9.5 mm. SS frame, 4 19 mm. solid round Al bars, hex nut, noncommercial	Bill Boehle, 2008	299	278	70	21	409	40	153
1162	Unknown "S," Version B	9.5 mm. SS frame, 4 19 mm. solid round Al bars, hex nut, tplastic tube spacers, noncommercial	Bill Boehle, 2008	325	286	74	19	408	43	25
1014	X-Rack	7.5 mm. SS frame, 5 19 mm. round hollow bars	Andrew Tupalski, 2006	250	248	46	19	218	25	57
521	Speleobooks Keychain Rack	5 mm. SS frame, 5 hollow SS bars, cap nuts. UNSAFE! Decorative use only.	Speleobooks, 1996	37	74	25	5	9	12	NA

URacks.html/090410
©2009, Gary D. Storrick