O-frame & U-frame Racks
(a.k.a. Closed-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. Closed-frame racks sacrifice this utility in favor of added strength. For general use, the extra strength isn't needed, so I prefer Open-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.

Image	ID ⇓	Device ↓	Description	Acquired	Weight ↓	Height ↓	Width ↓	Thickness ↓	Std. volume ↓	Int. Width ↓	Avail. Length ↓
	2571	Anpen	9.4 mm. SS frame, 2 22 mm. solid hyper & 2 22 mm. solid soft anodized Al bars, pinned threaded posts	Larry Brocker, 2020	508	218	85	22	405	26	53
	931	ASR NFPA	9.5 mm. SS frame, 1 long & 5 standard solid bars (3 color anodized), lock & cap nuts	Roy Schrader, 2003	943	315	111	25	891	37	109
	3308	Bassett Metal Studios Experimental	7.9 mm. SS frame, square SS bars (one /w hyperbar)	Bassett Metal Studios, 2023	217	163	69	20	220	19	56
	1234	Bassett Metal Studios Microrack, Version A	7.9 mm. SS frame, 1 hyperbar & 3 standard hollow SS bars, cap nuts	Howie’s Harnesses, 2009	430	269	70	27	498	18	109
	2458 3215	Bassett Metal Studios Microrack, Version B	7.9 mm. SS frame, 1 hyperbar & 3 standard hollow SS bars, lock nuts	On Rope 1, 2017 Kelley Deem, 2022	401	228	70	25	401	18	65
	3186	Bassett Metal Studios Microrack, Version C	7.9 mm. SS frame, 2 hyperbar & 2 standard hollow SS bars, lock nuts	Shawn Edgecomb (refined_trades), 2022	440	229	70	21	341	18	65
	389	Bassett Metal Studios Mini	8 mm. SS frame, 1 hyperbar & 3 standard hollow SS bars, cap nuts	John E. Weinel, Inc., 1994	348	225	63	19	269	16	72
	549 2400 2474	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 Bob Thrun Collection, 2017 Bill Liebman, 2017	150	119	41	18	88	19	0
	527	Bassett Metal Studios, Version A	9.5 mm. SS frame, 1 dual hyperbar & 5 standard 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 standard hollow SS bars, lock nuts	Barry Duncan, 2005	702	255	120	22	658	34	97
	928	Венто (Vento)	7.9 mm. steel frame, 2 20 mm. hollow painted steel bars, 1 standard Al bar, 1 Al hyperbar.	John E. Weinel, Inc., 2003	376	223	62	20	278	26	72
	1450	British, Version A	9.5 mm. SS frame, 5 solid 19 mm. Al bars, lock nuts	Jim Mousley, 2015	453	200	65	20	256	28	40
	2402	British, Version B	9.5 mm. SS frame, 6 solid 19 mm. Al bars, lock nuts	Bob Thrun Collection, 2017	574	277	65	19	336	28	90
	3072	Chkalov Aviation Plant	7.2 mm. Steel frame, 3 hollow bars & 1 hollow hyperbar, tubular posts	Artyom Babin (Артём Бабин), 2021	382	223	64	21	304	29	68
	1478	CMC 3D	9.5 mm. SS frame /w milled flats, Upper dual hyperbar, 1 large bar /w latch, inverted lower dual hyperbar	Inner Mountain Outfitters, 2016	483	171	106	32	569	20	0
	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	0
	3355	CMI Hyper Rack	7.9 mm. SS frame, 1 22 mm. solid hyper & 3 19 mm. solid Al bars, lock & cap nuts	Dorn, 2023	381	208	89	22	415	28	52
	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
	1293	Howell-N-Mann Version A	9.5 mm. Ti frame, Dual Ti/Al hyperbar & 5 short Ti/Al bars, lock nuts	Sam Howell, 1920	488	277	115	19	605	43	82
	1379	Howell-N-Mann Version B	9.5 mm. Ti frame, Ti/Bondo hyperbar, 2 short & 1 long Ti bars	Ed Sira, 2012	500	242	90	19	412	20	90
	1380	Howell-N-Mann Version C	9.5 mm. Ti frame, Ti/Al hyperbar, 2 short Ti/Al bars, 1 long Ti/Al dual-horn bar, pinned caps	Ed Sira, 2012	291	199	88	21	365	19	60
	391	Howell-N-Mann Mini	6.5 mm. Ti frame, 1 dual Ti/Al hyperbar 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, Version A	9.5 mm. Ti O-Frame, 1 dual Ti/Al hyperbar & 2 standard bars, screw gate	Howell-N-Man, 1993 Sam Howell, 2011	334	210	105	22	485	43	5
	1292	Howell-N-Mann Titan I, Version B	9.5 mm. Ti O Frame, 1 dual Ti/Al hyperbar & 2  standard bars, screw gate	Sam Howell, 2011	337	212	105	25	565	42	1
	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	457	282	105	22	651	43	24
	1290	Howell-N-Mann Titan Prototype	9.5 mm. Ti O Frame, 1 Ti/Al hyperbar & 4 standard bars, screw gate	Sam Howell, 2011	385	305	106	29	934	40	27
	1291	Howell-N-Mann Titan 4-Bar	9.5 mm. anodized Ti O Frame, 1 Ti/Al hyperbar & 3 standard bars, screw gate	Sam Howell, 2011	410	234	112	23	600	42	0
	395	Kong-Bonaiti, Version A	7 mm. SS frame, 2 22 mm. & 2 20 mm. solid unfinished Al bars, machined & pinned posts	Inner Mountain Outfitters, 1987	287	205	48	22	216	27	51
	1329	Kong-Bonaiti, Version B	7 mm. SS frame, 2 22 mm. & 2 20 mm. solid unfinished Al bars, machined & pinned posts	Geoffrey Storey, 2012	289	205	48	22	217	27	49
	1194	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, Version A	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
	1331	Krok 4-bar, Version B	8 mm. steel frame, 18 mm. bars (3 solid & 1 inverted hyperbar), galvanized, threaded posts	Gear4Rocks, 2012	535	202	71	18	256	26	39
	1333	Krok Speleo	8 mm. steel frame, 18 mm. hollow bars (3 plain & 1 inverted hyperbar), galvanized, threaded posts	Gear4Rocks, 2012	467	203	70	20	284	25	33
	1105	Krok 5-bar, Version A	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
	1351	Krok 5-bar, Version B	8 mm. steel frame, 18 mm. bars (2 hollow, 2 solid) & 1 inverted 18.8mm hyperbar, posts	Gear4Rocks, 2012	643	243	70	19	322	25	60
	1332	Krok 5-bar, Version C	8 mm. steel frame, 18 mm. bars (2 hollow, 2 solid) & 1 inverted 17.2mm hyperbar, zinc plated, jam & lock nuts, plastic cover	Gear4Rocks, 2012	607	240	70	19	317	26	66
	2519 3343	Kyle Isenhart Super Rack	9.5 mm. SS frame, 4 25 mm. solid square bars, spacers, hex & cap nuts	Ed Sira, 2019 Kelley Deem, 2023	779	305	62	25	483	39	101
	1057	Mio Mechanical MIO-R, Version A	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	24
	3049	Mio Mechanical MIO-R, Version B	9.5 mm. SS rods on cast Al body, 3 solid Al & 1 hollow SS bars, lever actuated brake cam, overspeed control	Brian Woodruff, 2021	1970	357	136	81	3924	29	24
	1459	Mio Mechanical MIO-R2, Version A	9.5 mm. SS rods on cast Al body, 4 solid 25.5 Al bars, lever actuated brake cam	Don Stephens, 2015	1382	300	163	80	3908	29	28
	1066	Mio MechanicalMIO-R2, Version B	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
	3321	Mio Mechanical MIO-R2, Version C	9.5 mm. SS rods on cast Al body, 4 solid 25.4 mm. SS bars, lever actuated brake cam	MX Pawn, 2023	1384	319	133	81	3414	29	18
	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
	3348	New Zealand	7.9 mm. SS frame, 5 standard hollow SS bars, lock nuts	Bru Randall, 2023	419	213	56	19	228	28	48
	3109	Orion-Alp 4-bar Aluminum (Орион-Альп Решетка 4 ролика Алюминиевая)	7.9 mm. plated steel frame, 3 painted solid Al bars & 1 inverted hyperbar, hex nuts	Artyom Babin (Артём Бабин), 2021	351	227	68	20	303	24	67
	2584	Orion-Alp 4-bar Steel (Орион-Альп Решетка 4 ролика Стальная)	8.0 mm. Steel frame, 3 U-shaped bars &  1 U-shape hyperbar, hex nuts	Artyom Babin (Артём Бабин), 2020	417	226	68	24	372	24	66
	3110	Orion-Alp 5-bar Steel (Орион-Альп Решетка 5 ролика Стальная)	7.9 mm. plated steel frame, 4 U-shaped bars &  1 U-shape hyperbar, hex nuts	Artyom Babin (Артём Бабин), 2021	492	226	84	25	465	24	43
	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, 3–Gate	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, 4–Gate	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, 6–Gate	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
	2532	Raimond	5.6 mm. SS frame, 5 grooved SS bars, spring & latch, hex and acorn nuts.	Gintautas Švedas, 2019	308	233	34	15	118	15	72
	398	Rescue Systems Inc., Version A	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
	2445	Rescue Systems Inc., Version B	9.5 mm. SS frame, 1 long & 5 standard solid unfinished bars, lock & cap nuts	Bob & Bob, 2017	999	333	111	25	941	36	100
	1179 1195	Rescue Technology Rigger Rescue Rack	9.5 mm. SS frame, 1 long & 5 standard solid unfinished bars, lock & cap nuts	Thomas Costello, 2008 William Deaton, 2009	987	355	111	26	1005	35	124
	2585	Ring (Рцнг), Version A	7.2 mm. Steel frame, 3 hollow bars & 1 hollow hyperbar, tubular posts	Artyom Babin (Артём Бабин), 2020	414	222	64	22	312	24	65
	3071	Ring (Рцнг), Version B	7.2 mm. Steel frame, 2 hollow bars & 2 hollow hyperbars, tubular posts	Artyom Babin (Артём Бабин), 2021	407	222	64	21	304	23	67
	517 3058	Roloff Rack, Version A	7.0 mm. SS frame, 3-10 mm. welded steel & 2-16 mm. pivoting Al solid bars, noncommercial	Ed Sira, 1995 cptnamerica2003, 2021	254	180	62	17	190	32	0
	3057	Roloff Rack, Version B	7.8 mm. SS frame, 3-10 mm. welded steel & 2-16 mm. pivoting Al solid bars, noncommercial	cptnamerica2003, 2021	319	214	65	17	238	39	0
	545	Roloff Rack, Version C	6.2 mm. SS frame, 3-10 mm. welded steel & 2-16 mm. pivoting Al solid bars, noncommercial	NSS Auction (Bill Papke), 1998	196	220	50	16	176	26	0
	3111 3113	Russian Homemade	8.1 mm. steel frame, 1 18mm. solid steel hyperbar & 3 solid steel bars, noncommercial	Artyom Babin (Артём Бабин), 2021	586	213	74	19	298	27	54
	396 2471	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 Bill Liebman, 2017	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
	2472	SBCI, Version C	7.3 mm. SS frame, 2 22 mm. & 2 19 mm. solid unfinished Al bars, machined & pinned posts	Bill Liebman, 2017	296	208	49	22	228	28	50
	2444	SBCI, Version D	9.5 mm. SS frame, 1 long & 5 standard solid bars (3 color anodized), lock & cap nuts	Bob & Bob, 2017	962	340	25	111	959	34	109
	399	Single Rope Technique DR3	7.9 mm. SS frame, 3 solid soft anodized bars, machined & pinned posts	Single Rope Technique Equipment, 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 Equipment, 1989	494	257	57	22	322	34	70
	1187	SMC NFPA 14400, Version A	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
	2521	SMC NFPA 14400, Version B	9.5 mm. SS frame, 2 SS single hyperbars & 2 SS bars, hex & cap nuts	Inner Mountain Outfitters, 2019	766	246	93	25	579	32	60
	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
	1415	SMC Micro Rack	7.9 mm. SS frame, 2 SS single hyperbars & 2 SS bars, hex & cap nuts	Inner Mountain Outfitters, 2014	408	239	70	22	360	18	77
	1423	SOB	9.0 mm. SS O frame, 4 standard Al bars, 1 inverted hyperbar	Gold Bucket, 2014	509	284	82	23	529	28	44
	521	Speleobooks Key Chain Rack	5 mm. SS frame, 5 hollow SS bars, cap nuts. UNSAFE! Decorative use only.	Speleobooks, 1996	37	74	25	5	9	12	0
	2489	Speleoshoppe SupeRack, Version A	9.5 mm. SS frame, 4 25 mm. solid square &1 round bars, spacers, hex & cap nuts	Kenneth Macke, 2018	881	321	82	25	661	39	112
	401 1378 2401	Speleoshoppe SupeRack, Version B	9.5 mm. SS frame, 4 25 mm. solid square bars, spacers, hex & cap nuts	Jennifer Kerrigan, 1982 Jack Hissong, 2012 Bob Thrun Collection, 2017	822	323	73	25	589	39	149
	1377	Speleoshoppe SupeRack, Version C	9.5 mm. SS frame, 5 25 mm. solid square bars, 1 Seaman bar, spacers, hex & cap nuts	Speleoshoppe, 2012	973	322	70	26	579	35	80
	1230	Storrick Femtorack	7.9 mm. SS frame, 1 16 mm. & 1 19 mm. SS bar, lock nuts	Gary Storrick, 2009	221	94	46	19	82	17	0
	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
	1264	Unknown	9.8 mm. painted SS frame, 6 19 mm. solid round soft-anodized Al bars, lock nuts	Ron Boomsma, 2010	521	239	64	19	291	28	67
	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
	3114	Vento (Венто)	8.0 mm. steel frame, 3 19 mm.  Steel bars &  1 19mm. inverted steel hyperbar, round posts.	Artyom Babin (Артём Бабин), 2021	604	223	72	19	305	25	63
	3168	Vertical (Вертикаль), Version A (ver 0301)	8.0 mm. steel frame, 3 18 mm.  Steel bars & 1 18 mm. inverted steel hyperbar, round posts.	Vertical (Вертикаль) via Artyom Babin (Артём Бабин), 2022	540	227	71	18	288	25	87
	3169	Vertical (Вертикаль), Version B (ver 0302)	8.0 mm. steel frame, 3 18 mm.  Al bars & 1 18 mm. inverted Al hyperbar, round posts.	Vertical (Вертикаль) via Artyom Babin (Артём Бабин), 2022	331	229	70	18	290	25	86
	3170	Vertical (Вертикаль), Version C (ver 0303)	8.0 mm. steel frame, 2 18 mm.  tubular steel bars, 1 18 mm. solid Al bar, &  1 18 mm. inverted steel hyperbar, round posts.	Vertical (Вертикаль) via Artyom Babin (Артём Бабин), 2022	329	228	70	18	289	25	85
	3171	Vertical (Вертикаль), Version D (ver 0304)	8.0 mm. steel frame, 2 18 mm. solid Al bars, 2 18 mm. tubular steel bars, & 1 18 mm. inverted steel hyperbar, round posts.	Vertical (Вертикаль) via Artyom Babin (Артём Бабин), 2022	355	228	70	18	288	25	68
	1429	WHiO, Version A	6.3 mm. Ti frame, 5 15.8 mm. tubular round Ti bars, hex & acorn nuts.	Bevan Trower, 2014	134	238	51	16	193	24	90
	1430	WHiO, Version B	6.3 mm. Ti frame, 1 15.8 mm. tubular round Ti hyperbar & 4 15.8 mm. tubular round Ti bars, hex & acorn nuts.	Bevan Trower, 2014	144	234	75	16	279	24	85
	1014	X-Rack	7.5 mm. SS frame, 5 19 mm. round hollow bars	Andrew Tupalski, 2006	250	248	46	19	218	25	57

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