What Dog Can Pull the Most Weight?
There is no single official answer, and anyone who gives you one without mentioning the pulling surface is guessing. Here is the honest, sourced version of dog weight-pull records: the biggest figures actually circulating, why you cannot compare them, and where the Boerboel fits.
The short answer
There is no single official all-breed weight-pull record, because results are not comparable across organizations or pulling surfaces. That said, the heaviest documented single-dog figure anywhere is 22,039 lb, recorded on rails for two Boerboel littermates, ColdRiver’s Sun WuKong (164 lb) and ColdRiver’s Mr. Wednesday (186 lb), who tied it at a UPF-sanctioned event in Pittsburgh on May 9, 2026.[3]
We checked every other federation that publishes results, roughly 100,000 individual result rows, and none has anything within 5,800 lb of it: the next-highest verified figure from any other body is 16,146 lb, also on rails, in W3PO competition in 2015.[7] Even so, UPF publishes no all-time records list and no organization ratifies another’s results, so 22,039 lb is the heaviest documented pull, not a certified world record.
The reason you cannot just name a “record” is the surface: a rail-cart number and a snow-sled number are different achievements even for the same dog. Get that straight and the whole topic makes sense.
Why you cannot name one record
Weight-pull numbers depend on the pulling surface and each organization’s rules, so they are not one leaderboard. A sled on snow fights the most friction and yields the lowest weights; wheels on dirt or grass sit in the middle; a low-friction rail cart allows by far the highest numbers. The UKC’s own rules make the gap explicit, crediting an advanced dog with up to about 65 times its body weight on rails but only about 25 times on snow.[1]
On top of that, different bodies (IWPA, UKC, APA, and the newer UPF) keep separate records on separate surfaces and do not ratify each other.[1, 2] So the honest framing is never “the record is X,” it is “the record in this organization, on this surface, is X.”
Rails, wheels, snow: the whole ladder
Nearly every confusing claim in this subject dissolves once you sort figures by surface. On rails, a steel-wheeled cart runs on steel rail, the lowest-friction setup in the sport, and the numbers run into five figures: 22,039 lb (UPF), 16,146 lb (W3PO), 14,445 lb (APA).[3, 7, 8] On wheels, a tired cart on carpet, dirt or grass, the ceiling anywhere is 6,250 lb.[9] On snow, a runnered sled fights both drag and breakaway stiction, and the ceiling anywhere is about 3,380 lb.[9]
One dog demonstrates the entire ladder by itself. Dezzy, the Greater Swiss Mountain Dog credited with that 14,445 lb rails figure, is recorded by the same organization at 730 lb on snow.[8] Same dog, same rulebook, roughly a twentyfold difference. That gap is friction, not the dog.
So a rails number and a snow number never compete for the same title. Any article that ranks them together is not measuring dogs, it is measuring friction. It is also why the UKC caps matter: its rules withdraw a dog once it reaches 65 times body weight on rails but only 25 times on snow, which is a rule, not a performance.[1]
Every federation’s heaviest, side by side
We went and checked. Every organization that publishes weight-pull results was swept and its own heaviest published single-dog figure pulled out, roughly 100,000 individual result rows in total. No federation on this list publishes an all-time records page, so with one exception these are the heaviest figures in each body’s own results, not records any of them claim. Read the surface column before you compare any two rows.
| Organization | Heaviest | Dog | Surface | Basis |
|---|---|---|---|---|
| UPF (Unified Pulling Federation) | 22,039 lb | ColdRiver's Sun WuKong (164 lb) and ColdRiver's Mr. Wednesday (186 lb), Boerboels, tied, 5/9/2026 | Rails | Published result |
| W3PO (World Wide Weight Pull Organization) | 16,146 lb | Moose, American Pit Bull Terrier, 104 lb, 4/18/2015 | Rails | Published result |
| APA (American Pulling Alliance) | 14,445 lb | Dezzy, Greater Swiss Mountain Dog, 100 lb, 5/27/2023 | Rails, carpet track | Published result |
| EWPL (European Weightpull League) | 9,006 lb (4,085 kg) | Zazza, Boerboel, 132 lb, 7/21/2019 | Not recorded by EWPL | Published result, surface unknown |
| EWPAS (European Weight Pulling All Stars) | 7,937 lb (3,600 kg) | Sigurd, American Bulldog, 80 lb, 10/23/2021 | Not recorded | Published result, surface unknown |
| Historical Guinness Book entry | 6,400 lb 8 oz | Ryettes Brandy Bear, St Bernard, 176 lb, 7/21/1978 | Wheeled carrier on cement | Historical entry, no longer published |
| IWPA (International Weight Pull Association) | 6,075 lb record (6,250 lb heaviest result) | Tank, Mastiff, 187 lb, 5/1/2022 (Noble, Mastiff, 200 lb, 3/9/2013) | Wheels on carpet. IWPA runs no rails. | Federation record |
| Iron Dog Sports Association | 5,456 lb | Hater (APBT, 39 lb) and Aset (Presa Canario, 103 lb), tied, 5/2/2026 | Not stated on the sheet | Published result, surface unknown |
| UKC (United Kennel Club) | Not derivable | UKC publishes only multiples of body weight, never pounds | Rails, wheels and snow all sanctioned | No poundage published |
| ADBA, NAWA, ABA | Unknown | No public results database exists for any of the three | Various | No results published |
Only IWPA’s 6,075 lb is a figure a federation itself calls a record, and IWPA sets records only at its Championships, which is why a heavier 6,250 lb regional result sits above it.[9] Everything else here is the heaviest figure in that organization’s published results.[3, 7, 8]
Numbers that look bigger, and why they are not
Five rows in the sport’s public data display figures above 22,039 lb. All five are in APA’s raw archive, and every one collapses on inspection: they are single-extra-digit typing errors, disproved by the percentage APA itself prints on the same row.[8] The 46,785 lb entry carries a percentage of 50.81, which for a 92 lb dog works out to roughly 4,675 lb, and that dog is listed second, behind a 5,575 lb winner. A 32,758 lb entry resolves the same way (29.24 x 112 lb = 3,275 exactly). A naive scrape of the sport’s results will tell you these are real pulls. They are not.
The only genuine figure anywhere above 22,039 lb is the Guinness dog sled TEAM record, 145,302 lb by 210 dogs in Whitehorse, Yukon in 2000.[10] That is roughly 692 lb per dog, and a completely different category from one dog on a cart.
The old Guinness record, and the version everyone repeats
Guinness lists no single-dog weight-pull title today.[10] It once did, and that entry is the source of a story you will see repeated constantly, almost always garbled. The actual printed record: a four-year-old, 176 lb St Bernard named Ryettes Brandy Bear moved 6,400 lb 8 oz of railroad steel on a four-wheeled carrier across a cement surface, 15 feet in under 90 seconds, at Bothell, Washington on 21 July 1978, owned by Douglas Alexander of Monroe, Washington.[11] Ten days earlier the same dog moved 6,600 lb but stopped five inches short of the required distance, so it did not count.
Three corrections worth making, because the wrong version is everywhere: the dog was not named “Ryan” (that is a corruption of the kennel prefix “Ryettes”), the owner was not “Douglas Alsop of Kirkland”, and it was on wheels over concrete, not a sled and not snow. That last point is the one that matters here: even this famous figure is a wheels number, under a third of 22,039 lb on rails, and the two are not the same test.
Pound-for-pound vs absolute
There are really two contests here. Bully breeds like the American Pit Bull Terrier dominate pound-for-pound (ratio) pulling, while northern and mastiff-type giants hold the highest absolute weights. As a striking ratio example, Whole Dog Journal reported that Banzai, a 43-pound American Staffordshire Terrier, pulled 3,900 pounds, about 90 times her body weight, as an owner-reported personal best.[4] No giant breed comes close to that multiple, and no small breed comes close to a giant’s absolute weight. Different questions, different winners.
Where the Boerboel fits
The Boerboel is a heavyweight puller: it competes in the top weight classes, holds UKC weight-pull championship titles, and, in Sun WuKong, produced the single largest number currently in circulation.[3] It is not the pound-for-pound king, that title belongs to the bully breeds, but on absolute weight and titled competition, it is squarely in the top tier.
For the full, honestly-labeled Boerboel picture, including exactly what is verified versus kennel-reported and where a son of our stud Peterbuilt Hakeem fits in, read our Boerboel weight-pull page and our Boerboel strength guide.
Dog Weight Pull Records FAQ
What dog holds the weight pull record?
There is no single official all-breed record, because results are not comparable across organizations or surfaces. The heaviest documented single-dog figure is 22,039 lb, pulled on rails by two Boerboel littermates, ColdRiver's Sun WuKong (164 lb) and ColdRiver's Mr. Wednesday (186 lb), at a UPF event in Pittsburgh on May 9, 2026. UPF keeps no all-time records list, so it is not a ratified world record.
What is the most weight ever pulled by one dog?
22,039 lb, on rails, tied by two Boerboel littermates, ColdRiver's Sun WuKong (164 lb) and ColdRiver's Mr. Wednesday (186 lb), at a UPF-sanctioned event in Pittsburgh on May 9, 2026. It is the heaviest single-dog figure in any weight-pull organization's published results. The next highest from any other body is 16,146 lb (W3PO, rails, 2015).
Has any dog pulled more than 22,039 lb?
No single dog on record. We swept every federation that publishes results, roughly 100,000 result rows, and nothing credible reaches even 17,000 lb. A handful of larger numbers appear in public data but are data-entry typos, contradicted by the percentage columns printed beside them. The only real bigger figure is a Guinness dog-sled TEAM record of 145,302 lb by 210 dogs, about 692 lb per dog.
What is the strongest dog breed?
It depends on the measure. By absolute pulling weight, giant molosser and northern breeds like Mastiffs, Boerboels and Malamutes compete hardest; by pound-for-pound ratio, bully breeds like the American Pit Bull Terrier lead. There is no head-to-head study that ranks breeds by strength, so any flat 'strongest breed' claim is an opinion, not a measurement.
How much weight can a dog pull?
Far more than most people expect, and it depends mostly on the surface. UKC rules credit an advanced dog with up to about 65 times its body weight on a low-friction rail cart but only about 25 times on snow. That is why the same dog posts wildly different numbers, and why surface must always be stated alongside the weight.
Is there an official dog weight pull world record?
Not a unified single-dog one. Different organizations (IWPA, UKC, APA, UPF) keep their own records on their own surfaces, so a rail figure and a snow figure are not the same achievement. Guinness World Records recognizes a greatest-weight-pulled-by-a-dog-TEAM record for sled dogs, which is a different category from a single dog on a cart.
Sources & further reading
- [1] Official UKC Weight Pull Rulebook (surface classes and multiples of body weight; the 16-foot pull). United Kennel Club. https://www.ukcdogs.com/docs/rulebooks/weight-pull-rulebook.pdf
- [2] International Weight Pull Association: rules and records (wheels and snow scored separately). IWPA. http://www.iwpa.net/
- [3] Official results sheet, 'Spring Into Bully Max' weight pull, 5/9/26, Pittsburg PA, rails: Boerboels Wednesday (186 lb) and Sun Wukong (164 lb) each recorded at 22,039 lb, the heaviest figures in the federation's published results. Unified Pulling Federation (UPF). https://unifiedweightpullfederation.com/assets/files/events/events_6a5b6241a0346.pdf
- [4] Whole Dog Journal: canine weight pull (ratio vs absolute; 'Banzai,' a 43-lb AmStaff, reported at 3,900 lb). Whole Dog Journal. https://www.whole-dog-journal.com/activities/weight-pulling/
- [5] Guinness World Records: greatest weight pulled by a dog team (Iditarod-type sled dog teams; not a single-dog pull). Guinness World Records. https://www.guinnessworldrecords.com/
- [6] Boerboel weight pull: records, rules and honestly-labeled numbers (companion page). Peterbuilt Boerboel. https://www.peterbuiltboerboel.com/the-boerboel-breed/weight-pull
- [7] Official result sheet, pull 15-10 'Summits 2015', Monroe MI, 4/18/2015, surface stated as Rails: Moose (APBT, 104 lb) 16,146 lb in 25.84 sec, 155.25x body weight. World Wide Weight Pull Organization (W3PO). https://www.worldwideweightpull.net/15-10-MonroeMI-Rails.html
- [8] Published results archive, 4,125 sanctioned events from 2003 to May 2026 (the source for APA's heaviest internally consistent result, 14,445 lb by Dezzy on rails/carpet, 5/27/2023). American Pulling Alliance (APA). http://www.weightpull.com/results/home2.asp
- [9] Championship records tables: the heaviest IWPA official record is 6,075 lb by Tank (Mastiff, 187 lb), wheels on artificial surface, Grand Rapids MI, 1 May 2022; IWPA sanctions wheels and snow only, never rails. IWPA. http://www.iwpa.net/IWPA_Championships.html
- [10] Heaviest weight pulled by a dog sled TEAM: 145,302 lb by 210 dogs, Whitehorse, Yukon, 22 Oct 2000 (a team category; Guinness lists no single-dog weight-pull title). Guinness World Records. https://www.guinnessworldrecords.com/world-records/heaviest-weight-pulled-by-a-dog-sled-team
- [11] Historical Guinness Book of World Records printed editions, 'greatest load shifted by a dog': 6,400 lb 8 oz by the St Bernard Ryettes Brandy Bear, Bothell WA, 21 July 1978 (searchable full text). Guinness Book of World Records via Open Library. https://openlibrary.org/search/inside?q=%22greatest+load+shifted+by+a+dog%22
Last reviewed July 2026. Figures are reported or federation-specific and are not directly comparable across surfaces or sanctioning bodies.
The Boerboel, up close
The heavyweight puller with the record currently in circulation is a Boerboel. See how the breed’s strength really works, and meet the line behind it.