Sturmey Archer 3 speed AW gearhub. How it works.

[@koosnaamloos4291]

About an hour ago, I opened an old 3-speed Sturmey Archer and found that three of those four prongs seen at 6:30 had broken off. No idea how that ever happened, but it did explain why the bike decided to fully lock up at speed. Thanks for the informative video!

[@davec1179]

Thanks for the video Dan As a boy in the 1950,s My bike had a 3/4 speed trigger but a 3 speed hub. Spent years trying to find the 4th gear that never existed.

[@TheKoolWhip]

GREAT job, Dan. I was born in 1958 and have one foot in the mechanical age and the other in the electronic age. It seems that an appreciation for mechanics has gotten drowned out by computers, video, circuits, and pixels. Thanks for an eloquent, clear lesson on the genius of mechanical design, and what happens when I click that little lever that enables me to get up the hill just a bit easier!

[@nigelbradley613]

10yrs ago I bought a 'box of bits' which made a 74 Raleigh Chopper. I couldn't get the gears to work so bit the bullet, stripped them, got rid of all the solid grease from 40+ years of sitting. lubed up and put it back together and it worked like a dream. I also converted it to 9 speed by adding 3 sprockets and welding on a rear hanger for a derailleur and using a friction shift for that. The hub has now done in excess of 5000 miles and still going strong. Of all my bikes, it would be the one I'd choose if I was riding up to 70 miles. I laugh when people tell me derailleurs are 'complicated'

[@nikitis13]

I just purchased my first SA driven bicycle and was curious to know the inner mechanicals of operation. What a piece of brilliant engineering! Thanks for a well presented video demonstration.

[@seniorcajun]

This reminds me of an Automatic Transmission from a car with a slightly different shifting mechanism

[@BloodyShambles1997]

Its complicated to fix and maintain by yourself I have to say

[@andyclark1173]

Thanks Dan. The best video explaining how this hub works. I have serviced all my hub geared bikes and have known the theory but your teaching explains all. Every time I’ve stripped a hub down I’m always amazed this feat of engineering has been around since 1902. Sturmey was a clever engineer.

[@johnd6487]

Well I grew up (and still live) in Nottingham, UK and my neighbour over the road worked in the Raleigh factory making those very gears.. but this is the first time I ever saw how they actually work. Thank you for pulling back that curtain of mystery.. and giving me a bit of a ride down memory lane.. the factory site is all redeveloped as student accommodation for one of our universities now lol

[@2wagondragon]

Thanks for sharing. That's very interesting info on the factory site.

[@johnd6487]

@@2wagondragon You’re welcome. I’m sure I read that at one point in history it was the biggest factory in the world - but I might have dreamt that lol. If you look out the movie Saturday Night and Sunday Morning the factory stood in for itself as the lead characters workplace (in the novel he worked at at Raleigh)

[@clicknsee450]

Really happy to understand this today .this is the best video on this 3speed hub.GREATTTTTTTTTTT VIDEO .

[@nicolaszoll2095]

I agree!

[@nkronert]

After all these years, I finally get to see the genius that went into this design. While in 2nd gear I used to "preselect" 3rd gear while applying torque and the hub would stay in 2nd gear until I stopped pedaling for a fraction of a second. Then it would snap into 3rd. Now I finally know how that worked 😊. BTW I never felt that the neutral position between 2nd and 3rd was a design flaw. It was a cool feature 🙂.

[@menoahgunzel8146]

Great video, I'm a bike class student in the Netherlands and have this chapter " speed hubs " it really helps me out. I'm gonna watch this video until I know 1000% sure how it works. Such a nice hub image that those Britians made this all without a PC os some kind of software! Brilliant! Greetings from the Netherlands.

[@alex20116529]

Fantatisc!!! I finally found someone that really explained how it works. Now understanding to gears I found the fault and fixed. Thank you so much!! You are a star!!!

[@2wagondragon]

Glad I could be of help.

[@clicknsee450]

Knowing the input ,output anf reactionary is one thing but making it work engaging the required gears and disengaging the unnecessary gears is the genius thing made by the inventor.genius inventor.

[@coreyshelton1550]

Thank you for this excellent informative video. I’m a Raleigh collector, so this to me was very valuable.

[@artv232]

Thanks for actually taking the time to make this video so that a bunch of us can learn this important aspect of bicycle mechanics. What a great explanation!

[@tarstarkusz]

That was a pretty understandable demonstration and explanation of the workings of a 3 speed. I find it amazing that the palls can withstand the torque of going up a hill without become burred or otherwise damaged and also the really tiny springs that allow them to ratchet.

[@lollycopter]

I guess as tiny as the pawls are, they're kind of like nails. Sheer them from side to side and they'll break, but angle and use them like a hammer and they'll be strong... as nails.

[@nicolaszoll2095]

Un Grand Bravo! This video is a great gift for those, like me, who want to understand how that great invention works. A big thank you for making that video so simple to understand. It was not easy I am sure but you made it.

[@alexanderboiko9283]

Very easy to understand, thank you very much from 2021! Watched couple of videos before, didn't get the part with the pawls, with you video it's like 2+2.

[@stevenolan3380]

Great demonstration - thank you - it is clear that you have spent many hours and it shows.

[@srriley7055]

Outstanding. I've been riding SA hubs for 50 years or more - actually more - and had a rough idea of their functioning, but this really explains it. Good work.

[@mrqreeny]

Awesome, I'm restoring my SA 3 speed from '86. Now I actually understand what is happening :)

[@josephgunn9002]

Thank you Dan, wonderful job! I've always wondered what was going on inside the axle of my '65 three-speed stingray, now I know - kind of. Truthfully, I'm stunned by the complexity of the thing, both conceptually and in the nuts-and-bolts.. A testament to man's ingenuity and the beauty of engineering. All that, AND a Sting-ray bike - for around fifty-seven bucks! The good old days. Thanks again!

[@2wagondragon]

Thank you for the comment. The technology involved really goes all the way back to the industrial revolution.

[@klausbrinck2137]

I watched other videos (there´s just a few of them), that were lacking a lot of information, watched them 10 times, and didn´t get it. This video explains it best, by far, and althought it has the usual length of such a video, it´s being perfectly explained 5 whole, separate times in this one single video. Through this repetition, I now have the feeling, that I understand the function since many years already (while in reality it´s just a couple of minutes), and that the knowledge has long matured in my brain... Thanks !!!

[@eefacam10434]

Bravo -great job! I'm very impressed at how you manage to remember the names of the components as the demonstration unfolds without any hums or hurs :)

[@Ducati999cc]

This thing is bulletproof. Ridden 4 years through rain and ice everyday, no problems at all.

[@ttehr42]

Much appreciated. Have cleaned and serviced these many times[ 50 years ago]. Now I know how they work completely.

[@Duffloop]

Best explanation of the internals so far - nice work sir

[@kathyfinn5996]

Awesome voice for a docu/video! Thanks for the explanation.

[@Paul.C.Barreto]

Thanks Dan. I've been curious about this system of gears for a while, and finally discovered your video. Very informative!

[@lightbeam6783]

This video brings back such fond memories. I had a 3speed Bomber Bicycle when i was a kid and I had to disassemble this same hub to replace the bearings and when I reassembled it , i had the issue you mentioned with the false neutral , and let me tell you I was a nightmare to get this adjusted correctly. Sometimes 2nd gear would engage and sometimes when shifting down from 3rd to 2nd i would get the slip and this sometimes resulted in painful injuries for a man downstairs... Thank you for this video!! Well presented!! I think the BSA hub is a better design.

[@johnacord5664]

That is why it is called a NUT BUSTER!

[@dallasgibson7578]

Great vid! Rescued a 66 huffy sportsman with the same hub, currently rebuilding and greasing it now, this video helped so much with putting it back together!

[@FatDelBoy]

The sound is only quiet at start. A very clear explanation. I liked the tapes showing the power transmission through the gear

[@clicknsee450]

Nice teacher .some thing unfolded amazingly bright and clear.very clear understanding of this.no video on utube is better than this definitely.

[@warrenwilbraham778]

So good I had to applaud! Now I do not have to take it apart to see how it works. The part with the electrical tape at the end was genius. Thanks for the effort.

[@KizzaKat]

Thanks for all the great videos Dan! I'm fascinated by the intelligence that goes into the internally geared hubs. Your videos do a great job explaining their workings and maintenance. I've owned many S.A. 3 speed hubs (AWs) and one 5 speed. While on the subject of gears, I think that the differential found on cars and trucks etc. is simply an ingenious invention. Necessity may be the mother of invention but brains make them happen! Dave D.

[@richtedwards]

Absolutely brilliant- really good explanation of what is going on- thanks for taking the time to make this film! best wishes Rich ( windmill hill bike doctor)

[@pascalvanlaere6709]

Thank you Dan for a very clear explanation , I finally understand how it works.

[@tochriss]

Always wondered how these work! Thanks for making the video.

[@elbaronrouge]

Fantastic video, really clear and informative, thank you for taking the time

[@2wagondragon]

Thank you for the kind comments. Semi retired trucker and semi professional bike mechanic. Not a mechanics teacher.

[@kamilpotato3764]

I got a problem with my 1980's SA 3 gear hub. It doesn't engage idle when walking bike(pedals are spinning). When pedalling I can feel force transmitted to pedals when I stop. I've have replaced chain, oiled hub, replace pin chain. Still no results. Bit hesitant to open it up.

[@downhill100km]

Great! I have been searching a video about internal gear working. because I want to maintain a my sram T3 by myself. This video is very helpful to me and my brompton friends. I will link this video on my brompton online club S.Korea. Thank you very much.

[@2wagondragon]

Thank you for the comment Trent. The outer bearings should be greased same as any bike axle bearings, but for the internals, a light oil such as ATF or light viscosity base oil with no additives is fine.

[@trentpuentes5716]

Thank you for the information. Now I can finish my rebuild.

[@Schenectadont]

+Dan Burkhart Would you also use ATF in the newer hubs such as the S-RF5(w)?

[@2wagondragon]

+Schenectadont I'm running an older XRF5 ball lock type on ATF, and it works splendidly well. Can't see why it would hurt a wide range type.

[@manuelluis5456]

Dan Burkhart Why it's soundless ??

[@thtttttt]

one of the clearer explanation. Thanks Dan!

[@tompearce6312]

I can't imagine how anybody came up with the idea for the hub in the first place! Great video anyway!!

[@errcoche]

Golden age of British innovation Tom. The British Midlands were the Silicon Valley of the turn of the late 19th Century and you had stainless steel being developed an hour up the road in Sheffield. They had no problem with the ideas. Materials and machinery to make their ideas were the problem. The engines in hybrids and fuel efficient models these days are based on ideas from 1882 ( Atkinson Cycle motor ) because developments we are making are in materials science.

[@robstorms]

Thanks for all the work you put into this to school us sheep. I really appreciate it ! Looked over a bunch of your vids, looks like you have an interesting and rich life !

[@2wagondragon]

Thank you so much for the comment. Yes, life is interesting. It doesn't take money to be rich.

[@007DavidCraig]

Have just bought a couple of"dahon"older folding bikes,great to have had an insight into how the"Sturmy Archer" gears work,they do seem lots more complicated than standard cogs etc with the"lever style operation"but maybe need less maintenance thanks for the informative+detailed explanations,lots of the time the detail is a little vague,yours is very explicate,cheers from Bonnie Scotland ,I want to use them in conjunction with my old vw camper(not running currently)fingers crossed next summer

[@finster101]

I always wondered how these things worked. Thank you for a good video explaining them. I subscribed and watched many of your other gearbox "tear downs" too. Good stuff!

[@jaroslav.karpycev]

Thank you so much! Even though I'm not perfect in English I've understood everything so clearly! This was very interesting lesson.

[@gregriutzel7834]

Excellent tutorial!! Theory to practice professionally done.

[@sato4kaiba]

Good work on explaining the working of this hub. I am thinking about using one of these on my bike. Thumbs up!

[@Gammaduster]

best explanation on KZbin, thanks a lot

[@stephenremington8448]

Great video, easier to understand than the supposedly simple animation videos of planetary gears.

[@p_khale07]

Great Video Sir , extremely easy to understand !! Will try overhauling my grandfather's Raleigh , with the same (in video) SA-3speedhub. Great explanation !!

[@DannyPRobinson]

Excellent video, thanks for this. I've taken these hubs apart before and I had a rough idea how they worked, but this explained a lot more.

[@2wagondragon]

You're quite welcome, and thanks for viewing.

[@mikehall7806]

Great video Dan. I've rebuilt my 1964 SA AW and I'm bench testing it in a vice. I can find all 3gears without the hub on but when I put the hub on I canot find 1st gear. I picked this hub up off of eBay just to see how thing actually work and to gain knowledge on refurbing one so I don't have a bike to put it on. Thanks, Mike

[@2wagondragon]

The one thing that comes to mind is that you may have over tightened the drive side cone when you re assembled it. It should be screwed down until it contacts and then backed off about 3/4 turn and locked down with the locknut. The bearing adjustment is done from the left side.

[@mikehall7806]

@@2wagondragon Well, I finally got het al back together and working. Here is a pic of the setup I came up with to check the shifting. I can turn either the axle nut and/or the brass lamp coupler to pull the chain and shift to all 3 gears. I'm posting the pic of the latest setup on bikeforums. Thanks , Mike

[@2wagondragon]

Thanks. always open to suggestions. I've been working on the lighting issue. I thought it was improving, but maybe not.

[@SZINNAPALM]

Thanks for showing all the internals and the function of this hub you answered my questions plus you answered what the hell the new drive gear with the 2 rows of pauls was about I found it on my gt intruder bmx rear hub (standard fixed, No archer on it)

[@jaekib]

Very nice presentation of an ancient enigma;). Thanks!

[@r872047]

Awesome video, thanks for taking the time out to make this

[@Cheezwizzz]

Incredible piece of engineering, thx for sharing!

[@MildLifeCrisis67]

Wow, THANKS! You just told me why the pedals spin freely in 3rd gear! A shift cable adjustment should do the trick... I was afraid it was broken. I just acquired 2 bikes, a '64 Schwinn and a '73 Raleigh, both with SA hubs...the Schwinn has the problem hub.

[@CyclingBristol]

Excellent video, many thanks for the careful explanation, I think I finally understand it but I still wouldn't like to try to put one back together.

[@tsitohainaranto1005]

Any solution to the false neutral you describe at the end of the video (17:50) ?

[@frundlemud]

Very good indeed. I have a K4 slightly different but this video will help me a lot.

[@zelupl2063]

You did great job explaining it. Thank You!

[@JeandePierre]

Many thanks, this is very useful, and nice to have an in-depth explanation, instead of one reduced to soundbites. A suggestion (not a cristicism): may I suggest that you try using more even/diffuse lighting, and perhaps a less cluttered background, so that everything is more easily visible?

[@moabe-biker6779]

Great video! I have a newer SX-rk3 I am having a problem with. It seems the spring is binding when I shift into 1st gear. When I shift into 2nd or 3rd the spindle chain relaxes but the IGH remains in 1st. I can maybe knock around the axle lightly and it will pop out to the right gear, or if riding I may hit a bump and that will release it out of 1st. Would you have any idea as to how I may remedy this situation? TIA!

[@iDominooo]

Thank you very much for this very informative video. I learned quite a lot about the function of the gear and you explained it really good :) Cheers

[@spacegazette4781]

Dan I have a problem with my 1958 Raleigh. The hub noticeably slows my rear wheel down. The chain sometimes moves with my free spinning wheel. I will re oil my hub but im still at a loss. Fyi, all ball bearings are loose enough and well greased.

[@KunioTaki]

Do you think it's strong enough to be driven by an engine? I have made a chainsaw bike, and I want a gear shifter, gear hub would be the best solution, but is it strong enough? The normal mountain bike casette system works well now, with that 2 little hammers. I see them here too, but they are bigger. Is that means, they are stronger than the mountain bike ones?

[@2wagondragon]

I don't really know the answer to that, although I don't think a chain saw motor develops too much torque, Is this a pedal bike with motor assist, or strictly engine power? I would think if you just used the motor to assist when moving, and not to start moving from a stop, it might be alright. If you do try it, let us know how it works out.

[@KunioTaki]

It has no pedals, just the engine, the torque is still not enough to start well, but it has already broke the common wheel's parts. I can't really tell you, I just tell you with this picture: img.koliken.hu/nagy/ha029.jpg The most single speed bikes has this. And this part has broken lots of times.

[@geoffreygee]

Nice job. I appreciate your time and effort.

[@edjuaro2]

This video was very helpful and informative!

[@laszlobacs]

Great tutorial with attention to details and very informative, thanks for sharing. I am in process of rebuilding an SRC3 Sturmey Archer hub and unfortunately not able to find a video neither a pdf. Any help would be greatly appreciated.

[@52tubs]

Sir can you help me understand why on my SA aw my first and only my first pedal stroke nothing engages for Id say 1/8 to 1/4 crank turn then no other slippage occurs , this is in any of the 3 gears , I did overhaul the hub , shifting is jyst right . Thank you for your time and expertise with these hubs . Regards

[@trentpuentes5716]

This is a great video to watch. I like how you take your time showing how everything works instead of going so fast I have to replay over and over to understand what happened. I do have one question for you. I also have an older sturmey archer from '61 that needs some cleaning. My question is how do I lubricate this correctly? I keep watching videos on how they use grease on everything. With your video everything is oiled and looks as if you don't use grease. Any videos or anything that can help me thanks.

[@johnacord5664]

I thought that the 3 speed hub had been discontinued long time ago. I am thinking of ordering a 3 speed W coaster brake for that vintage cruiser i bought from a friend. The derailleur is OK, but it is vulnerable to dirt and damage. You can say that the internal gear hub is bullet proof. The only advantage of the derailleur, is you have more gears and that system is light weight I am getting back to the geared hub.

[@geepuller1]

Great video. I have a project where I want changeable gears without a freewheel (kids pedal tractor). Is there any hub that can achieve this? the freewheel in this video is unfortunately integral to the operation of the hub, I was hoping that I would be able eliminate it.

[@Baltimore012]

Very much a teacher sir!

[@adampax]

Thanks for such an informative video! I wished I'd watched that before I took my hub apart to clean the outer cogs. I am afraid I may have let a bit of degreaser in to the main hub, possibly around the ball bearings. Do you have any advice for me? (E.g. Should I just coat everything in fresh oil? If so, what kind is good?) Thanks!!

[@johncunningham4440]

How would that drive hold up to electric bike power of 1500 watts or so?

[@GordoFlach]

Superb video! Thank you for posting it! From Chile

[@1961kickboxer]

Very good explanation thankyou.

[@davidjones4452]

really great explanation... thank you very much

[@GioMe-x7x]

SA 1st gear doesn't engage. Took it apart, greased it and oil....everything seems to be ok but it still 1st gear doesn't work. Any ideas what could be wrong ?

[@enriquequintela4453]

Very important video to me. thank you.

[@cloud-cr5gs]

Merci. J'ai un Raleigh de 1963. " Modernisé" surtout au niveau éclairage. Mais pour le réglage du moyeu ce n'était pas simple. Heureusement que youtube existe. Mais mon dieu que vous êtes " compliqué" les anglais 😂. Ma Jaguar 2,7 V6 ....il y avait un jeu de cale pour régler les tiges culbuteurs lorsqu'elles prenaient du jeu.Tout cela au bord de la route.... tellement british 😉

[@2wagondragon]

I've explored 7 speed Sachs hubs, but never a 3 speed. My main concern is the unavailability of replacement parts for them,unlike Sturmey Archer which has parts support for hubs going back many years.

[@mikebowers3547]

Do you have any videos on how to adjust the cable on the SA 3 speed?

[@ajmann07]

Great Job on explaining the internals of a planetary system. Wheres the best place to Purchase 3 or 5 speed for my Bike build. Or would you purchase a different brand ?

[@mcbain3949]

Great video Thanks , Shouldent the clutch be called the selector ?

[@2wagondragon]

Clutch is the correct technical term for the function it performs.

[@mcbain3949]

Ok , Dans the man .

[@zagajan]

Great video. Thank you !

[@yifus237]

Best explain ever!

[@scoop4321]

I just bought a Huffy single speed cruiser with a steel frame (a cheap bike, I know), and I want to install a Sturmey Archer 3 speed hub with a coaster brake. The rear hub spacing on the chain stay drop outs is 110 mm. I have researched and found only two Sturmey Archer 3 speed models with coaster brake that would fit: AWC (II) and S-Rc3(l). Both have 116mm outside locknut spacing. Which one do you think would be the best one for me? I think I can spread the rear drop outs wide enough to accept the 116mm hub.

[@Meastriser]

How do I lube this hub without taking the chainguard off and taking the plate off? Isn't there some kind of "indicator" hole I'm hearing about?

[@PCFithian]

Excellent, thanks for posting!

[@Jhandestam]

Hi Dan! Great video, thanks! I have a question, my shifting cable has been breaking off and I just can't handle it anymore, riding on the 3rd gear is getting tough. Is there anyway I can lock the clutch in position so the 1st or 2nd gear is always driven?

[@RolingRandom]

After watching your video. I can still not figure out why the 3rd gear is not working Years ago I had the hub apart, because it the time there was no gear at all. It was very dirty inside, almost like someone put in some saw dust :) I cleaned it a bit and put it all back together using fresh lithium grease. It’s completely possible I made a mistake, or maybe something is actually broken. Now if I disconnect the indicator pin I would expect 3rd gear. It’s not there. And the indicator pin seems to move in far enough. I need to set the shifter to the 3rd position to get second gear. 1st gear is working as expected. On the shifter it just looks like it’s skipping second gear. It’s all rather confusing, and I wonder what I could have done wrong. Perhaps I need to clean it better and don’t use thick grease.

[@2wagondragon]

Do you have the older model with the star clutch, or the newer model? In either case, a grease like a NLGI2 is too heavy for the internals. Older hubs used light machine oil, newer hubs are lubed from the factory with NLGI 00 semi fluid grease.

[@RolingRandom]

@@2wagondragon Thanks for the reply :) My hub is from 1990 and it's a drum brake model. I actually just rewatched you video. question: Is it possible to incorrectly assemble these hubs in such a way third gear is not working? Is it possible to mount the clutch incorrectly so it can not interlock with the planetary axles? (I would think not) Since first gear is working my problem must be with the palls in the ring gear. I will shoot some WD40 through the axle and let it soak for a while. It would be cool if this fixes the issue.

[@2wagondragon]

@@RolingRandom Can you confirm that you have the pre NIG model with the star clutch? If so, it is entirely possible that something, perhaps dirt or thick grease, is preventing the clutch from engaging the pinion pins which would result in a non functioning third gear. It is also possible that the pins and clutch are so worn that they do not engage positively.

[@RolingRandom]

@@2wagondragon Yes I can confirm that. For a while I thought I might have incorrectly installed the clutch. But I now know, that is not really possible. I can be clumsy but I'm not completely stupid :) The hub was extremely dirty on the inside and a bit rusty. Like I said it looked like, someone put in a handful of saw dust. It made me wonder how so much gunk could get inside the hub. Before I had it apart the hub would not select any gear. It wasn't so badly rusted, that chunks of the machined parts had rusted away :) But knowing myself I probably used way to much grease. At some point I will open up the hub, and then I'll shoot some video. For now I will shoot in some wd40. And let it soak in for a week and take some test rides. Perhaps that will dilute the grease a bit and maybe that will free up any stuck palls.

[@RolingRandom]

Thank you for your reply and videos. As a result of those I was able to get my bicycle fixed :) Here’s a video I made about the repair: kzbin.info/www/bejne/npiYZaqdm9d1f6c

[@gentlerowdy]

excellent info Dan - the 1st & the 3rd gear of my Raleigh Sturmey archer gearbox is not shifting well...i dont know what has gone wrong.

[@2wagondragon]

There are a few things which could be causing these issues. It's possible the internals need servicing, but it's more likely that it is shift cable related. First, it's important that the little roller chain on the indicator, that little chain that comes out of the end of the axle, not have any seized links, and that it does not bind. It's important to ensure that the indicator rod is not screwed in tight. It must be threaded into the shift key until it stops, and then backed off at least a half turn. This is to ensure it does not bind. Check that, then check shift cable adjustment. The cable should be fully taut with the shifter in the first gear position, with just enough free motion that you can pull the indicator out a tiny bit before meeting hard resistance. If that does not solve the issue, it may be time to open the hub for an overhaul.

[@excaliburjohndeere3887]

Hello Mr. Dan would like to get a hold of you. I have a few questions -like to add a motor to bicycle gears wondering how much torque can they take?hope to hear from you thank you

[@2wagondragon]

I have not done any testing on the input torque limits on any of these hubs, so anything I would say would be a guess. Note that manufacturers publish limits on input ratios, usually in the 2 to 1 range, but limits on actual torque values are harder to find.

[@tedvictor4918]

The torc of the rotation of the week against the hab whenpedling makes that titer and clamping the rim makes it esyer to undo as you are then using the opposit tork to exspand the hud an release tention .