DIY Reverse Tilting Cargo Trike #3 - Complete build
ฝัง
- เผยแพร่เมื่อ 26 ก.ค. 2024
- This is version 1.0 of making a cargo trike. In this iteration:
- New frame - explanation of extension and head tube
- New metal wishbone suspension with ball joints
- New steering knuckles
- New 3D printed wheel hubs
- Tilting mechanism
Checkout version 0.1 and 0.2 if you haven't yet:
- 0.1: • Cargo Trike with 3D pr...
- 0.2: • Cargo trike with 3D pr...
Have fun!
Video chapters:
0:00 Intro
1:11 Frame extension
3:38 Head tube
10:00 Double wishbone suspension
14:08 Steering knuckle
15:10 Wheel hub
17:11 Frame assembly
18:52 Test riding
20:53 Steering
21:21 Suspension and tilting
22:55 Next improvements - แนวปฏิบัติและการใช้ชีวิต
I am building a tilting recumbent trike and sometimes I come to your channel to see how you have solved some issues I also have. Very interesting and useful, thanks.
Thank you so much for writing that! Makes me super happy to know that my build helps others with their own builds. Of course, I'm also helped by many others sharing their builds on TH-cam.
Cheers!
This is fantastic. I'm still in the drawing phase for my project so thank you for lots of ideas and practical demonstrations.
Great video! Thanks for breaking it up in design element segments. Appreciate your explanation in the end... and... looking forward to your next video!!! THANKS!!
Thank you!
Very inspiring. I made a 4 wheel pedal car 40 years ago. I gave it away. I now want E Trike. Winter work!
That's a great compliment, thank you very much! I do hope to inspire others to build. Would be great if you share it as well;)
A very nice build. Thanks for the details. I was always wondering how to extend the steering column.
Nice build. I particularly like the nice feature of the opened “hole” in front of the crank system.
I am exceptionally impressed 👍. I am building a recumbent reverse trike go-kart contraption with my son. The build is really similar in design. It will help me when I get farther along.
I also really appreciate seeing a backyard builder on here using their PPE, thank you too for recommending it.
Thank you for your comment;) Happy to read that my project is helping! And pleeease use protective gear. It's just not worth getting hurt.
it's cool to see people using simple tools trying to design the mechanisms of their dreams. beautiful vehicle! 🚴♂️
Thank you! I hope to inspire other to do the same - work with what you have to create, if that is you passion;). Just don't work without protective gear! This is very important and can be obtained inexpensively.
Take. My. Money.
:)
Lacking self love.
@@suprememasteroftheuniverse❤❤❤
Very good about pressure adjust shock for load variation
Io vivo solo in bicicletta!!! Ho costruito una e-bike e....voglio fare una cargo. Ho trovato veramente interessante e chiara la tua dimostrazione, soprattutto il carro anteriore. Bravo, bravissimo 👏👏👏👏👏
Thank you very much!
@@pedro-neves ❤️👏👏
I'm amazed at how much you managed to do with relatively few and simple tools. I need to learn how to weld.
Thank you very much! Indeed, my policy is - work with what you have;) And I took a 3-hour welding course before starting to weld.
Cheers!
Are you using an electric arc welder on basic home electricity for this?@@pedro-neves
@@littlebrother82 hello, yes, I use a gasless system with fluxed core. The machine pulls a maximum current of 17.5 A on the grid side, so suitable for a low power connection.
Cheers!
thanks! @@pedro-neves
@@littlebrother82 no prob;)
Brilliant work
Very well done and explained. Thank you for sharing your experience 🙏
Thank you very much for the kind words!
Очень впечатляет! Восхищаюсь вашей работы!Удачи!🍀
Absolutely brilliant. You are my hero man. I am just so excited to build my own cargo bike one day soon
Thank you so much! I hope you do! Making stuff is awesome;)
Tenho uma cargueira que usa um único tubo central. É um modelo interessante e tenho pensado muito em dia e todas à frente. Muito boa a forma que você está construindo!
Looking forward to your next video.
Thank you! I already have one more recent than this one: th-cam.com/video/quPFFIaY86c/w-d-xo.htmlsi=g6GzWjwHQ3ISiO5W.
And I'll release a new one in the beginning of February.
Cheers!
Very interesting design
Awesome build and awesome documentation.
Thank you! Love your channel too!
Wow, excellent looking design.
Thank you!
The best i've seen on youtube, I do love different ideas.
Thank you very much! More iterations coming;)
LOve the way you made the wish bone.. beautiful work. I don't have a 3D printer need to find a way to make the wheel hub out of metal. The 3D printed wheel should also be the spoke wheel for maximum rigidity. WIsh you the best.
Sw
Nice tilting design...
Anazing, beautiful, thank you do much!
Nice job
You've got all kinds of patent material going on with your work.
Thank you!
I love your design. If you mix with rear suspension and the cable steering would be the perfect bike. I miss that you guide the rim in the plastic hub in addition to the screws. Congrats!
Thank you so much! I am working on a new design right now and it will have cable steering;)
Cheers!
Awesome Sauce!!!
Thank you so much for the details - BEAUTIFUL build! You should start a business!
Thank you so much! I'm continuing to make new build. Maybe one day I'll have one that is great to ride and can be built at an affordable price;)
Increible trabajo de investigacion y desarrollo. nuevo suscriptor.
atento a tu trabajo, desde Mendoza, Argentina. Gracias.
Gracias!
I'm not so sure about the steering and 3d printed wheel parts, but I love the suspension and tilting design.
There's some fancy complicated designs for cargo bike steering here on yt, but two steel break lines tensioned equally would most likely do better than the pushing rods setup you have going on.
Very interesting build, though. I'd like to see what other improvements you can come up with. Cheers!
Thank you! The 3D parts are there just for testing the geometry. The next hubs will be made of aluminium;) In the next version I will have adjustable caster, camber, scrub radius and steering ratio to make a comparative analysis and I'm considering steel cables for the steering;) Hope you enjoy my next video! It takes a while because it's a hobby project but it's very enjoyable. Cheers!
Ils semblent que les deux roues avant sont auto stables à l'arrêt
excelente!
Gostei muito dessa ideia
That's how a velocargo should be IMO. With added cargo weight, redundancy in safety is even more important. Not needing a beefy stand is also very nifty on a heavily loaded bike.
you made excellent thing!!!
Thank you!
Show parabéns 👏 pelo projeto muito bom mesmo 👏
Obrigado!
FYI, I think you need tubular spacers on the axles between the two bearings😮 this stops the nut pre-loading the bearings too much by crushing the bearings inner races together. Also, king pin inclination and Ackerman angle seem wrong to me.
Team juric channel has a very good tutorial on suspension! He is building a cyclekart in Australia, and knows his stuff✅
Thank you very much! Ya, in the hubs I tightened the but just enough to be tight and not crush the bearing but a spacer would indeed be better. For the king pin - yes, I learned this recently;) I have a big scrub radius. I'm redesigning the king pin for 0 deg. About the steering - also agree. Actually, the whole dimensions are full of tolerances. On the next version I'll put a serious effort in making the dimensions accurate. I'll check the channel that you recommend. Thank you for the tips!
Grinder and paint makes me the welder i ain't ;-)
Nice build and interesting wheel design, needs a TIG welder, fluxcore is horrible for thin stuff.
Aah, couldn't agree more! I'm a terrible welder with bad tools. In fact, the next investment for my shop is a TIG welder. Cheers!
Great work, stumbled across your video as was interested in exploring the idea of 3d printed steering knuckle for a project im doing, an electric mountainboard but with handlebar for steering to use as a mobility aid. If weight is an issue for you then would highly recommend 3d printing moulds and wet laying either carbon fibre or flax cloth, no welding required! stronger than pla and much lighter than steel. There is a technique for pressing 2 sided moulds called carbon fibre forging that may suit for the steering knuckle.
I cannot express how much I want to make carbon parts that way! I have never tried it but I've seen some videos about it and it looks great. Maybe this will be the project where I'll put some carbon parts made out of printed molds!!
This is the trike I want to steal all the way to South Korea.
That's the beauty of the internet;) You can take it almost anywhere;)
My opinion is that the steering axle of each wheel, should be point more close to the place where the tire touches the ground.
I mean a steering geometry, similar to a regular bike.
I guess that the steering of this trike in this configuration will be influenced by small obstacles on the road.
But maybe the steering setup was already changed, or the described effect is very small.
I am riding a kind of cargo recumbent trike which is also tilting.
Hello, I totally agree with your observation about the distance of the steering axle to the place where the tire touches the ground. This can be fixed by adding an angle between the upper and lower ball joints. I showed this in this video if you're interested: th-cam.com/video/q2GTZd428vM/w-d-xo.htmlsi=a6SMrjKUDZMQHY_Q.
Cheers!
Muito bom, vc e um cara inteligente!
Obrigado Ricardo! Espero que tire proveito do video;)
Fantastic build and I really like that you accomplished the design and implementation of a complex piece of engineering with only simple tools in what looks like the back garden of your flat. It shows you don't need an expensive workshop to do great things. Would you consider sharing some of the designs for the double-wishbone suspension?
Thank you very much! It is my small backyard plus a 3x2 meter shed;)
I promise that I will share the drawings of all the parts of the next build (including the wishbones)!
@@pedro-neves You've really inspired me to try something similar. Thank you so much.
Que inteligência Abençoanda por Deus em irmão arrasou parabéns vc faz por Encomenda
Ficou legal Pedro. Deve ser gostoso conduzir.
Obrigado! Ainda precisa de ns melhoramentos;)
You need to add some camber and caster angle in the front and it will feel much much better
I will test this with the design that I am making now. I'm making a setup with adjustable caster, camber, scrub radius and steering ratio. I'll try to find the best geometry!
Nice! Have you considered giving a slight positive caster angle to your front wheels? I believe it'll make the trike steering more stable and might also help a bit with the front suspension
Nice point, thank you! Actually, I'm working on a setup where I can adjust Caster, Camber, Scrub Radius and Steering Ratio. My next video will have tests, results, and a comparative analysis;)
You are a genius!
You are very kind;)
Das nenne ich Fortschritt und Innovation. 👍👍
Cool
Nice video and presentation.
I noticed the new suspension has no built in tilted head tube angle for a Trail length which is a standard in all two wheels bikes. It relates to dynamic balance and stability.
Thank you! That's a very good point! Since this version I made a few more iterations and I shared some geometry analysis. You can find it here if you're interested: th-cam.com/video/q2GTZd428vM/w-d-xo.htmlsi=ANjAb6xR_AW3Pyy8.
Cheers!
Those welds won't win any beauty contest but good job anyway.
No they won't;) I will transition to TIG welding at some point and work harder on proper welding but for now I'm still super novice. Thank you!
Hi Pedro. Many good ideas, very clever made !!! And nice made video + well explaned too🙂
What determind how much the bicycle tilt ?.
I'm thinking if you could benefit from these improvements ideeas:
* Only one long steering-rod, but thicker and stiffer ? Maybe supported in the middle
* A little Camber at the front wheels steering-knuckles, for better selfcorrecting after turning ?
* Centerpoint steering, at the front wheels steering-knuckles, for more stable steering when hitting e.g. a holes in the road ?
Maybee have a look at Atomic Zombies e.g. "Streetfighter" plans, where all these issues are well explained
Keep up the good work ! 🙂
Kind Regards, Kjeld
Thank you very much Kjeld!
Regarding your question - I started designing with only one constraint - the width. I wanted the trike to be able to pass on most doors. The tilting limits were a consequence of this constraint and the double wishbone design. In fact, the limits are never reached while riding which I think is good.
Regarding you suggestions - they are most appreciated! I am now redesigning the wheels because I want spokes and then I'll focus hard in the steering to make sure it's good. Hope you'll watch the results;)
what are the tube OD and ID? I had a similar idea, but was concerned about the flex (especially with the cargo weight, say, extra 100 kg). Tandem bikes have a double A-frame.
Cool soundproofing BTW :)
Hi there! The tube is 60 x 56 mm (wall of 2 mm). I think there's barely any flex. Super rigid. But I haven't tried with cargo yet. Still making changes to the tilting mechanism.
Thank you!
Wearing eye protection in shop 👍
I hope to incentive people doing DIY work to wear protection. Low cost for saving your life!
cool
Roata din față -stînga este compromisă.
True. These wheels were not super rigid. I made new ones in the meantime;) Check it out here if you're interested: th-cam.com/video/sU2ZS7Nlbj0/w-d-xo.html
Молодець! 👍👍👍
mantap bang
On a conventional recumbent trike the steering axles are pointing exactly at where the wheels touch the gound at an angle. I hope this info help.
Thank you! I believe I understand what you mean. I've been reading and watching a lot of material about steering geometry. There will be a lot of theory put in practice in the next version for sure;)
Disc brake calipers?
Also, the long frame tube you added, would make a great place to mount batteries inside for an e-bike.
/btw: you are a fabrication genius
Very well put, thank you for the constructive comment! I haven't mounted the calipers yet but they are considered - they will be mounted on the interface between ball bearings and axles.
As for the batteries, I also agree with you;) once I have a mechanical setup that I am happy with, I'll start converting it to electric.
In the next version, I'll show a version with some geometries that can be changed to do a comparative analysis. Stay tuned;)
Muito bom
Please reinforce the frame at the head tube extension, it looks like it'll be under huge stress if there were cargo on the front, and you cut out the part that would normally carry most of that.
The double wishbones look quite solid, but from there to the tire it looks quite flimsy. Might be not just the hub, but also the sheet metal, or there's not enough distance between the bearings to resist the bending load?
Thanks for caring! Adding cargo will definitely be a new phase and I'll add robustness to the frame.
As of the hub, I don't think it's bending at this point. The first thing (which will be the next part of the project) will be to make strong wheels because they are bending.
Lovely work man! how but that bad boy must weigh quite a lot? still really funny concept tinkering on my on simular project! :D
Thank you! Yeah, it's a little bit heavy for sure. Final version has to be on an aluminium frame;)
very cool design . an E version would be also be nice .
Thank you very much! Actually, my next video about the trike will be the electric conversion;) Already got the kit;) Cheers!
Wow great job. You are an inspiration to others. Cargo bikes are a good idea but just too expensive.
I think if you have wide handle bars on the bike you will have a more 1 to 1 turn effect with the wheels for steering, the wider bar makes you move it more for the same turn effect.
What do you think about making and selling the front part because this is most of the build?
Hello, thank you very much!
Indeed, I have considered selling kits. But only when I reached the point where it's very good and very durable. There are a couple of iterations newer than the one in this video. If you check my channel, you can find the newest on this playlist. I'm now working on some improvements. Maybe this will be the version where I can sell some parts;)
Cheers!
How well did the solid PLA hub hold up? Love the design btw, especially front
The PLA hub is the most resilient 3D printed part in the whole design! It's still rolling. I'm working on the new version and have been riding it around and the hub is just there, as it was. Note - I am not advising to have a PLA hub! This is just to test the design. You need a metal hub.
@@pedro-neves yep, don’t worry was asking as a proto!
hey Pedro :) Do you have any link about the Ball joints ? where to buy ?
Hello, sure, here it is: www.profibohrer.de/M12-angle-ball-joint-rod-end-bearing-SQ-12-RS. Cheers!
Very cool!hi maybe i can have the 3d model of the front suspension? i like very much it
Thank you! This version is still a little bit improvised. I will share all the 3D models in the next version.
Very Nice, where are you from?
Thank you very much! I'm from Portugal.
Could you share where you bought the bushings and ball joints for the wishbones?
Hello, sure! Here is a link to the ball joints: www.profibohrer.de/M12-angle-ball-joint-rod-end-bearing-SQ-12-RS.
The bushings, I 3D printed them (just an experiment). Cheers!
The steering seems a little too responsive, to fix this the steering arm at the bottom of the head tube should be shorter than the one on the pitman joint .
Hello, indeed the steering here was not great. I have made an improved version since : th-cam.com/video/q2GTZd428vM/w-d-xo.htmlsi=H1iWGJM9Lebtftys.
Cheers!
Muhteşem
Nice build. Can you tell me how long is the wishbone in the suspension?
Hello Failer, the wishbone is 164 mm long.
@@pedro-neves is that from joint to joint? Looks a lot longer on the video. Thanks anyway.
@@Failer__ Actually, the 164 mm is of the wishbone only from the bushings to it's limits so there is an extra ~ 5 cm of the ball joint part. So from joint to joint 169 mm.
In conclusion, there are multiple reasons why trikes have two wheels in the back with one single wheel up front.
The two wheels could be in back and would stabilize the trike on slanted roads. It's perfect with a motor on the front wheel.
With recumbents it’s common to have the two wheels on the front. Though these wheels are very large, and the design is mostly there to give you room for your feet.
Two wheels in front is by miles a better solution. Much more stable but much more complicated mechanically wise. Ask Piaggio or Morgan about that.
Like a bakfiets. I guess the two wheels up front can make steering harder.
The steering is not yet great. But I am thinking that the steering will be as great as in a two wheeler. I'm inspired by other 3 wheelers such as the Piaggio MP3. One of the advantages of the 3 wheel systems is that it decreases the crash rate. On a bike, the front wheel slipping will probably cause a crash but not on a trike.
I think a 10 speed transmission would be better for a cargo bike.
It needs low gears for sure if I am to pull cargo up hill! I also intend to add an electric drive.
I am not an expert, but I wonder if it would be safer to pay a local turner to lathe the wheel hubs out of solid Aluminum. Everything looks very solid, but not sure about the PLA wheel hubs.
The PLA hubs are certainly not reliable. These were made just for validating geometry. The next ones will be made out of aluminium just as you said.
@@pedro-neves Thank you for posting your build. It's inspirational.
Мастер!
Pedro, mas essas peças em 3d não seria muito frágil pra uma bicicleta de carga?
Olá Igor, boa observação! Sim, são muito frágeis. Elas são feitas por impressão 3D só para ver se funcionam. Os próximos hubs serão feitos de alumínio.
Wait, are those funky rims are 3d printed just like that?
Hello, the rim is metallic and the inside is 3D printed. I used the spoke holes to screw the rim into the 3D printed part. But this was not rigid enough, unfortunately. I have made new wheels since then. See them here if you're interested:th-cam.com/video/sU2ZS7Nlbj0/w-d-xo.htmlsi=7Q-SHwpNYh62S-Bn.
And now I'm working on yet a new version of the wheels;)
Cheers!
Better to use cables for the steeringsystem.
I agree! And I will switch at some point;)
Where did you find 3 bolt wheel rims?
Hello, I 3D printed the inside and fastened to a steel rim. Checkout how I did it here: th-cam.com/video/LFg6dwHqi8c/w-d-xo.htmlsi=X1YkktPCd0uhcw1H&t=246.
But, I don't recommend this. Unfortunately, the wheels were not strong enough.
I have a video just on how I made the current wheels: th-cam.com/video/LFg6dwHqi8c/w-d-xo.htmlsi=X1YkktPCd0uhcw1H&t=246.
And I'm working on the version 3 of the wheels. I believe these will be the best ones;)
From 19.30 onwards is the left front wheel slightly buckled. It appears to have a wobble in it. Nice job though.
Ya, the 3D printed wheels were to super rigid indeed. I already made a new version. Check it out here if you're interested: th-cam.com/video/sU2ZS7Nlbj0/w-d-xo.html
The Steering looks a little nervus ? May be must change the Steering Transmission ?
It is nervous;) you are right. There is a lot of elasticity between the steering bar and the wheels. My next improvement will be actually new wheels and then the steering.
@@pedro-neves
I got the same Problem and I make it better with longer handel Way to steer the Frontweels !👍
Hola, me ha gustado el vídeo está bien interesante pero, tengo, una pregunta. ¿ el anchó que le dio a la parte delantera, es igual al largó del manubrio? Un gran saludo a la distancia 🌎 Desde cuscatancingo, san salvador, El SALVADOR, C, A.
Hola Luis, si, es parecida. Quería que el triciclo pudiera pasar por una puerta;)
panes mata bichos en bicicleta !!
I think putting rider in the back is a huge design flow. Limits your cargo volume drastically.
Hi there! Ya, I understand what you are saying. And I think there are benefits for both designs. One benefit that I see for having cargo in the front is e.g. transporting kids and being able to see them while you ride.
@@pedro-neves Hey! Yeah, I get the temptation. Although personally I would still go with back seats because of the pain of million blind corners in urban areas. It's been a year now. What would you say about this particular issue, what's your experience?
@@user-pm8je4fo7e very good point! This really shows how it's good to discuss things and have different experience and point of view! My experience is mainly from Amsterdam, where I live. Most people here that own cargo bikes and trikes have the cargo bay in the front so this influenced me. I also tried a couple and I liked the driving experience. Riding a bike is very safe because there is space exclusive to bikes and there is usually pretty good visibility around the corners because you have the road on your left and the sidewalk on your right. Nevertheless, your point is still valid. I would like to see a study that shows which configuration is safer.
@@pedro-neves Thanks for sharing! In my experience there is clear ridgeline: if you mainly travel on general purpose roads alongside with cars, then it's frontseats for precious cargo. If you drive sidewalks - then it's backseats. I've been to Amsterdam long time ago, it was my understanding that you mainly have dedicated bike lanes as a part of carriageway. In my city in Russia dedicated bike paths are almost exclusively a part of sidewalks or are completely separated, but on intersections they still merge with sidewalks, not carriageway, so having a great deal of blind corners in residential areas is inevitable. Hence my stance. It wasn't too bad until e-scooter rascals came to scene tho.
I thought maybe bike-rikshas could give the ultimate answer since they withstood a trial of time and numbers, but no, turns out they differ from country to country. Although they are more or less consistant among the same country, which could be the tell that there is something else to the choice besides historical heritage, it's still hard to say from here what exactly are the reasons behind design choices in each case.
Hope this whole exercise of ours will give somebody a food for thought. Have a nice day!
@@user-pm8je4fo7e thanks for sharing your experience and thoughts! Indeed history plays a role. Once people get used to a certain system, this looks the best until someone somehow proves that something else is better. It's also obvious that cargo in the rear or in the front has different popularities per region. I try to explore different possibilities with my exercise. After I reach the limit of how this system can be, who knows? Maybe I'll test cargo in the rear;) Thanks and have a great day!
When will we see the panic stop test results?
I hope there won't be any panic but here's the newest version: th-cam.com/video/quPFFIaY86c/w-d-xo.htmlsi=TKEFXlbEvP4MjyTc
Cheers!
Sücht goud uut un foahrt ook goud awer wenn du nu vörn mehr gewicht upschmieten deist bün ik neej mehr so secker of dien vörderbau dat uuthollen deit. De 3D version seech een beeten stabiler uut ook wenn de neej uut metall weer. Sall ja eenglich een cargobike ween🤔 anners is dat ding echt top😍
hola pedro . podría comprar los planos para imprimir las piezas?
Hola, gracias por estar interesado! Mi próxima versión será mucho mejor. Y prometo compartir todos los dibujos.
any comparison video on tilting point on 22:38 ?
Hello, I tested with the tilting mechanism locked and did not like it. This is because it no longer behaves like a bike, it behaves like a quad, which I think is worse.
Then, I actually built a trike with lots of adjustable geometries and made a comparative study. You are welcome to check it out here: th-cam.com/video/q2GTZd428vM/w-d-xo.htmlsi=cgT6QeiBwYq5qcaE.
Cheers!
@@pedro-neves yeah i watch all your videos, what if the nut is on top of the holes vs on very lower. or no nut. it will move the point of tilting. there is no information from your video
@@ZuNunchaku, ah, sorry. Now I understand your question. Those holes don't actually change the point of tilting. The point of tilting is defined by where the wishbones are fastened to. Those holes only define the degree of freedom of one side pushing the other. At the time it made sense to me to test, but now I don't think it makes a difference as long as you make it in a place where it can move.
Hope this answers your question.
does it have ackermann steering_
Hi;) Good question! Yes, I designed for that but let me be honest - with the tolerance of my fabrication it ends up not being very exact. My next build will have more accurate parts and jigs to make sure everything is super aligned.
Where did you get the front wheels from?
Hi Nils, I used a standard rim and 3D printed the center. You can see how it's made in this video: th-cam.com/video/LFg6dwHqi8c/w-d-xo.html
Now, I have an improved version of the wheels. You can see how it's made in this video dedicated to the wheels: th-cam.com/video/sU2ZS7Nlbj0/w-d-xo.html
Вы показали как делали передний мост и рулевое управление
What is the turn radius on this bike ?
It's about 3m but the steering will be completely redone. I'll make sure to specify this number in the video!
this is awesome, cant wait to make one
Thank you! I hope you do! It's very rewarding to ride your own build. Cheers!
Predetermined breaking point steering tube......
в чем изюминка этого велосипеда?
For me it's the fact that it's a trike. I want to make it this way to be more stable and safe than a bike.
nice video, but i dont trust the pla parts
Thank you! And you are right;) I don't trust the PLA parts either;) I made them to test geometry but will replace with metal parts.