Handmade Ski Bike

Mar 10, 2011 at 22:30

I was given the opportunity during my senior year of high school to design and build anything I wanted (obviously within reason), so I chose a downhill ski bike. With a bit of research and trial and error, I have managed to successfully cut, mill, grind, and weld my own ski bike.

Living in the Bay Area makes it hard to get to snow easily, but the challenge and the potential award kept me working hard on my ski bike. To tell you the truth, it's kind of weird calling it a "bike" as a bicycle by definition has 2 wheels. I guess I could call this (and other contraptions like it) a "triski", but there is something funky about that...

Starting 6 months ago with a few rough sketches and ideas, I was able to whip together a set of scale drawings. Having never built anything like this before, everything was based on logic and hopes that it would work out. I had seen North Legion's ski bikes a couple years back, so I decided to base the rear ski assembly off their SMX bike. I really wanted to make it unique so I added a few twists of my own. The "Skewed Parallelogram Assembly" allows for the outer ski to carve harder than the inner one. In theory this would allow for a bit more of a "bite" on the edges without losing stability. While this was all great in theory, I had no tests to back it up. So with one shot at getting it correct, I fired up the lathe.

Over the course of the 6 months I tried to document my progress. While there are some gaps, I was able to cover most of the main assemblies. If you want to see more photos of the project, check out the link to the album at the bottom.

Initial Scale Drawings:

Frame and Swingarm

Main Pivot Blowup

Rear-Skewed Parallelogram

Main Pivot Caps and Sub-Pivot Covers (did not end up using the covers)

First Cuts:

Main Pivot Plates (before bending)

Main Pivot Plate and Rear Shock Mount Plate

Main Pivot Assembly:

Main Pivot Caps and Hardware (milled from steel rod-stock)

Main Pivot Plates (post bending) and Full Assembly

Layout for Welding:

Plates Clamped to Central Tubing

It all started to come together:

Shock Mount Plates Welded On

Headtube

Some Solid Looking Welds

Rear Assembly Coming Together

Rear Ski Interfaces/Pivots

Front Ski Interface/Pivots

Ready for Assembling/Welding:

All the Part Laid Out

I ended up using a different Fox Float than pictured here

Painting:

Getting Ready For Some Paint

Sanded and Prepped for Painting

Finished Main Swingarm

Parts of the Skewed Parallelogram

"Firetruck Red" With White Stripes and a Nice Gloss Coat

Small Hardware

5+ Hours Later it's Time to Let it All Dry

Drying Overnight

Finished Product:

While the parts initially were nothing special... I was impressed with how it turned out.

Transition Bikes pedals, stem, and saddle

The pedals appear crooked, but it's just the angle

Marley doing the final check

Some iPhone action shots:

Thank you Tam Bikes, Mikes Bikes, and Transition Bikes. There is no way I could have completed this without you!

Complete Photo Album.

transitionbikes.com
tambikes.com
mikesbikes.com

-Sam Pannepacker

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109 Comments

Score Time

+ 18

sidekicked (Mar 29, 2011 at 0:09)

If your thinking about moving on to a four year university, you should seriously consider Chico States Manufacturing program. Bay area is close too.. If you check some of my albums, and "shop" based project was done in our labs, hit me up if you have any interest..!

+ 11

pinityoufairy (Mar 29, 2011 at 3:29)

dude i'm an engineer and used to be a mechanic and this is one of the most awesome things i have ever seen. totally reminds me of the stuff i used to get up to in high school. big props to you.

trainboy17 (Mar 29, 2011 at 4:53)

this is awesome! i am currently constructing my own dirt jump frame. great motivation to get out and build more custom stuff!

GabrielDugas (Mar 29, 2011 at 8:48)

the desing is nice but somehow really related to northlegion product. looks awesome!

pannepacker (Mar 29, 2011 at 14:55)

@sidekicked, thanks for the recommendation. i am taking a gap year, but i hope to study something along the lines of engineering in a year or so.

@GabrielDugas, i based the idea off their pivots, but added my own twist to it

RideBikes927 (Mar 29, 2011 at 16:27)

thats dope!

GabrielDugas (Mar 29, 2011 at 20:40)

sick work honnestly!

i really want to try one someday

StefanGlander (Mar 29, 2011 at 22:46)

you should seriously patent that and sell them. id buy one. do you have a video?

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spongebomb (Mar 29, 2011 at 4:33)

Looks sick except for one part: The rear suspension doesn't make any sence since you'll be standing on it anyways. It only absorbs if you'd sit on it, which would be very akwards on that small low thing

amando96 (Mar 29, 2011 at 4:37)

Noticed this as well, why was it built like that?

RaleighVoid (Mar 29, 2011 at 4:43)

lol, mod required me finks

DexterH (Mar 29, 2011 at 5:40)

Well if you think about it, the rear suspension will work, and by having the pedals where they are which is the closest point to the pivot you are minimising the distance that they will move. So... for example if the rear suspension meant the skis could move vertically by say 4" and the pedals were a 1/5 of the distance from pivot to ski, then the pedals would move vertically by around 0.8" depending on the axle path which reduces the effect of a large bump.

Correct me if I am wrong though.... I think this suspension has the best placement of the pedals possible, unless they were mounted to the front frame and not the ski stays, but this would not allow the best riding positiion.

FerdiMG (Mar 29, 2011 at 6:53)

@DexterH
well you´re not wrong. but this rear suspension doesn´t work on this terrain.
this rear suspension can take the most power coming horizontal from the front, but as we are on snow there is no such power, because of the very low friction. well yes it can absorb vertical hits while standing on the pedals, because of the angle of the trapeze, but this absorbtion is so much lower than the absorbtion by the legs that this suspension does not work out.
got it? my technical englich is not that good, i think...

siradam (Mar 29, 2011 at 13:25)

No, I think Spongebomb is right. Whilst standing on the pedals, the mass from your feet will be directed straight down to the rear skis without involving the shock.
I dont think this is a problem though because your legs can do a perfectly good job at absorbing bumbs in most situations on snow, as proven by skiers! Your ass can't, but thats what the shock's for!

Awesome job, i hope you get some good fun out of it, post a video if you can.

pannepacker (Mar 29, 2011 at 14:49)

i agree with all of you and that is one of the big things i would change if i were to build another one. the only thing is you spend a decent amount of time on the seat once you get to the steeper slopes and higher speeds as you have a lot more control if you drag the inside foot as you turn. when you are sitting on the seat it is very active and helps a lot

RaleighVoid (Mar 29, 2011 at 15:01)

good shit

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WAKIdesigns (Mar 29, 2011 at 0:08)

DIY - the enemy of the marketing departments all over the world. Great job man!

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Nukerider (Mar 29, 2011 at 8:09)

Nice! Want to see some snow bike in action? http://www.youtube.com/watch?v=yENVzKaFz7k /> We actually built them for us and some friends.
If you want one, you can ask on my proflile.

billy-bike-club (Mar 30, 2011 at 20:30)

this is my snow bike and i didnt need to do a thing to it http://www.pinkbike.com/photo/782531/

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TLKDPROD (Mar 29, 2011 at 10:26)

Great accomplishment.
Nice to see people who build their own stuff instead of buying some of that disposable crap they sell to sell us over and over.
If you can do it, why NOT do it !!!

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Fufi7 (Mar 29, 2011 at 1:52)

Hi, it is really well built...you got it man! dont get me wrong on this, i mean, the concept of the rear is not really new... but it is still a great work!!
how does it work with the trapezoidal construction?
i have a commercial snowbike (north legion smx) on my own...but its very heavy and i want to work on something similar like you did but a little diffent framebuilt. (i actually had also the trapeze form in mind)

keep it up man!

pannepacker (Mar 29, 2011 at 14:52)

thanks! i know the concept isn't new, but i tried adding my own twist with the trapezoidal linkage. i found it worked great, but on the other hand i have never ridden a north legion smx so i have nothing to compare it too

Fufi7 (Mar 29, 2011 at 23:16)

Here are 2 vids of us riding this kind of snowbike. we have a blast riding a smx. this weekend we go for our last trip before downhill and dirt season starts.

http://www.youtube.com/watch?v=f7EYKQ2cND8 />
http://www.youtube.com/watch?v=wQ5J7B5_D5Q&feature=related

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Patman03 (Mar 29, 2011 at 1:03)

how heavy is it? and i would recomend putting one of those bmx handle bars on it as they stand up higher. the handle on your bike looks really low. by the way nice build i hope to do this in high school

taletotell (Mar 31, 2011 at 6:38)

I had a similar thought. I thought maybe a block on the ski to bring up the bar.

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frenchconnection418 (Mar 29, 2011 at 1:31)

Should have went with longer fork attachment for more rake. In the rear it could have been nice to try a double wishbone suspension setup for independant ski control and more squat/grip. Still cool to see someone do it! Smile

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markykiid (Mar 29, 2011 at 12:47)

does anyone from the uk know if we get to do something like this for a level coarses? atm im doing gcses and i want to know if we can do something like this but build frames or something similar? what coarse would it be?

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stompeinator (Mar 29, 2011 at 9:26)

Here's my ski/board bike, welds are terrible and its heavy as f*ck but these things sure are fun
http://www.pinkbike.com/photo/6364648/

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CougarBait (Mar 30, 2011 at 6:05)

That's rad as hell. Nice work, dude! There's no way I would've had the patience to follow through on something like that in high school!

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Dirt-Street-Park (Mar 29, 2011 at 0:43)

I know what I wanna do this winter...

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luckynmbr13 (Mar 29, 2011 at 7:02)

i made one of those, i just had two skis though mounted using skateboard trucks. it is pretty fun to ride in the snow and carve everywhere.

Leesethebeast (Mar 29, 2011 at 8:29)

Did the exact same thing, works great

[Reply]

lord-01 (Mar 29, 2011 at 4:05)

Is it me or the rear suspension is there for nothing since the pedals are bolted to the suspension frame?

pannepacker (Mar 29, 2011 at 14:50)

see my comment below

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JustinCovey (Mar 29, 2011 at 12:30)

needs some taller bars you should mount to pedals lower. legit though! just looks like you could go over the bars pretty easy.

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cyfa89 (Mar 29, 2011 at 6:38)

awesome build
but all inches - for that reason im never going to america Big Grin

the parellelogram idea is sweet

ever seen koski though?
http://www.koskisnowsports.net/

hankyman (Mar 29, 2011 at 7:46)

metrics stink anyway! lol they just dont really teach us that kinda thing here

cyfa89 (Mar 29, 2011 at 8:49)

nooo! imperial stinks!
i have used both and find imperial to be not as accurate/not as easy to use
why dont they teach you? we get taught both but more so metric

hankyman (Mar 29, 2011 at 8:55)

haha in America, the public educational system isn't really that great. other than that, i wish i didn't have to convert everything to metric, its a pain!

hankyman (Mar 29, 2011 at 8:56)

and imperial is waaaay less accurate, i was just trying to be silly rooting for inches and all, metric makes sense haha

dmadness (Mar 29, 2011 at 9:18)

metric is easier in most cases as its in standard units of 10 instaed of the imperial foot which is 12 inches..

12 inches = 25 mm =2.5 Cm

not that difficult really, and it is more accurate as it dispels 8ths and 16ths into solid numbers..

... still, I like imperial and metric the same, just wish the prints at work would pick one or the other... lol

cyfa89 (Mar 29, 2011 at 10:26)

1foot=30cm=300mm
1inch = 2.54 cm
Wink

i only really hate imperial as some of the american engineering is sub-standard to be fair

pannepacker (Mar 29, 2011 at 14:45)

i have grown up with both at school, but had to use it because almost all the tools in the shop only had imperial measurements

pannepacker (Mar 29, 2011 at 14:45)

but i do prefer metric!

dom69foco (Mar 30, 2011 at 14:52)

@cyfa89 there is no chance one is more accurate than the other. yes, millimetres are smaller than 1/16ths of inches, but thats precision. with both, you can get more precise. from a maths point of view, metric is good for calculators and imperial is good because 12 is much more divisible than 10

cyfa89 (Mar 31, 2011 at 2:10)

your point is valid Smile

but american engineering is often still pretty shoddy

[Reply]

Luseboy (Mar 11, 2011 at 9:55)

that did turn out sweet. nice job. some day i'll make a custom one, but for now, im having fun with my ready-made franken ski bike haha

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natewynanscreations (Mar 29, 2011 at 7:43)

good job, but it would been much easir to take a fully frame and then make a drop out bracket, verses a whole new back end.

pannepacker (Mar 29, 2011 at 14:43)

yea, i did consider that, but i wanted the challenge

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Dadulator (Mar 29, 2011 at 12:29)

Beautiful! Nice to see thoughts put into reality. Well done. You have a bright future - keep the flame burning!

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mantasv (Mar 29, 2011 at 3:12)

Where are the brakes??
Ok, if seriuosly, I would consider having pedals as low as possible.
Nice write up!

Samtheman1 (Mar 29, 2011 at 4:17)

your feet are your brakes or you just jump off i guess

spongebomb (Mar 29, 2011 at 4:35)

like with skiing and snowboarding: you brake by 'skidding'. also I agree on the pedals lower, and also losing the rear shock, it doesn't make any sence since he'll be standing on it, and the pedals are fit to the skis instead of to the frame

Patman03 (Jul 12, 2011 at 23:16)

If you look at the north legion merc the suspension is the same on the back. I've read on it and they say it relieves some o the stress put on the frame. I don't think it does much though.

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SIXPACKismine (Mar 29, 2011 at 4:52)

awesome!!
have u tested it with a bmx bar??
higher rise for better handling..

great work
peace

pannepacker (Mar 29, 2011 at 14:46)

thanks! i planed to, but haven't gotten my hands on a set or higher rise bars

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pecik91 (Mar 29, 2011 at 0:11)

Jaws miał to wcześniej Big Grin

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kinkmister (Mar 11, 2011 at 7:08)

was that the shop at your highschool?

pannepacker (Mar 14, 2011 at 11:48)

yea. we have a full shop

+ 14

aflo661 (Mar 29, 2011 at 2:42)

Im really impressed that you were able to do such a nice job in highschool. When i took shop class most of the kids couldnt make their welds look any better than bird shit after 3 years of practice, let alone use a lathe and actually think up a working machine. Excellent work and totally jealous Big Grin

kbakes (Mar 29, 2011 at 4:25)

That looks like a tonne of fun to ride! Great welds too btw. Dirtjumper version of that ski jump, hardtail and all http://www.pinkbike.com/photo/6201156/

thedemo7rider (Mar 29, 2011 at 10:25)

id put some bmx bars on it and thats a sweet ski bike i with i could have one like that

lol hers mine
http://www.pinkbike.com/photo/5388563/

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doorknob100 (Mar 29, 2011 at 16:22)

Did you do anything special to the backs of the skis?

pannepacker (Mar 29, 2011 at 19:06)

i used a bit of CA glue to seal the front ski off as it was wood, but the rear skis did not need anything because they had a plastic core

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spedaholic (Mar 29, 2011 at 19:21)

great job bro...amazing Smile

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freeridact (Mar 29, 2011 at 17:40)

hope you got a good grade, thats sick!!

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kouli01 (Mar 29, 2011 at 23:04)

That is absolutely fantastic! That’s got’a be so much fun to ride/ski.

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MadJeeperCJ5 (Mar 30, 2011 at 11:37)

You guys need to get on snowscoots...

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CHADA (Mar 29, 2011 at 5:12)

How have you attached the bike to the ski's?

pannepacker (Mar 29, 2011 at 14:46)

there are 4 screws per mounting plate and epoxy sandwiched in

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ryanreishripper (Mar 29, 2011 at 23:05)

I like the US Coast Guard Helicopter color scheme!

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Goldfinger (Mar 29, 2011 at 4:30)

With only one ski backside it would work better! for sure Wink

Fufi7 (Mar 29, 2011 at 23:22)

this is BS...you cant compare 2 ski to triski snowbikes...it rides completely different. i have a north legion smx and it is super fun. i have also tried a two ski snowbike...it also fun but different. riding on slopes the two ski is maybe little more fun and faster but doing tricks and fun stuff a smx is more fun.
check it out http://www.youtube.com/watch?v=f7EYKQ2cND8 />
http://www.youtube.com/watch?v=wQ5J7B5_D5Q&feature=related

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chris (Mar 29, 2011 at 13:21)

i think wheel base is too short

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nikoniko (Mar 29, 2011 at 6:18)

Stupendous ski bike man!
RidEOn!

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aaron221 (Mar 29, 2011 at 8:42)

http://www.pinkbike.com/photo/5979598/ this is my one

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dwdw (Mar 29, 2011 at 7:54)

Nice job! Thanks Pinkbike for posting.

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freeride95 (Mar 30, 2011 at 1:12)

Yeh, you did a great job copying a SMX.
It's simple just buy a smx instead of making your own.
And a smx looks 100 times cooler. I promise you they are a lot cooler to ride!
I got one you see ;-)

CougarBait (Mar 30, 2011 at 6:04)

Simplicity wasn't the point. He wanted to build something on his own as a learning/fun experience. Seems like he did an awesome job for an 18 year old dude w/ limited experience. I think the home made version is legit and shows true passion.

Spoilt83 (Mar 30, 2011 at 14:31)

Agreed with Cougar...It's about trying things for yourself. If no-one wanted to do it themselves, we would have almost progression in designs. The easy was isn't always the best. Great job on deisgning and building this!

freeride95 (Mar 31, 2011 at 9:03)

I agree that it shows true passion and I'm sure that it was a lot of work!
But it isn't a new invention. if you look at a smx you see that he have taken the idea.

Sean1708 (Mar 31, 2011 at 9:37)

he never says it was his idea, in fact he says that he based the rear ski assembly on north legion's SMX. and he did it for a school project so buying one would have been, well, cheating.

CougarBait (Mar 31, 2011 at 10:43)

Plus you can see he did all of his engineering diagrams by hand... that's freaking tedious, even if you are just making a copy! =)

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LukeCowley77 (Mar 29, 2011 at 9:47)

This is part of the reason why pinkbike is AWERSOME!

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andreasmoser (Mar 29, 2011 at 6:00)

Very cool!! Makes mine look like Canadian "bush league,EH!

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HardassBrute (Mar 29, 2011 at 13:59)

cool, u should post some vids!

pannepacker (Mar 29, 2011 at 14:40)

i'm going back up this weekend to get some. keep and eye out!

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MilesColtart (Mar 30, 2011 at 12:02)

it wont even work the pedal are welded to the swingarm !

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marvelus10 (Mar 29, 2011 at 12:58)

The seat is on backwards on the seat post. Was this deliberate?

pannepacker (Mar 29, 2011 at 14:41)

it was in some of the early photos, but you will notice i switched it around in the recent stuff

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platypusDH (Mar 29, 2011 at 14:16)

thats mean! nice job on it

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billybayne456 (Mar 29, 2011 at 3:14)

Insane idea

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ragdoll (Mar 29, 2011 at 2:14)

awesome build dude.

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Imyme91 (Mar 29, 2011 at 16:10)

that's awesome! hah!

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olliejones2608 (Mar 29, 2011 at 10:43)

looks so fun!

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Nithzen (Mar 29, 2011 at 9:05)

where is the brakes?

apachemauro (Mar 29, 2011 at 10:41)

dude, thats super cool invention! congrats!

pannepacker (Mar 29, 2011 at 14:42)

thanks! you brake like you were skiing... resistance from turning slows you down

Nithzen (Mar 29, 2011 at 19:19)

sorry, my intention was to have done a joke!!

pannepacker (Mar 31, 2011 at 17:39)

haha, no worries!

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mike81 (Mar 30, 2011 at 2:42)

Awesome

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MANdziur (Mar 29, 2011 at 13:24)

Blam.Kot

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ridingpassionate (Mar 29, 2011 at 14:43)

very nice job!

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sailnow2 (Mar 29, 2011 at 7:03)

sooo sick!

jumpbuilderdotcom (Mar 29, 2011 at 8:58)

Great looking project man. i built a dirt jump bike completely from scratch for my senior project too, i skrewed the geometry all up so urs turned out way better than mine so congrats. im studying mechanical engineering technology right now at Eastern Washington University, its a new school hybrid mixed major of manufacturing and engineering, you should look into it its hands on and a lot of fun and will hopefully transfer straight into some more custom bike building.

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