This shit is history. People will come back to this episode in years to come for reference and the rest. Paul Schmitt is a living legend and his contribution to literally every single facet of the the action and motion of skateboarding is undeniable. Best dude. Skateboarding.
For anybody wondering here are some truck wheelbase specs for the top four truck brands. Widest to Narrowest: Venture Thunder Indy Ace There is about a half an inch from venture to ace with roughly one eighth between each brand. For example thunder and Indy are only about an eighth inch apart. Not as much as people think. Small measurements make big differences. My preference is 14.25WB with indys. Second favourite is 14”WB with venture highs. Once you start changing deck steepness, truck weight, truck height, wheel size wheel weight you get into a mind melting range of infinite possibilities. This is called “the madness”. My advice is, DONT GO THERE! Find what works and stick with it. Only make small changes once in a while. Sometimes it’s better to focus on your skateboarding instead of your skateboard. That’s my two cents.
The way rog puts so much thought into landing a trick at almost 50 years old!! Love hearing his thoughts and feeling his dedication. Health and Happiness everyone!
I've been eagerly anticipating Paul's return to the Nine Club. Absolutely fascinating stuff, even though it can get very difficult to follow at times due to the archaic US measurement system. It's hard to overstate this man's importance in the world of skateboarding.
Met him once with his daughter and he was so cool to us. His knee was hurting like hell and he was still insisting on answering any questions my pals had.
Best guest ever. Professor Schmitt is so intriguing. I love all the science conversations. Y’all should do one with him and the neuroscientist together!
Schmitt is such a legend.Awesome episode.I didn't know your podcast existed until two weeks ago.You're all i've been watching for the last two weeks.Danny way,Vallely,Tommy g etc,bought it all back to me.I'm 49,started skating in1985,stopped in 1994,you've got me stoked on skateboarding again!!.i've just ordered a brand new set-up!.Mountain biking is gonna take a back seat for a while.Thank you for doing what you do,you're awesome dudes.peace.
I’ve always loved the ‘board setup’ part of the stop and chat but this is taking it to the next level. I feel like I’ve learnt so much about materials, measurements, dimensions, trucks, bushings etc. It’s fascinating and also cool to see Crobs set up and Jerons.
Literally was just talking about the professor and how crucial and awesome he is to skateboarding and how he is probably the last of his breed since big corporations are now going to have their money and interest in the sport. 3 HOURS!!!!! HOOO HEEE!
@@jakeambrosia5126 exactly my point. any new tech will be a guarded secret with restrictions on reproducing it and owned by the corporation instead of the engineer.
I removed my hangers, and put two drops of sewing machine oil in the pivot cups to get rid of that annoying truck squeak. I thought I'd only watch a few minutes, and was captivated for the whole thing. The Professor is epic!
This actually answered a few of the questions I have searched high and low ex. Grip tape under trucks…thank you guys so much for getting this man on the show!
Paul is an incredible gentleman. I spent an afternoon with him and Mike V at his workshop while they dialled in Mike's shape. Paul was so precise and professional in his process, yet so patient with Mike as they searched for those little details that made such a big difference.
@@P1Brand Ah man Jason so rad to see you pop up on here! Working alongside you both was such a blast. Shoot me an email sometime (in my bio) would love to catch up!
What a legend!!! The Professor blessing us with knowledge and insights left and right... Hats off!! May the skate gods be with you and bless you with health and wealth!!!
I never had skateboard madness just whatever feels good but after this I'm defs gonna be analyzing everything on my board. Thank you professor, this is always such fascinating stuff!!
Watched this channel for quite a while. The last interview with Paul was great. It had a different vibe than I’ve seen before on this channel. I feel like having one guy with a lifetime of experience really brought out the best in all of them. 👍
Paul Schmitt along with the 1985 -86 Schmitt Stix Skate Team( Lucero, Joe Lopes, Monty Nolder) are like family members to me. Xmas of 1986 _ Santa Claus left me Schmitt Stix "Lets Go Skate" VHS tape. This video may not be praised like the Powell vids from the 80s or the classic Santa Cruz vids or the vids that came out 4/5 yrs after these and in my opinion changed Skating overnight : Both H Street vids ( Hocus Pocus and Shackle Me Not) but to me this 30min video was everything to me. If a friend came over back then to my house they would always want to watch it. Always good to see Paul talking boards and to be honest is the guy to go to when. It comes to skateboard decks.. . Oh shit!!! Paul brings up the video in the beginning of the show!!!!
Professor S almost validated Roger’s lust for bearing spacers but stopped short or mentioning that manufacturing tolerances for wheels can be off enough that the spacers don’t fit perfectly causing unbalanced pressure on the bearings.
Dude! My trucks have been squeaking for month! I’d take the bones medium bushing off, rub WD 40 on them and that would work for a couple sessions but then the squeak would come back. Took Proffesor’s advice on putting the washer under the bottom of my bones bushings and it solved it right away! So much good info here
ive recently got my first twin tail deck, while it was good for nollie and fakie flip tricks, it completely eliminated my hardflips out of existence lmao. I learned hardflips on the nose back when a bigger nose than tail was the standard, could never do them on my tail. Brings me to the part where he talked about the meter while the shape can be good or enhance one thing it might take away from another. So the search continues for a deck that I can do all my tricks on.
Paul is such an awesome dude... I remember Schmitt Stix from way way back... always innovative...and apparently partially responsible for Nyjah's skating success ....solid guy Paul is and skateboarding is privileged to have him.
1:20:12 Stability in kingpins. Followed by correct bushing height and/or how squish from tighter setup affects the bushing sizing. how the angle of the hanger in the pivot cup. And how the contact points and pressure point on the bushings effects wear and pre tension. (Stored
Another great show always a privilege to listen to the Professor and nice to see him in such fantastic health the fact this man has been innovating and inspiring skating for nearly 50 years and is still so passionate and motivated to be at the cutting edge of development is testament to his technical know how and his immense love for skateboarding please get an episode live from his factory with a top 10 questions, Like a technical budget or buttery. Keep up the Superb work
1:15:08 the narrower your deck and trucks are the faster it will flip (kicksflips, etc). The shorter your wheelbase (considering both deck and truck combo) and deck length are, the faster it will spin (shuvits, etc). A lighter board will flip and spin faster. Of course you need to keep all of these specs within a range where it's still comfortable to ride the board and do other tricks as well.
44 years old and have broke my humerus after dislocating. I have loved skateboarding since my Walmart variflex in 89 . Niw my 9 year old skated a thank you . I ride Baker and Flight decks . 8.38 baker and 8.75 Salman lion . I tried the washer under bushing on my flight deck with K5 black widows after I switched the Indy 169s out after I noticed the weight difference. I want to keep up with my 9 year old so my wife’s setup is a welcome with thunders , I have a Reynolds 8.38 with Ace 44s I think and a Frankie hill Re issue with the Indys . 5 boards 3 different brands of trucks . I’ve invested over 1,000 in skateboarding. We’ve tried grizzly , black diamond, MOB tape and doh doh bushings independent, bones . The one thing I’ve learned is setup matters to me . The professor and you guys are an awesome way to learn while I work. I’m hurt and can’t not skate after watching an episode . My skate park deck ( flight ) has 54mm 99 conical spitfires. I love them . My street , sidewalk , downhill has the slime ball 56 mm 78 a . My bearings I love the most is Quantum bearings . The isotopes . Shout out to Bone Yard skateshop in Auburn ,Al .9 club you guys are on fire 🔥
Anyone remember New Wave decks??? I had a couple of Baker and Flip decks with it back in 02! When new they slid so F’ing Noice! The waves would chip funny and the ones i had didnt last long but they were interesting. 🤘👽
I love when he s on. I recently been counter sinking where I grab. It's like ripgrip but the holes drilled in the board. Awesome mod. Makes the board feel like it s more yours. Will continue this. Lein airs way more precise. Hells yes to the stacking. Lol.
Cool. I love Paul Schmitt. I just watched an old Colt Cannon video part yesterday. What ever happened to that dude? He would be a great Nine Club interview, I bet. He had a great personality, and was super gnarly. One of my favorites of the 00's era.
Couple of things that came up to mind when watching this episode. Kelly talking about thunder 147hi, it's between indy and venture low height wise. Just a touch higher than venture low. And talking about not getting those hardflips i think the board shape has to do something with it as well. Like a rounder tail doesn't behave same as a tapered one etc. Anyways great episode!
Paul Schmitt is a really interesting and charismatic guest every time he comes on. A question that came to mind is has anyone ever tried diagonal plys and what would the affect of that be?
I had those rails. I remember waiting at the Skateshop for my mom to stop by after her work ended so she could by then for me. Feels like the other day.
I'd love to see a limited reissue of the Turbine wheels. If for nothing else than to hear what they sound like but I think they'd sell quick especially w/ the way collectors are at this point. I'd love a reissue of those rails too. Nine Club special edition.
the trick to getting rid of the squeak and the click on bones bushings is to wax them and wax the hanger where the bushings touch. also wax the inside of the pivot cup. no squeaks. i think it makes them last longer too because there's less friction between the bushings and the hangers. might not blow out as fast.
![Chris Langan - The Interview THEY Didn't Want You To See - CTMU [Full Version; Timestamps]](/img/n.gif)
We need a 9 club episode where they go to his workshop for sure.
YES! That would be amazing.
yessssss please
Absolutely
I want Paul to help Chris get up on the courthouse.
@@BaxterDavis2365 that would be a good watch also they need to make that happen
This shit is history. People will come back to this episode in years to come for reference and the rest. Paul Schmitt is a living legend and his contribution to literally every single facet of the the action and motion of skateboarding is undeniable.
Best dude.
Skateboarding.
Damm, you nailed it!
For anybody wondering here are some truck wheelbase specs for the top four truck brands.
Widest to Narrowest:
Venture
Thunder
Indy
Ace
There is about a half an inch from venture to ace with roughly one eighth between each brand. For example thunder and Indy are only about an eighth inch apart. Not as much as people think. Small measurements make big differences.
My preference is 14.25WB with indys. Second favourite is 14”WB with venture highs.
Once you start changing deck steepness, truck weight, truck height, wheel size wheel weight you get into a mind melting range of infinite possibilities. This is called “the madness”.
My advice is, DONT GO THERE! Find what works and stick with it. Only make small changes once in a while. Sometimes it’s better to focus on your skateboarding instead of your skateboard.
That’s my two cents.
Ben please get on the nine club you are the best skate UA-camr
You’re the best Ben!
Found Ben!
Yeah I thought half inch from Indy to Thunder sounded a little extreme.
indys are really heavy with even hollow axles who makes a mag truck with ti hollow axles
I love how excited Roger gets when Professor Schmitt is on the show. He talked more this episode then the last five episodes combined
so true. you can tell he really looks up to him
The way rog puts so much thought into landing a trick at almost 50 years old!! Love hearing his thoughts and feeling his dedication. Health and Happiness everyone!
yeah, Roger is awesome !
Schmitt needs to be in Skate 4 as a character when setting up your board
Brilliant
Lol that would be sick
great idea
Sounds amazing & even better if he narrated the story mode
"These are Thunders, but I skate for Independent." LMFAO
Hahah anyone got a board with indies on it? Looks around no but I skate for indy though
Faustos are watching
Koston used to skate indys while on Royal
Corey duffel skated ventures while on ruckus
In all fairness, Indys, Thunders, and Bullet Trucks are all made in the same factory by the same company (NHS).
@@marcusprince3999 Thunder is Deluxe.
Chris "this is my symmetrical prototype"
Professor Schmitt *hold my ruler*
I'm glad you had the Professor back on. His first episode was my favorite interview on the Nine Club.
I've been eagerly anticipating Paul's return to the Nine Club. Absolutely fascinating stuff, even though it can get very difficult to follow at times due to the archaic US measurement system.
It's hard to overstate this man's importance in the world of skateboarding.
For real, it's all so interesting but I cannot relate at all due to the strange figures
@@matsvongegerfelt4007 Needed to have an online converter next to me while watching.
Met him once with his daughter and he was so cool to us. His knee was hurting like hell and he was still insisting on answering any questions my pals had.
Paul Schmitt is the best!
As a mechanical engineer and a skater, the Professor interviews press are just the best!
Best guest ever. Professor Schmitt is so intriguing. I love all the science conversations. Y’all should do one with him and the neuroscientist together!
Yes💪🤘
Chris: “I don’t want a quiver of boards.”
Made me laugh out loud alone in my house so hard for some reason. Such a good line.
Fastest click on a long time ... The professor is such an interesting guest
Schmitt is such a legend.Awesome episode.I didn't know your podcast existed until two weeks ago.You're all i've been watching for the last two weeks.Danny way,Vallely,Tommy g etc,bought it all back to me.I'm 49,started skating in1985,stopped in 1994,you've got me stoked on skateboarding again!!.i've just ordered a brand new set-up!.Mountain biking is gonna take a back seat for a while.Thank you for doing what you do,you're awesome dudes.peace.
Dope timing with Olympics yo. Get torque'd with nano tubes ::: this one dude is the glue from all eras of skating like no other. Cheers y'all.
Dr. Schmitt should just make a weekly 30min Video show called "Skate Talk, Tech Talk".
Another 3 hours of Paul Schmitt?! You guys are awesome!
agreed
Yes. This is what I needed
I’ve always loved the ‘board setup’ part of the stop and chat but this is taking it to the next level. I feel like I’ve learnt so much about materials, measurements, dimensions, trucks, bushings etc. It’s fascinating and also cool to see Crobs set up and Jerons.
Chris "I never been in a fight in my life" Roberts. I love Chris's self deprecating humor.
Literally was just talking about the professor and how crucial and awesome he is to skateboarding and how he is probably the last of his breed since big corporations are now going to have their money and interest in the sport. 3 HOURS!!!!! HOOO HEEE!
Plîlull000p00
big corp isnt afraid of making great product tho. they will always need a skate nerd
@@jakeambrosia5126 exactly my point. any new tech will be a guarded secret with restrictions on reproducing it and owned by the corporation instead of the engineer.
Oh hell yes! 3 more hours with Paul Schmitt?! My rainy Friday afternoon is officially booked.
Where’s it raining? It’s hot as hell here
I removed my hangers, and put two drops of sewing machine oil in the pivot cups to get rid of that annoying truck squeak. I thought I'd only watch a few minutes, and was captivated for the whole thing. The Professor is epic!
Careful as oil holds dirt and dust
Met and talked to Paul for like 15 minutes at the Dew Tour in Iowa. Real cool dude
wooooooow coooooool
@@DerAndreKanal You’re damn fucking skippy!
This actually answered a few of the questions I have searched high and low ex. Grip tape under trucks…thank you guys so much for getting this man on the show!
I love Paul Schmitt, the information he shares and has is so rad=}
Paul is an incredible gentleman. I spent an afternoon with him and Mike V at his workshop while they dialled in Mike's shape. Paul was so precise and professional in his process, yet so patient with Mike as they searched for those little details that made such a big difference.
Brock! I remember that day,
@@P1Brand Ah man Jason so rad to see you pop up on here! Working alongside you both was such a blast. Shoot me an email sometime (in my bio) would love to catch up!
Which board did it become?
What a legend!!! The Professor blessing us with knowledge and insights left and right... Hats off!! May the skate gods be with you and bless you with health and wealth!!!
Haven't even watched yet, but I loved the main episode on him, and I know for a fact I will love this.
When he said "Gimme, Gimme, Gimme"..who else was thinking, "I need some more"...?
DON'T ASK WHAT FOR!
Fascinating man. Could listen to him all day
We need more sweet, passionate people like Paul in this world. I am stoked my first board I. 1988 was a Lucero Schmitt Stix.
I never had skateboard madness just whatever feels good but after this I'm defs gonna be analyzing everything on my board. Thank you professor, this is always such fascinating stuff!!
aweeeeeesome!!! PS is the best!!! every skater likes this technical stuff and setup conversation!!!!
Watched this channel for quite a while.
The last interview with Paul was great. It had a different vibe than I’ve seen before on this channel.
I feel like having one guy with a lifetime of experience really brought out the best in all of them.
👍
You can tell Paul loves talking about his work, nice one.
Paul Schmitt along with the 1985 -86 Schmitt Stix Skate Team( Lucero, Joe Lopes, Monty Nolder) are like family members to me. Xmas of 1986 _ Santa Claus left me Schmitt Stix "Lets Go Skate" VHS tape. This video may not be praised like the Powell vids from the 80s or the classic Santa Cruz vids or the vids that came out 4/5 yrs after these and in my opinion changed Skating overnight : Both H Street vids ( Hocus Pocus and Shackle Me Not) but to me this 30min video was everything to me. If a friend came over back then to my house they would always want to watch it. Always good to see Paul talking boards and to be honest is the guy to go to when. It comes to skateboard decks.. .
Oh shit!!! Paul brings up the video in the beginning of the show!!!!
Professor S almost validated Roger’s lust for bearing spacers but stopped short or mentioning that manufacturing tolerances for wheels can be off enough that the spacers don’t fit perfectly causing unbalanced pressure on the bearings.
Roger is so nice and knows everything, love that guy
Dude! My trucks have been squeaking for month! I’d take the bones medium bushing off, rub WD 40 on them and that would work for a couple sessions but then the squeak would come back. Took Proffesor’s advice on putting the washer under the bottom of my bones bushings and it solved it right away! So much good info here
Paul, we need those slappy boards on the market!
I've never been more interested in learning about how each component of a skateboard can effect how it rides and reacts
His first visit was one of my all time favorite Nine Clubs! So stoked to see this.
Love the “I ❤️Canada” mug in the back!!
I'm pretty sure Roger is Paul's son, heir to the Deep-Dive-Skater-Dynasty.
Yeah I am pretty sure Roger spent the next week rehanging all the boards and checking the fit on all the doors to his house.
True love is the way Rog looks at Paul
@@KBSimRacing Yeah questions to where about of Paul Schmitt about 47 years ago have to be asked. Was he anywhere near Danvers ?
Edit - I do not have Prof. Schmitt levles of maths. He is not that old or Rog is too old...
Awesome! I used to work for Professor Schmitt before I became a tattoo artist, greetings from Tijuana and long live psstix.
I’d love to drink a beer or wine with Paul and philosophy about Skate stuff. From engineer to engineer, his mind is just brilliant.
Really glad to see this. Learn a lot from Paul every time he speaks on skateboard manufacturing.
ive recently got my first twin tail deck, while it was good for nollie and fakie flip tricks, it completely eliminated my hardflips out of existence lmao. I learned hardflips on the nose back when a bigger nose than tail was the standard, could never do them on my tail. Brings me to the part where he talked about the meter while the shape can be good or enhance one thing it might take away from another. So the search continues for a deck that I can do all my tricks on.
Chris "I haven't found a ruler long enough" Roberts
Love this I actually researched alot of the board companies and watched so many videos for my interview at a skate shop
Best guest. We need to learn about the boards we ride
at the part measuring chris' board. this is gold.
honestly i learned so much my brain is full for the day. so sick. thx guys.
PS is THE MAN!!! So Stoked you guy had him back on... Thank You Curb slappy rocks 8.5 for real... Skaters supporting Skaters 👍
Paul is such an awesome dude... I remember Schmitt Stix from way way back... always innovative...and apparently partially responsible for Nyjah's skating success ....solid guy Paul is and skateboarding is privileged to have him.
easily my favorite episode yet. so much knowledge from this guy. definitely going back and watching his ep
The washer under the bushing is going to be a game changer!
This was an unexpected surprise to see this morning. Thanks guys!
Love The Professor! 3 days a week of The Nine Club is awesome!
1:20:12 Stability in kingpins.
Followed by correct bushing height and/or how squish from tighter setup affects the bushing sizing.
how the angle of the hanger in the pivot cup.
And how the contact points and pressure point on the bushings effects wear and pre tension. (Stored
Another great show always a privilege to listen to the Professor and nice to see him in such fantastic health the fact this man has been innovating and inspiring skating for nearly 50 years and is still so passionate and motivated to be at the cutting edge of development is testament to his technical know how and his immense love for skateboarding please get an episode live from his factory with a top 10 questions, Like a technical budget or buttery. Keep up the Superb work
1:15:08 the narrower your deck and trucks are the faster it will flip (kicksflips, etc). The shorter your wheelbase (considering both deck and truck combo) and deck length are, the faster it will spin (shuvits, etc). A lighter board will flip and spin faster. Of course you need to keep all of these specs within a range where it's still comfortable to ride the board and do other tricks as well.
44 years old and have broke my humerus after dislocating. I have loved skateboarding since my Walmart variflex in 89 . Niw my 9 year old skated a thank you . I ride Baker and Flight decks . 8.38 baker and 8.75 Salman lion . I tried the washer under bushing on my flight deck with K5 black widows after I switched the Indy 169s out after I noticed the weight difference. I want to keep up with my 9 year old so my wife’s setup is a welcome with thunders , I have a Reynolds 8.38 with Ace 44s I think and a Frankie hill Re issue with the Indys . 5 boards 3 different brands of trucks . I’ve invested over 1,000 in skateboarding. We’ve tried grizzly , black diamond, MOB tape and doh doh bushings independent, bones . The one thing I’ve learned is setup matters to me . The professor and you guys are an awesome way to learn while I work. I’m hurt and can’t not skate after watching an episode . My skate park deck ( flight ) has 54mm 99 conical spitfires. I love them . My street , sidewalk , downhill has the slime ball 56 mm 78 a . My bearings I love the most is Quantum bearings . The isotopes . Shout out to Bone Yard skateshop in Auburn ,Al .9 club you guys are on fire 🔥
Kelly went the colour of his mug when he laughs. priceless
Love seein the Prof back on. Such a wealth of knowledge!
I love this show! I had a Schmitt stix with those rails,G&S trucks and oj 60mm wheels. What a trip this show takes my old ass on lol
I would love to hear his insights on wheels especially the effects of their shape and contact patch.
Epic. What a fountain of knowledge and stoke!
This episode is so good! Thanks guys!
This is going to be a good one
Thanks guys. Watching this again!
what an informative episode! Thanks Paul and The Nine Club
Literally commented asking to have professor schmitt back last week! Thanks guys!
Anyone remember New Wave decks??? I had a couple of Baker and Flip decks with it back in 02! When new they slid so F’ing Noice! The waves would chip funny and the ones i had didnt last long but they were interesting. 🤘👽
👽👍 Im glad that some people remember em! I don’t think they were too popular or they just didn’t take off.
Great episode, Schmitts episodes are up there with my favourites
I love when he s on. I recently been counter sinking where I grab. It's like ripgrip but the holes drilled in the board. Awesome mod. Makes the board feel like it s more yours. Will continue this. Lein airs way more precise. Hells yes to the stacking. Lol.
Cool. I love Paul Schmitt.
I just watched an old Colt Cannon video part yesterday. What ever happened to that dude? He would be a great Nine Club interview, I bet. He had a great personality, and was super gnarly. One of my favorites of the 00's era.
Couple of things that came up to mind when watching this episode. Kelly talking about thunder 147hi, it's between indy and venture low height wise. Just a touch higher than venture low.
And talking about not getting those hardflips i think the board shape has to do something with it as well. Like a rounder tail doesn't behave same as a tapered one etc.
Anyways great episode!
I love the professor, he has a wealth of knowledge about skateboards. Would love to meet him one day!
"damnit!...Kelly give me your board 😆 20 mins in and im already cracking up
Brand: "a collection of people putting out a perception"
The Nine Club and Paul Schmitt rule!
Paul Schmitt is a really interesting and charismatic guest every time he comes on. A question that came to mind is has anyone ever tried diagonal plys and what would the affect of that be?
1:39:27 "I wanna lean over and see the nut. " bruh kelly dying in the background! 😂😂😂
Blue nuts are the worst.
@@RyanLynnWood so good! 😂😂
@@datoad6787 you got to get the money shot. 🤣
Ryan wood that's the best part. 😂
Shortest 3 hours, this was so good.
I had those rails. I remember waiting at the Skateshop for my mom to stop by after her work ended so she could by then for me. Feels like the other day.
I'd love to see a limited reissue of the Turbine wheels. If for nothing else than to hear what they sound like but I think they'd sell quick especially w/ the way collectors are at this point. I'd love a reissue of those rails too. Nine Club special edition.
Incredible, incredible episode.
Incredible episode full of knowledge respect!!!!
Man I love this stuff! Gets my brain working 💪much love
This guy should be there at least twice a month. I love those talks.
They got the professor throwing out the lil, he said “ it’s just a lil microclimate”
this was so fucking good. this guy needs a youtube or something man. he really knows how to communicate things
chris roberts eyes when paul pulls out his bag of tools!
I’m glad someone else appreciated that 😂
OMFG ! I love it when SCHMITT is on . Utterly inthroling.
the trick to getting rid of the squeak and the click on bones bushings is to wax them and wax the hanger where the bushings touch. also wax the inside of the pivot cup. no squeaks. i think it makes them last longer too because there's less friction between the bushings and the hangers. might not blow out as fast.