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20" to 26" conversion. Mid School dyno build  RSS Feed

#1 2017-05-27 2:33pm

Jesse96ss
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20" to 26" conversion. Mid School dyno build

****DISCLAIMER PLEASE READ****

I understand frame geometry, I understand that certain people will get their panties in a bunch, people will argue that this is a terrible thing that I'm doing but this is NOT A HOW TO or me telling ANYONE to run out and build one yourself. I'm building this bike for my 6'6 dad. He wants to come ride with us on rides and he like the look of mid school Dynos. The build is nothing except extending all the tubes to fit a 26" wheel. Thanks for checking out my post.






I have 2 97/98 dyno air/compe frames laying around that I figured it would be a good start.

I started with these 2 frames and cut them up. http://uploads.bmxmuseum.com/user-images/234558/img_24835929f011b2.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24825929f011b9.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24815929f01203.jpg


I then sleeved every joint to mock up how it would go together. http://uploads.bmxmuseum.com/user-images/234558/img_24855929f03db8.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24845929f03e57.jpg


Got to work welding it up.

http://uploads.bmxmuseum.com/user-images/234558/img_24875929f09eb1.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24895929f09ebd.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24865929f09ec2.jpg

Last edited by Jesse96ss (2017-06-03 1:57pm)


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#2 2017-05-27 2:35pm

Jesse96ss
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Re: 20" to 26" conversion. Mid School dyno build

It sits with a 22" top tube and fits up to a 26x2.125 tire. It's all welded up, just needs a few touch ups and it's ready to be panited and built. http://uploads.bmxmuseum.com/user-images/234558/img_24905929f12c82.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24875929f12cc1.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24895929f12d3d.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24915929f12cb6.jpg


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#3 2017-05-27 2:36pm

Jesse96ss
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Re: 20" to 26" conversion. Mid School dyno build

Sorry about the pictures being out of order and upside down....roll


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#4 2017-05-27 2:41pm

azaussie
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From: Phoenix, AZ
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Re: 20" to 26" conversion. Mid School dyno build

Nice job. Can't wait to see it built up.

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#5 2017-05-27 3:19pm

Jesse96ss
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Re: 20" to 26" conversion. Mid School dyno build

Got the forks on and some beach cruiser wheels for a quick pic.

http://uploads.bmxmuseum.com/user-images/234558/img_24925929fb18c5.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_24935929fb18a4.jpg


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#6 2017-05-27 3:24pm

commi_killr
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Re: 20" to 26" conversion. Mid School dyno build

Bad ass!!


the great path, has no path.

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#7 2017-05-27 3:35pm

Lusk BMX
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From: Olympia, WA
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Re: 20" to 26" conversion. Mid School dyno build

You need to make those cuts more in the middle then pilot weld them back together.

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#8 2017-05-27 3:41pm

ymibhdu
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From: Brookfield, WI
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Re: 20" to 26" conversion. Mid School dyno build

;)Cool!  Now make a pit bike out of the scraps!


Please don't let me buy any bikes from you.  I have an addiction.  You wouldn't want to be an enabler, would you?

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#9 2017-05-27 3:52pm

BRICKOS2
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Re: 20" to 26" conversion. Mid School dyno build

^^^ For us amateurs playing at home - pilot welds?

How much sleeve is used - this is just smaller diameter tubing inserted where it joins?

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#10 2017-05-27 4:17pm

Jesse96ss
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Re: 20" to 26" conversion. Mid School dyno build

BRICKOS2 wrote:

^^^ For us amateurs playing at home - pilot welds?

How much sleeve is used - this is just smaller diameter tubing inserted where it joins?

Yes, Each weld has a sleeve.

Top tube has a 4" sleeve
Bottom tube has a 6" sleeve
Seat mast has a 4" sleeve with a 2" extension
Upper chain stays have a 3" sleeve
Lower chain stays have a 4" sleeve
Forks have a 3" sleeve on each side

Each with a small gap so most of the weld is below the surface of the tubes. Then is passed over 3 times, with each weld half way over lapping the last.

You can see in this picture the seat mast extension. Nothing is welded yet. The sleeves are holding everything together

http://uploads.bmxmuseum.com/user-images/234558/img_2484592a09f8a3.jpg

Last edited by Jesse96ss (2017-05-27 8:15pm)


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#11 2017-05-27 4:25pm

Jesse96ss
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Re: 20" to 26" conversion. Mid School dyno build

ymibhdu wrote:

;)Cool!  Now make a pit bike out of the scraps!

Thought about it. Haha
http://uploads.bmxmuseum.com/user-images/234558/img_2496592a0b188c.jpg

Last edited by Jesse96ss (2017-05-27 4:26pm)


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#12 2017-05-27 5:34pm

Minx20
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Re: 20" to 26" conversion. Mid School dyno build

cool

Will be checkn the progress out big_smile

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#13 2017-05-27 7:04pm

badassomar
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Re: 20" to 26" conversion. Mid School dyno build

cool

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#14 2017-05-27 9:51pm

cobra_standard
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Re: 20" to 26" conversion. Mid School dyno build

Cool project. I like how it looks raw with the two Donor bikes visible.


Never argue with a fool; onlookers may not be able to tell the difference. —Mark Twain

Wanted to buy;
Phil spider
Mongoose KOS bars
Peregrine Mad Maxx 24" chrome rim

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#15 2017-05-28 3:33am

Indyjps
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Re: 20" to 26" conversion. Mid School dyno build

Thats how I chop frames too,  sleeves.

Id really consider a quick coat of clear on the joints and ride it with the 2 paint jobs and decals showing.  Ride it like that for a summer.

It will make any frame geometry adjustments easier without having to ruin new paint or decals.

Last edited by Indyjps (2017-05-28 3:38am)


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#16 2017-05-28 6:19am

thesega
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Re: 20" to 26" conversion. Mid School dyno build

cool

I just did the same to a mongoose


I always hated when people Split the F/F. The Fork goes to that frame So why split it?
true ballers only ride proto-types
"This show is stupid, Turn it up louder"
jimmybills: 'costco broke my glove box'

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#17 2017-05-28 6:38am

numismatist
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Re: 20" to 26" conversion. Mid School dyno build

did you have to spread top and down tube for geometry changes?


My life? Jesus and tequila. I'm satisfied, and I cant deny it.

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#18 2017-05-28 6:39am

AlurencatBMX
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Re: 20" to 26" conversion. Mid School dyno build

Look ma, no jig ! cool


If you haven't seen the magical stars floating around whilst lying face down in the mud you ain't lived.

Skyways for show, spokes for go.

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#19 2017-05-28 7:31am

thesega
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Re: 20" to 26" conversion. Mid School dyno build

WHat did you use to grind down and smooth out your welds? Also How did you go about aligning the tubes?


I always hated when people Split the F/F. The Fork goes to that frame So why split it?
true ballers only ride proto-types
"This show is stupid, Turn it up louder"
jimmybills: 'costco broke my glove box'

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#20 2017-05-28 7:44am

jray02r1
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Registered: 2014-03-24
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Re: 20" to 26" conversion. Mid School dyno build

Very awesome build.  But I am kind of torn honestly.  I have been searching for that exact black/red dyno frame for a few years now.  Was a good friends bike back in the day and I will someday find one and surprise him with it.  I am subscribed to see the finished bike!

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#21 2017-05-28 7:55am

chillywilly263
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Re: 20" to 26" conversion. Mid School dyno build

Cool idea. Might just be the angle of the picture, but the bottom bracket looks crazy high.


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#22 2017-05-28 9:03am

Jesse96ss
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Re: 20" to 26" conversion. Mid School dyno build

numismatist wrote:

did you have to spread top and down tube for geometry changes?

Not at all. That's why I used 2 frames. I cut the chrome one near the head tube so all I would have to do is build the rear triangle then lay the painted section on top to figure out where I'd cut it. It was definitely a learning experience while doing it. big_smile

The hardest part was the upper chain stays. I had to bend the upper chain stays at the standing platform to line up with the dropouts.


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#23 2017-05-28 9:06am

Jesse96ss
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Re: 20" to 26" conversion. Mid School dyno build

thesega wrote:

WHat did you use to grind down and smooth out your welds? Also How did you go about aligning the tubes?

I used a 80 grit flapper wheel. The sleeves aligned the tubes pretty well. Then I clamped a straight edge on each side before tack welding it.


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#24 2017-05-28 9:09am

Jesse96ss
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Re: 20" to 26" conversion. Mid School dyno build

jray02r1 wrote:

Very awesome build.  But I am kind of torn honestly.  I have been searching for that exact black/red dyno frame for a few years now.  Was a good friends bike back in the day and I will someday find one and surprise him with it.  I am subscribed to see the finished bike!

I bought the frame on here. It was on here for quite a while.

The bottom bracket is in the same spot as it used to be... might be the picture.  My starting measurement was adding 3" to the lower chain stays.


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#25 2017-05-28 9:20am

Jesse96ss
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From: Tampa Florida
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Re: 20" to 26" conversion. Mid School dyno build

Took it for a quick ride. Wheels are junk but other then that it rides great and is HUGE!

http://uploads.bmxmuseum.com/user-images/234558/img_2498592af8dfa1.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_2499592af8dfb9.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_2497592af8dfe7.jpg
http://uploads.bmxmuseum.com/user-images/234558/img_2500592af8e002.jpg


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