# My sons new bike with a twist



## Demo9 (Nov 20, 2006)

I dreamed of the day when I could build a bike for my son. So the time has come and this is what I did. I started off with a 09 Specialized 12" Hotrock.

The first order of business was the hubs. I found a set of DK Mini Sealed bearing hubs on ebay. 








They laced up perfectly. When I tried to install the front wheel i found that the fork spacing is different on this bike. So I machined up some new spacer for the front hub. 








The rear fit perfectly








Next was some 3pc. cranks. This sounded like a good idea until I noticed the bottom
bracket had a smaller id. and a narrower width than a normal bmx. I purchased a bottom bracket and cranks off ebay and started machining















I turned the OD of the bearing adapter down to fit the smaller kids frame.








I then had a friend machine the cranks for me. He shortened the arms to 90mm and 
rethreaded them.


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## Demo9 (Nov 20, 2006)

Next I had to narrow the spindle. I cut a 1/2" out, threaded both pieces, then reassemble the spindle with a piece of allthread. I then Tig welded the spindle back together. It turned out straight as an arrow.






















I then assembled the modified parts. I used a 34t front ring and an 18t rear with a Sinz 
Hollow pin chain. The pedals are Free Agent mini's








Last was the brake. I purchased a Linear Pull brake adapter from Jenson Usa. I had the brake arms from an old bike, the lever is a Sinz Mini Lever.






















I'm not super happy with the brake. It's still a little hard for a 2 year old to pull. I am going to put a disc brake on as soon as the adapter is available from Atomlab.

Here's the finished product:


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## highdelll (Oct 3, 2008)

*You're up for "Dad of the Year!"*

Nice job man:thumbsup: 
I especially like what you did with the spindle.
It's funny, the drivetrain looks MASSIVE on that bike 
(does he ride w/ the seat that low? i'm guessin no, but just wonderin')


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## Demo9 (Nov 20, 2006)

He's graduating from a Specialized Hotwalk that he started balancing when he was 19months. The seat is that low so he can touch the ground better. He hasn't quite grasped the pedaling thing yet. He should be rippin in a couple a weeks I hope.


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## JD1 (Feb 1, 2011)

That...is...effing....CRAZY! Cool. Nice job.


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## NYrr496 (Sep 10, 2008)

Very cool. Nice work.


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## Demo9 (Nov 20, 2006)

Just a little update. The bike finally got a disc brake :thumbsup:


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## NYrr496 (Sep 10, 2008)

That brake is hysterical. I LOL'd when I first saw it. Oh well... He'll have no trouble stopping.


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## Sheepo5669 (May 14, 2010)

is that a 8'' rotor? jk haha


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## highdelll (Oct 3, 2008)

Demo9 said:


> Just a little update. The bike finally got a disc brake :thumbsup:


Don't ya know that 69.420% of braking force in the front? :madman:
Good job :thumbsup: - now we have another skidiot!


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## the-one1 (Aug 2, 2008)

highdelll said:


> Don't ya know that 69.420% of braking force in the front? :madman:
> Good job :thumbsup: - now we have another skidiot!


I can see him putting a front rotor on that wee bike and at the touch of the levers, the kids fly otb face flat into dirt.:eekster:


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## highdelll (Oct 3, 2008)

the-one1 said:


> I can see him putting a front rotor on that wee bike and at the touch of the levers, the kids fly otb face flat into dirt.:eekster:


It was supposed to be funny :idea:


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## canonshooter (May 10, 2009)

That rocks! My son is 3 and tears up his Strider. I cant wait for him to get pedals! Although I am thinking of putting him on a 16 next year and then after he out grows that I have an old Raleigh M80 frame that I am going to build up for him when he is big enough for it. 

Tonight I was in the basement pulling the cranks and BB out of my Ells and he was right there with the BB wrench helping out. Good times.


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## Demo9 (Nov 20, 2006)

The main reason I went to the disc is my son, at 2.5 had a hard time stopping the bike 
with the linear pull brake. With the disc he now has no problems and it looks cool. I have already built a bike with a front disc brake. I set it up so it just barely slows him down. He rode the bike in Whistler this past summer at age 3 1/2.


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## highdelll (Oct 3, 2008)

Demo9 said:


> The main reason I went to the disc is my son, at 2.5 had a hard time stopping the bike
> ....


yup, remember, that a lil'-uns fingers (esp. at that age) are not very strong...:thumbsup:


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## highdelll (Oct 3, 2008)

Again, DAD of the year 









You got any closeups of the brake mods? Or are they actually making li'l frames w/ mounts?


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## Demo9 (Nov 20, 2006)

canonshooter said:


> That rocks! My son is 3 and tears up his Strider. I cant wait for him to get pedals! Although I am thinking of putting him on a 16 next year and then after he out grows that I have an old Raleigh M80 frame that I am going to build up for him when he is big enough for it.
> 
> Tonight I was in the basement pulling the cranks and BB out of my Ells and he was right there with the BB wrench helping out. Good times.


I just put this 16" bike together, it started out life as a Specialized Hotrock. It has a lot better geometry for riding trails and jumps and has a pretty low stand over.


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## Demo9 (Nov 20, 2006)

The front tab I Tig welded on. The rear is an aluminum thread on adapter for the rotor and the caliper mount are both made by www.choppersus.com. You can use a flip flop hub or get a Trials bike hub and lace up a new wheel. I have done both on different bikes. *The Redline is for sale if anyone wants the ultimate kids bike, it only weighs 17lbs* I also threw in an in action picture.


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## canonshooter (May 10, 2009)

How much for the Redline?


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## Maida7 (Apr 29, 2005)

looks very expensive


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## zazen (Sep 15, 2005)

Man, looks like I really got to step up my game. +1 on dad(s) of the year. Can't wait for the future 16", 20", 24", 26" then 29" builds. No way you can settle for off the shelf parts now. Nice work gentleman. Props. Your sons have no idea how cool their dads are.


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## Demo9 (Nov 20, 2006)

No need to worry I have the 20" already done :thumbsup:


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## MondoRides (Feb 18, 2004)

*Nice!*



Demo9 said:


> No need to worry I have the 20" already done :thumbsup:


My son is only 6 weeks old now so we're many months away from putting him on his first bike but this thread has provided me with plenty of inspiration.

BTW, what fork do you have on the Scott? Looks like a modified Marzocchi Shiver. Not sure I've seen a dual crown this size before


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## Demo9 (Nov 20, 2006)

Yes, its a Single crown Shiver. I cut the crown off and put a crown off a 05 Marz 888. I then removed ETA and coil out of one side and converted it to air. My son is now 4 and he rides it around the hood but thats about it. FYI, I bought my son his first balance bike at 1 and he started balancing it at 19 months, so I say start them young


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## rrl (Sep 21, 2008)

Demo9 said:


> No need to worry I have the 20" already done :thumbsup:


where can i get a bike like this?? just beautiful!!!!:thumbsup:


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## Cinq (Jan 2, 2003)

What a great topic! I just ordered a few things for my son's Hot Rock 20. When I first looked at all I would like to change, it didn't double but quadruple the price of the bike.. I decided to first let him have fun with the standard setup and now things are used up, I start replacing them with better components.

Kind regards,

Clemens


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