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  1. #1
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    Kids 20" Ibex mountain bike build up (with GOOD components)

    My 6.75 year old has a 20" wheeled Ibex aluminum frame mountain bike. It has one of those pseudo-suspension front forks with disc tabs… this got me to thinking, “Hmm, convert to a disc front, but what about the other components?”. At the present my favourite local wheelbuilder is lacing up a set of Alienation Runaway trials rims to a set of “AEST” (ultra-no-name from China) red anodised disc hubs. In the meantime, here is a glimpse at some of the components that are going onto his bike once I get the headset, stem, and wheels:
    IMG_0753

    When all is said and done, the bike should weigh five pounds less than stock—the bike currently is a heavy bloated turd since the crappiest components made from granite and lead seem to find their way onto kids bikes. Just received the green anodised Chris King headseat today (February 7th).
    Last edited by Leopold Porkstacker; 02-08-2013 at 05:23 PM.
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  2. #2
    turtles make me hot
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    That's gonna be awesome. I did the same thing to my son's 20" GF Precaliber.

    Now, he's 8 and is on a 24" bike I built him. He wants to keep the 20" around so HIS kids can ride it... He's killin' me.
    I like turtles

  3. #3
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    subscribed!

    I noticed the cranks seem standard length (170-175); Do you plan on getting them shortened?

  4. #4
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    Quote Originally Posted by 08FXT View Post
    subscribed!

    I noticed the cranks seem standard length (170-175); Do you plan on getting them shortened?
    They’re the 165mm length versions. Was tricky finding an online retailer who stocked them, but I eventually found them at Pricepoint, of all places much to my amazement— I’d first started checking all the smaller online places first (Cambria, Blue Sky, Jenson, etc.) but then once again Pricepoint saved my bacon. The stock cranks are 165mm, so the pedaling geometry will be unchanged.

    Although I am plopping down some semi-big dollars on the upgrade components, I’ve focused on getting the most cost-effective parts by shopping around. For example, I got the Sram twist shifters for $20 a set, X7 rear derailleur (short cage) for $40, front X7 derailleur I believe was around $35, and the rear cassette I cobbled together from a lightly used (less than 100 miles) Sram DH 9-speed cassette (11-26) which I changed into a 11-30 setup (intermixed PG970 cogs with the DH ones)– the DH cassette new was only $29. The hubs were less than $90 including shipping (direct from China ) but are of amazingly acceptable build quality. The Thomson Setback seatpost wasn’t cheap, but was from a bike that I rode for a couple thousand miles. Complete set of Avid BB7 mechanical disc brakes (levers + rotors + calipers + cables/shrouding + pads) from Blue Sky Cycling was $120, and I am only using a disc on the front—this was a complete front/rear set that I am splitting between both of my sons’ bikes (both have a front only disc). Obviously I could have cut corners cost-wise on the Raceface Atlas cranks and the $130 Chris King headseat but substituting for something affordable and bomb-proof (Truvtiv Howitzer BB = $30) but I love the anodised blingy bits— these are components that can be transferred to another bike later on, so it’s my pretend “return on investment over ‘X’ amount of time”.
    Last edited by Leopold Porkstacker; 02-09-2013 at 10:43 AM.
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  5. #5
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    Quote Originally Posted by Leopold Porkstacker View Post
    The stock cranks are 165mm, so the pedaling geometry will be unchanged.
    I think 165 is too large, but stockers were 152. The guy you bought it from probably broke the 152s or the kid used it for jump park riding when he was 9 or 10yo. IBEX BICYCLES

    Other 20 inch bikes are 140-145. I use 145 on my daughter's bike. It was a bit long for her last year, watching her pedal around. It should almost be OK now. When my son moved off the 20 inch last year, 145 fit him perfectly. He's on 152 now. I do size it on the large side for various reasons. Some folks use 130s on 20 inch bikes.

    For a rough idea, CRANK LENGTH – Which one? » Bike Fit » Steve Hogg's Bike Fitting Website . If you think about it, I fit 175mm with about 33inch inseam. My wife uses 165mm. If we go with the sizing for your son at 165, I should probably be running around 195-200 cranks, which will make the pedaling too choppy for me. It would keep the seat low for the large pedal circle and make it easier to transition climb to descend without a dropper post (1" lower seatpost extension), but will probably hurt my knee in the long run.

  6. #6
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    Quote Originally Posted by IAmHolland View Post
    I think 165 is too large, but stockers were 152. The guy you bought it from probably broke the 152s or the kid used it for jump park riding when he was 9 or 10yo. IBEX BICYCLES

    Other 20 inch bikes are 140-145. I use 145 on my daughter's bike. It was a bit long for her last year, watching her pedal around. It should almost be OK now. When my son moved off the 20 inch last year, 145 fit him perfectly. He's on 152 now. I do size it on the large side for various reasons. Some folks use 130s on 20 inch bikes.

    For a rough idea, CRANK LENGTH – Which one? » Bike Fit » Steve Hogg's Bike Fitting Website . If you think about it, I fit 175mm with about 33inch inseam. My wife uses 165mm. If we go with the sizing for your son at 165, I should probably be running around 195-200 cranks, which will make the pedaling too choppy for me. It would keep the seat low for the large pedal circle and make it easier to transition climb to descend without a dropper post (1" lower seatpost extension), but will probably hurt my knee in the long run.
    Well, you must be right, as I double-checked today and the cranks are 165mm, not 152mm. Kinda strange, the cranks are some “no-name” brand, I think is something like “SunSomethingSomething”.

    Anyhow, more component porn pictures to be had:
    Tires for the build:
    IMG_0757
    Controls for the helm:
    IMG_0755
    I cannot get enough of the red anodised stuff:
    IMG_0756
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  7. #7
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    Wow, I have been scouring the web lately for stuff like this. My 4yo has been riding a lot. Recently got into BMX after mastering his Strider. He now rides a micro bmx.
    I picked up a 16" Scott Jr Volt that he loves riding around the park. While looking for cheap upgrades for it I got the idea to start on a 20" MTB that'll be ready for him when he moves up. Any frame recommendations to start?

  8. #8
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    Quote Originally Posted by Jordan300 View Post
    Wow, I have been scouring the web lately for stuff like this. My 4yo has been riding a lot. Recently got into BMX after mastering his Strider. He now rides a micro bmx.
    I picked up a 16" Scott Jr Volt that he loves riding around the park. While looking for cheap upgrades for it I got the idea to start on a 20" MTB that'll be ready for him when he moves up. Any frame recommendations to start?
    Any semi-decent frame should be fine. I am no kids bike expert, I just went with the Ibex since I got it at a swap meet for $100 and it was in perfect condition.
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  9. #9
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    I completed the build late last night:
    IMG_0827
    IMG_0822
    IMG_0824
    IMG_0825
    My boy is super-stoked!!!
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  10. #10
    turtles make me hot
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    Looks most excellent.
    I like turtles

  11. #11
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    Thanks! My boy is soooo excited. I am sure he’s been completely distracted thinking about the bike while in school today. Hopefully we’ll have a chance to break it in on the trails later on this afternoon.
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  12. #12
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    How'd you balance your lunch on the handlebar like that?
    Nice bike!

  13. #13
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    Quote Originally Posted by indianadave View Post
    How'd you balance your lunch on the handlebar like that?
    Nice bike!
    Actually, my lunch is more along the lines of this monstrosity:
    IMG_0046
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  14. #14
    Havok
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    That bike is amazing, I've found a hotrock to work with. Can you give a little more detail about those wheels? Did you build them? If so, what are the specs?

    EDIT: Nevermind, I just read your first post all the way through
    Last edited by Jordan300; 04-03-2013 at 10:39 AM.

  15. #15
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    Quote Originally Posted by Jordan300 View Post
    That bike is amazing, I've found a hotrock to work with. Can you give a little more detail about those wheels? Did you build them? If so, what are the specs?

    EDIT: Nevermind, I just read your first post all the way through
    But, if you have any other questions, please ask.
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  16. #16
    Havok
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    Have you weighed it?
    I've become more concerned with the weight of his bike lately. My son is smaller than average and has a hard time with his 21lb 16". I'm hoping to keep his 20" to 20lbs.

  17. #17
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    Quote Originally Posted by Jordan300 View Post
    Have you weighed it?
    I've become more concerned with the weight of his bike lately. My son is smaller than average and has a hard time with his 21lb 16". I'm hoping to keep his 20" to 20lbs.
    For sub-20 pound weight reduction, I would reccomend ditching a suspension fork and try to come up with the lightest possible rigid fork. Problem is that most BMX 20" rigid forks are overbuilt with such a huge margin since they need to be able to survive adult weight riders landing massive jumps. An optimized weight kids rigid MTB fork should be plenty strong at less than 1 pound (450gr) but probably does not exist as a pre-made stock item you can just easily order.

    My 7-year old daugher is trying her first kids cyclocross races on a 21#, 20" MTB this year, definitly is a challange for her to lift the bike over cyclocross barracades.

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