Viewing 40 posts - 1 through 40 (of 61 total)
  • Dads. Building the nice 24" Wheeled MTB for your Kids – Crank info and Build
  • johnski15
    Free Member

    Hi,

    I’ve build my son as 24″ Wheeled MTB as I din’t want to pay £800-£1500 for an Islabike Creig.

    I searched and searched for info and ideas with regards to the build and basically needed some info on crank shortening. There is a little bit about and a few places that shorten cranks for you, but if you don’t want the cost (Circa £50 to £60), lag time and just fancy building the whole bike yourself here’s what I did.

    So I decided I wanted to build an ‘Islabike Creig 24 Pro’ for a fraction of the money and spec it how I wanted it, but trying to emulate the weight of the Creig (9.02kg without pedals).

    This is what I’ve done:

    Donor Frame: 2013/2014?? Carrera Blast (2nd hand off Gumtree – full bike – cost nothing as I sold all the parts I didn’t want).

    I stripped, powder coated and rebuilt using:

    The Spec needed to be light and user friendly for a skinny 8 year old.

    Wheels: Stans Crest 24″
    Hubs: Novatec D772SB / D771SB White
    Discs: Shimano SLX 160mm
    Tyres: Schwalbe Rocket Rons (Folding) with inner tubes.

    Forks: Exotic Carbon Disc – I don’t see the point of Sus forks yet.

    Brakes: Shimano Deore M615
    Bar: Easton Monkylite Carbon (25.4mm)
    Stem: KCNC Fly Ride 50mm

    Saddle: Madison Y04 Junior
    Seatpost: Fire Eye FE-PA Alloy
    Seat Clamp: Superstar Components

    Derailleur: SRAM X7 Type 2.1 Medium
    Shifter: SRAM X9 10sp
    Crankset: SRAM S600 powerspline (length reduced to 140mm)
    Chain Ring: Uberbike N/W

    BB: Truvativ Powerspline
    Headset: Token TK011A 1 1/8 Inch Pyro Alloy

    Bike weighs in at 9.2/3 KG without pedals.

    Hope you like it.

    The current SRAM S600 Powerspline cranks/BB are heavy, So I’ve shorten some old Shimano Zee 68/73mm Cranks to 140mm and will be installing them with a Shimano Saint BB. The chainline is fine as I will be using the N/W Uberbikes ring that will retain the chain while fitting.

    Any questions/asks about the cranks and the shortening process jut ask, I’ll try and get the photo up of the process.

    Cheers,

    John

    br
    Free Member

    Looks good.

    I did an equivalent using an alloy Identity Dr Jekyll, started with 24’s and then went to 26’s when he got taller.

    Found some 2.4 Racing Ralphs too, less than 500g and ran them tubeless.

    johnski15
    Free Member

    Just wanted to add:

    Final Drill hole for the pedals on the crank was performed with a 13mm drill bit. As the pedals are imperial 9/16th in my case, it is recommended that you use a 33/64″ drill bit – equivalent to 13.1mm. I used 13mm without issues at all.

    I did however, used 3 stage 9/16th 20tpi taps, 1st, 2nd plugs to cut straight treads and a final to cut the treads correctly – these I got from an engineering company in West Yorkshire via ebay. £15 for left and Right.

    kayak23
    Full Member

    Looks brilliant. Nice job.

    johnski15
    Free Member

    Thanks

    poah
    Free Member

    Why does it say trek on the frame and fox on the forks?

    You’d be surprised at how effective a proper suspension fork is for kids. I think I got Lewis’s blast down to under 23lb with a suspension fork and pedals.

    drliamski
    Free Member

    What was the total budget, weight of donor bike?

    wzzzz
    Free Member

    Bike looks great!

    You could run an old 28mm stanchion SID (pre 2007).

    These only weigh 1.3kg, and 80mm forks can be knocked down to 63mm easily.

    New bushes cheap from DFS

    Change the damper oil for a lighter weight oil for the lighter rider.

    These will obviously grow with them into 26 wheels.

    http://faqload.com/faqs/bicycle-components/suspension/rst-f1rst-air-24-versus-28mm-rockshox-sid

    http://faqload.com/faqs/bicycle-components/suspension/rockshox-sid-race-2001&template=29

    neilforrow
    Full Member

    Looks spot on and I’m half way through the same thing. Where did you get the wheels / rims from.?.

    ocrider
    Full Member

    I’ll just leave this here if anyone’s looking for kids cranks at a decent price.

    Op, who did you get the crests from? Jra?

    takisawa2
    Full Member

    I’d intended to revamp my lads 24″ Hotrock but have revamped a 26″ model with a 12″ frame instead. He’s borderline big enough for it but he likes it.

    [url=https://flic.kr/p/QmZx5F]Rowan's Hotrock[/url] by pten2106, on Flickr

    eulach
    Full Member

    I’m sure someone else did something similar about 6 months ago, also rigid forks with fox stickers.

    ads678
    Full Member

    Yeah, I’m sure I’ve seen that exact bike before. Strange. Still don’t like the trek and Fox stickers.

    reggiegasket
    Free Member

    If you fancy some sus forks then these are really good; plush and tunable. I run them on my daughter’s Cube 240.

    https://www.bike-discount.de/en/buy/f1rst-air-24-mtb-suspension-fork-black-51499

    yossarian
    Free Member

    LDC make some nice, short cranks. Quite pricey new (70ish quid) but plenty of s/h options.

    jonathan
    Free Member

    Nice build – like the colour. You could have gone for something more exciting than Trek though, the world was you oyster 😉

    Nice info on the crank shortening. I was about to shorten some (or get a mate who already had the necessary tools to shorten some!), but ended up going for 150mm Thorns, which were short enough (and really nice cranks too).

    Need for sus depends a lot on where most of the riding is happening. It was a priority for me, but those Exotic forks look great (light, simple, etc)

    dirkpitt74
    Full Member

    Looks nice.
    Did something similar for my lad.
    Still need to swap the cranks though and also got some shimano hydraulic brakes, SRAM shifters & mechs to upgrade the current Deore combined cable brake/shifter set up.

    Would like some lighter wheels but the cost is pretty high.

    neilforrow
    Full Member

    dirkpitt74 – what fork is that and I’m guessing you lowered it?? F80? Looks like the A-C height works…

    dirkpitt74
    Full Member

    Yep F80’s. Didn’t lower it, just set the sag a bit lower.
    A-C works OK it’s only slightly longer than the original forks.

    johnski15
    Free Member

    I posted again, as I hope it may help someone in the future, due to my new learned Knowledge with shortening cranks and knowledge of which cranks can be shortened.

    I’ve never came across a post on the web that mentioned Shimano Zee’s as a possible set of cranks that you could physically shorten i.e. they are not hollow forged, and have enough AL to drill and tap for pedals – so you now have a choice of which cranks you can fit with a light BB.

    In addition, I found a BMX set that are exactly the same build as Shimano Cranks (2 piece and 104BCD), so you can run a Light Shimano Hollow Tech II BB, but the cost was very prohibitive for me at £165. They are Bombshell Ratchet 2 Piece Cranks and you can get them at 140/145mm lengths if you are flush enough to buy them – Zee’s can be picked up for £70 or as in my case £23 second hand.

    Decals were the choice of my lad….I’ve got a trek (among others) and he likes it… So for him they are amazing – tried for Santa Cruz but he declined – ads678 – Member there you are mate – so you can bore off about how you don’t like them in every post I put.

    Stans Crest came from:

    http://www.tritoncycles.co.uk/components-c9/rims-c123/stans-notubes-ztr-crest-24-rim-p11098

    dirkpitt74 – Member – Those forks look the MINT – Like the ‘FOX’ decals on yours pal!!!

    drliamski – Member – Weight of Donor bike was 13.45Kg and Budget was £495, However this will be for both my son’s as I have a 5 (nearly 6 year old) on my 8 year olds 20″ Islabikes Beinn for the next 2 years or so, so in my eyes money well spent + I’ll get to build a 26″ small frame when the time comes – already looking forward to that.

    Cheers

    ruffride
    Free Member

    Op how tall is you lad my boys are 6 and 7 but still use there 16 inch wheeled bikes, not been out much due to house moves but I don’t think they would get on a 24. Have you u a pic of him on the bike so I can see if it looks massive cheers.

    johnski15
    Free Member

    @ruffride:

    He’s 131cm mate and is really growing into the bike. He’s out grown the Beinn 20, and I’d took him to Evans Cycles to have a go on the Hoy Bonaly 24 and the LBS to have a ride on the Cube 240 and they fit nicely, so decided on the build, He was about 128cm at that point (Summer 2016).

    ads678
    Full Member

    ads678 – Member there you are mate – so you can bore off about how you don’t like them in every post I put.

    Suit yourself, consider me bored….. 😐

    ruffride
    Free Member

    Ok cheers both my boys aren’t that tall so I may still try an build a sweet 20 inch

    johnski15
    Free Member

    Suit yourself, consider me bored…..

    Nice one, no need to post on this again then.

    curvature
    Free Member

    Dont underestimate how building a bike like John’s will get you saying just one more bit to go!

    I got the cranks for my son’s bike from the States from somebody who had shortened them but never used them. They are Sram S600 so would be interested to know the difference in weight compared to the Saints?

    I’m now embarking on building up a 26″ wheel bike based on a small Cannondale frame.

    Spec so far based on ebay, stw classifieds and sales –

    Cannondale F800 frame
    Sid forks
    Novatech hubs in red
    Superstar Carbon XC rims (£70 for the pair in their sale!)
    SLX brakes
    XT 1×10 transferred from his current Core bike.

    My son is currently 143cm so not sure if the Cannondale will be a bit too big come March when he is 10 but the Genesis Core that he is riding is starting to look a bit small.

    On the look out for a short stem, narrowish carbon bars and carbon seat post if anyone has some?

    NorthCountryBoy
    Free Member

    Hi i was in a similar situation to the OP a few years ago. Decided to build a better spec isla Crieg 26.

    Bought a complete Kona fire mountain 14″ and sold everything off it.
    Fitted mostly decent kit from my parts box 1 x 9 XT
    Mavic cross ride wheels
    Some very light flat Spesh bars
    A new 50mm stem from china
    Glow in the dark pedals from one one
    Avid elixir bekaes with braded lines
    100 mm fork rockshox revelation alloy with steerer keep the weight down.
    The only thing I couldnt get around were the short cranks. So I bought those from Isla bikes.

    johnski15
    Free Member

    NorthCountryBoy – Member

    The Kona looks fantastic!!

    curvature – Member

    The SuperStar rims are a bargain – they’ll be so sweet when buit up.

    I’ll get some photos of the Shimano Zee cranks up, they are rough at the minute, but it will show the progression of the time and effort on them… I’ll weigh them when I’ve lobbed off the excess length.

    cookeaa
    Full Member

    ruffride – Member
    Ok cheers both my boys aren’t that tall so I may still try an build a sweet 20 inch

    If you are after a quality 20″ frame, I spotted this Charge cooker 20″ frame on eBay earlier, for £40!

    I would have snapped it up, but my eldest is 7 and likes her pink hotrock 20, hence I am onto planning her next bike (24″) and browsing threads like this one for inspiration…

    ads678
    Full Member

    Nice one, no need to post on this again then.

    Not quite sure what I did that was so wrong, I only commented that i’d seen the bike before in another thread (that i’m pretty sure i didn’t even post on) and said that I didn’t like the stickers! I wasn’t the only one either. If you can’t take a bit of criticism, don’t post pictures on a public forum!

    I’ve also built up a bike for my 8 year old son, from a carrera blast frame and proper bike parts. We took it out to Les Gets last summer and gave it a proper test, so I can vouch for the RST F1rst air forks if you ever fancy going for suss forks rather than rigid.

    dirkpitt74
    Full Member

    That charge frame is a bargain.

    kevj
    Free Member

    I did something very simlar with my lads bike. Bought a 2012 Kona Fire Mountain and stripped it back for a ready for a red powder coat. Upgraded gears to SLX 1×9 and bought a set of Superstar 24″ wheels with a view to change back to 26″ when he started to outgrow the bike.

    Me and him heading up to Gregs hut on Cross Fell.

    He has a new set of wheels on now so should get another year or two out of this bike, although I am tempted to upgrade the fork.

    neilforrow
    Full Member

    Regarding kids forks – the RST F1rst looks like a good bet (along with used sids or the F80’s as above).

    In my searching – the cheep’est I’ve found is:

    https://www.aliexpress.com/item/24-inch-mountain-bike-lock-adjustable-ultra-light-aluminum-alloy-tube-rst-disc-V-brake-mtb/32708796973.html?spm=2114.40010308.4.2.3arz5G

    Is this site a scam – or ligit?

    fooman
    Full Member

    Let me add some 24” wheeled full sussers to this thread, these were outgrown a couple of years ago so can’t remember exact spec, and indeed changed it over time;

    First bike is a modified Carrera Blast with X-Fusion rear air shock (especially short <150mm)
    Fox FL80 forks painted white dropped to 50mm travel (a whopping 1Kg lighter than the standard fork!)
    Hydro brakes and trigger shifters
    Standard Blast wheels, crank, 1.9 Schwalbe Black Jacks

    Next is a 14.5” Trek Fuel frame with Fox Float rear air shock, this was quite a light frame by FS standards
    Rockshox SID 28mm forks, X-Fusion dropper, hydro brakes and trigger shifters, 155mm cranks (later used Suntour XCT JRs with bashguard)
    Alexrims 24” ACE with Shimano hubs and 2.1 Schwalbe Black Jacks set up tubeless using a 20” BMX tube as a rim strip

    qwerty
    Free Member

    SR-Suntour XCT JR 152mm cranks with removable rings (i went 30t N/W with 10spd 11/36 cassette) £21.62: https://www.amazon.co.uk/d/Sports-Outdoors/Kettenradgarnitur-SR-Suntour-T20242-Z%C3%A4hne-schwarz/B0029MP3AO

    johnski15
    Free Member

    I’m currently in the process of sourcing some Alex ACE 24″ rims they are approx 400g.

    Not bad at all and should be a nice wheel set on a very cheap ebay bargain (new) Bontrager 10speed hubs – £23

    ian martin
    Free Member

    On the shortening of the cranks, are you not better at fitting a threaded insert?

    You can get a crimped type which pretty good.

    poah
    Free Member

    johnski15 – Member

    I’m currently in the process of sourcing some Alex ACE 24″ rims they are approx 400g

    I think you might struggle with that one.

    Rich_s
    Full Member

    ACE20s were out of production and stock last year when I asked.

    dirkpitt74
    Full Member

    qwerty

    SR-Suntour XCT JR 152mm cranks with removable rings (i went 30t N/W with 10spd 11/36 cassette) £21.62: https://www.amazon.co.uk/d/Sports-Outdoors/Kettenradgarnitur-SR-Suntour-T20242-Z%C3%A4hne-schwarz/B0029MP3AO

    I picked a set of these up a while back for my lads bike but not fitted them yet – didn’t realise you could remove the rings.

    How do you get them off?

Viewing 40 posts - 1 through 40 (of 61 total)

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