Erin's 20" lightweight.

Ok, so this might not be your next dream ride, but hopefully there's room on here for this little thing we've been working on. My daugher's Isla bike was stolen from her school last year, so this will be its replacement, and lighter then most kids bikes available.
Hopefully many of the parts will be good to use on future projects when she out grows this one!

Frame- Planet X Giovanissimi Aluminium -Bought new on eBay £15
Wheelset- Kinlin Nbr rim DATI hub- Bought new from Alibaba Express
Crankset- Turn 3 BMX single ring- U.S. Made C.N.C. Square taper
Gear set- Ultegra Di2 6770 10 spd internal - Bought used on eBay, £270, levers sold on here £90

The Di2 gear set is made up of climbing buttons, Alfine display as forward junction box, a seat post battery and a 10 spd mech.
I've removed and drilled the left side down tube cable stop for the internal cable routing. Also drilled the right hand chain stay end for the derailleur wire.
I'll take some more pictures and post as it comes together.

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This is gonna be baller. That's one lucky daughter.
Subbed.

A couple more pics, the wine bottle is for scale, this thing is tiny.
One thing I have learn; there's more than one 20" wheel size, beware when buying tyres and tubes, always check the I.S.O. (Ertro) sizes.
You can see in the last pic. the hole drilled in the chain stay for the Di2 wire.

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This thing is crazy. Subbed

2017 forum build of the year contender for real.
Needs arrospok/disc wheels.

Did they make Arrospok in 20" ? Perhaps this kind of thing, not sure I'd get a 10 spd cassette on them though!

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Spin did bmx trispokes...

Subbed. This is rad.

https://www.aerospoke.co/product-category/wheels/20-inches/

Nice project, sub'd!

I looked at sourcing 20" spoks for my shopper build. As @edmundro points out they are on the website but in 12+ months not a single one has popped up on ebay. Those plastic spoke things make me wary.

The rest of this project looks amazing. My 4 1/2 year old may get something similar later in life.

I think it would be wrong not to get these for £45

https://www.aliexpress.com/item/20er-lighter-newest-20-inch-folding-bike-T800-K-3-full-carbon-fiber-fork-carbon-bicycle/32787508881.html?ws_ab_test=searchweb0_0,searchweb201602_2_10065_10130_10068_433_10136_10137_10138_10060_10062_10056_10055_10054_302_10059_10099_10103_10102_10096_10052_10053_10050_10107_10051_10106_10084_10083_10080_10082_10081_10110_10111_10112_10113_10114_10033_10078_10079_10073_10070_10122_10123_10126_10124,searchweb201603_9,afswitch_1,ppcSwitch_3,single_sort_0_total_tranpro_desc&btsid=9b3f8acb-46d8-41d0-b94b-e362cf9552d5&algo_expid=216fe5cb-cef4-487e-b5eb-26df8c798b9e-1&algo_pvid=216fe5cb-cef4-487e-b5eb-26df8c798b9e

If you can find a pair with 1" threaded steerer, 406 wheel size, and 74mm O.L.D. spacing I'd snap them up. I think the only option for a decent lightweight fork is custom made. But let's just say the budget has stretch about as far as it will go already.

Anyone got any ideas for pedals?

http://www.chainreactioncycles.com/odyssey-twisted-pc-plastic-pedals/rp-prod50956

https://www.liv-cycling.com/gb/liv-sport-pedal

For small feet maybe these are good

Or look at Kid's Race BMX Pedals -tiny (but quality) pedals for small feet

These look very nice, some good stuff available for BMX race bikes for kids. These are probably the ones- thanks.

Not much progress this week, work, sick kids and household drudgery taking precedence. I know, in what kind of crazy world do we live?

Anyway two days off coming up Monday and Tuesday so we should be almost done this week, might have to fit some temporary brakes and pedals before the extended brake shoes turn up so I can fit the Planet X brakes pictured.

Also you might notice all the thread sticking out of the front wheel quick release. This is because the front hub is just 74mm O.L.D. I had to cut almost an inch of new thread on this (titanium) skewer

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Nice light Planet X brakes, unfortunately the drop is not quite enough, hence the extended brake pad holders.

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Not much progress this week, work, sick kids and household drudgery taking precedence. I know, in what kind of crazy world do we live?

Anyway two days off coming up Monday and Tuesday so we should be almost done this week, might have to fit some temporary brakes and pedals before the extended brake shoes turn up so I can fit the Planet X brakes pictured.

Also you might notice all the thread sticking out of the front wheel quick release. This is because the front hub is just 74mm O.L.D. I had to cut almost an inch of new thread on this (titanium) skewer

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Couldn't get that link to work before, now it does these also look good, lightest of the three suggested. 🤔

Nearly finished, chain, brake cables and pedals to go on. I should wait till they are fitted to post more pictures, but I'm more excited by this bike than any I've put together for myself before.

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Looks mint! What are those cranks?

What a great project - and you seem to be #doingitright. I got several of the giovanissimi frames when they were rock bottom at PX (for wheels sized 20", 24" and 26") and have built up the first two. I have been waiting on the 3rd to post the CP thread (that and the end of the GT debacle).
I had SO many issues with tyre clearance and brake alignment (some of which you also seem to have encountered). I am impressed you have sourced all the parts so quickly as it took me months (though I had a very tight budget for it so most parts were cannibalised or scavenged). In the end, despite careful measurements and as much info as I could find on childrens' bike fit, the boy I built the 20" for has not quite grown into his! 😫
Looking forward to seeing the final build and I hope your young rider gets on with it!

Love those cranks - look like motorcycle con rods.

It lives!

Many adjustments and a few changes required, but it's nearly there.

Biggest problem is probably chain line, because the chain run is so short, you don't get as much side to side play in the chain as you would on a full size bike. It will select all the gears okay, but it doesn't run very smooth in the lowest. It's better with the ring mounted on the inside of the spider, so I think I'll try a slightly narrower BB at some point. It's running a 113mm UN55 at the moment. I tried it first with a 103 mm but that was way to short and the crank arm didn't clear the chainstay, I'll try a 110 mm first and if that's not enough, I'll go for a 107 mm and maybe file a bit off the arm.

hanford and russmeyer

The Cranks are made by Turn 3, in California, they come in all sorts of lengths and colours are are intended for Mini BMX racers. I got mine from Twisted Concepts, a purveyor of BMX componentry in Essex.

Brakes need some adjustment too, I couldn't get the back one to open evenly today, so we had some rub. Anyone had and experience with this kind of brake caliper? :-
https://www.lfgss.com/comments/13519886/

We need to do some bike fit adjustments too, Erin was looking a bit big on it on its first shakedown runs today, hopefully just saddle position but if not I might be after a 24" soon jdmitch !

I added up what it cost today, bad move. Lets just say less than my best bike but more than any of the others. Having said that, if anyone wants me to build them one, I'm sure we could work something out that didn't involve the sale of any vital organs.

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