My first jump/pump track bike - Planet X Jack Flash based

[grahame]

No pictures yet, but my 8 year-old daughter is really getting into riding pump tracks, so I bought one of the £50 raw aluminium Jack Flash 25th anniversary frames and decided to build it up as cheaply as possible.

The frame has a tapered headtube, and I don't want to spend £100s on a fork for a £50 frame, so £37 on a new headset with a bottom race to allow 1 1/8" straight steerer forks to be used in a tapered frame (hopefully arriving in the post today) and I'm away.

Build sheet - everything from spares boxes or already owned unless noted:
Frame - Planet X Jack Flash 25th Anniversary raw aluminium - £50 (plus £15 shipping)
Headset - Da Bomb Loop 4 in 1 - £37
Stem - Brand X 80mm
Bars - Truvativ
Grips - Yeti Lock-ons
Brakes - XTR 950 levers, Avid BB7 front disc, XTR 950 V-brake rear.
Front wheel - Deore hub, DT Swiss 533D rim, Sapim double butted spokes and brass nipples.
Rear wheel - Surly singlespeed hub, Shimano 18 tooth freewheel, Ryde Zac 2000 rim, DT Swiss double butted spokes and brass nipples
(Both wheels handbuilt 3x by me, using spokes I already had of the right lengths, hence the different brands)
Tyres - Schwalbe Hans Dampf 26" x 2.35" front and Schwalbe Nobby Nic 26" x 2.25" rear, both running tubeless with Joe's schrader valves and sealant and 25mm Gorilla tape as rim tape.
Chainset - LX with a single ONZA Buzzsaw 36 tooth chainring.
Bottom Bracket - (A new) UN72 found (forgotten about) in the "travelling spares to take to events" box. A real feel good moment finding it.
Chain - KMC half-link
Pedals - DMR V12 (yellow, but needs must)
Seatpost - Easton E50
Saddle - a tatty but usable Flite
Seatpost clamp - Halfords QR 31.8mm diameter, £5. (They were open, had one in stock, all the clamps I had were 28.6mm diameter)
Total spend: £97

 

[novocaine]

looks good.
stem might be a tad long for a jump bike though and 36-18 might be a bit tall but meh, fit and hope.

I've hovered over the buy it button a few times at that price, but always managed to resist.

 

[grahame]

Thanks for the feedback/tips, Novocaine. My initial build idea was to use as much as possible from the spares boxes and minimize spend to see just how cheaply I could make a funtional pump track bike. If the stem is too long, then I'll get a 50mm replacement. If the gearing is too tall, a modern Truvativ Descender 32 tooth chainset and SRAM DUB bottom bracket (spares from a modern bike build) will replace the current setup, and a couple of links will be removed from the chain.

I think all the £50 raw aluminium ones have gone, but there are some of the £80 black ones left.

 

[reanimation]

Any pics? I bought one of the disc only ones last year but not been happy with the bits to build yet. I was tempted to build another for my partner. Is this for you? Jack Flash seem pretty long for a jump type frame, partially why I went for one, so short stem either side of 50mm and wide bars should do it. What is your daughter on? Mine's same age and seems to have shot up recently and technically outgrown her most recent Frog!!

 

[grahame]

It is for me. I have a long spine and short stumpy legs so it suits me just fine. Not a great picture, but here it is, along with my daughter’s B’Twin (Decathlon) singlespeed MTB. Since this picture was taken, the stem has been swapped for a 50mm FUNN stem, and the freewheel for one of the lovely, seemingly bombproof White Industries ones. More pictures to follow sometime soon.

 

[reanimation]

Looks ace, Nice build and good use of V brake mounts!

Is it nice to ride?
I've dodged Alu bikes so long I'm actually quite excited to build and ride one or 2.