WTB: 24" wheels, V brakes, 50mm stem, other bits for Islabikes renovation

My youngest is moving up a bike size and after some thought we're going to keep his brother's old Islabike Beinn 24 rather than buy and sell — but sort out some manky bits and improve the bike in the process.

I'm looking for:

• 24" wheelset to replace the knackered Islabikes one — for rim brakes
  
• 24" tyres, something smooth-ish and light like Maxxis Torch; ideally similar width (1.75 / 47mm)
  
• 8spd trigger shifter
  
• V brakes — something better than no-name / tektro basics that came with the bike
  
• 50mm 31.8 stem
  
• potentially also a junior crankset (140mm cranks) — one of the junior BMX ones perhaps. Something that'd allow fitting regular chainrings rather than the bolt-on proprietary Islabikes (rubbish) one. I have a 104BCD ring which would fit so that size would work and seems to be the BMX standard.
  
  

Looking at that list I wonder if it's a bit crazy as there's no much left of the original bike! But if I can find things at reasonable enough prices and make it a bit better in the process it'd work well. And we might try out spray.bike to really pimp it too.

If nothing shows up I'll maybe reconsider but if you have anything lying around from kids' or BMX builds that you think would do the job, I'd love to hear more...

All would need posting as I'm in Newcastle.

What is the use case? I wouldn't bother upgrading the brakes or chainset.

I think the steerer is 1 inch not 1 1/8, for the stem (you probably know this already).

I put Schwalbe Black Jack on my son's 20 inch Islabike Beinn, which have good clearance and offer a bit more off-road.

One of the best upgrades is pedals (bigger/ grippier).

Hm, I didn’t know that about the steerer. I whacked a spare stem on just to get an idea of the sort of reach he’d need and it seemed fine - will measure though just to be sure.

This project is the result of him needing to step up to 24” wheels but not settling on mtb or going for one of the road islabikes. He was previously on islabikes but then had a Merida 20” mtb most recently. I’ve suggested that rather than another modern mtb which will be great at flying down mountains (1% of its use) and so-so for family rides (great fat tyres which are exhausting on road/path and straight bars which aren’t great for longer distances) and school commuting (lack of mudguards), we keep his brother’s mtb for the occasional proper mountain ride and kit out the Beinn as a sensible but slightly-less-rubbish-than-it-was bike for everything else. Not the sort of bike the market seems to offer, at least at secondhand prices.

Definitely needs new pedals, I agree! Just weighing up relative cost vs likely benefit. Thanks for your tips.

Shelved this idea. It’s crazy. Going to sell and buy him something more suitable with the proceeds. If anyone is selling a Luath 24 that they don’t mind posting I’d be interested to know more.