My Carrera Blast 24 rebuild

Thought I’d join in the fun of spending lots of money and time by getting a battered Carrera Blast and rebuilding it with better parts. Hopefully I don’t end up spending as much as a new Islabike Creig 24 in the process…

I had an eBay search for “carrera blast” and just what I was looking for appeared last week: a local to me but not near a city Blast 24, described as a bit broken (front mech doesn’t work). Managed to be the only bidder so this was bought for £40. Here it is in all it’s glory:

From a quick glance the frame has some scratches but nothing serious. The list of components that are various shades of rust include: cassette, front mech, chain, brakes. The fork when compressed ejected sticky water out the preload cap. The rear brake sticks on and needs to released by pulling it back again. It would have been nice to have some bits to sell, but to be honest for £40 I’m not upset if everything goes in the bin.

Before I got out the tools I weighed it: the complete bike weighs 13.7kg, 5kg of that being the wheels.

My son came back from school and was “a bit” excited to see what I had to show him. We grabbed a hex key and started taking bits off…

Interested in this, I have a carerra blast in bits in the garage.

I bought my niece and nephew each one of these with the intention of ‘doing them up’ to give to them for their birthdays last year. I ended up just scrapping the whole lot and buying a decent second hand Spesh 24 and Trek 24 instead. I did manage to salvage a brake lever off one of them to use on nephew 3’s BMX though, so not all was lost! 😆

This is more a reflection of just how far gone (bar the frames) all the bits were on the bikes I bought were though…

I’m wanting regular updates rossburton!

Daughter’s Commencal Normal project is down to the frame. Everything else worn, stuck or too heavy. It’s the most expensive second hand frame in history.

Good job generous folk off here have helped with the new bits!

Unless by some miracle they actually work, throw the calipers immediately in the bin before they fail for no reason or rub or over-cam or……

EDIT – Good luck with the project though, I always rather liked the Blast 🙂

state of that lawn. good luck with the bike!

Kids are now in bed so part 2. 🙂

For some reason someone at Halfords thought it would be funny to use T30 bolts to attach the callipers. The cranks were attached to the square taper axle using a 15mm bolt which all my books suggest was antiquated a decade ago and my socket set only went up to 14mm. Finally got everything off apart from one crank for which the thread the puller screws into was pretty comprehensively destroyed. Ended up taking it down to my LBS in the morning, who phoned back that afternoon proudly telling me they’d got it off: they had to file the sheared threads to get a puller in, then discovered that the bottom bracket had fallen apart so the tool to remove that wouldn’t work either. An hour and six tools later, they won! Also got a new cartridge headset installed at the same time (old one, of course, fell apart during the strip down and the shells were corroded).

Now the frame has been stripped we can weigh it: 1.78kg with a headset.

2.5kg a wheel seemed rather excessive, removing the tyres and tubes (apparently made of a black flexible form of lead), rotors (looks and rusts like steel, but also a lead-iron alloy), and cassette (some rust but a serviceable 7 speed) bought the scales down to 0.9kg (front) and 1.1kg (rear). That’s not too shabby and considering the only feasible upgrade involves Stans Crest 24″ rims (£70 each!) I think I’m going to try wrapping less than a kg of gorilla tape around them to see if they’ll go up tubeless.

state of that lawn. good luck with the bike!

That lawn has the strangest grass: leave it and it goes an amazing even green but then gets straggly, cut it and you discover that it was only the top inch that was green and the rest looks dead. Walking on it is like walking on a 50 tog duvet though!

Component breakdown:

Saddle clearly too large for an 8yo bottom. Replacing.
Seatpost passable. Would like a lighter one but not high on the priority list.
Seat clamp: the bolt is a little rusted but this is a QR clamp that still works. Unless someone has a purple anodised one for the right price, keeping.
Shifters: clearly had water in, seen better days. Currently 3×7 but I’m going 1x and my son wants a trigger not grip shift, so replacing.
Brake levers: mechanical, bit too big for little hands to be honest.
Bars: more iron-lead alloy. Replacing.
Stem: wrong shape, huge. Replacing.
Forks: heavy coil RST Capa forks. Replacing.
Bottom bracket: destroyed, replacing.
Cranks: until I discovered a shorn thread I would have converted this from triple to single, but needs replacing now.
Front mech: literally a piece of rust that started to disintegrate as we took it off. Redundant.
Rear mech: buried under all the grease and grime might be a usable mech, will leave in something to clean it with.
Brake calipers: unlike the newer Blasts which have reasonable brakes, these look rather “industrial”. Replacing.
Pedals: not pimp, pedals should be pimp. My son wants purple ones.
Wheels: a bit weathered but the hubs and freewheel seem fine. Will attempt to run tubeless to keep the weight down.
Rotors: I genuinely can’t believe how heavy these are, and they’re rusted. Replacing.

Post of the day for me.

Good luck!

(as you may tell I’m posting when I get a moment)

Final update for the state of play right now. The bits box now has in it:

Carbon bars (from STW)
Stem (shorter, narrower) (eBay)
Carbon 24″ rigid forks (Carbon Cycles, actually new)
New rotors for my susser (STW), so the Blast can have the ones on that now.
Madison Y04 saddle (from STW)

Ordered and should be arriving next week are:

Brakes, Deore M615 as they have reach adjust and small levers (eBay)
Cranks, Suntour JR-T202 triple with 152mm arms (some shop on Amazon)

I’m probably going to get a 9-speed Sora rear mech which can take 11-32 cassettes, and a 7-speed Altus trigger shifter. This means in the future if the wheels get upgraded I can jump to 9 speed just by changing the shifter. First I’ll clean the old one though.

Bottom bracket will be ordered once the cranks have arrived. A little unsure about square taper: they come in all different axle sizes so should I just go for the narrowest as 8yos have narrow hips?

Hopefully Sunday will be Start Building The Bike day with my son, so should have some more photos tomorrow evening!

118mm for that suntour crank. Un54 About £13 or you can get a tange-seiki unit that’s about 215g off eBay for 27.

Great thread.

I found that the thing is to enjoy the building and the end product, and not worry about the cost when you discover all the things that need replacing.

Hoping to get a thread/pic of my daughter’s new bike up when it’s back from the LBS later in the week. Took it in to get some Deore brakes sorted “We’ve got a pair of SLX been on the shelf too long, we can do them for the same price….” Would have been rude not to.

Bottom bracket will be ordered once the cranks have arrived. A little unsure about square taper: they come in all different axle sizes so should I just go for the narrowest as 8yos have narrow hips?

I made this mistake with my daughter’s hotrock, went too narrow and put the chainline too far inboard, bottom sprocket (11t) derails the chain from the chainring.

My temporary fix is to set the limit on the rear mech so that gear is off limits (she’s not using it anyway). But do consider chainline, smaller wheels an shorter stays mean the shifting can be more sensitive to it…

That reminds me, our frame still has half a bearing shell welded into it, I am inspired to attack it again today.

Are you going for a frame respray?

I made this mistake with my daughter’s hotrock, went too narrow and put the chainline too far inboard

Doh, chainline. <slaps forehead>

118mm for that suntour crank. Un54 About £13 or you can get a tange-seiki unit that’s about 215g off eBay for 27.

Is that from experience, or does the crankset have that written on somewhere when I get it? UN54 appears discontinued, UN55 is 15 quid on CRC though. Looks like a winner.

Are you going for a frame respray?

I was considering it but my son (and my daughter who is set to inherit my son’s current bike) are quite keen to get the build going, so we can leave it for now. Maybe next winter. Green is the colour he wants anyway so we’d just be neatening it up.

halfords sell VP sealed BB’s for 9.99. Will have 118s in stock in 99% stores.

118mm is the standard size for the blast running a triple.

Can’t see mention of the front mech replacement – just rummaged and can stick a 34.9 LX in the post, if of any use.

I’m going 1x with this, going to try the 12-28 I already have but there’s the option of 12-32 too. Should be enough range…

Thanks for confirmation of the axle size, Edinburgh Co-op have them and loads of other little bits I need for 9 quid so I’ve just placed an order. Square taper confuses me 🙂

Damnit the 9 quid one has the wrong shell size. 30 quid seems a bit keen.

s that from experience, or does the crankset have that written on somewhere when I get it?

What I fitted on Lewis’s old blast before I sold it as I took the thorn crank off.

Okay does anyone know if there exists a bottom bracket cable routing guide that takes an outer?

you can get lightweight inner tubes and lightish wheels from tarty bikes

You can also get rocket ron in 24″ but i think they are utter rubbish in terms of grip so have never used them

OLd 28 mm SIDS for lightweight air forks

9 speed grip shift are cheap – i think i got X0 for under £20

rossburton – Member

Okay does anyone know if there exists a bottom bracket cable routing guide that takes an outer?

you can get stick on/ziptie ones. I used those on Lewis’s blast for the rear brake and mech. I didn’t put them under the BB though

I put 24″ rocket Ron’s on my lads Blast rebuild, and they seem pretty good. Worked well in Les Gets and Samoens last summer, and fine in local mud.

I went straight for 1×10 set up with an XT 11-36 cassette and a 42t expander ring, Slx rear mech and deore shifter. Narrow wide superstar chainring but added a bash guard so his school trousers didn’t get caught in the chain!!

Great bikes.

I was trying to find a 32t-ish bash guard (I’m going 32t single chainring) but the only one I could find was the Hope one. As great as they are, that’s a bit excessive… All the cheap plastic ones are 40t-ish which is a bit huge really.

I would go 30t rather than 32t

Yeah the Hope on is pricey but I just happened to have one laying around so used that.

I was torn over 32t vs 30, looking at other similar bikes shows a huge range of options. Worst case that’s a quick swap.

Stupid crown race means no building today. 🙁

For all you guys building your kids bikes I am putting in the classifieds my sons SRAM 150mm cranks.

Judging by the interest in this thread you might have a bidding war!

I’ve a 113mm UN54 you can have. It’s used but buttery smooth. I’ve also a RF bash guard, came off my 5, was running a double, I think it was a 36t.

Did some more buying today: got a new Sora mech off eBay for six quid, and an Altus shifter from a proper shop.

Still need grips. I really like the look of the Spank Grom grips – thin and narrow to suit small hands, but black with green are basically impossible to find in this country. I’m a little tempted to go with bar tape, anyone else tried this?

All I need now is to get the crown installed on the fork… LBS trip tomorrow.

I replaced the bb on my 5yo daughters bike (a scott contessa) and was surprised to see it was specced wide, 120 something. Don’t know if this down to the bike / chainline or if there’s a biomechanical reason for it.

I picked up a blast on ebay last night, so following the thread with interest 🙂

Today’s update:

Bought a 32t bash ring from here which should look good on the cranks when they eventually arrive.

After discovering that the new crown race is not split and a very tight fit, decided that I didn’t want to hit my new carbon forks with a big hammer and took it down to the LBS.

Spent the rest of my lunch with a 6mm drill and drilled out the cable guides so I can go full outer for the gear and route the hydraulic brake cable. Hopefully my Wilko special round file managed to get the big lumps off!

Still need to find something to hold the rear mech outer under the bottom bracket. Quite tempted to model something from Sugru…

Got the Rocket Rons here as well in 24″; have gone up,tubeless, although the sidewalks took a fair bit of sealing, and seem to grip well enough. Light too.

Hopefully I’ll report back on how my Halfords rims + gorrilla tape + Rocket Rons go up over the weekend!

After dinner we went to the garage and did the first bit of spannering: fork, stem, and bars on. It was decided that the seat is the most important piece of the bike so that also went on, although you’ll notice that I was terrible at eyeballing the seat tube angle.

Carbon Cycles fork, 800g
Unbranded eBay stem, 150g
Answer carbon bars, 130g
Stock seatpost, 285g
Madison Y04 saddle, 290g

Need to find a cheap/light seatpost I can cut down to replace the stock one.

Brakes arrived today so they’ll be going on next, but with comedy long hoses until my cutting tools arrive.

Also never doing bike build stuff with the kids at 6pm, they’re far too hyper/tired to focus!

Looks good so far.
Be interested to see how you get on going tubeless. Thinking of giving it a go on my lads blast.