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Technical & Reference Section => Tech and Restoration => Topic started by: Midschoolfool on July 23, 2020, 04:04 PM

Title: Refinishing carbon cranks
Post by: Midschoolfool on July 23, 2020, 04:04 PM
Thought I would bung up a thread on this. So I have hit the limit on my bikes now. I have no space for any more (booooooo). No one said I could not upgrade the ones I have though :D

A couple of years back I bought some forged carbon cranks for my fixie not fixed. They were totally battered. So I wet sanded out all of the scratches and bad clear coat (they were shiny eww I hate shiny carbon !)

(https://i.imgur.com/vPibWku.jpg)

I repainted the pedal inserts as they too were battered. Did that by hand.

(https://i.imgur.com/LYRYAKj.jpg)

IIRC I paid about ?40 for those. The hollow Kooka ceramic BB cost more than the cranks  :LolLolLolLol:

Any way when I built my GT I spent an awful lot of money on it, but couldn't find any cranks I liked. It too is ISIS, it currently runs these arms and spider.

(https://i.imgur.com/YmkDWMI.jpg)

I mean they are OK, being CNC machined and all (and made in the UK) but it is time to upgrade. Don't worry, the micro gearing has long gone and I had a new back wheel built with a race hub that's sealed.

(https://i.imgur.com/YP06uns.jpg)

So here is what I bought.

(https://i.imgur.com/qTx1B5g.jpg)

(https://i.imgur.com/30jqEGr.jpg)

I am going to sand off all of the clear coat and the logos. Get them to plain carbon. Then I will decide whether to use decals or leave them plain.

(https://i.imgur.com/acOBIp4.jpg)

Got a new 48t ring too.

(https://i.imgur.com/rfx9lMH.jpg)

So all in all it will be a nice weigh shave.
Title: Re: Refinishing carbon cranks
Post by: Mikku on July 24, 2020, 11:38 AM
I like the look of those. :daumenhoch:

Slightly off-topic but I keep seeing non-bmx cranks (including carbon ones) and often think about putting them on a 20" but then start worrying about getting the right spindles, BBs and chainwheels, and give up on the idea. ::)
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on July 24, 2020, 12:49 PM
I like the look of those. :daumenhoch:

Slightly off-topic but I keep seeing non-bmx cranks (including carbon ones) and often think about putting them on a 20" but then start worrying about getting the right spindles, BBs and chainwheels, and give up on the idea. ::)

It's actually really easy tbh. My GT was a BB30, but came with a euro sleeve. As soon as you press that in the world is your oyster. With race bikes now there really isn't such a thing as BMX cranks tbh. They are all pretty much the same as a mountain bike. What I like about these FSA is they are single ring bolts only. So no lugs sticking out the back side. You just remove the dual ring set up and put on a single ring.

Carbon cranks are just so light dude. It's absolutely mental tbh. Like, my PK Ripper fixed came in weighing 19lbs stock. However, it had a set of 4130 BMX cranks on it ffs. With a solid spline. I don't know why, because it sure wasn't a BMX !

(https://i.imgur.com/IKM2dnG.jpg)

It's much more of a BMX now but it's still a flying machine. Good thing was the 19mm Euro BB costs about ?30, so I put that to work on other frames. That now has a ceramic hollow Kooka BB and the weight loss was enormous. I mean sure, my wheels are pretty heavy but then I am a fat ass and that is the only thing that really worried me about riding such a light machine.

My Standard runs American - Euro with a 19mm BB, as will my Fat Boy (well, American - euro - square taper). Most race bikes now are using the external cartridge, with raceface or what not arms and a single speed sprocket.

The only mistake I have made thus far was buying a stupidly wide ISIS BB that just would not work. Turns out it was for a trials bike. Still, it gave me an excuse to whack it apart and take a good look at how it works  :LolLolLolLol:
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on August 01, 2020, 05:26 PM
Phase one complete. That was horrible. Took me about an hour of solid sanding.

(https://i.imgur.com/V4tfwwr.jpg)

Need a clean, then touch ups then clear etc.
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on August 01, 2020, 08:22 PM
(https://i.imgur.com/ohxjee1.jpg?1)

(https://i.imgur.com/EgH3iYz.jpg?1)

(https://i.imgur.com/KBX9ZDd.jpg?2)

I usually hate shiny carbon. But I saw them when they were wet and they looked killer.

Just need to repaint the pedal bosses and touch up the back of the drive side, job's a goodun. Not bad for less than ?60.
Title: Re: Refinishing carbon cranks
Post by: BMX1973 on September 19, 2020, 05:40 PM
Lovely job.  :4_17_5:
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on September 19, 2020, 05:42 PM
Thanks. Odd you posted today !

I just literally took them up to the loft for fitting soon.

I ordered a chain ring from China. You can bet how that went (it didn't). Must remember to grab one from the UK.
Title: Re: Refinishing carbon cranks
Post by: Picklez on September 20, 2020, 08:23 PM
yeah, they've turned out really nice. Good skills as always  :4_17_5:
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on September 22, 2020, 04:11 PM
I managed to find a chain ring in the UK.

(https://i.imgur.com/IYtUPwA.jpg)

It's 44t but that doesn't matter too much. So hopefully soon I can finish the GT too. That would be nice.
Title: Re: Refinishing carbon cranks
Post by: Mikku on September 25, 2020, 12:33 PM
Those cranks came out great! When you get fed up with them and fancy a(nother) change, please lmk as I might well have another home for them in the form of my recently acquired GT! Keeping them in the family, as it were! :daumenhoch:
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on May 24, 2022, 03:28 PM
More fun with carbon !

Today's fun was prepping a HED 3 wheel for matt clear. The brake surface was covered in white shit. Oxidised really bad. Not done on that yet, but it's infinitely better. It's drying now, and will get matt clear tomorrow.

(https://i.imgur.com/RViNMkC.jpg?1)

This side had tubular glue all over the lip. Hence why it will be more work.

(https://i.imgur.com/RizS6ZY.jpg?1)
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on May 25, 2022, 04:19 PM
Done.

(https://i.imgur.com/NRYnBXi.jpg?1)

(https://i.imgur.com/4Z4bdyx.jpg?1)

I did the fork too. Repainted the silver area black, leaving the exposed carbon section, then flat cleared the lot.

(https://i.imgur.com/ZpDMQP9.jpg?1)

(https://i.imgur.com/PhdMybn.jpg?1)
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on May 26, 2022, 04:08 PM
And done.

(https://i.imgur.com/EMvYfcO.jpg?1)

(https://i.imgur.com/imdvyQ0.jpg?1)
Title: Re: Refinishing carbon cranks
Post by: SDF on May 26, 2022, 04:27 PM
And done.

(https://i.imgur.com/EMvYfcO.jpg?1)

(https://i.imgur.com/imdvyQ0.jpg?1)
They look mint👍👍
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on May 26, 2022, 05:26 PM
It's only the rear. I don't really like mags on the front. Oddly the fixie crowd are obsessed with them on the front with a spoked on the rear, which is weird.

(https://i.imgur.com/8Q6x8kP.jpg?1)

That's how they will go. It's hilarious, because the front wheel is 7000 alu and even with all of the drive gear on the rear the rear still weighs less  :LolLolLolLol:

I do like the full disc wheels (like, carbon) but crosswinds where I ride would literally take you off the bike. That's probably why I am not fond of mags on the front. You can really feel it when it gusts.
Title: Re: Refinishing carbon cranks
Post by: Mikku on May 30, 2022, 12:03 PM
Looking good mate! Make sure to post up some pics of the complete when you're done! :daumenhoch:
Title: Re: Refinishing carbon cranks
Post by: Midschoolfool on May 30, 2022, 03:06 PM
Cheers Mick. Had a nightmare weekend. The Hope stuff I need was supposed to be delivered Saturday. I waited, and waited, and waited. Then...

(https://i.imgur.com/X0DKFJI.jpg)

ARGH. Got up this morning, having been pretty depressed yesterday, and as if by magic  :angrysoapbox:

(https://i.imgur.com/i0u3F46.jpg?1)

So someone just wanted to go home early. The bike was sitting like this.

(https://i.imgur.com/1vghiqT.jpg?1)

Not good. It was just waiting to fall over. So I scoured every parts bin I had and cobbled enough together to get the spacing correct. It looks like turd but at least I could cut the fork.

(https://i.imgur.com/h1tZJld.jpg?1)

Will replace those in a bit, and fit the head doctor. Having tons of issues with the rear brake. Firstly it doesn't reach, so I had to order these on a prayer they will arrive (not from China, but seller is)

(https://i.imgur.com/Gdyg1zU.jpg?1)

And then the sleeve which holds it on was not long enough. Seriously you couldn't make it up. So I had to buy one of those too, longer so it actually works.

(https://i.imgur.com/As0owzF.jpg)

But hey at least I can button up the front end later.
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