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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.
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