Just got my 10 year old son a new bike, it’s a pretty good fit, apart from the cranks.
They’re 175mm raceface, can they be cut down 25mm and redrilled and tapped? The new hole would be in the recess, so not as strong as they should be, but that should be fine for a child.
Anyone with the knowledge and equipment in S Wales able to do the job or can recommend anyone?
Thanks

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Yes, they can be cut down, if, the remaining cross section of crank has enough meat for the pedal threads to bike into. Ben Cooper of Kinetics in Glasgow is your man.

Matt @ 18Bikes has done this before – but he blobs weld onto the crank first then machines it flat so you get a full depth/strength pedal thread.

Might be cheaper to get different cranks, mind…

I don’t think those Race Face will. I’ve just ordered a set of Suntour XCT 152mm cranks from Germany/Amazon for £22 or look at SJS for Thorns 152mm offering.

Thorn do a range of short cranks.

Kinetics was recommended to me by staff in sunset cycles today, but I was hoping to get it done locally if possible. I’ll look up some 152mm

Buy some 152, flog the ones you have, you’ll gain money rather than spending it.

Will they be a different bb fitting and chain ring?
I’ve got a 32 tooth narrow wide on it atm.

I would doubt that they could be shortened by 25mm. They look to have a very similar cross-section to Race Face Ride crank arms (which I measured up fairly recently for a similar reason) – On the Rides, the recesses at front and back only leave about 3mm thickness, once you’re away from the solid bit where the current hole is. Shortening by 10 or 12mm would be about the limit without adding new metal, and would only be possible if the original hole were plugged.

I did find Highpath when I was looking (haven’t used them, though) – they do crank shortening, and also sell bolt-on shorteners (pricy!)

(Must type faster!)

I bought the suntour xct 152mm cranks from amazon for my lads bike. I already had a few square taper bb’s, and running it with a superstar NW ring.

The suntour do look a bargain and not worth altering the raceface.

My son has the suntour cranks with a 30t narrowide..no issues

suntour takes a 118mm sqaure taper and the thorn takes a 113mm square taper. you can take the rings off the suntour and fit a 30t N/W, the thorn doesn’t come with rings. The suntour is a bit heavier but not my a huge amount.

Those suntour cranks look ideal.
I bought cranks from Isla bikes for our lads bike there 152mm square taper with a pre fitted 28 tooth ring.
They cost about 35 quid irc.