The Boy and I started building his new bike at the weekend, based on a 14″ Cube Attention SL frame from Bike-Discount. Hit a bit of a problem when we came to fit the brakes, though: BB7s are a complete non-starter (see below) as there’s barely any space inside the stays.

According to the spec sheet the complete bike came with M315 calipers. So they’re the obvious option, I guess. They’re cheap enough, reach-adjustable, and it looks like they use the same pads as my Spyres, which is a bonus.

Anyone know from experience whether anything else will fit a 14″ Cube? Or whether anything else has identical dimensions to the M315? Needs to have adjustable reach, as The Boy is only 9. I’m totally out of touch with hydro discs as I’ve (nearly) always used BB7s.

Just wondering whether there are better options out there for a similar (low) price; maybe something that comes with Centerlock rotors, as I’ve already got some spare 6-bolts but I could use Centerlocks on some wheels I’ve not yet built…

Just built up the same frame from the same supplier for my eldest by transferring all the bits off my Inbred.  So I can reliably say that an ancient XT Calliper (Couldn’t attempt to say which version but at least 14 years old) fits fine (As do the 26” wheels).

Cheers. Yours is a 14″, too?

And yeah, 26′ wheels here, for now at least. The not-yet-built wheels are 650b, which may or may not end up on this bike 🙂

Yes 14” perfect fit for him with masses of growing room.  I was a bit worried that the 26” wheels would mess up the geometry but its fine (I can always swap bits round if I ever se a pair of 27.5” forks going cheap).  The only problem I had was getting the B-set screw on the rear mech right (I had to swap out the screw for a longer one because the mech hanger is slightly odd, at least for a nine speed mech).

Thanks.

Yeah, did wonder about the mech (also 9sp); haven’t fitted the chain yet but the top wheel only just makes it to the biggest sprocket with the L screw right out. Did think it looked like I was going to have to go all-in on the B screw as well.

In its current form (bars and wheels on but no seatpost yet—got another slight issue where the seat tube is 0.5mm fatter than the supposedly matching Cube clamp, so it might be Wet ‘n Dry time unless I can find an oversized clamp in the spares box) it looks like it’s going to be rather short, I’m almost wondering whether I should have sized up. Maybe just an optical illusion because the front seems quite tall even with a 26″ fork and wheel in it. Will have to see once he’s actually on it.

Having had a browse there doesn’t seem to be much in the way of better brakes without spending way more than I want to, so I think I might just get the M315s. It’ll be the first time I’ve had to work with hydros in well over 15 years 🙂

It was the first time I had had the bleed kit out in a while (My other bike has a pair of twenty year old hope minis on which, touch wood, seem to be maintenance free).  The QR Cube seat clamp they supplied the frame with was a perfect fit so I would check they’ve supplied the right size.

I was worried about the L screw too but it just makes it.  Size wise it is spot on where I hoped it would be.  We were in N Wales last week so he rode round the Beast at Coed y Brenin as a bedding in ride.  After the first half a mile he was riding like a demon, so its everything I hoped it would be.

What sort of age/height are your kids?  My eldest (10 next month) is on a 24″ wheeled Carrera Blast right now and fits it fine, but I’m well aware that it won’t be *that* long until he’ll probably start to fit on a 14″ Cube running on 26er wheels.

I don’t have him to hand but, extrapolating the last couple of markings on his height chart, probably something like 146-147cm, aged 9 and a bit.

Shimano slx fit fine so I would imagine most shimano calipers will fit. The hanger is direct mount so don’t forget to remove the b link from the mech or you’ll have a weird mech position.

It might be the adapters …. if you just sit the caliper over the rotor (loose) will it fit?

I couldn’t fit a 203 rear using the shimano adapter but a £2.50 “lifeline” one worked …

It’ll be the first time I’ve had to work with hydros in well over 15 years

It’s a bit like discussing if it’s worth buying halogen over incandescent bulbs… and totally ignoring LED.

LED and hydro have both moved on massively and prices dropped… whereas mech/halogen are still where they were.  You can buy 315’s for almost less than nothing…  if you count a free set of pads and hose etc.

It might be the adapters …. if you just sit the caliper over the rotor (loose) will it fit?

Good thinking, but sadly no, no room. Though I did notice that in the image above I’d used the +0 adapter for the front, not the +20 for the rear. Doh.

LED and hydro have both moved on massively and prices dropped

Oh, for sure. Got nothing against hydraulics, it’s just a maintenance process I’ve not had to bring into the workshop thus far 🙂

Got nothing against hydraulics, it’s just a maintenance process I’ve not had to bring into the workshop thus far

Deffo not the big deal you might think …. at least not today.