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My daughter wants lower gears (currently on 1x9), so I'm thinking of adding a triple chainset. Cheap heavy ones are available for £20, I think I have a front mech and thumbshifter*. Any better ideas? 1x11 seems to be more expensive, and I'm worried that the larger mech is going to be low to the ground given she's on 26 with small tyres.
* in true 'daddy's an MTBer' style the mech is XT and the shifter is Dura Ace/Paul's components
I bought these for my lad. There don't seem to be too many other choices if you want a granny ring.
https://www.sjscycles.co.uk/cranks/150-thorn-10464-pcd-triple-crankset-mk2-black/
I bought a pair of Spa Cycles cranks, like Bez has linked to, in 160mm length, for my 10 year old nephew's bike build. (Raceface ring, 9 speed XT rear mech & shifter, Sid forks, Pro2 hubs...)
He seems quite happy with it. 😐
Edit ; the cranks feel a bit heavy in the hand, but fit the boy better than a pair of 175 XTs he could have had.
Ground clearance won't be a problem, but clearly switching to 1x11 is going to cost a lot more than retro fitting a 3x crankset (especially as most of the triple crankset options will be at the "cheap n heavy" end of the market).
FWIW, my 9yo son rides XT 1x11 (11-42) on a 26" wheeled 650b frame and clearances etc. are all good. We use SRAM's 155mm NX crank (32t), available for £90 from Amazon. With this combination, the bike is geared low (it's only ever used for "proper" mountain biking, so tall gears aren't needed) and we've never felt the need to change from the 1x11 which provides more than enough range for him:
Obviously a 1x11 setup will not be as cheap, but it's a lot less faff for kids to only have one shifter, especially in technical terrain when they have a lot of other stuff to worry about!
Well she's taken to 3x well enough when she rides her sister's bike, who also seems happy with it. But 3x still gives a lower gear I think.
EDIT hmm no there's basically nothing in it between 22/34 and 32/46
my son rides a sunrace 11-50 with a NX crank 28t ring. climbs up everything I take him to. waiting on a short, 130mm, crank coming for my youngest (8) to go with my old 11sp kit. what size of cranks do you want?
my son rides a sunrace 11-50 with a NX crank 28t ring
That's a properly low gear!
When we first built this bike, it was with a 30t and the 30/42 ratio was almost unusably low for him, so he asked that it be swapped for a slightly larger chainring to give him a taller high gear. How does your son manage with the 28/50 ratio and does he ever actually use it?
Not sure how "nice", but Shimano Alivio (and lower down the range) comes in 165mm
It has 152mm on it now, which are ok. Dont' want to go too long as her saddle is still low for stability reasons.
Don't think she has front cable routing though so it might have to be a full length cable outer under the BB and one of those front mechs that have the cable stop built in. I think I have one.
I see some narrow cranks from HUP components in 135, 145 and 155mm, currently sold out but more on the way.
Moving to 10-speed gives you 11-36 cassettes (and Zee mechs have a short cage but still handle this range), combined with a 32t ring lets our son get up quite a killer hill in our local woods. Also is she really using the smallest cog, or would dropping to a smaller chainring shift the ratios enough?
I'm a huge fan of single rings for kids as the extra complication of extreme chainlines and knowing that if you want to drop another gear you need to fiddle both mechs just isn't worth it IMHO.
The ring is non replaceable anyway.
Isla put 11 spd 32T and 11-42 on the back of the 24" MTBs.
We've had no issue with the mech and the gear is low. You might be able to get a smaller chainring on depending on what cranks you end up with.
Also means you could go 10 speed with an 11-42 if that was a better price.
Isla appear to be the only ones specifying with this range of gears so far. I'm guessing some more might catch up in the 2019 ranges.
10sp 11-42 is hard to find though no?
EDIT ah, there's Deore, still £40 though. I'd need a new shifter, do I need a new mech as well? Currently 9sp Acera
My kids have the Suntour XCT ones one their bike because they are cheap and the chain rings are removable. Yes they need a square taper BB but they do the job fine and are really not overly heavy. Mine are both running NW chain rings on them, for 23 quid you can't go wrong.
Nope easy to get now as you've found. If it'll get them pedaling up bigger hills then worth it. Or alternatively they can keep pedalling while complaining :0)
Not sure I think a 9sp mech should work but I'd be putting a Deore with clutch on personally to stop chain drops.But you may not have that issue.
So 10sp 11-42 would cost £90 to upgrade inc chain. That's comparable to the triple option with the Thorn cranks, quite a bit cheaper than 11sp, and about 3x the cost of the triple option, but with a bit less weight and much less bodging of cables.
Still not as low of a gear tho.
<span class="skimlinks-unlinked">But</span> you may not have that issue.
Probably not, it's already 1x, the chainset has two plastic guards either side of the ring which seem to be enough to keep the chain on.
There are some very nice ones if you are willing to spend similar to decent adult cranks.
Obviously the NX start at 155mmm so before going to expense/trouble woe out what size you need.
The best sizing I found is actually using the bottom of this page
https://highpath.co.uk/crank-shortening/
The Austrain ones are already posted above or Trailcraft do a SRAM direct mount and sell the chainrings down to 26T (though the BB is Shimano std)
Jnr runs a med (M8000 GS shadow) on 24" wheels and has yet to damage it... On a 26 wheel a med cage mech shouldn't be any issue at all.
I didn't buy either btw but just made our own.. he runs Zee (cut to 142mm) on his Enduro/DH and some old LX (cut to 145mm) on his XC but he runs a bigger chainring and smaller cassette on the XC for racing.
but just made our own..
Same here, I chopped down some old square taper LX I got for a fiver or so a while ago, for some reason I settled on 143mm, might have been based on some height vs crank length formula off the interweb, of course children tend to get taller over time, so it's pretty arbitrary in the end really...
So 10sp 11-42 would cost £90 to upgrade inc chain.
There are some wide range (11-40) 9 speed cassettes about too, so you might be able to extend the current 1x9 setup for less...
Edit:
Worth a whirl?
https://www.amazon.co.uk/dp/B07CZD7TPF/ref=cm_sw_r_cp_apa_.NRJBbRFJAT3C
Wow, when did Hope start selling them?
I called them a couple of years ago when they started making them for the Academy bikes to see if they would sell a set
of course children tend to get taller over time, so it’s pretty arbitrary in the end really…
So long as they are short enough... as opposed to too long..
135 and 150, seems tredz are the only place that sell them but £215 without a ring is Pretty unjustifiable for me at the moment, those academy bikes look awesome though don’t they.
I went 1x10 and used this on wee lads bike
https://www.planetx.co.uk/i/q/CAEGEXSP/el-guapo-1x10-range-expander-sprocket-with-cog-kit
Sunrace do a 11-40 9 speed cassette - that with a 30T or 28T NW is pretty low - both my 26" wheeled boys are on 30-36 lowest and I don't get (m)any complaints.
Needs a med range mech and I expect it'll be a bit agricultural but its cheaper than swapping the lot out. We only have a triple left on the smallest's 24" and its a PITA - he never remembers to use it to get the range necessary for a tight 7 speed block, it shifts the 'wrong' way compared to the right hand (gripshift), and even with good maintenance it isn't easy to use.