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  1. #1
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    Shorter Crank Options

    I'm looking for a shorter crankset for my 10 year old to go on his XS Dawes Haymaker 27.5" bike (more on the choice of this bike in a separate post). It came with a 3x8 drivetrain with a SUNTOUR CW10-XCT-T312 crankset, which has a 175mm crank length and square taper interface. My son has a 27" inseam and really needs shorter crank arms. Based on my budget, I found 3 options.

    1. Drill and tap the existing cranks. There is plenty of meat on these cranks and the geometry would allow for this option. Cost: ~$60 for the tools

    2. Suntour
    XCT Jr 152mm crankset (XCT414-JR). This is a 9 speed crankset that is super cheap at $33. I found conflicting information online about whether this would work for my setup.

    3.
    Trailcraft 140mm or 152mm Cranks 2x setup for $80. I assume these would work.

    Any thoughts? Ideas? Advice?

  2. #2
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    Are you sticking with 2x/3x or will you go to 1x? I would go with option 1 or 3 or similar cranks. Heck I've got old cranks that my kids have grown out of like a set of Thorn cranks. I would not do option 2, as the XCT are boat anchors.

  3. #3
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    I have not read anything on the benefits of going 1x (besides weight savings). Is it for more experienced riders? I would think having more gear ratios available would allow for handling of more varied terrain.

    I am leaning towards drilling and tapping. That way I can go a little shorter than 152mm.

  4. #4
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    rifty have you worked out the crank length ?
    My 7yr old uses 140mm and proper cranks start at 155mm (SRAM GX)

    Scroll to the bottom of this page for the best I've found way top determine

    https://highpath.co.uk/crank-shortening/

    The Suntour are just rubbish.... (in so many ways...but including the way they don't actually FIT the BB... the ones came with my kids bike basically squashed the aluminium but basically all the bits seem stuck together rather than engineered - its like the sum parts of all the cheapest bits)

    You can get SRAM S600's for (in the UK GB£10 more) .. they are bottom end SRAM but they feel engineered in every way... compared to the SunTour

    Older Shimano also just seem better ....I did some Alivio's, newer Shimano with Hollowtech BB's also have hollow crank arms so theoretically can't as a general rule be shortened (except Zee which are heavy)

    I have not read anything on the benefits of going 1x (besides weight savings). Is it for more experienced riders? I would think having more gear ratios available would allow for handling of more varied terrain.
    It's for almost everyone who doesn't do cycle-camping-adventure and carry camping equipment up mountains or expert XC who do a lot of firetrail/paved and want a very specific gear for cadence reasons.

    There are lots of benefits other than weight .. many seem a bit insignificant but they add up to what most find a better experience.

    Quite honestly I didn't even ride my newest bike 2x... first thing I did was rip off the double...Jnr has run 1x pretty much the whole time he had his 24er... (about 2 weeks before I shortened the cranks)

    You can easily have a 40/42 on the back and a 30T on the front and this should provide every needed gearing... on Jnr's bike I took off the smallest (11T) and just added a 40T expander and 12T lock ring... this is a bit limiting in that he can't go much faster than 25mph with 24" wheels .. however I'm happy with that as that is more than fast enough to hit a tree. He never needs an easier gear than 1st... and indeed rarely uses 1st anyway (which we call his zero gear) .... if he ever needs it then he is on single track and riding something so steep he is struggling for traction and/or keeping the front wheel down... (steeper than 45 degrees)

    I run a 1x11 42 with a 32T on the front on my 27.5 ... the extra 2 teeth is underwhelming over the previous 1x10 40T. I just never seem to need the 1st gear but its there if needed.

    You can ALSO just remove a the 16T and 18T on XT and replace with a 15T

    It's less clutter on the bars ... simpler and less likely to go wrong/get damaged.
    It's also cheaper (spec for spec) and easier to upgrade ... less to change and compatible with new parts when parts get damaged.

    Quite honestly, I'd not go back.... I was perfectly happy with a 1x10 with 40T expander on the back... I don't carry 50 kg of tents etc. and I'm not racing XC at a level that it matters where I'm riding on paved surfaces and I want a specific cadence

  5. #5
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    If you haven't seen this thread: Choices for kid-sized Crank Sets

    check it out. Definitely a well discussed option but most are leaning towards 1x at this point.

    SRAM NX of GX would be my current recommendations if 1x is an option.

    These guys have a good amount of info and sell shortened cranks and offer shortening services:

    Short Bicycle Cranks
    WTB: Med Bontrager Ti Lite, PM Me...

  6. #6
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    Thanks for the info. I think 1x makes a lot of sense. Drop the weight and simplify.

    For crank length, I have a Trek 220 3x crankset from a friend to try out. It has 2 holes, the longer of which is in the low 150s. I'll see how my son does at that length first, then tap a set of better cranks at that length or a bit shorter if necessary and go 1x.

    Now if I could only unscrew that stubborn 8mm crank bolt...

  7. #7
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    Crank weight info:

    The Suntour XCT T312 175mm crankset I just pulled off the bike weighs 979g total. Here is the breakdown.

    Left crank: 304g
    Right crank: 346g
    42T cog: 145g
    32T/22T riveted cogs: 171g
    4 screws: 13g

    By comparison, the Trek 220 crankset I installed is 947g total. The rings of both sets are heavy steel and the cranks are bomber. These were designed with brute force and zero elegance.

  8. #8
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    Definitely 1x. I updated my three kids bikes with 1x8 and 1x9. If you have money and time go for 1x11. But I used the Suntour XCT Jr 152 mm crankset - where I removed the largest wheel (screwed). Economical option - although some would not agree on the quality.
    And I am not sure whether it is 10 or 11 compatible.
    As for the weight, change the tyres. They usually weigh a ton. Then handlebar, stem and wheels (difficult to find light wheels in 24").

  9. #9
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    I ordered the 152mm Suntour XCT Jr T312 crankset directly from Suntour NA. Tip: if you create an account add the items to your cart and then walk away, a few hours later they will send you an email with a discount code. Mine was 15% off.

    My plan is to remove all the steel chainwheels from this crankset and put on the Race Face 30T narrow wide. The rear is 8 speed right now. I'll see how that goes first before I decide to spend the money on going 1x9, 10 or 11.

    As for the wheels, I find the info on wheels/tires/hubs, etc. to be mindblowingly overwhelming. The bike has a set of Kenda Small Block 8 27.5x1.95 tires on rims described simply as "DA21S 650Bx32H DOUBLE WALL, ALLOY BLACK" so not sure what they really are. Kenda does not have weight info listed for this tire, so no way to know what my weight loss per dollar could be unless I weigh them directly. Anyone have a recommendation on a lightweight value wheelset? Potentially tubeless, or does that get expensive?

  10. #10
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    Quote Originally Posted by rifty1 View Post
    I ordered the 152mm Suntour XCT Jr T312 crankset directly from Suntour NA. Tip: if you create an account add the items to your cart and then walk away, a few hours later they will send you an email with a discount code. Mine was 15% off.

    My plan is to remove all the steel chainwheels from this crankset and put on the Race Face 30T narrow wide. The rear is 8 speed right now. I'll see how that goes first before I decide to spend the money on going 1x9, 10 or 11.

    As for the wheels, I find the info on wheels/tires/hubs, etc. to be mindblowingly overwhelming. The bike has a set of Kenda Small Block 8 27.5x1.95 tires on rims described simply as "DA21S 650Bx32H DOUBLE WALL, ALLOY BLACK" so not sure what they really are. Kenda does not have weight info listed for this tire, so no way to know what my weight loss per dollar could be unless I weigh them directly. Anyone have a recommendation on a lightweight value wheelset? Potentially tubeless, or does that get expensive?
    cheap tire weights vary enormously - even what is meant to be the same tire....
    I pulled two of the kids 24 ... both meant to be identical and once was a good 30% heavier than the other....

    Both tires weighed more than the tires and wheels they were replaced by!


    27.5 you have MASSES of choice on wheelset and tires... the limiting factor will be the tire clearance on the bike.... (in terms of width)

    I got a brand new set of 650B wheels in a new year sale for £100
    They aren't brilliant wheels... but they aren't bad and lighter than the stock wheels came with a mid range ($3000) bike.

    They were marked down and then marked down for sale original RRP was £400 which is more than they are worth ... but the manufacturer is a bit that way... (they rarely don't have a sale)

    Anyway ... point is you will have a huge selection to choose from... and you can take your time a bit ... decide what tyre widths you want... as this will influence rim width...

    Also shop about for tires.... there are many options but you need to find ones that match your riding and climate (rocks vs forest etc.) and you don't need to match front and rear... indeed most people don't...you usually want a more aggressive, softer and often wider tire on the front... and an easier rolling on the back....

    I usually ride forest... for example and its often wet...
    On my front I have a Hans Dampf 2.6" (pretty much all rounder) and on the back (just because i had it spare) a Racing Ralph 2.4"... last weekend I rode rocks and punctured the Racing Ralph.... (ripped on a sharp rock) ... HOWEVER it actually sealed itself (I'm quite glad as I didn't take a spare tube and it was a 20 mile walk back ) (to be fair its a busy place so I'd probably have found someone willing to sell me one)

    This is the first puncture I've noticed since going tubeless and its on very lightweight tyres riding sharp rocks...

    So in terms of expense.... I'd say it's actually cheaper by the time you count tubes and puncture repair....

    Initial costs are some valves (you can make your own from old inner tubes but its $10 a pair...) some tape ... depending on your rim/tire combo you can buy the special stuff or use gorilla tape.... (I use some called T-REX which seems even better than gorilla)

    The reason it depends is how much space you have in the rim/tire .... if its a bit slack then I use the T-REX (Gorilla) as it would take 2-3 wraps of more expensive but a bit lighter special stans tape...but when its a tight fit the special tape (thin) is better...

    Special tubeless tires and rims work best... but most are now... some tires have cheaper non-tubeless ready.... they work too... just take a bit more sealant

    I've probably seated a dozen rim/tire combo's.... of these only 1 required a soda bottle (ghetto way) .. probably half I didn't even need to remove the core.

    There are known easy combo's... if you want to make life easy then take a known easy rim/tire combo and pay a bit more for tubeless ready.

    It sounds really complicated but is actually a lot easier AFTER you do the first one.
    Some combo's you really might need a compressor (or modifed soda bottle) .. but in my experience its rare.

  11. #11
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    FYI, here is weight info for the 152mm Suntour XCT Jr T312 crankset:

    Total 895g
    -Right crank 298g
    -Left crank 243g
    -42T chainwheel 144g
    -22T/32T chainwheels 198g
    -Screws 12g

    If you replace the stock chainwheels with a 37g RaceFace 30T narrow wide, the total weight drops to 590g

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