# Reality check



## Svengal (Dec 10, 2017)

Sorry for the excessive length of this post. If you get bored, the first two sections should give you the basic idea of what I'm getting at. Thanks for your help.


Summary:
I'm thinking of picking up a Norco 2018 Fluid 4.3 HT+. I've got a few questions and am also looking for people to weigh in with opinions. Specs are:

Price: $720 (CAD) (aprox $560 USD)
Frame: Aluminum ?w/ hydroformed downtube?
Head tube angle: 69 deg 
Effective seat tube angle: 72 deg 
Rear center: 385 mm
Wheelbase: 939 mm 
Standover: 695 mm 
Crank length: 152mm
Weight: shop says "just over" 29 lbs
Gearing: 1x8 with 28T chainwheel and 11-34 cassette
Fork: SR Suntour XCM24+ (coil, 6.6 lbs!)
Brakes: Tektro Hyd. Disc, 160mm (probably Tektro HD-M282)
Tires: Chaoyang MTB 24" x 2.6

Questions:


Most other 24" mountain bikes I see are not this wide (24" x 2.6). Is this too cumbersome?
The stock cranks are 152mm wide. Based on MTBR forum post "Crank length on kids bikes" and the referenced articles, an appropriate crank length for my son is 140mm. Should I switch it out right away? I'm hesitant because its been years since I kept up to date on bikes and everything's changed. The learning curve that would be involved in figuring out compatible components, but maybe the bike shop will do this for me. Plus I'm already stretching the budget a bit, so I'm hesitant to add any more cost
I'm a little worried about the weight, but based on what I've seen I can't get lighter than this unless I spend more, or forego the front suspension and knobby tires he wants it. Thoughts? What components would you suggest consider swapping out first to reduce weight? Maybe seat post to cheap carbon or for about $250 an air fork?
The chainstay length and wheelbase are a bit shorter than most I've seen on 24" bikes. I'm thinking this should be a good thing, making the bike feel agile and playful. I used to ride a criterium bike and don't have any experience with mountain biking, so maybe I'm misjudging?

Background:
My eight year old son finally got riding this fall. When he was younger he was great on his run bike, but his 16" came with training wheels that stayed on forever. He basically didn't have any fun riding that bike. Hardly rode it at all. This fall I finally realized to learn to ride he needed to first get comfortable balancing again. By this time he could barely fit on his 16 incher, but had inherited a 20 inch bike from his cousins.

I took the crankset off the 20" bike (which has a hand brake) and we took it to a nearby paved path with a consistent and gentle slope. His second time out we took both bikes and after a few warm up laps he felt ready to try the bike with pedals. At first I had him just use the pedals as a place to put his feet - another point of connection with the bike. It wasn't long before he was able to turn the pedals over as he coasted downhill. I put the pedals back on his 20" bike and a few more sessions and he was able to produce some torque and deliver enough power to the ground to propel himself on flat sections.

Finally! Too bad it took me so long to figure out the right process. Poor kid!

Not long after, we started going to the grocery store by bike and doing some 3-4 mile rides. With winter coming on it would get dark before he got tired, but I can tell he's hampered by the bike. The seatpost is maxed out, his leg never straightens enough and his knees come up too high. So, I am looking for a 24" bike.

The criteria:
On our rides so far, my son's smile was always bigest when we were on dirt. We live in the Vancouver, BC area, on the north shore so trails are nearby if not quite at our doorstep. That said my son is not ready to go downhilling. Not sure I even want him to - my neighbor nearly severed his thumb recently. We'll probably also ride to get around town to the library, grocery store, etc.

I can spend about $500-$700 CAD ($400-$550 USD). I guess I could nudge this upward for something compelling, but I don't think I need to given that my son just begun to ride. He won't really need a super high performance bike. Islabikes, Spawn and Trailcraft make neat stuff but they're all about double my budget.

My son wants a bike that has a front suspension, knobby tires and maybe a rear suspension and disk brakes too. I want him to have a bike that's light and fits the budget.
Regardless of whether it is a good idea or not, I know my son will be disappointed if his new ride doesn't have a front shock and knobby tires. Who wants disappointment at Christmas? Front suspension and knobby tires makes the list.

Hydraulic disc brakes are widely available. That's added weight, but everybody says they're nicer to use and I've always hated the look of caliper brakes on mountain bikes, In short hydraulic brakes will thrill him and me, so they make the list.

I've left rear suspension off the list of requirements due to added weight, poor performance in my budget and not really being needed for the type of riding my son will do.

Which leaves weight being dictated by the other factors.




Trail use (not DH)
$500-$700 CAD ($400-$550 USD)
Front suspension.
Knobby tires.
Hydraulic disk brakes.
Reasonable crank length
Light as possible given other requirements
Other requirements


Trigger not grip shift
low enough gear for hills
decent frame geometry and rider position

Other possible options are:

MEC Ace Ltd.
Price: $450 (CAD) (aprox $350 USD)
Frame: 6061 Al ?single? butted
head tube angle: 70 deg 
effective seat tube angle: 73 deg 
rear center: 420 mm
Wheelbase: 1000 mm 
Standover: 610 mm 
Crank length: 165mm
Weight: spec'd 27 pounds, measured (on bathroom scale) 29 pounds
Gearing: 1x8 with 32T chainwheel and 12-32 cassette
Fork: RST Capa
Brakes: Tektro Hyd. Disc, 160mm (probably Tektro HD-M282)
Tires: Duro Rugged Wolf 24 x 2.0

Ghost Kato 24".
Price: $525 (CAD) (aprox $410 USD)
Frame: 7000 series Al ?w/ hydroformed downtube?
head tube angle: 71 deg 
effective seat tube angle: 73 deg 
rear center: 415 mm
Wheelbase: 955 mm 
Standover: 550 mm
Crank length: unknown
Weight: spec'd 27.4 pounds
Gearing: 2x8 with 27/34T chainwheels and 12-32 cassette
Fork: RST Capa
Brakes: Tektro Hyd. Disc, 160mm (Tektro HD-M282)
Tires: Innova 24 x 1.95

If you made it this far, I'm impressed. Thanks again.


----------



## svinyard (Aug 14, 2017)

Geez. Hard pass on that bike. That fork alone is utter trash and worse its over 6lbs. 29lbs total is going to make things crappy for him. I know a lot of adults here in the PNW (I'm south of you on Mt Hood) who won't buy a bike over 28lbs due to the climbs we do... We all live on a mountain up here ☺). A nice 24in bike with rigid front would be fine for his ability. I'm a big fan of hydraulic brakes for kids for the safety factor (hand fatigue is real) with our weather but if you aren't running downhill, they aren't a must. 

Orbea 24 MX is where you should start. You right about the cranks. You want to be close to 140mm. Absolutely no front suspension at your price point. It's just marketing and actually hurting your kids ride.

If it was my kid in his situation... I'd skip the mountain bikes. BMX first. If you want your kid to speed up his skill set fast and really ride with you (you live in Mecca man)... get him on a decent BMX bike for 350$ to 250$ and take him to every skate park, pump track and trail you can find (indoors too). He will learn to really push his bike and have all the body skills he needs. Then you can drop cash on a nice 24in or 26in Mountain bike and he'll actually be able to really mountain bike and stay out of the ER. Don't underestimate these kids either. With the right bike and consistent riding skills terrain, they will be doing stuff you will pass on in months not years.

Welcome to forum btw, you came to the right place and its AWESOME that you are doing your due diligence on the bike. I think there are only a very few things where dropping cash actually makes a BIG difference...and their bike machine is one of those. There are some guys/Dads on here who have done an awesome job with their kids and def pass it on well. It definitely makes a difference.

Final comment, you really should put him in a Bell Super 2R/3R (2ish lbs) at some point. With as light and comfortable as they are (and your cool weather) there really isn't a good reason for him to not have a full face helmet at some point soon. Especially once he starts to develop. They come in handy on the big hits...but also on the stupid silly stuff like kids bumping into their brother just standing around and face planting on the end of a handle bar. A few Dad's around here already know the pain of getting multiple teeth removed from their kid and huge ER bills. Just not worth it.


----------



## hobiesmith (Mar 1, 2008)

Idk what to suggest either because at that price point, those cheap bikes with forks are so heavy. I like the bmx idea though.


----------



## Svengal (Dec 10, 2017)

Gosh! I know people are good, but everybody's in such a hurry these days, so I really appreciate the lengthy response. I've been going round on this for awhile. Thanks. It really helps to be able to get somebody else's thoughts on the matter.

I like the BMX idea too and it was not something I had thought of. I also agree on the rigid fork. I guess its a matter of adjusting my son's expectations. Hmmm. I'll have to think a bit more about this.

Good point about the helmet with chin bar. Will do. Had to snicker when I read


> ...but also on the stupid silly stuff like kids bumping into their brother just standing around and face planting on the end of a handle bar.


I love kids but they do the darnedest things sometimes.

Thanks again. I'll report back when I figure things out. Or more likely when I get myself totally turned upside-down again.


----------



## Steve-XtC (Feb 7, 2016)

Everything depends what you plan to ride... (with him)
Given where you live you have a lot of good riding available but $600CAD is the price of a decent fork not bike. (New) Even a proper shod is approaching that. 

There are a couple of general but perhaps less obvious things that can't (easily) be changed on kids bikes. (Obviously you can't turn a HT into a Full Suss)
1) Discs or not - either you have a disc hub and mounts or you don't 
2) The cassette or freewheel... and 8 speed will be a freewheel... so it can only be changed for other (heavy) freewheels

Both of those are wheels and the mounts are frame... you can change forks for the front mount and get some adapter thing for the rest chain stays but overall best to decide before you buy. 

On the other hand, where you are there is a lot of opportunity for a decent used bike. 
Check Pinkbike BuySell for example

For hard tails the frames are all of similar weights... its all the bits make the difference. 
The Orbeas are nice and have good trail geometry 

Jnr (8) now has 2 bikes, his Race XC bike is a cheap cannondale weighs <20lbs BUT the only original parts are the frame and fork... everything else is replaced. Most of it was bought discounted but its still a fair investment but he's racing so that's why. 

He used to use this as his trail bike but we started doing more blacks and uplifts and we ended up getting a used Norco Fluid Full Suss. Also the Cannondale has really long chain stays making it really difficult to jump/manual (the chain stays are the same as my adult medium) 

The Norco we changed the fork (its designed around a 26" fork for the 24" wheel) and shed a few lbs but the wheels were just lead weights.... everything on them was heavy from the hubs, spokes and rims to tires ... the front wheel weighed more than both his racing wheels with cassette... (that heavy) .. its just the wheels and fork that were heavy.. 

Having changed out components its now about 22-23lbs (or 25 lbs with DH tyres) 

For the HT's the majority are pretty similar frame weights so something like the Orbea with short chain stays is good... whereas for the FS the frames can be very different in both performance and weight but there are really only a handful of proper ones anyway. 

You can also buy a half decent kids 24" fork ... the RST F1rst ... I know a friend just ordered one from the US... and this is being put onto the Orbea frame (the other thing with the Orbeas is all the frames have disk mounts) (Its where I'd start doing it today but I'd buy a used one)


----------



## Danimal (Nov 18, 2004)

Buying a used Orbea MX 24 may not be realistic in the US due to the very limited QTY that were imported. I get the sense that the QTY imported has increased in recent years, but I still believe it's a needle/haystack situation.

Dan


----------



## Szy_szka (Oct 29, 2015)

I am all about weight reduction but this discussion never ends. There are so many options and the only limiting factor is your budget. 

Folks get preoccupied with the discussion about how to get the weight down and suggest things like a BMX bike and a skate park. Well, that's cool but you missed the point communicated by the OP: "my son’s smile was always biggest when we were on dirt." You see, the kid doesn't want to be in the bike park; he wants to get his hands and feet dirty on the muddy trail. 

I say, just get him on the best bike you can afford and simply ... ride! Adjust your expectations and take your time to see what needs to be upgraded. This option never goes away. For now, simply enjoy every moment on the trail with your kid!


----------



## svinyard (Aug 14, 2017)

Szy_szka said:


> I am all about weight reduction but this discussion never ends. There are so many options and the only limiting factor is your budget.
> 
> Folks get preoccupied with the discussion about how to get the weight down and suggest things like a BMX bike and a skate park. Well, that's cool but you missed the point communicated by the OP: "my son's smile was always biggest when we were on dirt." You see, the kid doesn't want to be in the bike park; he wants to get his hands and feet dirty on the muddy trail.
> 
> I say, just get him on the best bike you can afford and simply ... ride! Adjust your expectations and take your time to see what needs to be upgraded. This option never goes away. For now, simply enjoy every moment on the trail with your kid!


1- Weight kills fun for kids not riding gravity who are newer to the sport. A 29lb hard tail bike for a beginner kid is not a smart purchase where there are better options that are similar price, way lighter and fit better. Not that you suggested he buy that bike of course. We as adults know all too well that the right bike makes all the difference. Multiply that by 10x for a kid. I wasn't suggesting he drop 1300$ on a TC but instead go cheaper or similar price as his existing budget and make a smarter purchase that will cut many lbs off the bike and improve his chances of really riding legit trails with Dad (an amazing experience). Its a no brainer. A 6lb spring fork, I can't advocate that for any little kid. We are here to help after all, right?

2- I didn't mean to imply grabbing a BMX bike and only go to the skate park. Instead get a BMX and go to a skate park, pump track and trail...indoors included. That's great advice I was given by guys whose kids ride bigger than my 5yro...and my 5yo rides big. I'm passing that on and wish someone had told me earlier on. A cheap Framed Impact 18 for 99$ would do that in a heart beat. And they could probably still swing a nice rigid too and be close to the budget (as I implied).

Some manuf. are doing stupid stuff with bikes and making Frankenstein machines in effort to sell bikes. There are good bikes for 500$ and there are AWFUL bikes for 500$.

FWIW, this Cujo 24" looks like a decent plus bike. I don't know the weight but if its reasonable it'd be a good buy for 449$. Apparently the 20" version is fairly light, maybe this is as well.
Cujo 24 Mountain Bikes, Road Bikes, eBikes - Cannondale Bicycles

Side note, I've put hands on the new fluid+ bikes for kids. They are nice bikes but even the shop owner said that it'd be better to drop 650$ for the Norco Charger 2.1 (20" tho). with an air fork or go with something rigid. Said that they just put those cheap coil forks on there because kids want a bike that looks like Dad's and the manuf are throwing trash on there to just move product.

This a nice looking 24" without the silly fork. I'd want to know the weight (tires are big!). Has hydraulic brakes and 9 gears. 32t chainring up front is typical...though for any of these bikes it may be worth it drop the chainring to a 28T for the climbs around you (usually and easy and cheap swap).
https://www.giant-bicycles.com/us/xtc-jr-24plus


----------



## Danimal (Nov 18, 2004)

Seems several threads lately have come with a random recommendation to get kids into BMX. I didn't get that from the OP.

Dan


----------



## svinyard (Aug 14, 2017)

When I see a Dad pop in here wanting to get their kid into Mountain Biking and wanting the right bike.... I see that as a guy who wants to ride with their kid. No one wants to ride the walking trails forever, you only get so many years with the kids. So I tell them what others have told me. Get your kids into BMX to cross train their riding and they will improve at mountain biking MUCH faster.

Some dudes on here mentioned it, parents of some pro kids told me the same thing and when I talked to some local pro Enduro guys... they all said the same thing. Get your kid to ride some BMX in addition to the Mountain bike if you want them to catch up to you quickly skill wise. Which is a total thrill as a Dad. Nothing like sharing some adrenaline rush with your little guy for the first time.


----------



## SactoGeoff (Aug 11, 2017)

The desire for a fork is a limiter at that price point.

My first suggestion would again be the Orbea MX24. + swap the cranks. Then eventually start down the path of modifications to drop some cheap weight.

Not sure if you can get your hands on a Cleary Meerkat 24" rigid. 24lbs. But you could buy that, swap the shifter for a trigger $25.00 from the Cleary Site, and just ride. I know they are on sale via a few US sites. Not sure about access in Canada. 

Then 6mos down the line, for summer riding, throw on an RST F1RST fork on it. The fork will cost you a couple hundred bucks. But it's the best blend of price/weight out there.

Carbon bars and seat post would drop around .5-.75lbs down the line. Could be done for $50-80USD. Without too much effort.

As he progresses, you can put on Kevlar tires for a little lower rotational weight. If you really want to go crazy after your quarterly bonus, you could throw on some super lightweight Stans Crest wheels & convert to tubeless tires. It would be a rocket. And those wheels would have some resale value.

FWIW the longer you go down this rabbit hole of analyzing, the more you will spend. I started with a $650 budget and ended up spending $1400 + Super3R helmets. And the carbon water bottle cages just showed up! Have fun!


----------



## kabayan (Oct 25, 2004)

My suggestion is to get the Norco and, instead of getting the air fork, get a bmx bike. Or better yet, for close to the price of an air fork, you can get an entry level bmx race bike. Ride the bikes around everywhere. Hit North Shore BMX for a couple of novice races. You'll still have the option of putting a wide range 8 speed cassette or narrower tires on the Norco later on.


----------



## Steve-XtC (Feb 7, 2016)

Danimal said:


> Seems several threads lately have come with a random recommendation to get kids into BMX. I didn't get that from the OP.
> 
> Dan


I think its two different things....

I never rode BMX but I have lost count of the number of pro riders who's answer to when did you start riding MTB starts with "I started BMX at ...."

I'm sold except I don't have time without sacrificing riding time with my kid and Jnr.s mother wouldn't be interested enough to take him along when I can't.

This falls into the "if I had a different job and lived somewhere else" category of things.

I do think that if you ride single track and grandly trails it is a fantastic way for the kid to learn the skills needed much more quickly.

At the end of the day there are kids who never even cycle... so any bike is better than no bike... even the Walmart one... but what can be realistically ridden depends on the kid, where you live and sorry to say the bike.

It's become very popular lately (the last 5 years or so) for adult "do everything" bikes... I should know I pretty much ride my trail bike from uplift to XC trails... but its far harder (or next to impossible) with a kids bike because everything is more extreme compared to the size/weight of the kid.

Being a bit blunt you can either get a do most stuff OK bike or get a bike (or bikes) for a specific job but doing MTB seriously isn't cheap.

Jnr. has two bikes... one close to being an extreme XC and another trail/enduro bike. I'm not saying this is for everyone.. just saying the perspective it gives.

90% of the time there is a very clear choice over which bike for a ride and one an 8yr old can make.

The XC bike is also good for gravel and certainly passable on paved roads but it's geometry doesn't work well on gnarly trails... and with his size and weight he struggles to manual it. It's got the RST F1rst fork which is a fantastic fork for what its designed for (XC with a kids weight) but its not really needed for kids XC racing (most of which you could do on a CX bike).. but it is nice on longer and slightly gnarlier rides to prevent arm fatigue.

The trail bike is great on gnarly trails and downhill days but even with the XC wheels on is a drag on fire roads or tame XC. Its still lighter with a dropper and FS (11kg with light tires or nearly 13kg for DH) than most of the more budget HT's but that extra 2kg over the XC and the extra travel/rear shock is really noticeable when its out of its element and this is far from being a DH focussed bike. That said it climbs really rough trails better than the XC... and pointed slightly downhill it blows it away...

*If you know what you and the kids want to ride then that's a great start.*
Except most of us don't....



> FWIW the longer you go down this rabbit hole of analyzing, the more you will spend. I started with a $650 budget and ended up spending $1400


I completely agree .. had I known how things were going to turn out I'd have saved money by just going for the right bike(s)....

Except ... that only really applies if the OP's son gets into MTB.

I think a lot of us are thinking WOW if I lived there.... but there are however many million kids in BC 90% of whom will never ride semi-seriously.



> I can spend about $500-$700 CAD ($400-$550 USD). I guess I could nudge this upward for something compelling, but I don't think I need to given that my son just begun to ride. He won't really need a super high performance bike. Islabikes, Spawn and Trailcraft make neat stuff but they're all about double my budget.
> 
> My son wants a bike that has a front suspension, knobby tires and maybe a rear suspension and disk brakes too. I want him to have a bike that's light and fits the budget.
> Regardless of whether it is a good idea or not, I know my son will be disappointed if his new ride doesn't have a front shock and knobby tires. Who wants disappointment at Christmas? Front suspension and knobby tires makes the list.
> ...


Dad hasn't indicated if he rides or what he does ride if he does. 
For a kid knocking about with his mates etc. almost anything will do.. 
If he gets serious then he'll also know at that point what he is actually riding

I hadn't ridden seriously in years and had a hybrid when Jnr started out (not till he was 5) ... because of where we live we have local trails and dangerous roads so we drifted into single track... but there was no plan ... it's just what happened.

A chance carpark meeting with another Dad/Son got him into racing XC ... and we travel to the uplifts (as they are in the UK) and do camping+cycling weekends

Non of that was known in advance and had I bought a $1400 bike straight off it might have been one of those on eBay advertised as "now grown out of - only ridden twice"

Had I known the future I'd have gone for the $1400 straight off and saved money... except you don't know. I've also gone from my own hybrid to an XC bike to 140mm trail bike.... but a different chance encounter and he might be riding road or have taken up kite surfing or who knows what.

I used to ski and board... but haven't since my son was born .. I'd love to teach him but there is only so much time and money.


----------



## Svengal (Dec 10, 2017)

So much good information and so many good ideas. Some real gems. Reading through, so many thoughts people expressed seemed spot on. I particularly liked all the info on BMX and the idea to just get a bike you can afford and get riding. Thanks everyone.

I ended up buying the MEC Ace Ltd. I know the fork suspension isn't needed, or even good at this point, but I also know my son will be disappointed without it. I get that. Sometimes the thing I myself *want* isn't the *practical* thing. I'm not going to force him to ride a rigid fork. Besides, he'll ride more if he's excited about his bike.

This was the cheapest bike I was looking at which leaves me a little money to do something about the shortening the crank from 165 mm. Not much to be done about the chainstay and wheelbase length, but I think it'll do for now and if he seriously get's into it I can resell and get something better. The store said they would help me sort that out with after Christmas. 

I really like the BMX ideas people have put forward. As a mater of fact, even when my son was too big for his run bike, but still stuck on training wheels, we would go to the BMX track and just run around it. It was almost funny how stoked he was to just run the course. I think he might go for BMX in a big way. Funny I hadn't even thought of BMX for him, though it seems obvious now. Thanks kabayan for the tip about North Shore BMX. I hadn't been aware of them.

So I started looking for a BMX bike. Geez they all look the same. My riding experience is nearly all road based from nearly before SRAM became popular! (Where the heck did the time go???) And Campy doensn't even seem to get kitted on BMX bikes. Talk about non-applicable knowledge sets. I guess I'll poke around the web for a mtbr forums equivalent for BMX. Thanks svinyard for the reference to the Framed Impact 18. This gives me a reference point. Any suggestions for BMX forums to read would be welcome.

Steve-XtC, a lot of good comments in your post. Especially the bits about not knowing the future and the randomness of parenthood and childhood. Funny parallels here. I too haven't ridden seriously in years and have a hybrid (and a mountain bike and road bike in pieces waiting to be reassembled). As an aside I used to ski, but for the usual reasons hadn't in about 16 years. I'd gotten to the point where I was at peace with it. Then three years ago my son came home and said he wanted to learn to ski. As svinyard said in his original post don't underestimate what these kids can do. My son now lives to ski. And also to swim and to bike and to do math and to read, but mostly to ski. He skis double blacks and on certain terrain I am seriously just trying to keep up.


----------



## JCLW (Jan 21, 2018)

Svengal said:


> I ended up buying the MEC Ace Ltd.


I've been a longtime lurker but as I am in the exact same boat as you were I decided to register and post - especially as the MEC Ace Ltd is currently at the top of my list for exactly the same reasons it was high on your list.

This is the bike you got him? https://www.mec.ca/en/product/5053-234/Ace-Ltd-Bicycle

My daughter is turning 8 soon and I'm looking for a ~24" bike for her.

How tall is your son? How does the bike fit him?

My daughter is 52"/132cm tall with a 22"/56cm inseam.

Judging by the image(s) on the MEC site it looks like there is plenty of material available to drill and tap the cranks to ~140mm - can you confirm that these are the cranks the bike came with?








How are the tires it came with? I'd probably be looking to replace them with something a little easier rolling (and lighter) - maybe even some Maxxis DTH.

Thanks!


----------



## Steve-XtC (Feb 7, 2016)

JCLW said:


> I've been a longtime lurker but as I am in the exact same boat as you were I decided to register and post - especially as the MEC Ace Ltd is currently at the top of my list for exactly the same reasons it was high on your list.
> 
> This is the bike you got him? https://www.mec.ca/en/product/5053-234/Ace-Ltd-Bicycle
> 
> ...


The spec says LASCO FM25 32T cranks 
I think these are 152mm so not long enough to shorten to 140mm as you need at least 26mm extra length (9/16 ths pedal axle x 2)

However these aren't bad cranks and worth keeping for when they grow.
Regardless of what you spend on the sq taper cranks you won't save much weigh over a half decent pair with a alloy chain ring because they don't weigh much to start off... most of the weight is in the bottom bracket.

If you are going to cut and tap your own (a lot easier than you might imagine) then the SRAM S600s are a good bet and you'd spend a lot to save 100g.


----------



## JCLW (Jan 21, 2018)

Thanks for the reply Steve,

A close up of the image on the site shows that they are stamped 165 - I don't know how accurate that image is but MEC is usually pretty good.









If I got that bike and if they were really 165 (lots of ifs) I'd be tempted to machine them down to 140.

If they were 150-something I'd probably leave them and look at alternate cranks because, as you pointed out, they would have to be cut down by at least ~25mm to clear the existing hole with ~10mm of metal around them.

Looks like they are available in sizes from 170 down to 115 which makes me wonder why MEC picked 165 (if that is in fact what they are): Chainwheel & Crank Sets FM25-32X-GOX

Her 20" bike has 125mm cranks.


----------



## Steve-XtC (Feb 7, 2016)

JCLW said:


> Thanks for the reply Steve,
> 
> A close up of the image on the site shows that they are stamped 165 - I don't know how accurate that image is but MEC is usually pretty good.
> 
> ...


If you are happy machining then don't let it bother you either way. 
I've done several sets and it takes 30 mins then however long finishing 
If they are 165 they you can cut them .. if not grab some $40 solid cranks and cut them and save these for when she's grown.

The only thing to be careful is not overheating alloy if you are used to machining steel. 
We have some 152mm lasco off his Norco and they are if anything a bit lighter than the sram ones but I don't think I actually weighed them but either way it's a few grams ...

why they put on 165 ... that sort of thing just seems to happen on kids bikes.. maybe an accountant spotted they were 2c cheaper.

I lent a friend the sram s600s and (565g with chainring) he bought the trailcraft 140 sq taper ones and fitted same chainring 516g so only 39g saved and I could probably drop another 10g on the s600s if I machined off the 3x parts.


----------



## Svengal (Dec 10, 2017)

> This is the bike you got him?


Yes.



> How tall is your son? How does the bike fit him?


54 3/4" tall with an approximate inseam of 23". Tough to get him to hold still long enough to get a reliable inseam measurement. Great fit, with some room to grow, but not a big stretch.



> can you confirm that these are the cranks the bike came with?


Yes. That looks right. Also, I can confirm the bike does have 165mm long cranks. The imprint on the crank arm does read 165. Specs/docs on this crank were difficult to interpret if I recall, which may explain the confusion on this point.

I was pretty concerned about the crank length and I can see when my son rides, shorter cranks would be better, but I've kind of let it slip off my priority list. I have a drill press and some limited experience in machining metal (in a hacking kind of way), but I've wondered how I'd fixture the crank so when I drill the hole it ends up parallel to the spindle hole. If anybody has tips on this I'd appreciate it.

I did look into buying new cranks. A supplier suggested going with 152mm based on my sons size specs and the fact that kids grow. I was convinced all in all despite my son's ideal crank length is 140mm. Perhaps consider sizing up to 152mm?



> How are the tires it came with? I'd probably be looking to replace them with something a little easier rolling (and lighter)


I don't have a ton of experience to help you here. Unless it is a deciding factor I would suggest getting the bike and changing them if you want to later. Obviously they have more rolling resistance than the crit bike I used to ride and even the clunker hybrid I have access to now. That said, my son and I went out and did ~23k recently, so its not too bad.

Overall I would note that my son LOVES the bike. Yes, its got a 6 lb fork that he doesn't need. Yes, the cranks are too long. Yes, the chainstays could be shorter. But he wants to go ride *every* chance he gets.

Hope that helps


----------



## Steve-XtC (Feb 7, 2016)

Svengal said:


> Yes.
> 
> 54 3/4" tall with an approximate inseam of 23". Tough to get him to hold still long enough to get a reliable inseam measurement. Great fit, with some room to grow, but not a big stretch.
> 
> ...


It's way easier than it might appear.
When I did the 1st set I made an elaborate jig to align them. 
It's really not needed.

The last set I used blocks of wood with a piece of oak on top. The hard part is drilling slowly enough and making sure you break out cleanly. I just held this down with some F clamps to keep it still and prevent it rotating and used a hand drill with good speed control.

I used a 13mm final because the charts for Steel and 9/16 are a bit larger and a bit of extra alloy is not a problem to tap.

So long as you get the pilot hole straight you are fine. Just drill very slowly or you melt the alloy which isn't good as the heat treatment around it will also suffer. I just aligned the drill parallel to the F clamp by eye and this worked perfectly enough on 4 crankset so far. I also just stuck them in a bench vice and did it that way but the bit to watch for is making sure they are at 90 deg to the crank axle as opposed to the Crank arm ... you can also stick a pedal in to guide you in the pilot hole.

I didn't use any type of coolant or lubricant drilling but you could if you wanted.

I cut after drilling ... again try and keep the temp down ... it's soft alloy so even just using a hacksaw by hand is not going to take too long.

I tried shaping the end on the bench grinder but it's really easier to cut the corners at 45 deg and then use a file... again it's soft alloy not steel... then quickly just run the 13mm drill through a final time before tapping.

For tapping I used some normal thick grease and did 2 turns forwards and one back in general... I used mid quality taps and these are more than good enough for alloy.

Anyway I'd say stress less it's easier than you think and well worth getting the correct size.
So long as the cranks are solid arms it's really quite easy (despite me having the same reservations as you before doing the 1st set)

Getting the correct size will make a lot of changes to riding .. you can raise the saddle and they will be in a better position.

We recently tried the 152mm and going from 142mm made a negative difference even now he's grown considerably so I now think I should have started smaller... he is forced out of the saddle more which doesn't matter on a 20-30 min kids race but does when we cycle trails as he is tired out way sooner.


----------



## Svengal (Dec 10, 2017)

Steve-XtC, Thanks for the encouragement and tips. I'll give it a shot when I get the chance.


----------



## Steve-XtC (Feb 7, 2016)

Svengal said:


> Steve-XtC, Thanks for the encouragement and tips. I'll give it a shot when I get the chance.


I did the 1st set in some SRAM s600 that are about $35 new ... it felt better knowing I'd only $35 to mess up... however 2nd set were some shimano Alivio used off eBay for $15 ... so that would have been even less stressful

After that I did some new external B.B. shimano new Zee considerably more expensive and it all went easy but they ended up about 15g lighter so not worth the expense...


----------



## JCLW (Jan 21, 2018)

Svengal said:


> Overall I would note that my son LOVES the bike. Yes, its got a 6 lb fork that he doesn't need. Yes, the cranks are too long. Yes, the chainstays could be shorter. But he wants to go ride *every* chance he gets.
> 
> Hope that helps


Glad to hear he loves it!

That helps a lot - especially in regards to sizing.

Like your son, my daughter would be disappointed if her new bike didn't come with certain things (front suspension, disc brakes) even though she doesn't really need them.

I'd love to get her something like a 24" Ti Trailcraft but it's not going to happen until I win the lottery.

If he's OK with the 165mm cranks you could just leave them. On the other hand it looks like it would be pretty easy to drill and tap them if you wanted - I can't really comment on clamping without seeing them but Steve had some good points. A local machine/fab shop would probably do it for for cheap as well. Trailcraft/Islabikes seem to use 140mm cranks on 24" bikes, Spawn uses 155mm.

Thanks again!


----------



## Steve-XtC (Feb 7, 2016)

There is no exact formula for crank length but the best I found is at the bottom of this page (scroll all the way to the bottom)
It uses an "outer leg measurement" which makes a lot of sense.

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

When Jnr got his 24 I made the cranks 142 (I'm not sure why I added 2 except I was erring longer) but he was probably 135 or so.

They were MUCH better but I should probably have gone shorter. 
Either way, It meant the saddle went up and his whole body position changed to a better position so we were riding further.

It was actually a bit scary in that I thought if they were not completely at 90 degrees they would feel strange but in reality most of us has slightly twisted feet. Me more than most I guess and my right foot always points out a bit (so my heel wears the chain stays) so the small error from being 100% exact doesn't matter In other words, it's comfortably within the capability of drilling by hand.

Getting the pilot hole straight to the spindle is the hardest part as the crank arm itself is usually at an angle so visually misleading. A pedal inserted before you drill will make it easier then you are just drilling parallel to it.

After the bigger hole will follow it and then it's a case of managing the breakout to prevent it jamming when the drill leaves the crank.

Be careful to control this or the crank could spin round and hit your ankle... I found clamping the crank to wood works.

I still had the wooden jug I made up when I did the 2nd and 3rd sets but I just didn't use it. Perhaps though it's worth doing just for the confidence ??

Alloy is easy to drill... it's worth making sure the bits are sharp just to prevent them wandering but the main thing is just to drill slowly. You can stop and check alignment. If it was going wrong you can still turn the crank over and drill from the other side.... my pilot was 5mm and the final hole is 13 so ifnit wandered badly you have a lot of overlap (mine never have and I'm somewhat middling when it comes to workshop stuff)


----------



## SactoGeoff (Aug 11, 2017)

JCLW said:


> If he's OK with the 165mm cranks you could just leave them. On the other hand it looks like it would be pretty easy to drill and tap them if you wanted - I can't really comment on clamping without seeing them but Steve had some good points. A local machine/fab shop would probably do it for for cheap as well. Trailcraft/Islabikes seem to use 140mm cranks on 24" bikes, Spawn uses 155mm.
> 
> Thanks again!


Spawn uses 155mm cranks because they have a gravity mindset. Similar to BMX where the rider is standing the majority of the time. Downhill and dual slalom is done while standing. Or even sprinting towards a jump. Giving more leverage for that sprinting style and a wider stance for stability with obstacles. It's great for 2-5min.

Whereas for any sort of trail riding they are sitting the majority of the time. A properly sized crank will help immensely with efficiency/endurance. Along with a better riding position so they can see better and apply a more efficient pedal stroke. Because the pedal stroke is smaller, it's less exhausting. Just imagine if you went out for a bike ride with 225mm cranks instead of the stock 172/175.

I believe getting the correct crank length is equally as important as say, a super lightweight wheel set. It's a big factor. And it's too often dismissed IMHO.

When I ordered our Yama Jamas I also ordered 140mm Brood cranks. My kids are 52" with short legs. And frankly, even the 140mm is pushing it. But it works. I saved the stock 155mm cranks for when they're almost ready to move up to a 26" bike.


----------



## str8edgMTBMXer (Apr 15, 2015)

if you still have ??s about BMX, let me know...gonna sub this thread, and then maybe get an answer after work...lunch break is almost over...been shopping BMX bikesf or the last 2 years, so I might have some insights for you if it is still applicable


----------



## Steve-XtC (Feb 7, 2016)

SactoGeoff said:


> Spawn uses 155mm cranks because they have a gravity mindset. Similar to BMX where the rider is standing the majority of the time. Downhill and dual slalom is done while standing. Or even sprinting towards a jump. Giving more leverage for that sprinting style and a wider stance for stability with obstacles. It's great for 2-5min.
> 
> Whereas for any sort of trail riding they are sitting the majority of the time. A properly sized crank will help immensely with efficiency/endurance. Along with a better riding position so they can see better and apply a more efficient pedal stroke. Because the pedal stroke is smaller, it's less exhausting. Just imagine if you went out for a bike ride with 225mm cranks instead of the stock 172/175.
> 
> ...


I'm 5'10" and 175's kill my knees and hips on longer rides ... 170 it just disappears

I'd never even connected the two until I started looking at crank length for Jnr ... in fact I just thought at the time that the cranks would be the right length for the size of bike... obvious eh??? When I actually looked I had one bike 175 (M frame FS) and the other 170 also M frame hardtail and the hardtail left me less beat up all week than the FS...after which I'd spend a week recovering my knees and hips (I'm getting on a bit)

Then I just swapped the cranks over ... what a difference!!! Now the FS leaves getting older me less beat up than the HT...

I really wish I'd known this 30 years ago when I was doing all that damage but my younger body could mask it away .. and I really think in part my bad knees and hips are due to using the longer cranks for years ...

Back then I also rode a lot of road and was in the saddle a lot more ... but I always suffered knee and hip to some extent ...

Anyway once you actually start looking you are most manufactures accountants don't actually give 2c as to crank Length ... only what the parts cost with their deal with SRAM or Shimano... hence why they will sell a women specific XS with 170 or 175mm cranks !! Or when they change their deal and switch shimano/sram the same bike model this year has different length cranks... as if it's a different bike when they just changed the paint and groupset

The same goes for kids bikes...
155mm is the smallest commonly available but rare and limited choice ... then 165 is where shimano starts still low numbers on whole bikes then more 170 and most 175

As you say it's less important sprinting out of the saddle but it's also a few cents to save to the accountants...

155 is buyable ... smaller means special manufacturing and I'm sure many kids bikes end up with whatever length the accountant chooses.... it must be quite a heartbreaking thing for he engineers and designers who probably set out with a properly proportioned bike


----------

