any cyclists on the forum? (question about parts suppliers...)

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Lykho

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#119084 20-May-2013 08:50

I'm having a hell of a time finding an NZ store that will sell a single left crank arm (170mm, square taper) or crankset for under $60.

anyone have any bright ideas? any little-known stores with good prices? should I just get a new cheap bike from the warehouse?

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#822228 20-May-2013 08:58

http://www.probikekit.co.nz/components.list is very popular with people I cycle with, freight is about $20.

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jeffnz

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#822229 20-May-2013 09:00

Just looking at pricing and you are right it would be cheaper to buy an old bike

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nickb800

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#822238 20-May-2013 09:29

Have you looked at torpedo7? No single cranks for under $60, but a few options for cranksets at $120

Lykho

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#822241 20-May-2013 09:32

nickb800: Have you looked at torpedo7? No single cranks for under $60, but a few options for cranksets at $120

yep, someone just told me about them yesterday.

they've sold out of the $20 single cranks ... which makes me wonder where those came from and why no one else has anything in a similar price range.

Dunnersfella

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#822252 20-May-2013 09:58

Square taper 170mm cranks would either be VERY old, or basically, cheap rubbish.
You're better off to buy a new set... BUT, there are issues with this.
Some questions.

1: Do you need the drive side, or non-drive side (the one without the chainrings on it).
2: If you do need a drive side crank, you need to ensure you can swap your chainrings over to it. The PCD (the bolt pattern) is definitely a mine field. There's compact cranksets, standard, integrated all-in-one etc etc. Many cheaper square taper cranks won't allow you to remove any chain rings, which in turn means you have to use new chainrings on and old chain / cassette / jockey wheels... and these seldom mesh well together. Or in other words, add new chainrings into a worn drivechain and you'll get slipping + chain suck.
3: Why do you need a new crank to begin with? Did it come loose and slog out? Did it get bent during a jump or big drop? Did the pedal insert fail?
If it came loose / is creaking, then the bottom bracket axle will also be damaged.
The axle is on a taper, and if the edges are worn in any way, the crank will either come loose again (damaging the axle even further) while creaking worse and worse over time.

If it was my money, I'd buy a new bike.

nickb800

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#822253 20-May-2013 09:59

What's your timeframe? There a few cheap options on Ebay e.g. this for ~$30

Dunnersfella

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#822260 20-May-2013 10:03

I should mention, not all axle holes are drilled on the same angle... so make sure it matches the one you already have, or one will be at 45 degrees to the other crank!
Oh, and as Shimano own a patent for the axle taper, other companies 'work around' this patent, meaning it won't always work well as a friction fit on your bottom bracket.

Yup, I used to be a bike mechanic. Yup, cranks are a problematic area, especially square taper units.

Lykho

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#822264 20-May-2013 10:07

Dunnersfella:
3: Why do you need a new crank to begin with? Did it come loose and slog out? Did it get bent during a jump or big drop? Did the pedal insert fail?
If it came loose / is creaking, then the bottom bracket axle will also be damaged.
The axle is on a taper, and if the edges are worn in any way, the crank will either come loose again (damaging the axle even further) while creaking worse and worse over time.

If it was my money, I'd buy a new bike.

it's warped (no longer square) from use. because of the taper, it's hard to tell with my amatuer's eye if the bracket is still good, but I'm told it's a harder metal so less likely to be part of the problem.

this is just an MTB for commuting. The Warehouse has one for $120 ... are they so dodgy that it would be better to harvest the crankset from it rather than assemble the whole Warehouse bike, and have some spare parts, or use the whole new bike, or just spend that $120 on whatever crankset a reputable bike shop stocks?

Lykho

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#822268 20-May-2013 10:12

Dunnersfella: I should mention, not all axle holes are drilled on the same angle... so make sure it matches the one you already have, or one will be at 45 degrees to the other crank!
Oh, and as Shimano own a patent for the axle taper, other companies 'work around' this patent, meaning it won't always work well as a friction fit on your bottom bracket.

Yup, I used to be a bike mechanic. Yup, cranks are a problematic area, especially square taper units.

mmm, this is a shimano crankset, too...

is it time I just ditched this bike? (I think I'm throwing bad money after good because I wasn't smart enough to dump it instead of getting it serviced last year and now it seems a shame to throw it out after I've paid to keep it fixed up)

Dunnersfella

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#822269 20-May-2013 10:14

Just because the bottom bracket axle is made out of harder material, it doesn't mean it's not damaged.
It will be.
I'm struggling to remember an occasion where I've seen a slogged out crank, and the BB was fine.

Basically, you'll be able to buy a bike for around $150 on Trademe that will have been purchased by a "I'm going to buy a bike to get fit, and never actually ride it" person. I got one of these for my fiance, and she's stoked with a practically brand new bike.

Lykho

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#822271 20-May-2013 10:16

nickb800: What's your timeframe? There a few cheap options on Ebay e.g. this for ~$30

well, I use it for 10k every day, and it's click-clacking back and forth with every rotation, so...I'm not sure how much longer I'll tolerate it, probably as long as it takes me to decide if it's stupid to fix this bike instead of replacing it, unless a very cheap solution voids that issue.

there're also cheap ones on Amazon, but I would imagine the time-frame would be terrible, if they ship to NZ at all.
http://www.amazon.com/XLC-Alloy-Crank-Arm-Diamond/dp/B005YO157O

marmel

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#822350 20-May-2013 12:10

Why not just buy another crankset off trademe? Older style square taper crank sets come up for sale reasonably often. The other choice would be to get another bottom bracket and crankset, maybe a Shimano octa link or Isis style, you should be able to pick up both for $50. I just purchased a brand new shockcraft external bearing bottom bracket last night off trademe, $21.

Dunnersfella

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#822560 20-May-2013 17:50

If you buy a crankset, make sure of two things...
1: That your chain rings will simply swap over.

2: You buy a new BB at the same time (right cup size + correct axle length). Stick with a Shimano bottom bracket, then ensure the crank is attached with an accurate torque wrench by someone who knows how to use it (remember, greasing square taper bottom bracket axles is a fools errand, it's a press fit after all). I know quite a few mechanics who swore they didn't need to use a torque wrench, of course, they were the mechanics who had the highest number of 'bring backs' for clicking cranks / damaged (over torqued) spindles etc.
Square taper cranks are just terrible... no wonder they were replaced by the (still annoying) Octalink / external bottom bracket standards.

Lykho

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#822745 21-May-2013 02:04

marmel: Why not just buy another crankset off trademe? Older style square taper crank sets come up for sale reasonably often.

haven't seen anything suitable, and at least I'd know I got the right thing if I went to a store. the more parts I have to buy the more potential for getting it wrong. getting just a 170mm left arm would be ideal.

Lykho

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#822747 21-May-2013 02:10

Dunnersfella: Square taper cranks are just terrible... no wonder they were replaced by the (still annoying) Octalink / external bottom bracket standards.

is that why it's so hard to find a quick and easy replacement?

and 'terrible' why? for what? to whom? ... is there a good reason to get a newer style crankset and bracket instead of whatever fits this one? would I notice any benefit from doing so? this one's seemed fine for a good 8+ years, but I've had nothing to compare it to.

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