ThatChap

I seem to have a tiny percussionist living in my bottom bracket. I have a 5 month old Globe single speed bike which makes an almost tuneful rattle of noises when I'm actively cycling. My assumption is that the cassette is broken in some way. I want to have a look but I cannot mesh my crank extraction tool with the crank arms, it's as if the threads are incompatible. I don't want to force it lest I cross threads whereupon I will pedal it off a bridge.

I have faced exactly this problem before with the same sort of 'square taper' spindle. The design seems fundamentally flawed as the softer alloy of the crank cleaves to the steel of the spindle and becomes separable only by deity-class power. Previously, the solution was to angle grind the assembly off and replace everything. [Going mental with a rubber mallet only achieved the major concussion of my friend and a surprisingly pleasant drive to A&E.]

Given that I don't want to experience another episode of face-shaking rage, could it be possible that I do indeed have an incompatible crank extractor? It's a Bikehut tool purchased from Halfrauds: https://goo.gl/mReqA. The threads are fine as are those on the bike, which are completely unsullied. I cannot seem to 'engage' the threads. I would expect/want to screw in the extractor right to bedrock then further tighten true with a spanner as I've enviously seen on several YouTube videos.

cny-bikeman

Nothing I can tell you here beyond what is easily found on Sheldon's site (Google "sheldon crank extractor") but here goes anyway.
What's important is not the bike brand/model but that of the crank arm.

The only possibilities besides the standard size thread are smaller diameter, so if you had the more rare TA/Stronglight crank your extractor (which is for standard threads) would fit loosely, and it does not sound like that is the case.

The entry threads (I can't find the proper terminology to the arm are likely damaged, but try turning the tool counter clockwise to see if that helps you find the proper place to start - should click into the entry thread. If that does not work then you need to repair whatever damage is present in order to allow the tool to thread in.

FBinNY 

Besides doing your best to pick up the lead and thread the remover in properly, there's not much you can do. If you can eyeball a single damaged thread on the arm you can dress it out carefully with a file. Damaged 1st threads are fairly common among people who don't use crank dust caps, who'se real job is to protect the threads.

If all else fails, a pair of Jacob's Chuck removal wedges (cost about $10.00) will remove cranks without damage, even if/after you strip the threads.

BTW- I'm wondering if your issue is BB related at all. Were you very careful to pull the wheel back and remove all the chain slack?

dsbrantjr

Wouldn't a 5 month old bike still be under warranty and the repairs be the responsibility of the dealer? Perhaps before you go messing about you should see if they can resolve your problem. If there is something loose riding the bike will only cause more damage.

Regarding the crank extractor, you did retract the inner plunger sufficiently that it doesn't interfere with getting the outer threads engaged, right?

JanMM

I'm sure you must have removed the crankarm fixing bolts first?
On some older cranks, that's not as obvious as you would think.

JanMM

Good point.

wrk101

+1 And some cranks have a separate washer besides the bolt. Be sure to get that washer out before attempting to use your puller, or you WILL strip the threads on your crank. Ask me how I know.......

JohnDThompson 

Otherwise, your LBS may have a thread chaser to clean them up:

Kimmo

I seem to recall one of the guys at my co-op saying something about there being a larger-sized extractor for some sort of oddball cranks... was he mistaken?

Canada Panda

Does the smooth tip of the plunger unscrew or pop off? My puller has a removable tip that is either kept on for systems with a crankarm bolt or removed for systems with a crankarm nut.

ThatChap

The crank puller threads seem to be perfect (here), the metal appears to be a lot harder than the relatively soft alloy of the crank arm. In fact, it's so soft that just by applying pressure with my fingers it looks as though I've stripped the lead-in threads (here). The crank arm threads are protected by hex key bolts which completely seal the socket, so no issue with dirt.

I've spotted chuck wedges but there is no indication of the depth - definitely doesn't look deep enough to bridge the gap between crank and bottom bracket.

Definitely, definitely the problem is the cartridge. The casing is broken I'm fairly sure. I've had precisely the same symptoms with a prior bike which I subsequently had to angle grind to replace.

I think the Suntour chainset is just crappy. I went to Evans cycles to cry at the mechanics who gave it a go with my puller tool and theirs - no joy. It feels as though it's a compatibility issue - they say no. If I cannot remove these cranks, I'm going to go completely ballistic. I'm going to send an email to Suntour now.

ThatChap

Yes, I'm supremely confident I know what I'm doing. The problem is that my crank extractor (here) doesn't seem to mesh/fit with the crank socket (here). As you can see, I've probably destroyed the threads now so I will have to find another solution which doesn't end with a stress-induced heart attack. The thing that really blows my mind is how pathetically soft the crank arm metal is and general insanity of the square-taper pressure fix, cotterless solution. It's as if it was designed by a sadist. I will email Suntour, I think they are at fault for making the threads uselessly shallow.

nhluhr

There is an extractor for square-taper cranks and another for octalink style cranks. The main difference is the plunger diameter.

scooterfrog

pickle fork, ball joint separator

Amesja

Looks like those lead-in threads to the crank arms are toast. They might be repairable by an LBS with the proper tap -then again maybe not. They look pretty bad. What did they look like before you started the job?

clasher

Those threads look ruined to me. I'd use a tie rod separator to take the arm off. I have a thread chaser for crankarms but I don't think there is enough good threads to chase in this case. Crank puller threads are really fine and easy to strip... I always thread the remover in very carefully... usually clean the tool and threads before each use and use a bit of oil on the puller... can't be too careful.

ThatChap

Honestly, I was ridiculously careful when initially trying to screw the puller in. The threads are absurdly delicate on these particular cranks, it's as if they're lightly textured for aesthetics. Having to be brain-surgeon ginger with bike components is a nonsense. However, I've ordered this, my kind of price point and I've heard good things. We'll see how it goes; I'll report back.

I freally don't want to use any sort of violent method e.g. hammers, cold chisels and the like. My last resort is an angle grinder and purchase of a chainset which is absolutely not Suntour.

If all this kills me, please can someone delete all my on-line accounts.

ThatChap

That tie rod separator looks more like it. There is quite a gap between the frame and crank, levering it out makes more sense. I've tried (in the past) an automotive extractor and cold chisels to no avail though.

spinbackle

If all this kills me, please can someone delete all my on-line accounts.[/QUOTE]

If someone does that then it will appear as if you never existed. Where will all your bike stuff go?

Canada Panda

Big chain auto shops commonly have those tools available for borrowing. Here in Canada, Canadian Tire will let you borrow a tie rod tool or a standard two-jaw puller for a deposit on your credit card, refunded after you return the tool. Would save you the purchase price if the tool doesn't work out for you.

Kimmo

Square-taper's not particularly sexy, but it generally works just fine IME. Certainly a vast improvement over cotter pins, which was its purpose. I like how the soft ally gives me the option of just continuing to crank on the bolts if I think the BB's a bit long; it works well. I've never had a crank arm fail, either at the joint or in the extraction threads either, touch wood.

If you have a spare extractor, you could try cutting some slots and grinding a short taper in the thread so you can use it as a tap to chase the threads...

Amesja

It might be possible for a bottoming tap to cut those threads out if a skilled operator could get the tap to start in the right place so that it lines up with the good threads further in. It might be necessary to bevel out the first couple of threads so that the tap can "find" the deeper threads to index into so that it alighns with them.

It wouldn't hurt anything if it didn't work though as the threads are destroyed either way.

Since this is not one of those super-cheap spindles with built-in bolts it would be possible to try this before removing the crank arm since it wouldn't be in the way of the tap.

But it wouldn't be hard to pull that crank using a typical bearing puller. It looks like that crank arm has lived a hard life anyhow and is already beat up on the outside anyhow just as much as it is inside those threads.

At this point it would just be easiest to just take this to your LBS. They can deal with it and it won't cost any more than buying the bearing-pulling tools.

nhluhr

You're right, it IS nonsense. These threads can handle a little abuse. They simply are NOT as delicate as some people here are suggesting. Somebody really hosed yours. Either yours were already screwed up or you screwed them up with some serious hamfisted action.

At this point, the only thing that will non-destructively take that off is a pickling fork.

ThatChap

The bike came with a free service which expired one week (working) after purchase, no major damage or wear issues were found. It was a few weeks after that when I noticed one of the brake cable stays had been pilfered. Luckily, a chap at a Specialized (sic) shop took pity on me and gave me one free, provided I stop crying.

I completely removed the inner plunger. It did occur to me that the inner plunger could engage with the threading of the tapered spindle itself to assure a perfectly perpendicular angle of attack but then I laughed and thought about the overall design failure.

ThatChap

Seriously, I can smear the threads off with my finger. Amazon do a pickle fork for 1p which seems pretty reasonable to me.

I really don't want to start going at my bike with a hammer though, I fear I might lose my mind with the thought of damaging such a beautiful steed and run off to the nearest motorway brandishing two rubber mallets and gurning at cars in nothing but knickers.