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Slight wobble in square taper
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Does anyone know much about square taper cranks?
I use a shorted square taper on my TT bike and noticed the drivechain seemed to be making tonnes of noise.

I deduced that the noise was coming from a small side to side movement in the chain causing rubbing on the sprocket above the one the chain was currently sitting.

The side to side movement was due to the chainring moving very very slightly from side to side, which seems to be the crank/spider not the bb.

I understand ST is old tech, but I like the narrow factor it gives me ~130mm, and nothing on the current market comes close to that.

I don't know if this noise costs me anything in terms of watts, but wondering if anyone knew of a fix? I've tried all 4 positions of the chainset.
Maybe I could shim the chainring?

Also I can remove the noise by pushing slightly on the rear mech cage to reduce tension of the lower chain as it goes to the front ring.
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Re: Slight wobble in square taper [Tom_Hughes] [ In reply to ]
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IIRC there are different types of square taper cranks and BB.

Do yours match?

Maurice
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Re: Slight wobble in square taper [mauricemaher] [ In reply to ]
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J.I.S., J.I.S. Low Profile, and ISO (sometimes referred to as the Campagnolo standard).
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Re: Slight wobble in square taper [Tom_Hughes] [ In reply to ]
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This was the downside to square taper. If not properly tightened, wobble ensured. If nor corrected, the crank would round off a bit and voila, the crank is ruined. Keeping it square and tight is critical. Back in the day (when we only had 5 and tsp freewheels, a coke can shim was helpful in extending crank life once the rounding had started. A hammer was necessary to think out the shim a bit.
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Re: Slight wobble in square taper [mauricemaher] [ In reply to ]
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Not exactly.
Mine are 7400 shimano which are low profile jis, which are impossible to get hold of!
I have tried both ISO and JIS standard but seem to wobble on both. It's really small but with cassette and chain tolerances being so small it's enough!

Interestingly I have 2 identical chainsets. Both wobble, maybe I have used them with the same BB that's distorted them.

If it wasn't for the fact they are shortened and rare I would get another set!
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Re: Slight wobble in square taper [Tom_Hughes] [ In reply to ]
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http://www.philwood.com/products/bbhome.php

Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
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Re: Slight wobble in square taper [fredly] [ In reply to ]
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I'd seen those but too costly and hard to get hold of.
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Re: Slight wobble in square taper [Tom_Hughes] [ In reply to ]
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Phil has always been easy to order from, and they're still in production. LBS can order them for you, last time I needed one of these, had it in a week.

Expensive, yes... but they will, actually, last forever.

Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
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Re: Slight wobble in square taper [fredly] [ In reply to ]
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I'm based in the U.K. I asked several dealers who couldn't get them
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Re: Slight wobble in square taper [Tom_Hughes] [ In reply to ]
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I can get you a deal on almost any Phil Wood product.
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Re: Slight wobble in square taper [jimatbeyond] [ In reply to ]
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In the UK?
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