Praxis Works chainring bolt torque spec

Discuss light weight issues concerning road bikes & parts.
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SpecializedColnago
Posts: 208
Joined: Thu Dec 29, 2016 11:33 pm

by SpecializedColnago

Does anybody have a torque spec for Praxis Works aluminum chainring bolts. Ive searched on this forum and did a general google searches and can not seem to locate anything more than a generic torque range for aluminum chainring bolts. Ive tried Praxis Works' webpage as well with no luck. Thanks for the help.

by Weenie


youngs_modulus
Posts: 512
Joined: Wed Sep 20, 2006 1:03 am
Location: Madison, WI USA

by youngs_modulus

Is there a reason you think that the generic torque spec wouldn't work for the Praxis Works bolts?

SpecializedColnago
Posts: 208
Joined: Thu Dec 29, 2016 11:33 pm

by SpecializedColnago

Well the generic torque range for aluminum chainring bolts is 44-88 inch pounds so definitely a large disparage in torque there.

youngs_modulus
Posts: 512
Joined: Wed Sep 20, 2006 1:03 am
Location: Madison, WI USA

by youngs_modulus

Again, is there a reason you think that range won't work for your bolts? That's not an especially large range in absolute terms.

Believe it or not, people were able to assemble bicycles even before torque wrenches were common in bike mechanics' tool boxes. I don't mean to be snarky, but an exact torque specification may be less useful than a little common sense.

44-88 in-lbf works out to 5-10 NM. That's not a huge range: from as tight as a typical stem clamp bolt to twice as tight as a stem clamp bolt. Since chainring bolt threads (M8x0.75mm) are nearly twice the diameter of common stem clamp bolt threads (M5x0.8mm) you can be confident that 88 in-lbf is not excessively tight.

If you're uncomfortable with ambiguity and want a single number, try 7.5 NM (66 in-lbf). It'll be fine.

Alternatively, tighten your chainring bolts 'til they strip and then back 'em off a quarter-turn.

sp3000
Posts: 174
Joined: Thu Aug 21, 2014 7:12 am
Location: Sydney

by sp3000

SpecializedColnago wrote:Well the generic torque range for aluminum chainring bolts is 44-88 inch pounds so definitely a large disparage in torque there.


I have had a very bad experience using a torque wrench when tightening aluminium chainring bolts... mine were dura-ace 7800 bolts and before I even got close to the correct torque they bolts started to deform.. after having to drill them out and buy new bolts I learned my lesson.. from that day i never use a torque wrench on chainring bolts, they are too short and too soft so I find the best is by hand until they feel right (which is very easy to feel).

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