Bikeguide.org - Bike maintenance for BMX'ers

The Street => The Bike Shop => Topic started by: Radix on January 21, 2016, 05:59:59 AM

Title: Recommended Torque Settings
Post by: Radix on January 21, 2016, 05:59:59 AM
Hi there,

I've just brought my first bike in many moons and am about to build it up, and want to do it properly. I can't seem to find anywhere that has recommended torque settings for the various bolts on a BMX.

If any of you guys are as OCD as I am apparently being with this new bike, any tips would be sincerely appreciated. In particular I want to get the stem bolts right, as I always used to have issues with slipping bars, and this is back when the biggest bars available were 8.25", so far less leverage than the 10" behemoths I'm putting on my new build. However, on the flipside - I once snapped a stem bolt by over tightening...

Whilst I'm on the topic of slipping bars, do any of you guys use this stuff:

http://www.chainreactioncycles.com/finish-line-fiber-grip-assembly-gel/rp-prod30012

A friend of mine recommended it to help stop the bars slipping, but I'm somewhat cynical, as it's meant for carbon, not steel.
Title: Re: Recommended Torque Settings
Post by: Stoked on January 21, 2016, 06:34:45 AM
Where's BPN when you need him?
Title: Re: Recommended Torque Settings
Post by: Sasha on January 21, 2016, 12:39:43 PM
The carbon paste has little bits of grit in to help grip things like carbon posts and handlebars when your max torque is something low like 4Nm. A well knurled set of BMX bars in a decent stem shouldn't need it. I saw on the Eclat website a while back that they recommend tightening one of their stems to about 39Nm, which I think is excessive. Cranks and pedals should be 40Nm, a BMX stem can probably be about 12-15Nm.
Title: Re: Recommended Torque Settings
Post by: dude... on January 21, 2016, 05:49:00 PM
my odyssey brake lever has a sticker saying the torque rating is 4nm, i dont think ive ever seen another bmx part where this info is provided
Title: Re: Recommended Torque Settings
Post by: Radix on January 21, 2016, 06:13:02 PM
Cool, cheers for the input guys. 12-15Nm sounds good, 39Nm sounds nuts ('cuse the pun!).
Title: Re: Recommended Torque Settings
Post by: Radix on January 22, 2016, 05:11:38 AM
How about the bolt on top of the forks to tighten the headset?
Title: Re: Recommended Torque Settings
Post by: amishrob on January 23, 2016, 02:17:03 AM
How about the bolt on top of the forks to tighten the headset?
no torque setting as it's only used to preload the bearings. it shouldn't need much.
Title: Re: Recommended Torque Settings
Post by: Radix on January 24, 2016, 03:33:43 PM
How about the bolt on top of the forks to tighten the headset?
no torque setting as it's only used to preload the bearings. it shouldn't need much.

Cool - thanks. And how about the wheel axle bolts? In particular female hubs.
Title: Re: Recommended Torque Settings
Post by: Sasha on January 26, 2016, 03:25:22 PM
You can go to town on wheel bolts. 40Nm should suffice though.
Title: Re: Recommended Torque Settings
Post by: Radix on January 26, 2016, 07:24:43 PM
Nice one - thanks everyone  :)

Finally got my bike built up today. Guess I should do a bike check now....  ;D
Title: Re: Recommended Torque Settings
Post by: jonathan on January 27, 2016, 11:43:09 AM
in my time working on bikes in shops, I used a torque wrench a LOT. on a bmx bike though, most of the bolts are so big and the forces put on them so extreme that I don't see the point. I think rear 3/8" axle nuts on a "regular" bike is 20 foot-pounds, but I would definitely put a lot more into it on a bmx bike. 99% of the stuff I worked on was road and mtn bikes that have tiny 4m bolts holding everything together that will strip if you're not careful and precise and threaded bottom brackets with JIS tapered cranks and chainring bolts that will come loose if you don't tighten then enough (which it seems most people don't). I would not get too hung up over accidentally over-tightening anything on your BMX bike.