Torque 5nm vs 6nm

[Daos]

Hi,
Decided to start a bit of diy and I'm planning to buy a torque wrench. I've got a bike with an aluminium frame and carbon fork. The bolt on the stem is rated at 5nm whilst the seatpost is rated at 6nm.
Do I need an adjustable wrench, or would a 5nm fixed wrench be enough?
I'm trying to decide between these 2:
http://www.wiggle.co.uk/lifeline-essential-mini-torque-wrench/
http://www.wiggle.co.uk/lifeline-essential-torque-wrench-set/
I've seen some recommendation for torqing a bolt to a slightly lower value than it's rated at (eg 4.5 instead of 5), but not sure if 5 would be enough for a 6nm seatpost.

My concern with an adjustable torque would be how well is it calibrated and that's why I'm wondering if I would be better off with a fixed torque wrench (and save some money). At the same time, would I really miss an adjustable wrench, any other specific use for it?

 

[Yellow Saddle]

Just get the fixed one and add a little when doing the 6NM bolt. But don't under torque it, stick to the recommendation. The necessary safety margins are already built in. It is not like the not-so-tech-savvy bike consumer can be trusted to compensate for things like that.

 

[themosquitoking]

http://www.aliexpress.com/item/Pion...-3-500-Nm-023-001/32331462233.html#magnet-ads
Something like that doesn't need resetting back to zero after use like an adjustable torque wrench and gives you any torque measurement you want.

 

[Deleted member 1258]

I've got one of these

https://www.giant-bicycles.com/en-gb/gear/product/giant.tool.shed.torque.wrench/589/38792/

 

[themosquitoking]

the interests of disclosure i have something similar also but i saw one of the things i posted earlier at an lbs and wished i had one of those instead.

 

[slowmotion]

Get one of these.....
http://www.pvrdirect.co.uk/products...rometer-Style-3-8Sq-Drive-2-24Nm-147-1770lbft

You can buy a set of hex bits to suit it for under a tenner on Ebay.

 

[Daos]

Thank you very much for all recommendations, it is amazing how fast you can get a bit of advice here, much appreciated!
Meanwhile I had a look at my older MTB and it's stem has a 8nm bolt.... guess I'll end up needing an adjustable wrench...?

I've also found this Topeak at a reasonable price:
http://www.evanscycles.com/products/topeak/combo-torq-wrench-set-3-12-nm-ec049347
Would it be any good? I'm considering the Topeak versus the Sealey STW1012 and the LifeLine Essential Torque Wrench Set on wiggle (both around 30 but the LifeLine comes with bits included).

 

[Smurfy]

My concern with an adjustable torque would be how well is it calibrated

In a proper engineering fitting shop, no one uses the dial on the torque wrench. The wrench will always be set using a separate instrument, which is regularly calibrated by an external provider.

Having said that, none of my bikes have any carbon components, and I don't bother with a torque wrench, apart from the crank bolts, as that is within range for the one I use on my car.

 

[Milkfloat]

I've got one of these

https://www.giant-bicycles.com/en-gb/gear/product/giant.tool.shed.torque.wrench/589/38792/

I have the same but with the original branding and half the cost.

http://www.bike-discount.de/en/buy/mighty-torque-wrench-set-2-24-nm-incl.-7-bits-30385

 

[Sittingduck]

Don't over-do the seatpost bolt. Easily done and they require less torque than you may think. If doing by feel,anyway.

 

[raleighnut]

A lot of the time it depends what material the bolt is screwed into, you'll strip the threads in aluminium before the steel bolt snaps so the torque figures for a 5mm bolt and a 6mm bolt won't be that different.

 

[Old jon]

Have to agree with Yellow Tim, torque wrenches need calibrating regularly. Mine was bought with a calibration certificate, so was expensive. Peace of mind is worth the money IMHO