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Mo Murphy



Member Since: 01 Jun 2008
Location: Letchworth Garden City, Herts
Posts: 2250
United Kingdom 1984 Defender 90 BMW M57 3.0 Diesel HT Auto Pennine Grey
custom90steve wrote:

In all honesty I wouldn't bother with the torque settings and use your own judgement.


You're not serious are you ?
Matt, torque to the specifications in the instructions, don't take chances with towing equipment.
Mo The Land Rover 90 - Many are called, few are chosen.

50 Shades of Pennine Grey
Post #318286 23rd Mar 2014 8:53am
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Matthew_Mills



Member Since: 16 Feb 2014
Location: Somerset
Posts: 152
England 
My wife says I have OCD... She's wrong of course I just like to do things properly, if I didn't I'd have someone else do it!

All torque setting followed...

If i do tow... They will be checked afterwards too...
Post #318367 23rd Mar 2014 2:01pm
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wildrover



Member Since: 09 Oct 2011
Location: Notts
Posts: 51
United Kingdom 
How much is that bumper and where did you buy it from.
Post #327700 1st May 2014 11:03pm
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RFT



Member Since: 13 Nov 2010
Location: Cheshire
Posts: 683
United Kingdom 2010 Defender 130 Puma 2.4 HCPU Zermatt Silver
Torque required to load a bolt increases significantly with bolt diameter, as there is a squared function since the load acts over the area. For M16 8.8 grade 240Nm seems sensible weareas for an M10 it may be 45Nm.

M16 bolts have 24mm AF heads and the spanners are significantly longer than the 17mm AF spanners required by an M10 bolt, there is a good reason why they are longer you need a lot more torque to tighten them.

But the lubrication and surface finish of the bolts & nuts is often overlooked, a phosphated bolt may only require 75% of the torque to provide the same residual bolt stress as a black bolt.

The joint design must also be taken into account, its the bolted joint subject to vibration, cyclic load, thermal cycling. is there sufficient bolt length to permit elongation and hence induce some elasticity into the joint design.

ok im boring myself now, in summary... for a pair of M16 8.8 grade bolts that are holding a hitch on to vehicle that may well be dragging 3.5Te of trailer with 175Kg of nose weight 240Nm seems correct, a recheck of torque after 1 month is also a good idea.

Good night

Richard 130 Puma HCPU with an Artica 240LR Demountable Camper

Last edited by RFT on 3rd May 2014 1:25pm. Edited 1 time in total
Post #327704 1st May 2014 11:54pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17478
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
RFT wrote:
M16 bolts have 25mm AF heads ....


24mm (not 25) for a standard ISO M16 hex head.
Post #327751 2nd May 2014 8:27am
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RFT



Member Since: 13 Nov 2010
Location: Cheshire
Posts: 683
United Kingdom 2010 Defender 130 Puma 2.4 HCPU Zermatt Silver
yes 24mm fat finger on key board syndrome 130 Puma HCPU with an Artica 240LR Demountable Camper
Post #328027 3rd May 2014 1:25pm
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