BIKE RACKS AND CARRIERS FOR CARS MEGATHREAD - all questions asked and answered here

Dales Cannon

lightbrain about 4pm
Staff member
Always a good investment. Does my head in that some people think ugga duggas are good enough for bolts that will kill you...
Don't google that last sentence.
The 3/4" version says 65 - 450 Nm.
When I did the rotors on the gts I asked my mate at hsv what torque for the 6 pot claipers? One of the engineers gave me the whole 130Nm plus 75 degrees (ish, cannot remember) or vft.
 

Haakon

Keeps on digging
Don't google that last sentence.
The 3/4" version says 65 - 450 Nm.
When I did the rotors on the gts I asked my mate at hsv what torque for the 6 pot claipers? One of the engineers gave me the whole 130Nm plus 75 degrees (ish, cannot remember) or vft.
Assume those are one time use torque to yield bolts?
 

Dales Cannon

lightbrain about 4pm
Staff member
Assume those are one time use torque to yield bolts?
No.
Lots think/thought they were but the bolts were going through aluminium blocks which would yield earlier than the bolt. I did some calculations and the bolts were getting to less than 50% while tty is more like 70% and they don't really go to yield unless the bolts are made of really special shit. The engineer said they recommend replacing the bolts but that was just a precaution against poor practices and the bolts were just grade 12.9 cap heads. I think I put new bolts in but not sure. Bolt tension and pretension values are based on strict calcs. I have had to do quite a few over the years in vatprious duties.
 
Last edited:

Haakon

Keeps on digging
No.
Lots think/thought they were but the bolts were going through aluminium blocks which would yield earlier than the bolt. I did some calculations and the bolts were getting to less than 50% while tty is more like 70% and they don't really go to yield unless the bolts are made of really special shit. The engineer said they recommend replacing the bolts but that was just a precaution against poor practices and the bolts were just grade 12.9 cap heads. I think I put new bolts in but not sure. Bolt tension and pretension values are based on strict calcs. I have had to do quite a few over the years in vatprious duties.
Interesting, I don’t think I’ve seen bolts with a torque plus angle specification that are not TTY.
 

latheboy

Likes Dirt
Lots of head bolts now have torque "X" plus half turn.. you don't reuse them..
I have torque wrenches up to 3/4"
Dad has a 2" torque wrench that goes up to 1 million ( maybe) but it's 6 foot long and heavy.. it was for rock bolts in tunnels..
I rarely use them unless it's an engine but I have been doing it for a long time and understand.. my first comment wasn't so much about torque as the poor retention of spring washers..
Odd that Mr Suzuki would put them on a modern bike..
 

Dales Cannon

lightbrain about 4pm
Staff member
Lots of head bolts now have torque "X" plus half turn.. you don't reuse them..
I have torque wrenches up to 3/4"
Dad has a 2" torque wrench that goes up to 1 million ( maybe) but it's 6 foot long and heavy.. it was for rock bolts in tunnels..
I rarely use them unless it's an engine but I have been doing it for a long time and understand.. my first comment wasn't so much about torque as the poor retention of spring washers..
Odd that Mr Suzuki would put them on a modern bike..
 

takai

Eats Squid
Torque plus angle is torque to yield. It’s designed to get the bolt into elastic deformation consistently.

As for a spring washer, they aren’t about torque settings per se, but rather about vibration. That said it looks like you have nylocs on the bolts anyway which provides the same protection.

Also checking in on the multiple torque wrench crew (9 I think)
 

beeb

Dr. Beebenson, PhD HA, ST, Offset (hons)
Torque plus angle is torque to yield.
Nope. In certain applications and if designed that way, yes. But that doesn't mean all applications.

Various bolts in heavy vehicles have torque plus angle, and bolts are reusable (sometimes only a limited number of re-uses and bolts must be stamped to indicate re-use though). My (rough) understanding is the torque is to effectively 'seat' the bolt, and the angle to apply the specified tension to the bolt/stud hardware.

For a specific example - One set of engine head bolts has sequenced torque, then two stages of angle-torqueing - and bolts can be reused up to five times.
1678144576519.png


1678144606689.png


Talking about some pretty high-grade hardware in these instances though.
 

Sheepie

Likes Bikes
I don't think the argument is as much about correct torque as it is that spring washers do not do the job people expect them to do. The Bolt Science link that I posted earlier is but one that demonstrates that spring washers when under vibrational load are actually worse than not using them.
Here's a couple of videos as credible as your link showing the spring washers better than nothing? - all of these videos have a lot to be desired for using for actual proof.
Self Lock Vibration Test
Nord-Lock Wedge-Locking Washers - Junker Vibration Test


In terms of why we are talking torque, what started this was:

Notice OE don't use spring washers on their cars anywhere?
We did tests at work and they are crap .. correct torque and flange bolt/nuts are the way forward..
Now it's not wrong that correct torque (read clamp force), giving stretch to the bolt within the elastic range will resist loosening to vibration, getting into that range and not going over requires adequate tooling - the amount of people who I've seen put my racks together with 2 shifters is unsettling.

The fastener in question here is an anti-vibration hitch bolt, there is no nut, it threads through a plate fixed to the hitch insert bar (bottom rail). We were having issues with people having to re-tighten this multiple times, the addition of the spring washer stopped that completely. Even without doing the math, logically thinking, if the spring washer isn't permanently deformed into a flat washer when the fastener is removed, it must be adding spring load axially which by nature will help resist loosening, the nature of the washer gives a good visual indication as well for those without the tools (even if there are a surprising amount of torque wrenches in this particular forum).
 

takai

Eats Squid
Nope. In certain applications and if designed that way, yes. But that doesn't mean all applications.

Various bolts in heavy vehicles have torque plus angle, and bolts are reusable (sometimes only a limited number of re-uses and bolts must be stamped to indicate re-use though). My (rough) understanding is the torque is to effectively 'seat' the bolt, and the angle to apply the specified tension to the bolt/stud hardware.

For a specific example - One set of engine head bolts has sequenced torque, then two stages of angle-torqueing - and bolts can be reused up to five times.
View attachment 397613

View attachment 397614

Talking about some pretty high-grade hardware in these instances though.
Its still TTY, just lower in the plastic deformation zone and therefore they deem any residual strain in the bolt acceptable for a limited cycle period.
 

Dales Cannon

lightbrain about 4pm
Staff member
Keeping strictly on topic my favourite head bolt is the one that Porsche created for the 917. They found nothing off the shelf gave characteristics that maintained the right amount of stretch for aluminium and magnesium so fuck it let's make our own brew and bolts.

Most spring washers that are cookie cut out of steel are fucking useless. I prefer nylocs, thread locker, cig hot glue or a combination of these. Proper spring washers bite into the head of the bolt to stop it rotating backwards and loosening, the shit you get at bunnies or most bolt and nut shops deform when tightened and don't bite at all. But anyway who cares? As I said working out the correct pretension is a whole science in itself. Keeping that within limits that do not kill the bolt or assembly and doesn't come loose is sometimes tricky. I had to work out pretension on some rotating 'cylinders' that had fixed knives bolted onto them. Lots of stress fluctuations. Too low and the knives flew out and killed the operator, too tight and the knives flew out and killed the operator. In the end there was about 15Nm between the two! Packaging meant the bolt sizes and number were limited because then failure of the 'cylinders' became a real possibility.
 

beeb

Dr. Beebenson, PhD HA, ST, Offset (hons)
Its still TTY, just lower in the plastic deformation zone and therefore they deem any residual strain in the bolt acceptable for a limited cycle period.
Doesn't sound like TTY/plastic deformation to me (which implies permanent deformation even once the tension is removed per my understanding?). Sounds more like deep into the elastic deformation range, and limited uses/cycles to limit 'work hardening' or whatever the stretch version of that is...

NFI though - I obviously didn't design the engine, I was just the mug who was swinging on the 6-foot length of pipe trying to pull that final 90-deg angle-torque stage up.
 
Top