Allen bolt length

[Will1985]

I'm adjusting my position on my TT bike at the moment and I want to lower the armrests which can be done by taking out a type of spacer and changing a bolt.

As far as I can tell, the existing one is an M6 bolt (? same as headsets) with about 4cm between the bottom of the head and the end of the bolt which is not totally threaded all the way along.
On SJS I have found what I need, but it describes lots of different lengths: do they refer to the thread length or the entire bolt length?

 

[Landslide]

Either way of describing it would make sense to me. I'd suggest giving them a call.

 

[tyred]

It would usually refer to the length from under the head to the end of the bolt.

Can you not just cut yours to the correct length? Put a nut on it first and it will remake the threads after the cut.

 

[Will1985]

I could cut the bolt, but I want the option of going back to higher armrests.

 

[02GF74]

allen head, aka cap head lengths are described as being from the shoulder to the end - as you state.

now set screws are threaded all the way whearas bolts are not - bolts having a threaded section that is something like 2 1/2 times thread diameter so nearer the head there is a solid part; as you can imagine, this applies to longer lengths since a short bolt would appear identical to a set screw.

This applies to some allen head bolts; in other words you can buy fully thread long bolts or partly threaded.

 

[yenrod]

So, someone actually races round here and not just tours...