Crashbars

Sakura

Well Known and Active Forum User
Non-VOC Member
Hi all,
I have plenty of material to make up a stainless steel crashbar. My original intention was to use a 5/8" MS bar with s/s tube sleeves and s/s hex ends, threaded at each end only with hex tube supports bored through either side in the middle. The 5/8" MS bar is a close fit in the front UFM sidecar mounting.

On doing a bit of reading I am concerned that sliding down the road on it might bend the sidecar mounting. I understand that the proprietary bars have a linking stud in between two sides that gives a bit in impact. Anyone got details of this arrangement?
 

bmetcalf

Well Known and Active Forum User
VOC Member
My Britax-style crashbar is solid SS hex bar, turned down to leave hex's at each end, with a connecting stud through the S/C loop in front, probably made by Maughans. I have "tested" it twice, bought new studs from Vinparts, buffed out the gouges on the end, and reassembled. No damage to the loop. My testing speed was >50 mph each time. Renewing the steering head bearings and rebuilding the forks put a stop to my testing career, with no regrets.
 

b'knighted

Well Known and Active Forum User
VOC Member
I make crashbars by using M16 studding (sorry). I fit a suitable length with a stainless lock nut and plain washer either side of the sidecar mount. Stainless tubing clads the studding with a stainless domed nut on each end. Standard Vincent tools don't fit the nuts which I think are 22mm, but you don't have to do anything with it at the roadside. I figured that being studding, its core size would be adeaquate for normal strength without risking damage to the forging. I find the bars are useful as tie-down pionts for when the bike is on the bench as loops of strap or hooks crossed in front of the sidecar fitting give good triangulation. I also make 2x4 timber props which can be slid onto the crashbar. Get the right length and by tilting the bike it will swing into a vertical position . It is then easy to lift the bike onto one leg while the second is swung into place. This can hold the bike up while removing the front wheel and is easier to deploy than the front stand.
 

Sakura

Well Known and Active Forum User
Non-VOC Member
Hi,
16mm X 2mm (metric coarse) has a core of 13.5mm, roughly 17/32". I could turn the centre portion of my 5/8" MS bar down to this, or perhaps even 1/2", but does anyone know the dia. of the Vinparts, Maughan or other manufacturers centre stud?

I'm guessing they may use high tensile - my bar is mild steel. Any views on the material used?
 

bmetcalf

Well Known and Active Forum User
VOC Member
My bars are solid bar with female threads and all three pieces of the assembly are SS.

Carl Hungness has bored his out for wires to LED indicators let into the ends. If I had a lathe I might do it for the weight savings!
 

Sakura

Well Known and Active Forum User
Non-VOC Member
Hi Bruce,
Thanks for your responses. If the bars either side are solid with female threads they must be linked with the stud. Can you remember what size OD the stud is - 5/8, 1/2, 3/8?

Presumably the bars either side must have a spigot to locate in the bore of the sidecar mounting?
 

bmetcalf

Well Known and Active Forum User
VOC Member
The stud is a good fit in the loop and locates the assembly. Measure your loop ID and see what inch fraction is slightly less. Me remember? - LOL!
 

Sakura

Well Known and Active Forum User
Non-VOC Member
Thanks Bruce. That must mean the stud is 5/8".

From that I reckon that my use of 5/8" MS bar should allow sufficient "give" in the event of sliding contact with the road - unless, of course, somebody knows different?
 
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