Northy
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| posted on 1/1/05 at 11:27 AM |
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Only lasted 500 bloody miles.....
Well, the Cortina cycle wing brackets I got from Lolocost have only lasted 500 bloody miles (I've attached a picture). It's craked where I
would expect it to, on the edge of the weld, is this know as a stress raiser?
Anyway, anyone any good ideas how to fix it? I don't want to have to re-make the whole things really. I was already planning a brace between the
two parts of the upright.
Cheers
 
Rescued attachment Cracked cycle wing bracket.jpg
Graham
Website under construction. Help greatfully received as I don't really know what I'm doing! 
"If a man says something in the woods and there are no women there, is he still wrong?"
Built 2L 8 Valve Vx Powered Avon
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marc n
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| posted on 1/1/05 at 11:44 AM |
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have a look at the way we made ours they are made from 19mm x 1.5mm tube and are bent in our tube bender.
these are indistructable ( tested removing cones and markers around various circuits ) 
bust 5 sets of arches 0 cycle wing brackets
have a look under bodywork section on the web
regards
marc
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Alan_Thomas
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| posted on 1/1/05 at 11:53 AM |
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Mine failed in exactly the same place plus the guards were bouncing around all over the place which is probably what caused the failure.
I rewelded the fracture then bent another strip of 3mm steel to 'double up' the entire strip. T weld this to the original around all the
edges and have now done over 2k miles without further problems. The guards are now rock steady as well!
- Alan
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Ben_Copeland
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| posted on 1/1/05 at 12:01 PM |
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It never sease's to amaze me at the quality of lolocost's products  
Quick and easy method is to do what Alan said. Reweld with more metal on
Ben
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Dave Ashurst
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| posted on 1/1/05 at 12:13 PM |
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Hi Northy
It is a very common failure, and yes, it is a stress raiser of course, and a bad fatigue detail. Any place where there is an abrupt change in section
in a loaded member is a stress raiser. Add a weld at that point and you have a built in thermal weld stress too, plus the possibility off micro
cracking just to get things started!
You need to smooth the transitions in the load path. Bracing isn't the issue really unless you've got something very clever in mind.
Mine was a recurring problem until I got down to it properly. I welded an extra 3mm thick narrow strip on top of the flat strip on mine, following
the curve and butted up to the rod. Tapered in thickness is OK, thinnest at the wing end, as thick as the rod at the other. Sort of like a fishing
rod, but stiffer!
Do a full penetration butt weld to repair the cracked part before adding the section thickness with fillet welds.
The grip end of the rod is a bad fatige detail too, i.e. where it's welded to the plate bolted to the upright. The plate needs to be thicker
between those welds and the bolts. The plate WILL crack eventually unless you deal with it.
The last fatigue detail in the load path is the bolts themselves at the upright. If you used locknuts to space the wingstay plate off the upright,
then sooner or later the mounting bolts will crack! Mine broke a couple of times until I used crush tubes cut to length as spacers. They increase
bending stiffness and importantly hold the bolts in direct tension. No more broken bolts.
hope that helps
Dave
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Northy
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| posted on 1/1/05 at 12:21 PM |
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Er cheers Dave,
I didn't really take that in, perhaps the few shandys I had last night are clouding my thoughs?
Any chance of a picture? Are you using the Lolocost jobbies then?
Cheers
Graham
Website under construction. Help greatfully received as I don't really know what I'm doing!
"If a man says something in the woods and there are no women there, is he still wrong?"
Built 2L 8 Valve Vx Powered Avon
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Jon Ison
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| posted on 1/1/05 at 12:29 PM |
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if you aint allready done it i cured mine by bracing the two arms togethor with a piece of flat bar drilled to allow the top ball joint to pass thru
it so it was clamped in that area, does that make any sense ? prob not.
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JoelP
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| posted on 1/1/05 at 12:43 PM |
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i started making mine yesterday. im using 25x3mm bar. So far, i've got a bit with a hole in the middle, that will bolt under the clamp at the
top of the strut. Bent forward at the top and backward at the bottom, i plan to have another piece under the steering rod to support the front, and a
piece coming back and up from the bottom balljoint nut to support the back part. Main problem im having is making sure that nothing hits the wishbone
or brake flexi when at lock.
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Mark Allanson
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| posted on 1/1/05 at 01:55 PM |
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I have used 13mmx1.6mm round and square erw, I have removed all the stress from the steel and moved it to the GRP, this may fail instead, but I think
it is worth a try, I may even add transverse braces.
 
Rescued attachment ModCycleWings.jpg
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Dave Ashurst
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| posted on 1/1/05 at 10:02 PM |
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quote:
Er cheers Dave,
I didn't really take that in, perhaps the few shandys I had last night are clouding my thoughs?
Any chance of a picture? Are you using the Lolocost jobbies then?
Cheers
Doh! My fault. Too many shandies here too!
Anyway, I did the same as Alan Thomas. It works well.
I was also trying to say that more cracking came later on. It took a while to realise why it was getting wobbly again. The wingstay baseplate
cracked repeatedly and so did the bolts where it's fixed to the cortina upright.
Mine aren't Lolocost jobbies I think, but they are almost identical, bought from another locost parts maker at a show about 3 years ago. This
is what they were like new (pic below), do they look like yours?:
I'll try to remember to make them pretty and take a new photo later.
Dave
[Edited on 1/1/05 by Dave Ashurst]Image deleted by owner
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Northy
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| posted on 1/1/05 at 10:11 PM |
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Cheers Dave
They look identical to my Lolocost jobbies. Tempted by some MNR ones, but I think I'll have to fix these ones really!
Graham
Website under construction. Help greatfully received as I don't really know what I'm doing!
"If a man says something in the woods and there are no women there, is he still wrong?"
Built 2L 8 Valve Vx Powered Avon
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Dave Ashurst
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| posted on 1/1/05 at 10:11 PM |
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does this help?
Image deleted by owner
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Dave Ashurst
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| posted on 1/1/05 at 10:13 PM |
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notice the bent bits
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Northy
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| posted on 1/1/05 at 10:19 PM |
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Now I see what you mean, and re reading your earlier post now makes sense!
So smooth transitions is the future, not garlic bread! (Guess what I'm watching)
Cheers
Graham
Website under construction. Help greatfully received as I don't really know what I'm doing!
"If a man says something in the woods and there are no women there, is he still wrong?"
Built 2L 8 Valve Vx Powered Avon
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Stu16v
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| posted on 3/1/05 at 10:32 PM |
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quote:
not garlic bread!
So this isn't the future then?
[Edited on 3/1/05 by Stu16v]
Dont just build it.....make it!
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Northy
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| posted on 3/1/05 at 11:16 PM |
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Nope, it's "everything under one roof!"
Graham
Website under construction. Help greatfully received as I don't really know what I'm doing!
"If a man says something in the woods and there are no women there, is he still wrong?"
Built 2L 8 Valve Vx Powered Avon
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Humbug
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| posted on 5/7/05 at 09:43 PM |
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quote:
Mine aren't Lolocost jobbies I think, but they are almost identical...
Oh bum! - mine look the same as these and are fixed with bolts onto the upright the same way. Also, they do seem a bit wobbly
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JoelP
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| posted on 5/7/05 at 09:55 PM |
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a stitch in time...
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Mark Allanson
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| posted on 5/7/05 at 10:55 PM |
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I have 900 miles and not even a stress crack!
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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NS Dev
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| posted on 6/7/05 at 08:47 AM |
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Mine are from Stuart Taylor and are the same as the ones that Dave Ashurst pictured.
Think I may get on the phone to MNR as I cannot be bothered to make some (no time!!!)
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splitrivet
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| posted on 6/7/05 at 09:01 AM |
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Made mine from tube as well photo in archive.I would think using flat is a recipe for disaster due to the stresses put on it its bound to flex and
lead to cracks.
Cheers,
Bob
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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rusty nuts
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| posted on 6/7/05 at 05:33 PM |
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Got mine from Luego , lasted about 500 miles before one broke luckily I didn't lose the wing. Have reinforced with heavier gauge steel now seem
a lot more solid , time will tell
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RoadkillUK
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| posted on 6/7/05 at 06:53 PM |
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Mine are from lolocost, mine have done approx. 4000 bumpy miles and are as strong as ever.
I'll let you know when/if they fail.
Roadkill - Lee
www.bradford7.co.uk
Latest Picture (14 Sept 2014)
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