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FKS brake problem and a possible solution

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ponybloodbath
Posts: 22 - Karma: 40
Today i had an unfortunate attempt to bend my 115mm FKS brakes to 90mm, i was doing everything according to the video guide but the brakes snapped into pieces... bad luck i guess

my question is - Is it ok to cut the brakes at a reqired width and then tig weld them? a motorcycle mechanic actually suggested doing this, he said that the brake will be more firm and will hold better that after bending which decreases stiffness..
Jan 23 2014 1:51PM
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Huck_Norris
Posts: 11487 - Karma: 18,627
Well yes and no. It will be on there, but the quality of the weld will determine how well it stays on there. Also if it gets too hot you could melt your shit bad. On top of that there's a zone around the welds afterwards where it's more brittle. All things considered I'd leave welding it as a last ditch effort if I couldn't get other brakes.
Jan 23 2014 2:55PM
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ponybloodbath
Posts: 22 - Karma: 40
the weld is going to be really good and strong, done by an experienced mechanic, so i hope it will hold. Unfortunately welding seems to be my last chance as in my hometown there is no place to get other brakes for them. I will have them back tomorrow and will post some pictures if it's successful
Jan 23 2014 3:06PM
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ponybloodbath
Posts: 22 - Karma: 40
i really have no idea why the fuck those breaks broke during bending, first of all i tried it without heating, took it slow, but it snapped when i was finishing the "conversion". when i realised i fucked up, i decided to give it a try with heat. well, heating the brake made it a bit easier, but this time i believe i was kinda impatient.
Jan 23 2014 3:09PM
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MartianMan
Posts: 1101 - Karma: 2,099
Want to explain the significance of your username?
Jan 23 2014 3:26PM
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ponybloodbath
Posts: 22 - Karma: 40
nothing to explain really. when i was 14 this was my xbox live gamertag. didn't like undersized horses at that time. but of course now i'm thinking of changing my username to something with "$" and wu-tang

Jan 23 2014 3:37PM
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rozboon
Posts: 1642 - Karma: 868

Bending brakes is usually for making them larger, not smaller... when you shrink brakes it leaves them with horrendous long legs that are just begging to get caught up and broken.

Personally I would hit up Rossignol/your local shop and try to get some narrower brakes from them.

But failing that, sure, a good tig weld should be just as strong as the rest of the metal. Just remember that everything involved will get hot as f*ck so it may melt the feet of the brakes a bit. If you want to do it nicely, grind the 2 halves of the join for either a single or double V (so they're like \ / or > < ) so the weld doesn't sit proud.

Good luck finding out the metal involved so you can choose a filler rod though :/

Jan 23 2014 5:29PM
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zyzzbrah
Posts: 113 - Karma: 336
FKS have 90mm sized brakes don't they? why dont you just get those
Jan 23 2014 7:12PM
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Tucks
Posts: 2120 - Karma: 161
They likely broke because the new metal alloy they are using with the wider brakes is more brittle/less malleable then the skinny brakes of previous years.
Jan 23 2014 8:44PM
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ponybloodbath
Posts: 22 - Karma: 40
update
actually hit up guys at Rossi today and WOW the have a huge box at their main office in Moscow with FKS/Pivot turntables with brakes from 64-80 up to 130mm. The only downside is that they sell a pair for $100, but its actually better to pay once than ruin a pair of XXL brakes which you can sell/trade.

Nevertheless, the idea of welding is still in my head and we'll do it during the weekend i guess. never hurts to have some backup brakes
Jan 24 2014 5:10PM
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ponybloodbath
Posts: 22 - Karma: 40
2 rozboon

yeah man, i will suggest the tech guy what you've said, seems pretty logical

2 tucks

the alloy is now real shit if compared to the old ones. pardon my english, but i can describe it somewhat "cellular", as it looks like a sponge inside with little pores. actually i saw in some other thread that rossi are using some "white steel" for the new brakes which is really more brittle and can't stand bending, especially without heating
Jan 24 2014 5:16PM
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Tucks
Posts: 2120 - Karma: 161
That's what I said...?
Jan 25 2014 7:42PM
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ponybloodbath
Posts: 22 - Karma: 40
Click for larger image

well i guess it worked
Jan 26 2014 2:46PM
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ponybloodbath
Posts: 22 - Karma: 40
http://imgur.com/wBZ28Ad
Jan 26 2014 2:46PM
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