Dogbones - materials query

Right i need to raise the back end of my bike, coz of the underseat exhaust i have fitted. As wanna gonna make some new dog bones, but then i read some of the articles on how if they brake you might die, so i thought i'd buy them from a reputable source

however a freind has asked me whether i'd like to make them outta carbon fibre. Sounds like a stupid question, but i'd really like to make sure, but i'm right in thinking that the tensile strength of carbon fibre is gonna be better than the stuff suzuki make them out of??

Also, i think raising the back end by about 40mm is the normal? how much shorter should the new dogbones be from the standard 140mm ones, 100mm sounds too simple, when you consider the angles of the swing arm, shock etc, any help would be great

[glade]

carbon fibre may be better in tension, but only if the lay-up of the fibres is in the right direction. It may be worse in compression but a bottle of somerset's finest cider is stopping me figuring it out exactly.

Frankly there is no reason to use carbon for these parts. Weight saving will be negligible, cost/ease of manufacture excessive, and integrity of the component highly questionable for this application.

And no-one will see it anyway!

I'd stick with some grade of steel or a thoughtfully designed aluminium part.

Originally Posted by glade

I'd stick with some grade of steel or a thoughtfully designed aluminium part.

I'd stick to steel every time, and professionally made steel ones at that, from a reputable source. You really don't want this to happen because 18 months on I'm still feeling the pain








That's the result of badly made alloy dogbones breaking on a Bandit 600, I was lucky nothing was coming the other way as I slewed sideways across the road at 50mph before highsiding into a high grass bank on a Norfolk country lane. Don't muck about making your own, buy them from a firm who have a clue and insurance to back it up.

[glade]

that looks quite nasty!

Originally Posted by glade

that looks quite nasty!

Believe me, it was. I came off worse than the bike, which needed 20 quid spending to get it back to its, admittedly very shabby, former condition. I needed a month off work with a broken ankle and I still suffer the effects of it. I was only doing 50 as well, but 2 weeks previously had been doing this at Mallory Park on it.

[yorkie_chris]

If I was tempted to make my own I'd be using steel, probalby of fairly high carbon content.

yeah, i've kinda changed my mind, i'll just buy them, whats the highest you can rise it, i have a cbr600rr underseat exhaust and it rubs the rear tyre two's up even with the preload on full

Steel steel steel i wouldnt use alloy ones unless they where original ones steel has the best qualities for this imo alloy is to brittle and as happened there can just shear.

Gixer thous have alloy dogbones, never heard of them shearing.

As i said wouldnt have a problem with them if they where original equipment as they will have been subjected to rigorous testing but i wouldnt buy aftermarket alloy ones