My IP-057 project

[Carbon_Dude]

So far I've seen people post way more Chinese rigid fork failures than frame failures. Contact Bert at xMI play and see what he will do for you.  However I think I would be considering a Niner fork as a replacement, I haven't seen anyone post about breaking one of those.

[RS VR6]

Jenson has the Niner forks on sale for 250. QR only.

http://www.jensonusa.com/Niner-Carbon-Rigid-29-Fork

[IoC]

Jenson has the Niner forks on sale for 250. QR only.

The Niner "RDO" version has 15mm through-axle. On sale for $299....I may have to make my wife mad at me, because this'd let me change my bike to a 19lb gravel racer.

http://www.jensonusa.com/Niner-RDO-Carbon-29-Fork

[IoC]

Only thing that is a little annoying is the internal cable routing (which was much easier to do than I expected) is setup backwards for us aussie builders.  The runs are to suit left hand drive countries where the brake levers are on the wrong sides. But it does work out ok.

I believe with Shimano hydros you can just disconnect the brake lines from the levers and reconnect each to the opposite lever.

[timwa]

Hi guys, thanks for the responses.  Rock - this did all just happen from slamming the brakes - I did not hit anything.  I was riding on smooth road at the time so was really nothing to hit.

And having a good look at the failure points this morning, I would say what has happened is the left leg broke first upon the heavy brake application, and after it has failed the resulting twist right leg has caused it to fracture at the top.  If you understand loads and breaking forces, you can see that the failure mode of the right leg is due to twisting, not bending. The shape of the fracture reveals this.

It did all happen fairly quickly tho.

Tim

[timwa]

The Niner "RDO" version has 15mm through-axle. On sale for $299....I may have to make my wife mad at me, because this'd let me change my bike to a 19lb gravel racer.

http://www.jensonusa.com/Niner-RDO-Carbon-29-Fork

Thanks for this link - I will have to give this some serious thought.  A question tho.  The specs say suits rotors up to 185mm.  Right now I run 203mm brake rotors, fitted with the 203mm caliper relocation mount.  Any reason this size wont fit the niner forks?

Thanks again.

[Carbon_Dude]

I would think you would just need the proper caliper spacer for the rotor.  I'd be surprised if you did not already have the spacer on the old fork as most are designed for 160mm rotor and to go larger you always need a spacer.

[timwa]

Hi Carbon_Dude.  Yes I know the forks are designed for 160mm and you need the spacer to get to 203mm which I am already using.  But given that, why have niner then put on a limit of 185mm?  Are the 203mm too powerful for the forks? Or is there another reason?

[Cnasta]

Now this is something I'd rather not have seen If you can get this riding on tarmac with 20km/h, imagine what happens when doing 50km/h on a rooty forest descent.... Hope my fork is better build and this is a exception.

At least you're not hurt, this could have gone really bad easily

[timwa]

Agree Cnasta - I have already had a worry about this as well.  I am trying to decide if maybe I should pay the extra for a name brand for the all important forks.

[Carbon_Dude]

Hi Carbon_Dude.  Yes I know the forks are designed for 160mm and you need the spacer to get to 203mm which I am already using.  But given that, why have niner then put on a limit of 185mm?  Are the 203mm too powerful for the forks? Or is there another reason?

Possibly Niner wants to limit the torque load on the fork to what a 180mm rotor can impart to the leg of the fork.  Having the larger 203mm rotor may have contributed to your initial failure.

[timwa]

Yeah - that's what I am worried about ....

[Patrick C.]

Wow, 203 mm rotor on a city bike?  I use a 160 for cross county and rough trails, and never thought I needed more braking power (more skill, maybe:)).  I also wonder if the fork would have held up with a smaller rotor.

[MTNRCKT]

Wow, 203 mm rotor on a city bike?  I use a 160 for cross county and rough trails, and never thought I needed more braking power (more skill, maybe:)).  I also wonder if the fork would have held up with a smaller rotor.

I'm sure it contributed. If Niner wants to limit rotor size to 185mm on their forks to reduce torque load (assuming that is their intentions) than I can only assume the same guidelines should be followed for a chiner carbon fork. Not saying it shouldn't be able to withstand that - I'm really not sure - just saying I feel confident it played a role in the failure.

[timwa]

When I bought the chiner fork I did check the add copy to see if there were any limitations and none were stated.  But yes, I do now wonder about the big rotor.

And I like big brakes for city riding because city drivers are crazy!