gschreckchat@comcast.net

I tend to thnk the stresses are less than clamping a front wheel in the fork and having a 180 pound rider riding on it at high speeds on corners and hitting bumps in the road. In a rack, there in no weight on the frame and fork, there are no sharp impacts (unless it is contact with your garage), and the side to side loads are less than cornering with a wheel clamped in it. I suspect it was a part that was gonig to fail anyway, and you were lucky enough for it to occur when you were not on the bike.

--

George Schreck
gschreckchat@comcast.net
(503) 502-0425

-------------- Original message --------------
From: Andrew Hayes

> While zipping along I-84 on the way in to PIR this afternoon my bike almost flew
> off the top of my car. One of the front dropouts on the carbon forks ripped in
> half and the front of the bike flew off the Thule roof rack. The only thing
> preventing it from falling onto the highway was the rear tire plastic tie-down
> ratchet. End result: a bike dangling on the side of the car; one broken and
> bent Thule carrier; one broken Cannondale Super Six carbon front fork; and a
> fairly scratched and dinged car. It could have been much worse; but it still
> wasn’t pleasant (or cheap).
>
> I’m no carbon expert; but I think that front fork roof rack design isn’t
> very carbon friendly. It places a huge side load on the dropouts; so as the bike
> wiggles back and forth in the wind it stresses your poor dropouts. The end
> result: snap! It’s possible that when I clamped down the fork quick release
> system bolts didn’t grab both sides of the dropouts evenly; or that perhaps it
> wasn’t properly seated in the past and caused unseen damage. (I'm skeptical,
> however!) Whatever the cause, I thought it wise to warn OBRA folks that the
> combination of fork mount roof rack and carbon bike needs some special attention
> to make sure you don't suffer the same fate as me.
>
> I ended up replacing the damaged rack with a side-arm style system; and the bike
> was noticeably more stable in the windy gorge on the drive home this evening.
> _______________________________________________
> OBRA mailing list
> obra@list.obra.org
> http://list.obra.org/mailman/listinfo/obra
> Unsubscribe: obra-unsubscribe@list.obra.org

Dan H

I'm skeptical the rack caused the fork to fail. I've used that system with
carbon forks a lot working the NRC circuit and driving hard with bikes on
the roof.
I used to sell a lot of roof racks and I have often observed people loosen
the binder and tip the bike sideways to get a grip on it instead of lifting
the fork straight up. I have seen steel and aluminum fork ends bent in this
way and always the user is mystified as to why this happened.
Another thing to look out for is lawyers nubs. If the fork is not seated all
the way into the binder, the lawyers nubs will get pinched and put a great
deal of side load on the fork ends.
I have also heard of locked bikes on roof racks that have been stolen when
the thief simply snapped the fork ends off.
I believe fork binder type roof racks are perfectly safe when used properly.
Even though you had tense moments and some damage, you could have going down
German Town when the fork failed. That's another reason to clean your bike
often because in doing so, you will look at and touch every part of your
bike.
Recently I had a customer ask me "what's the worst thing that could happen
if my (cross threaded) pedal fell off?" I said, "you could die".
Be safe out there.

----- Original Message -----
From: "Andrew Hayes"
To:
Sent: Tuesday, July 15, 2008 10:48 PM
Subject: [OBRA Chat] Front fork mount bike rack warning!

> While zipping along I-84 on the way in to PIR this afternoon my bike
> almost flew off the top of my car. One of the front dropouts on the carbon
> forks ripped in half and the front of the bike flew off the Thule roof
> rack. The only thing preventing it from falling onto the highway was the
> rear tire plastic tie-down ratchet. End result: a bike dangling on the
> side of the car; one broken and bent Thule carrier; one broken Cannondale
> Super Six carbon front fork; and a fairly scratched and dinged car. It
> could have been much worse; but it still wasn’t pleasant (or cheap).
>
> I’m no carbon expert; but I think that front fork roof rack design isn’t
> very carbon friendly. It places a huge side load on the dropouts; so as
> the bike wiggles back and forth in the wind it stresses your poor
> dropouts. The end result: snap! It’s possible that when I clamped down the
> fork quick release system bolts didn’t grab both sides of the dropouts
> evenly; or that perhaps it wasn’t properly seated in the past and caused
> unseen damage. (I'm skeptical, however!) Whatever the cause, I thought it
> wise to warn OBRA folks that the combination of fork mount roof rack and
> carbon bike needs some special attention to make sure you don't suffer the
> same fate as me.
>
> I ended up replacing the damaged rack with a side-arm style system; and
> the bike was noticeably more stable in the windy gorge on the drive home
> this evening.
> _______________________________________________
> OBRA mailing list
> obra@list.obra.org
> http://list.obra.org/mailman/listinfo/obra
> Unsubscribe: obra-unsubscribe@list.obra.org
>

Andrew Hayes

While zipping along I-84 on the way in to PIR this afternoon my bike almost flew off the top of my car. One of the front dropouts on the carbon forks ripped in half and the front of the bike flew off the Thule roof rack. The only thing preventing it from falling onto the highway was the rear tire plastic tie-down ratchet. End result: a bike dangling on the side of the car; one broken and bent Thule carrier; one broken Cannondale Super Six carbon front fork; and a fairly scratched and dinged car. It could have been much worse; but it still wasn’t pleasant (or cheap).

I’m no carbon expert; but I think that front fork roof rack design isn’t very carbon friendly. It places a huge side load on the dropouts; so as the bike wiggles back and forth in the wind it stresses your poor dropouts. The end result: snap! It’s possible that when I clamped down the fork quick release system bolts didn’t grab both sides of the dropouts evenly; or that perhaps it wasn’t properly seated in the past and caused unseen damage. (I'm skeptical, however!) Whatever the cause, I thought it wise to warn OBRA folks that the combination of fork mount roof rack and carbon bike needs some special attention to make sure you don't suffer the same fate as me.

I ended up replacing the damaged rack with a side-arm style system; and the bike was noticeably more stable in the windy gorge on the drive home this evening.