Hanging my bike by the front wheel - OK for the carbon fork?

craker

Due to the increasing number of bikes in my shed, I'm now hanging them from a rafter on the roof. Is it OK to do this with a carbon forked bike by the front wheel? The strain is 90 degrees out from what it is designed for.

dennisn

If you have that little faith in a carbon fork maybe you shouldn't be riding one.

Dennis Noward

carlstone

I should hope so. My bikes all carbon fibre, I'm over 15 stone and regularly hurtle down hills at around 40mph trying to miss MOST of the potholes. I'm sure there is some engineering type who will work out what forces are acting on the fork in all sorts of directions at thet speed, so 18lb of static force will not be a problem.

By the way, thats how I store my Planet X when I take it to work, on the office wall behind me.

Gerry Attrick

Whoa! Steady on Mr Si, Dennis. There are lots of questions people want to ask but may be afraid of a "heavy" response. The only way anyone learns is by asking others with more experience. Let us encourage that.

dennisn

Gerry Attrick wrote:

Whoa! Steady on Mr Si, Dennis. There are lots of questions people want to ask but may be afraid of a "heavy" response. The only way anyone learns is by asking others with more experience. Let us encourage that.

I meant it more as a sort of "you need more faith in your bike" type of statement.
Not trying to be an a**hole but sometimes I let it get away from me.

Dennis Noward

JWSurrey

Well, it is an interesting point.
I cannot see a way that a similar tension force across the entire fork could be induced by normal riding.

Couple that with various "health and safety" style notices that state a carbon forked bike should not be transported in a carrier which locks the bike down using the drop-outs due to the unusual stresses induced, and there could be a point in this.

I would hazard a guess these are just product liability style statements as I've not come across anyone who has had a dropout fail on them, and drop-out whilst they're onboard.

The dropouts appear to me, to be designed to take a compressive load - If I'm right, it's inserted in to the end of the carbon fork, and glued in to place (maybe it's bonded).

Personally, it wouldn't bother me, however I am considering storing mine the right way up on the roof, using plastic coated hooks - One under the saddle and one under the bars.

ademort

Hi we have had this discussion before,its fine to hang your bike by the front wheel or back wheel, it could never damage the carbon fork.Think about it logically for a moment, when you ride your bike it supports your weight without any problem, say minimal 70 kilos and maybe more. Lets say your bike weight is 10 kilos then when you hang your bike up it supports the full 10 kilos then its obvious that it cannot do any harm at all.I have one carbon and two alu bikes and hang them all from hooks on the roof in the shed without any problem. There is really no argument over this subject. If carbon was as brittle as many people seem to believe then the frame would fall to bits as soon as you went over your first large bump in the road or pothole. Ademort

craker

Yeah - I know it must be OK just didn't want to make a silly mistake Like overtightening a carbon stem - easy to do, and after all it 'must be strong enough' however you're applying a stress in a way it wasn't designed to withstand...

ademort

Yes ok, but in this case the stress is minimal, If in doubt just picture carl stone, weight 15 stone flying down a hill at 40mph on an all carbon bike, in short just have faith in your bike and a little bit of confidence building might not go amiss. I wonder if you have ever ridden your bike at speed down a hill, if you have not then go and do it. It will do wonders for your confidence, just remember it is carbon not paper.Ademort

craker

ademort wrote:

I wonder if you have ever ridden your bike at speed down a hill, if you have not then go and do it. It will do wonders for your confidence, just remember it is carbon not paper.

Oh yes - did 50 on it for the first time a few weeks ago. Confident? By the time I slowed down to more normal speeds (30 something) I had an ear to ear grin all over my face.

I built the bike myself, tightened the stem without a torque wrench and when you've got your head down at silly speeds the thought does flit through one's mind. All the road vibration really flexes the forks at that speed.

ademort

Bloody hell, i am jealous, i live in Holland and its ages since i ridden at 50mph as our only hill is about 200km away and i have not been that far south yet.I have ridden at 50kmh on many occasion.

hamstercp

JWSurrey wrote:

various "health and safety" style notices that state a carbon forked bike should not be transported in a carrier which locks the bike down using the drop-outs due to the unusual stresses induced, and there could be a point in this.

I think it's that some badly-designed carriers push the fork blades together rather than squeeze each dropout (like a hub does) - that could certainly crush a carbon fork and wouldn't be exactly a great idea on any fork.

dennisn

I think I said something like this in another topic but it bears repeating.
Every year some friends and myself make the 24 hour, each way, drive to the
Rocky Mountains for the Bicycle Tour of Colorado. We have a standard
front fork clamp bike carrier and all ride different bikes, steel, carbon,
aluminum, & titanium. No problems with any front forks.

Dennis Noward

SteveR_100Milers

mr_si wrote:

Due to the increasing number of bikes in my shed, I'm now hanging them from a rafter on the roof. Is it OK to do this with a carbon forked bike by the front wheel? The strain is 90 degrees out from what it is designed for.

Has it broken or cracked? No? then its fine. You really have to go some to break CF, so long as the part is properly designed and manufactured. I'll bet you could hang from your bike and you won't break them. Given the wide range oif forces that bicyle front forks are subject to, there is probably a high degree of isotropy in the mechanical properties for obvious safety reasons (consider the litigous USA market for example).

JWSurrey

Dennisn - Thanks for the "real world test result" - That's good news to hear.
I think some posters are missing the point - It's not the carbon that's the problem - It's the fact that a lot of carbon forks have a metal dropout inserted in to the end of the carbon fork - This item will, under normal riding conditions, be loaded in such a way as to force it further in to the carbon fork:
What we're talking about here is the equivalent of a load trying to pull the dropout from the fork.
If you want an exaggerated example, you can haul a supertanker with a tug rope, but you can't push it with the same rope!

Anyhow, I think the point has been answered most usefully by Dennisn - If a bike can survive a long road trip in the rockies, where the rocking action and lateral forces induce a more signifcant tensile dynamic load on the dropout, then hanging the bike should be fine.