Carbon Fibre Handle

Thanks to the efforts of Scott Wallis, i now have a Carbon Fibre handle. It is a prototype he made for me to test. It is a molded carbon fiber and Kevlar reinforced polyurethane handle. It has almost no flex and is VERY strong. He has molded it out a little bit for more finger space, and it works very nicely, and I still testing it, but as of now there are no flaws i can think of
With this you get the sleekness of a miyata and the comfort of a reeder!



here is a link to some pics


Very nice…scrumptious. Fruity even. This should be on RSU. How much did it cost to make?


I am playing around with shapes and materials and gave Scott the handle to try out. I am not making them to sell right now as they have not been tested long enough. The shape will change a little more also.
I am glad you found it flavorful.:slight_smile:

Scott Wallis

pretty nice handle!
I had contemplated building a c/f handle as well, but had not thought of using Kevlar. Are you concerned about the handle fracturing on impact? (Despite its great structural strength, c/f composites do seem to have a problem with that.)

Have fun.

You are correct, and that is why I didn’t make one until I came up with this “hybrid” design. This handle is not a typical composite laminate part in that it is really a pressure cast part with fiber reinforcement in the thin, high stress areas. I used an extremely tough (and expensive) polyurethane resin rather than the epoxy resin matrix you would normally find in a carbon fiber part. I rode with a cast, unreinforced version using this resin on my muni for 2 months until it finally broke, then added the fiber on the next one based on the failure. The Kevlar insures that even if the resin and CF failed from impact, the part would not separate because of the extreme flexibility and tensile strength of Kevlar.
But, as I said I am still experimenting and testing. Thanks for the comments.

Scott Wallis

Just one question … with the handle big enough to get your fingers through past the nuckles is there a danger that your fingers could get trapped and broken during a UPD ??

I have been told that that is the case with the old DM metal handles.

My hands and knuckles are bigger than Kid Scott’s, so they don’t go through that far. Also, when gripping you do not wrap your fingers nearly that far around so it would have to be the result of some pretty extreme contortions for it to happen.
That’s why I gave it to Scott to test. :astonished:

Cool. Looking forward to you sharing your experience (and maybe eventually posting some details on your design [materials, curing times, temps, etc] and/or making your handle available for sale).

Have fun,

As I understand it Aramid or ‘Kevlar’ isn’t as stiff as Carbon, but much more abrasion resistant. The Aramid fibers will fray and fluff where Carbon shatters, making it good for fairings and helmets where you want the part to protect durring a crash. However, this quality is usefull for the survival of the pilot -not the part. Aramid is not as stiff as Carbon, and when paired with such, does not contribute much to the stiffness of the part; rather, the Carbon supports to breaking load, then drop all the load on the Aramid. If stiffness is the goal, then you are better off by replacing the Aramid layers with the Carbon. That said, Aramid might be an asset in places like the leading edge of the handle, where it might typically hit and drag the ground.

Estheticly, Aramid/Carbon weaves look way cool; I would be tempted to coat the outside of the handle on looks alone.

An all Carbon handle would weigh a good amount less than a reinforced handle- but your solution seems far more practicle!

Would you mind posting some pics of your molds? How many parts is it?

Great work Scott.


Well said, Christopher. Matching the pros and cons of both materials is quite a quandary.
When I first started thinking about how one could design a c/f handle, I had a circumferential trough in mind that would allow insertion of some tubing (e.g. silicone type tubing) which could act as a bumper and protect the handle proper. But it seems Scott’s solution is much superior (and much more elegant than a “bumper for the bumper”).

Have fun,

You are right about the properties of CF vs. aramid(Dupont Kevlar). Actually, the part is stiff enough without any fiber, it is in there to give strength and fatigue resistance. I am not using an aramid/cf weave but rather a cf cloth on the surface with Kevlar sandwiched between. Kevlar does fray very badly so I didn’t want it on the surface of the part where it could be exposed by an abrasion. In race car body panels made from carbon fiber, Kevlar is sometimes used in the center of the laminate to hold the parts together and keep them off the track in the event of an impact that shatters the CF and the resin matrix. Kevlar is a pain to work with. An all CF handle could be very light and look very cool, until it hit the ground and the fibers started splintering.
There are a multitude of ways to make something like this, and every solution is a compromise.

Enjoying the comments,
Scott Wallis

Re: Carbon Fibre Handle

That Handle looks sweet! Can’t wait for the production run! :slight_smile:


Re: Carbon Fibre Handle

“S_Wallis” <> wrote in message
> I rode with a cast, unreinforced version using this resin on my muni for
2 months until it
> finally broke, then added the fiber on the next one based on the
> failure.

What was the failure? Where? Have you done some abrasion testing?
Urethane is a great choice for the handle.

The handle looks great!

Why use CF at all? The Kevlar should have added quite a bit of stiffness
over the original unfilled urethane.

To save on the cost of the urethane, could you thin out some of the thick


Drip, drip, drip,
(salivating over amazing handle)
that looks awesome!!
c’ant wait to hear about the testing/availibility to the public.

Oh, and this is open to anyone… whenever you need something tested… i’d be more than happy to take the part (no matter what) through some very tough field work :stuck_out_tongue: . seriously!

good work!


Re: Re: Carbon Fibre Handle

Good questions, all.
The failure was on the lower surface where it wraps around the seat lip, not at the edge of the CF reinforcement plate as might be expected. It occured a little while after a 45 minute session of repeatedly climbing the same hill to try to get a little higher each time. I was pulling up on the handle for all I was worth(not much, really) the whole time, then a while later I slammed it hard on the asphalt and it broke. My pulling arm was sore for 2 days afterwards so I think it was fatigue, not just the impact, that caused the failure.
Most inexpensive thermoset urethanes are either brittle or flexible. It is hard to find one that behaves like a good thermoplastic as far as toughness goes. This one is good, but I am going to test others with a lower flexural modulus.
Kevlar on the surface could have the fuzzing problem mentioned earlier and it would be very visible since the part has no surface coat. So the CF and black resin was a safe solution for now, but I do have some Kevlar tests planned.
The final tooling will have some thickness changes, but you can’t really make much difference and still maintain a comfortable, rounded shape.
My abrasion testing is done on rocks and asphalt, and it only lighly scuffs the surface of the handle. Also, it can be easily sanded and buffed out. Again, Kevlar would not allow that.
I think I have told you more than I know, and certainly more than I planned on telling, but you guys are asking good questions.

Scott Wallis