stainless steel frame

I know a guy who has offered to make me a stainless steel 26" - 28" unicycle
frame. I will probably use Miyata bearing holders.

Does anybody have any ideas on the pros and cons of a stainless frame?

I am looking mostly at the following properties (in order of importance)

Weight - is it heavier that alternatives?
Strength - how does it compare to alternatives?
Durability - how will it stand up to alternatives, my main use will be for
off-road and beach riding.
Price - this is not too important as I will be getting it done as a favour
(I hope).

Thanks for all your technical advice,

Wayne van Wijk
wayne@jester.com.au


O–( >–|-o

OUCH! Just fell off my unicycle.


There are two examples of stainless steel frames in the unicyclist gallery located here:

http://www.unicyclist.com/gallery/albun81

and here:

http://www.unicyclist.com/gallery/albun90

The second one is mine. Common 300 series stainless steel has about identical properties to mild steel regarding strength and weight. As with all unicycle frames, design has more to do with strength and weight than the materials used to build the frame. My stainless steel frame is heavy because of the bearing holders, crown and wall thickness of the fork legs, not because it’s stainless.

CrMo is a good material for frames because a thin wall CrMo tube is less likely to dent than a thin wall mild steel tube. The result is that thinner wall tubing can be used resulting in a lighter frame with the same strength as a mild steel (or stainless) frame. The other advantage of using CrMo is the wide range of size and wall thickness that’s available. Stainless tubing on the other hand is fairly limited in size and wall thickness.

As for durability a stainless frame should be next to impossible to destroy - especially if you’ll be riding the uni on the beach. What I think is neat about stainless is the finish. I polished my frame with a Scotch-Brite pad so if it gets banged up all I have to do is polish it out again.

Steve Howard

I really like the look of your frame Steve.

Wayne,

Is that Ian Aitcheson who’s building it for you? I’ve tried about 10 times in the last week and a bit and I can’t get hold of him. I just get the answering machine. Do you know where he is? Which beaches will you be riding at? I rekon if you’re getting it done as a favour and stainless steel is reasonably strong, light, durable, etc. which it seems to be then get it. How light does it have to be if it’s for off-road and beach riding?

Andrew

A quick update on the stainless frame …

Just finished a MUni ride on a trail that follows a small creek with several foot bridge crossings. At one point the MUni wound up in the creek with just the seat sticking out of the water. The Chinese bearings might not fair too well from being under water but the frame will never rust!

Andrew - If I were to make another frame like this I would probably not ovalize the tubing quite as much. I pressed the tubing to 1/2" thick but 5/8" thick would be stiffer. It’s not that this frame isn’t stiff enough but there’s plenty of side clearance between the frame and the tire and 1/8" less clearance wouldn’t hurt a thing. Also, I would increase the top clearance slightly - about 1/4" or so. Yesterday I picked up a rock in the tire tread and it tick, tick, ticked on the crown for about 6 revolutions before dislodging.

Steve Howard

How did that happen with an ace rider in the saddle?

Excuse the newbie question, but what is the point to ovalizing the frame? Is it just to increase clearance? Or are there other reasons?

Thanks,
Daniel

Re: stainless steel frame

Thanks for the help Steve.

I think that I will go ahead and get it made. Hooray - a new beach cruising
unicycle is soon to be born into the world.

Wayne.

“showard” <showard.e9xeb@timelimit.unicyclist.com> wrote in message
news:showard.e9xeb@timelimit.unicyclist.com
>
> There are two examples of stainless steel frames in the unicyclist
> gallery located here:
>
> http://www.unicyclist.com/gallery/albun81
>
> and here:
>
> http://www.unicyclist.com/gallery/albun90
>
> The second one is mine. Common 300 series stainless steel has about
> identical properties to mild steel regarding strength and weight. As
> with all unicycle frames, design has more to do with strength and
> weight than the materials used to build the frame. My stainless steel
> frame is heavy because of the bearing holders, crown and wall thickness
> of the fork legs, not because it’s stainless.
>
> CrMo is a good material for frames because a thin wall CrMo tube is less
> likely to dent than a thin wall mild steel tube. The result is that
> thinner wall tubing can be used resulting in a lighter frame with the
> same strength as a mild steel (or stainless) frame. The other advantage
> of using CrMo is the wide range of size and wall thickness that’s
> available. Stainless tubing on the other hand is fairly limited in size
> and wall thickness.
>
> As for durability a stainless frame should be next to impossible to
> destroy - especially if you’ll be riding the uni on the beach. What I
> think is neat about stainless is the finish. I polished my frame with a
> Scotch-Brite pad so if it gets banged up all I have to do is polish it
> out again.
>
> Steve Howard
>
>
> –
> showard - ------
> ------------------------------------------------------------------------
> showard’s Profile: http://www.unicyclist.com/profile/452
> View this thread: http://www.unicyclist.com/thread/21710
>