wheel rim

[penny farthing]

When building your wheels, has anybody ever thought of rolling their own wheel rim, or even know where to source the aluminium extrusions.
I have often thought this would be a very interesting challenge, working out the spoke hole distance and whether to drill or punch the said holes.



Hope this topic sets your minds racing



Penny farthing

[hubgearfreak]

I have often thought this would be a very interesting challenge, working out the spoke hole distance and whether to drill or punch the said holes.

it would indeed be a challenge, but getting the circumference of the bead seat correct would be the difficult bit.
drilling a hole every 10 degrees once it's been rolled wouldn't be too much of a bother

[Mick F]

I often tell people that I've "made my own wheels". They are rightly impressed, but I'm sure they aren't under any illusion that I "made" anything! (I should say that I "built" my wheels from already made components.)

Is it possible to make a DIY rim?

Even if you could make a rim, the problem would be to get it accurate enough to fit a tyre properly. We already hear horror stories of rim/tyre combinations too tight or too loose.

[penny farthing]

I went into the local engineering works today, and they say that it is not a problem to roll the extrusion. The problem is finding the type suitable for your bicycle wheel. The size is no problem either, as you decide what size of wheel you want and then use Pi to work out the length. Once you know the length you roll it till the two ends meet, the raduis will be whatever raduis you used to work out what length you needed.

[thirdcrank]

penny farthing

I think you may have missed the point - touched on above - that the problem is one of tolerance. We get regular queries on here about tyres that are difficult to fit / difficult to get seated properly on the rim. In other words, even manufacturers' tolerances are apparently not accurate enough to ensure that rims are exactly the right size.

[hubgearfreak]

unless (s)he means for a penny farthing, where the (solid) tyre is supplied as a length in a number of metres that you have to wrestle with and insert a steel joiner in?

for a 635/584/590 & etc. rim, it'd be a pointless exercise

[ferrit worrier]

Once you know the length you roll it till the two ends meet, the raduis will be whatever raduis you used to work out what length you needed.

Not quite that easy! If you use a triple roller to roll the extrusion two rollers will be fixed and one will be adjustable to bring the rim "round" as the end of the extrusion passes the roller it will have a flat section. it's a bit difficult to explain the geometary of it. you would in effect need slightly more than the circumference to compensate for the "flat" which would be cut off after rolling. the length of the circumference may differ from straight to rolled as the outer of the rim may stretch while the inner whilst unlikly could compress there will be many factors to take into acount like the thickness of the inner bed of the rim (the bit between the beads) against the thickness of the outside of the inner wall (the bit the spokes go through).

As for spoke holes I'd drill in a jig in a good quality drill, punching would be difficult as you would have to pass through a void.

certainly food for thought, lots of tech stuff to overcome.

[ferrit worrier]

unless (s)he means for a penny farthing, where the (solid) tyre is supplied as a length in a number of metres that you have to wrestle with and insert a steel joiner in?

for a 635/584/590 & etc. rim, it'd be a pointless exercise

Thats just jogged my memory. Many years ago there was an article in either Model Engineer or Engineering in miniature about a guy who made a penny farthing. If I'm not mistaken he used a lenth of square section tube cut in half along it's length then rolled with a solid tyre and home made spokes. I think the article was published late 70's early 80's?

Malc

[penny farthing]

The rim is a 54" and the tyre is solid but without the spring through the middle. It is actually 3 tyres glued together, This has given no trouble so far and in fact I have done so many miles that they will soon need replacing.

When rolling the extrusion you apparently allow 1" longer that required and cut 0.5 " off each end after rolling. The tyre is no problem becuse you have picked the measurements of the extrusion before you roll it.

I thought about opening out 2 rims and welding them togther, but it is easier to roll a flat extrusion rather than trying to open out an already rolled extrusion.

I just think that if I decided to build another penny farthing I would like a go at making the wheel rim as well.

[ferrit worrier]

Wel done if your building a "Penny Farthing" I do remember the artical in the magazine I'm sure it was a construction guide so it might be worth while contacting ME and EiM and seeing if you can get back copies I'm also sure that there was a drawing for the rolling jig or at least a good set of pictures.

Good luck
Malc

[rogerzilla]

Keith Bontrager used to cut 700c rims and re-roll them as 26", before lightweight 26" rims were manufactured. If thy're pre-drilled you can get a 32 out of a 36, sort of. Now that *is* bonkers.