18 Replies Latest reply on May 28, 2010 7:22 AM by Dougal Hiscock

    Solidworks Bible bicycle-how to mate spokes in wheels?

    Roberta Schneider
      This is a college class, even the instructor can't explain how to do the spokes correctly.  Apparently there is an angle involved, does anyone know the proper steps it takes for this?
        • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
          Matt Lombard

          Bicycle spokes are far more complex than most people give them credit for being. There are several spoke patterns possible for different purposes. The most popular is called "cross 3" which is a good general purpose pattern giving reasonable strength-to-weight. Cross4 is typically used on higher load situations, such as heavy duty touring bikes. Lower cross patterns use shorter spokes, thus are lighter, and used for racing. You can even use a radial spoke pattern, but typically that would be used on a wheel with no torque (not the drive/rear wheel, and ideally no brakes).


          All of the cross patterns are also woven, so they go over some spokes and under others. A single wheel can also mix patterns, such as Cross4 on the drive side of the rear wheel, and radial on the non-drive side. And on top of all of that, wheels have different numbers of spokes from roughly 20 to 48 or more, and on more modern race bikes the spokes are not necessarily spaced evenly. On wider rims, spoke nipples may also be offset from the center plane of the rim. In some wheels, all spokes might go to the inside or outside of the hub, but in average wheels, the spokes alternate inside, outside on each left and right flange.


          Short answer is that if you are looking for a correct model of the spoking pattern on a bicycle, you will have to provide a lot of other information to get something specific. You can buy a book called The Bicycle Wheel written 30 some years ago by a guy named Jobst Brandt. It will answer some of your questions, and raise others.


          When I used to assemble real bike wheels, I did it by taking adjacent spokes inserted into the hub from opposite directions, and separate them on the rim by a set number of holes. I don't remember any of this off the top of my head. I worked in a bike shop, and we had reference wheels and reference books for this. In the real world, spokes are work hardened stainless steel, and hubs are typically machined billet aluminum, so the final assembly and tensioning involves some deformation of the hubs.


          Getting around to answering your question, I don't remember exactly how I did it in the example in the book, but I would probably mate a point on the rim to the axis of the spoke, and how you mate the spoke to the hub depends in part on if you modeled any straight area after the head of the spoke, which I would make concentric with the hole in the hub. You can't really hope to do this exactly in CAD since the assembly of spokes in a wheel definitely involves some permanent deformation of both hub and spoke.


          If you are talking about the kids bike on the cover of the 2007 book, that was just taken from a photo somewhere. It's not an actual SW model. There is a bike used as an example in several chapters, and the wheels for that are correct for either cross3 or 4, and probably 36 spoke 26" wheels. I was a little lazy and did not weave the spokes, which would bend them slightly. It just didn't seem worth the time based on what I needed the example assembly to show. The spokes I used are butted spokes, but I have forgotten what gage.


          Just as an interesting aside, how is the stress distributed in a bicycle wheel when you apply a load at the axle, with the tire against the ground?

            • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
              Jeff Mowry

              Whoa, excellent reply.  I used to bend my wheels every hour or so when I was learning proper trials techniques on my mountain bike (used to be a fairly technical rider), so I knew how to true a wheel quickly with spoke wrenches.  Never built a wheel, though.


              As to the question, from what I understand, the spokes are tension devices and not compression.  So, supposing weight is applied to the wheels from a rider on the bicycle, the spokes generally pointing up from the hub are pulled on to keep the hub from falling, so the tension is in the generally vertical spokes above the hub.  Other factors would change this (such as jumping off large ledges and landing on the ground, harsh braking or other acceleration, or slapping a soccer ball with the front wheel) to whichever spokes would best absorb tension energy as applied from the rim to the hub.


              Once our snow melts, I'm eager to (attempt) riding my old non-suspension, super-light Bridgestone MB-1 again--at 9,000 feet.  Lots of ways to achieve oxygen deprivation around here.

              • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
                Derek Bishop
                I know from bitter experience as a teenager clowning around with a friend on the way down a big hill that if he slams on his brakes and your front wheel hits his back axle, your spokes get quickly shredded. The resulting shape of your front wheel makes it very difficult to pursue said mate to dispense justice.
                • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
                  Harold Brunt
                  This is a pre-caffine answer but isn't the load on the spokes at the top side of the hub (the one's under tension with the rim)? If I were to model a bicycle wheel I would make my life easy and choose a Velomax since those are straight pull spokes. I have an R18 with at least 10K miles on it.
                  • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
                    Dan Bertschi

                    Is there anything Matt doesn't know about?!  I'm impressed, Matt, simply because I'm a cyclist/tinker and have built several sets of wheels. Brandt's book is still a classic, it sits on my cycling shelf with several others just on wheels.


                    To the topic at hand, how to do a spoke in SW? As one poster said, what do you want to do with it?  I've created them in-context, with a hub & wheel assy.  I've also created them as part features, where the wheel assy is a single part. In any case, you have to ask 'Why am I modeling this?'  That will tell you how much detail to use, and how important it is to be 100% accurate in your depiction.  Are you modeling the spoke head? What about the nipple?  The hole in the wheel, is it riveted? What about spoke holes in the hubs? Radiused or chamferred?


                    If you just want to show a 'spoke pattern', make it as simple as possible with in-context point-to-point creation & no mates.  Then you can resize your hub & wheel, and the spoke will resize.  If it was only that easy on a real bike wheel!!


                    Happy Trails!


                    P.S. You don't have to cross spokes if you don't want to... theoretically ... I figured I'd better add a disclaimer before someone gets hurt after reading my post and looking at my wheel lacing.  BTW, that's a front wheel.  I'd NEVER do that to a rear wheel.

                  • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
                    John Sutherland

                    Perhaps you should start by telling us whether you are modelling for manufacture, presentation or simulation.  Until we know what you want to achieve, we can only recount our tales of our misspent youth.

                    • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
                      Roberta Schneider
                      I am so sorry, I really failed in asking  of the question.  This is a basic assembly project that is in one of the Solidworks Bibles.  we are given each piece (spoke, hub, wheel, etc) and the task is to properly assemble it.  The spoke has a set angle which works for all that enter the hub from the outside. the tip/nipple of the spoke has a cone shape, and the holes in the hub are also cone shaped/countersunk.  The problem we can't figure out, is how to flip the spoke so that the cone shaped tip of the spoke will align with the countersunk hole. I will attach the wheel with the spoke sticking out at the wrong angle to show our dilemma....I appologize for asking such a remedial question, but our whole class is stumped-including our instructor.
                      • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
                        Roberta Schneider

                        ok we figured it out....we needed to change the configuration of the spoke part...Front in  vs  front out....

                        • Re: Solidworks Bible bicycle-how to mate spokes in wheels?

                          Here is a bicycle wheel I created for a project. I made it as a series of revolves, and I made the sopkes circular arrays. it is not correct, but it serves my purpose. I hope it gives you a idea of how to start.

                          • Re: Solidworks Bible bicycle-how to mate spokes in wheels?
                            Dougal Hiscock

                            Here's mine:


                            3X spoke pattern, 2mm DT spokes and nipples, Shimano deore disc hub, mavic F519/XM719 rim, hayes disc rotor.


                            To model one correctly, you've first got to understand how to lace them correctly.

                            There are four seed spokes, the rest are patterned off these.  You need to mate these four, rotate the rim or hub until the spokes protrude into the nipples the same in leading/trailing then lock it down and create the pattern.