Hi
Really love your bike! I'm working on a 1981 model gs750E my self and would like to do a similar wheel conversion. What are the dimensions on your tires and wheels?
I've also considered making my own hubs with a lathe and manual mill. There's a guy who sells bolt on conversions, but they're pretty expensive. Follow link :
http://cognitomoto.com/collections/...2005-gsx-r-hub-bolt-on-conversion-laced-wheel
I'm just a bit concerned about getting the hub strong enough. If I'm using the same alloy (6061-T6 Aircraft grade aluminum) and try to follow the design closely do you think that is good enough. Or will I have to get someone to calculate material strength?
-Lars
We ran some analysis on the hubs I made and they had a good safety factor with 6061. I would recommend doing as much CNC over manual as possible. Concentricity is the most important thing you can have if you're making anything on a rotating assembly and doing that manually is tough. I will tell you this though, I wish Cognito Moto would have been making more conversion stuff back when I started this project. That leads me to make a PSA
TO everyone,
If you're interested in doing just about any type of conversion and someone makes a kit for it DO NOT HESITATE to buy it. No matter how expensive it may seem it will still save you time, money, and stress (among other things). In fact, if it's not expensive it's probably not worth buying. The reason these things cost money isn't just because some independent part manufacturer is greedy, it's because of the many processes required to manufacture just one GOOD part. You must first conceptualize the part, sketch it, think about it. That's the easy part that almost everyone can do. Then you need to collect real world data. For something as simple as a hub you still have dozens of measurements to take and even when you think you've got all the measurements you still missed at least one ha. Once you have that you can start to make a technical drawing. This is where you may find mistakes or discover you need to make revisions. Back to the drawing board. Make adjustments. Draw a 3D model so that you can run FEA to make sure it's a safe part. Draw 3D models of the interacting components in the assembly (forks, wheels, axles, etc.). This is so that you can test the fit and clearance before you take the time to produce a real-world part.
All of this has already taken way more than a day's work so unless you don't need to work for a living finding the time can be difficult because this process can literally turn into a part time job.. that you don't get paid for haha! After several revisions you finally have a design that seems to interact nicely with all of your other components. It's time to start the process of bringing it to life. Begin by attaining your stock aka raw materials (which are expensive), then buy your tooling (which is expensive), oh and fire up your personal CNC machine (which almost nobody has just sitting in their garage waiting to be used and oh ya, it's expensive). Wait for all of it to show up to your house.... After a week it all shows up. Now you need to tell your machine HOW to make your part. Unfortunately, even in today's modern world, we still have to tell the robot what to do rather than it reading our mind. This is why we have CAM software (Computer Aided Manufacturing). With CAM software you can take your 3D (CAD) model and begin designing a machining process. Yes, you don't just need to design the part but you also have to design how the part is to be made. MORE DESIGN WORK. You must create a tool path for each tool it takes to make your part, of which there will be several. This takes time and is definitely not fun. One mistake here and you break that nice carbide endmill you just waited a week for or ruin that beautifully expensive block of aluminum by crashing a bit into it. Once you've simulated what your machine must do to make your part, it's time to take it all the way. Fixture up your stock and "send it", as the kids say. IF you're not a full time machinist you're GOING to make mistakes, because even they do. Some mistakes will be costly. Costly in lost time, lost money, lost hair.. or likely all three.
You finally get your measurements right, your design right, your machining process right, and the part comes out of the mill looking like a beauty! K, now go bolt it on. All it took was 100 labor hours, ~$200 in stock and tooling, ~$0-$2000 in specialty software, ~$5000-150,000 in specialty machines, an engineering degree (who knows the cost of one of those nowadays), and a can-do attitude! Obviously I'm being a bit dramatic here and there are other ways to save cost but that usually requires you taking advantage of other peoples' time and resources.. Do yourself and your friends a favor. For the sake of all that is good and holy buy an off-the-shelf kit. Get on your computer, buy the part online, wait for it to show up on your doorstep, and install it. Someone else literally already did ALL of the work. Don't let that be in vain. Encourage small manufactures to keep making cool stuff by buying it when it's available! Even though the price may seem high it is still cheaper than a stress related heart attack. Through the process of building this bike I have gained a new respect for those who make aftermarket parts. It's not easy and the prices usually reflect that. To put it in perspective, I have every tool available to me. The software, the hardware, the education, and the experience. After making parts for this bike and realizing the work involved in the process I can finally appreciate the price offered by companies like Cognito Moto. Now the only time I make ANYTHING is if what I want doesn't already exist.
Lastly, If what you want doesn't exist and you can't find any other alternatives you may actually have a good idea! Send it to a company like Cognito Moto. If there's enough interest in your part they'll make a small batch. You'll get a top end professionally manufactured part without the one-off price tag. It's a win for everybody. You, the manufacturer, and the other's who may stand in need of the same part.
End Rant
Thanks for all of the compliments! Winter is pretty cold here and we had to move shops AGAIN. Beggars can't be choosers I guess. The bike just needs some time and love. I'll get going on it again very soon.
How about the Motogadget M-unit?
