Ok, whats with this rag joint and sprocket ? Is this correct ?

[abefroman]

went to put the sprocket and rag joint on my bike and I noticed that the holes for the split backing plates DO NOT line up with the holes in the sprocket. when I put all the bolts in and tighten them up, they "flare out" on the nut side because the backing plate holes are further apart than the holes in the sprocket. It seems that it is designed this way on purpose ! is this correct ? looks like a damn onion blossom on the nut side with the bolts/nuts flared out !

Also, my genesis astra has 48 spokes, so I drilled 6 holes in my sprocket to go between the spokes. then I tried to bolt it all together with the rag joint to "match drill" the 6 holes I drilled in the sprocket but it doesn't line up. I'm a structural / mechanical engineer and this just doesn't make sense to me - bad design, or am I missing something ???

i cant seem to be able to upload the picture of the sprocket and split backing plates. The picture shows that the holes do not match.

 

[Master-shake]

Re: Ok, wtf with this rag joint and sprocket ? Is this correct ?

Well, I would have to say the reason your rag joint and sprocket don't line up has a lot to do with the fact that you drilled new holes. It would seem to follow that if your going to drill new holes in the sprocket you would need a new ragjoint because the diameter of the plates is fixed.

I would suggest using the original sprocket holes but only using 6 of the nine bolts. If you take the advise be sure to use lock nuts for each bolt because if one gets even a little loose the whole sprocket will come out of alignment.

By the way, you wouldn't happen to be a tech doing all that mechanical engineering stuff would you?

 

[maniac57]

Re: Ok, wtf with this rag joint and sprocket ? Is this correct ?

there are TWO sizes of rag joint. Sounds like you may have one that has mixed parts from the two sizes. The backing plates should line up with the sprocket and rubber. You may have a set of the smaller backing plates.

 

[abefroman]

Re: Ok, wtf with this rag joint and sprocket ? Is this correct ?

Ok, I've figured out the problem... WRONG PARTS from gasbike. they are putting another sprocket in the mail to me today.

My problem with the bolt holes was NOT because I drilled new holes. I drilled new holes because the parts didn't fit. I have a degree in structural and mechanical engineering. I actually drew up the sprocket, wheel, rag joint, and split rings in AutoCad and I drilled new holes with a drill press. The modifications I made to the sprocket (new holes) would have worked, but I called gasbike.net and they are sending me a correct sprocket.

I also intend to put an engine kit on a micargi puma which has a 68 spoke wheel. I'll draw it up in CAD and modify the sprocket to fit - in the same way.

cheers

 

[racie35]

Re: Ok, wtf with this rag joint and sprocket ? Is this correct ?

I dont get how you could draw up all 3 parts on autocad and have it still not work? lets see the file.

 

[abefroman]

Re: Ok, wtf with this rag joint and sprocket ? Is this correct ?

I'd attach the file but for some reason I cannot attach it here. It turns out that there are two sizes of sprockets. one with a small bolt hole circle pattern and one with a large bolt hole circle pattern. Gasbike sent me the sprocket with the small bolt hole circle pattern and the rag joint and split metal backing plates for the large bolt hole circle pattern. That's why they didn't line up. I mainly drew it in CAD because I wanted to overlay the bolt hole circle pattern OVER a drawing of where the spokes are....because my bike has 48 spokes and the sprocket is designed to work with wheels of 36 spokes. With the correct sprocket (that should be in the mail) I can get 6 of the 9 bolts to go through without hitting the spokes. If I want more bolts, I can overlay my CAD drawing on the sprocket and drill 6 more holes.

what I'd really LOVE to have is a sprocket with a 1.375" center hole and NO BOLT HOLES drilled !!! that way I could overlay my CAD drawing for my 48 spoke wheel and my 68 spoke micargi wheel and drill my own bolt holes. I think that with the correct sprocket I might be able to drill my own holes and use a smaller bolt hole circle pattern and have plenty of metal between the 9 standard bolt holes and my newly drilled bolt holes.

So, it outta work out just fine. Thanks for all the replies !!!

and if I could figure out how to attach files here, I'd put up my CAD drawings for the different wheels for all to use... i'll keep working on it.

 

[racie35]

Re: Ok, wtf with this rag joint and sprocket ? Is this correct ?

I kinda get it now