Mystery Solved

rbike_imp

Running like a top
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Regarding Jim Alfaro and 7th Gear Designs - Warning 7th Gear Designs Sprockets The mystery is solved, but what a mess. So here is the story of what is going on.

I have never met Jim personally. I contacted him after extensive exhaustive effort that many have mentioned they were not willing to do. Jim rarely (now make that never) answers phone calls or email. Rightly so, because he is a farce impersonating a manufacturer. I know manufacturing (my business) and Jim is no manufacturer. He apparently subs all of his work out. This would not even be so bad except he represents himself as the actual manufacturer.

In one of his few emails I received, he said there was a problem with the "blanks" (material) and that was causing a delay. That led me to check into PBI sprockets that provides blank sprockets (http://shop.pbisprockets.com/product.sc?productId=503&categoryId=56) figuring he gets the xx tooth sprocket blanks from them then drills the mounting holes, but after talking to them, he never purchased from them. So maybe he is not lying - NOT! Their blanks are aluminum not steel anyway.

I was deciding if I should add this item to my company (start manufacturing sprockets) for the benefit of me and the forum and ....
I was at the point of turning this over to the police, when today to my sheer surprise, a box arrived from Azusa Engineering (Azusa) with 2 sprockets inside - no paperwork. A 19T & a 37T with 7GD lasered on the side. However, I was supposed to receive a 19T & a 35T from Jim. HMMM, another mess up to deal with.

After looking at the 37T, I realized a 35T is impossible. It will never fit/attach. The outside of the 5 attachment holes are within LESS than a SINGLE mm (see pic at end) of the center hub hole for the wheel shaft! So for him to have originally promised that the 35T will be possible to install/manufacture proves he doesn't even qualify as a viable "designer". He already "made" (make that sold) a 37T for Peking Duck and should have known especially when I asked the question.

So, this afternoon, I followed up with a call to Azusa Engineering and got "the Rest of the Story". I had originally in fact contacted them (along with a half dozen others) before I contacted 7GD. I spoke to their manufacturing supervisor that said the son (of the father and son team {owners}) was wanting to make steel sprockets, but the dad did not want to. After a few months of that, I came across Peking Duck's post and started a conversation with Jim. That story is above and .....one of the most UNPROFESSIONAl pieces of _____ I have had to deal with in decades.

As a manufacturer and my discussion with Azusa Engineering, I'll explain what happened - The machines that do this work require many hours to set up, required dedicated operation to the same material - aluminum,, steel, ... extensive time to change and clean out after a new different production material is to be used.

Well, Azusa Engineering, like my company uses aluminum for many reasons, and it will be months before a breakdown will be initiated and a swap over will occur for the few steel runs needed. So because 7GD does not manufacture the item, he had to keep coming up with new (one after the other) LIES to explain why the product has not shipped. When he ran out of lies, he just avoided answering the phone or email. One time his better half answered the phone on a Saturday by mistake while they were on vacation in Texas. All he had to do is tell the truth and I would have been patient, but NOOOOOOOOOOOO!

As part of my business, I am able to process/coat these items professionally. I am going to coat the 19T front with Bright Nickel and the 37T rear with Yellow Zinc. One bad item is that the $100 of Honda OEM parts I purchased for the 35T won't be needed for it to be installed/work. The good news is that I will not need to break the chain and use the parts to shorten it - initially, unless I think it should be.

Another item of good note, because I am not going to break the chain initially, I am going to do the R&R install myself because I won't need the special tools required for a chain mod. Bolt & unbolt.

I'll post before & after pics, but I did not want to delay getting this info out so that ALL may avoid a future disaster with 7GD. Should any 13CBs desire this steel vs aluminum sprocket mod, I will probably arrange future production runs - TBA.

 
Why can't people just be honest about this stuff. If saves A LOT of hurt feelings and bad press. I would think that he has lost any chances of getting any more business for these bikes (at least from this site) and maybe more from his dishonesty.
 
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Thanks to all that have PM'd & posted support! It is the only bad issue I have heard of on this forum since I have been a member. It is such a Great Group! 'wish I could make this summer's ride, but can't.
 
Thanks for the update, rbike. I'm glad something reasonable came out of it, but sorry you had to cop all the crap on the way through.
 
Wow, this is all very profoundly interesting and disturbing at the same time.
 
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Peking Duck or Others (if have 1st hand info) - I'm reviewing all threads and advice before installation of mt 19T & 37T "Installation was a breeze. Here's a tip - to loosen or tighten sprocket nuts, do it with the wheel in place. Stand on the right side, put your foot on the rear brake, use a 19mm socket and a 1/2" drive ratchet/breaker bar, and you can break loose the nuts with ease. If you take the wheel off before loosening the nuts, you will be fighting to hold the wheel. Reassemble and torque the nuts in the same way - 80 ft/lbs torque."

I have a substantial impact wrench & compressor - Do you still suggest your method of loosening Q5 nuts before wheel removal? This may be moot, but the attention to detail I do in manufacturing, leaves no room for just guessing or assuming. I already made 1 mistake assuming 7GD was OK.
 
Break the nuts loose with the wheel installed unless you have a way to clamp the wheel down to your work bench.
 
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kennyw, I'll try my impact wrench with everything still on and attached and attempt to loosen the Q5 sprocket nuts first - like plying with cool tools - lol. It should be not significantly different than a local tire change that doesn't need to keep wheel on the ground to loosen nuts before lifting the car on a lift. Impact wrenches usually have enough torque to overcome the initial momentum required. I don't think I'll even have to put the wheel in gear. I'll probably try it with the Tx in neutral first. I'm a few weeks out still (have to plate sprockets first, ...); I'll report back with everything I observe/learn.
 
rbike, glad your problem was resolved. When I ordered my sprockets from him first, I was aware he did not personally manufacture them, and that it would be a fairly specialized, custom item. To tool up for one-offs, especially material change, takes some effort. I had contacted every sprocket manufacurer I could find, including Azusa, and almost nobody wanted to make them in steel. Now we know why. (One other source made me one after several attempts, but still unhappy with result).

In my opinion, the steel sprocket was worth the effort for me and for some others who got them in a more timely manner. In the debate between steel and aluminum, the increased durability of steel would, for me, make aluminum a no-go.

As far as the removal and installation instructions, an impact wrench is fine for removal, but you still have to hold the wheel to torque the nuts.

In regards to the last point:

"After looking at the 37T, I realized a 35T is impossible. It will never fit/attach. The outside of the 5 attachment holes are within LESS than a SINGLE mm (see pic at end) of the center hub hole for the wheel shaft! So for him to have originally promised that the 35T will be possible to install/manufacture proves he doesn't even qualify as a viable "designer". He already "made" (make that sold) a 37T for Peking Duck and should have known especially when I asked the question."

The recessed portion is for clearance for the flange nut - it has no bearing on the strength or function of the sprocket. If the recessed area overlapped the center hole, not a problem at all, so a 35T, or less, is easily possible. This should be obvious to anyone looking at it. This, along with your prior comments and questions on chains, all makes me question how you are qualified to criticize someone else who is a designer.

Can you explain what is meant that "35T" is impossible?
 
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PD, I did not see your reply the other day when you posted it due to the limited time posts are on the forum home page. I do not know if you are trying to defend 7GD or what, but as a manufacturer, I know manufacturing and he is no manufacturer.

I do not know every manufacturer's ability, knowledge, or what machinery they have access to, but in this case to make this product efficiently and cost effectively, one needs to do Wire EDM - see the Wikipedia link for details (Electrical discharge machining - Wikipedia). If my company were to do manufacture these sprockets with our CNC machines, they would cost into the 4 figures each for T&M. Hence that is why a dedicated wire EDM manufacturer that has the templates is the way to go and I choose not to do it myself.

Regarding my post "After looking at the 37T, I realized a 35T is impossible. It will never fit/attach", I was not trying to get deeply specific because some get "headaches", but if you look at the picture, I drew an arrow to the inside edge of the Q5 nuts that attach to the wheel studs. There is less than a SINGLE mm clearance. If the sprocket was reduced to a 35T the edge of the nuts would be over an open area of the sprocket that would eventually leading to sprocket failure due to uneven loading on the sprocket surface!

I did contact Azusa Engineering before 7GD, but there were internal differences on wanting to manufacturer sprockets in steel. I kept looking and came upon your post. I wish I hadn't. Regarding him being a designer, 7GD was to do a 35T and DIDN'T, because IMHO he had no idea how or Azusa didn't, or they agreed a 35T was not viable. I never received a 35T. He had Azusa ship me another 37T like yours.

"The recessed portion is for clearance for the flange nut - it has no bearing on the strength or function of the sprocket. If the recessed area overlapped the center hole, not a problem at all, so a 35T, or less, is easily possible. This should be obvious to anyone looking at it. This, along with your prior comments and questions on chains, all makes me question how you are qualified to criticize someone else who is a designer." I don't think you understand the mechanical engineering and stresses involved (explained above) from your reply. In no way am I trying to upset you personally, but I am significantly qualified and he is a ________!

 
Ok both have had a chance to respond to each other. We will not turn this into a peeing match between forum members online. You are welcome to PM each other and "discuss" all you want.

if this thread degrades, we will lock it down. Comprende?
 
rbike, if you reduce the OD on the sprocket, you will not change the bolt pattern that attaches the sprocket to the hub. You would still have the exact same, less than a mm clearance. You could end up with higher stress in the reduced section between the teeth and nut. This could be fix by reducing the size of the "speed holes".

The stock Honda sprocket has the exact same nut to hub clearance with a thinner sprocket that gets wider at the teeth (shaped like an I beam if you look at cross section).
 
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Thanks Kenny. You are 100% correct! I was in a brain dump mode after receiving a 37T instead of the 35T I had ordered. I was trying to figure out why he did not do the 35T I had ordered. I shrank the inside vs outside edge - my bad. Even I make mistakes - you caught me on a rare moment- lol. Maybe I will get a 35T someday.
 
The sprocket you purchased only reduces the section as a C'Bore because it is cheaper to build it that way than to machine the entire surface to match the Honda profile.

The only feature I could have an issue with as a Mechanical engineer is the speed holes in the aftermarket sprocket. They greatly reduce the strength of the sprocket compared to stock by relying on a smaller section area to carry the load compared to the original resulting in much higher stress concentrations. Some of that material is not heavily stressed and safe to remove, but those slots are fairly large. Without running the numbers I do not know if it is an issue for this application though.
If you want to see some interesting sprocket design... Wisconsin Racing posted a video showing the load paths of a sprocket under acceleration (engine braking would act in the opposite direction meaning you can't make your sprocket look like this and expect it to work in the real world).

https://www.facebook.com/photo.php?v=398...=3&theater
 
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Kenny, Thanks again! In between these post, I recontacted the actual manufacturer and they are going to build me another sprocket-I can't say enough good about them. This time it will be a 35T! AND it is not going to have any cutouts. It will be full strength. I should have it relatively soon too. It is not going to take 4 months this time. I'll post the pics when I get everything.
This brings up my original concerns though. Thankfully, I have all the parts required to shorten the chain (will be necessary) to a correct length, but will utilize the local store for the chain break/mate tools.

I'm crossing my fingers regarding having enough clearance from the slider. With a couple of links removed, it should assist with that situation - time will tell if enough. I'll keep all updated. If everything works out, I'll have a new 37T available if someone ....
 
kennyw_imp said:
The sprocket you purchased only reduces the section as a C'Bore because it is cheaper to build it that way than to machine the entire surface to match the Honda profile.

The only feature I could have an issue with as a Mechanical engineer is the speed holes in the aftermarket sprocket. They greatly reduce the strength of the sprocket compared to stock by relying on a smaller section area to carry the load compared to the original resulting in much higher stress concentrations. Some of that material is not heavily stressed and safe to remove, but those slots are fairly large. Without running the numbers I do not know if it is an issue for this application though.
If you want to see some interesting sprocket design... Wisconsin Racing posted a video showing the load paths of a sprocket under acceleration (engine braking would act in the opposite direction meaning you can't make your sprocket look like this and expect it to work in the real world).

https://www.facebook.com/photo.php?v=398...=3&theater

I have not seen a sprocket fail as you describe on a bike - the chain will break first or rip the teeth off first. I don't think they can generate enough traction.
 
The link I shared was to a formula SAE team. They use a motorcycle engine in a small racecar. With an aero package creating down force and sticky racing tires, that is where you would start to see failures because the sprockets are loaded higher than on a motorcycle. It is also an engineering design competition, so it is important to go through the small details of every part of the car design.

On a bike, I would need to know more to know the limiting factors and actual loads. But, most factory sprockets wear out at the teeth first and they are likely designed that way intentionally for the intended applications. Most of that wear is from dirt and grime getting in between the mating surfaces.

In an aftermarket sprocket, you can cut material out of the center safely up to a critical point. The load will redistribute to the remaining material. The more material you remove means higher load and greater deflection (bending, twisting, stretching) on the smaller cross section that remains. All metals have an elastic region where all of that deflection can be recovered once the load returns to zero. As long as you don't exceed that linear limit, the material will go back to its original shape.

Then there is fatigue, bend a paper clip back and forth until it breaks and you have experienced a fatigue failure. The reduced sections on a sprocket will bend more than a sprocket without a cutout. They will then fail from fatigue faster than a sprocket without cutouts.

I cannot tell you if a sprocket will fail first from normal wear at the teeth or catastrophic fatigue in the reduced section without first knowing the geometry, material, and load parameters. I can only tell you I am concerned enough to say it is worth checking if you design a new sprocket.
 
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