6-bolt 44BCD to 4-bolt 104BCD Double supported Top Hat, for 135mm O.L.D. Disc Brake Hubs

[FurryOnTheInside]

I have been messaging the manufacturer of the stainless steel top hat sprockets on eBay and after some thought and measuring I have asked him to make a stainless steel top hat adapter to connect standard (cheap to replace or try different sizes) 4-bolt bicycle chainrings to the disc rotor mount of a 135mm O.L.D. mountain bike hub, in perfect alignment with the engine sprocket.

If anyone wants to get in on this, it might make it a little bit less expensive for me, haha!
At the moment I am just asking for a one-off custom made part, so if anyone else wants one it might be best to let him know while he is setting up his lathe for me.

This is for the common standard 135mm mountain bike / multi speed hubs so not the 110mm width usually found on dedicated single speed bikes, such as @Tommy Griffin was asking about on the thread which inspired this one.

Thanks Tommy for putting me in contact with the manufacturer here http://www.ebay.com/itm/Motorized-B...ash=item2a6781ea1d:g:~3MAAOSwa-dWh719&vxp=mtr


If anyone has thoughts on the design I'd love to hear them.

 

[FurryOnTheInside]

Okay so it turns out that the manufacturer is a dweeb.
I was told it would be ready in two weeks and that was over a month ago, I haven't been able to get any response from the guy so I'm just going to have to move on.


Here's some photos of an adapter spider, similar to what I would have now if the eBay guy wasn't such a dweeb.
What I wanted was very much like this but with four arms and a bit more offset, and either thicker or preferably steel instead of alloy.

Which should fit very well on one of these if only they made the adapter with a little more offset.

Oh well. I can keep looking for someone to machine this adapter for me, but it's going to be more expensive to have it done in the UK, and it's more time. So I think I have to go right back to where i started and make the home made thing that is not pretty but will hopefully do the job (if not quite as well).

So here's my "design" for a work-around solution to the lack of a decent offset adapter. What do you think?

I can buy two of these flat adapter plates..

and I can cut one in half then shove/wedge it behind the rotor mount and put long m5 bolts through to trap it.

Obviously I don't believe in drawing using a ruler. Haha

But you can see that the only threaded part is the six holes in the rotor mount flange of the hub. The adapter plate's six holes are m5 clearance.
I'm not happy that there's no way to tighten up the inner adapter plate but I don't know if it would actually fail because of this.
I can certainly put extra bolts through to join the plates for extra security after the first six and four.

All the pieces used for the m10 bolts to go through are clearance fit too so it's only the nut that has a thread there too.
I tried to find some sleeve nut or barrel nut that is 10mm diameter and 20mm long to save a little weight on this bit, but it looks like I'll have to go with the m10 x 30mm button head bolts and nuts.

Okay, thoughts, anyone?

 

[Frankenstein]

How are you getting that plate behind the rotor mount? Thats a big step to get past it looks like..

Edit: nvm I saw the cut and wedge thing afterwards..

 

[gary55]

Not even close to as elegant as what you guys are doing, but functional, fully adjustable, proven to last longer than the teeth on the sprocket, cheap and easy to build.View media item 60792View media item 60791View media item 60790

 

[FurryOnTheInside]

Not even close to as elegant as what you guys are doing, but functional, fully adjustable, proven to last longer than the teeth on the sprocket, cheap and easy to build.View media item 60792View media item 60791View media item 60790

I do really like your design. It's simple and effective, and it's certainly less expensive than mine!
Your design seems to suggest that my inner (split) plate may be unnecessary.
In which case I can include it anyway but not worry too much about it being "loose" on the six bolts.
Obviously nine bolts are more secure than four and steel plate is stronger than alloy, but hopefully my inner plate is just a bonus to help keep it rigid (as the sprocket is offset further right of the rotor mount on mine).

Okay so it seems like there's no obvious problems so I'll go ahead and order the adapter plates and the bolts.

 

[gary55]

I like what your doing with this as well. I also think the split plate for rigidity is a good idea with the 4 spoke alloy design. Is there any room between the back of the split plate and the spoke flange to get a nut on the M5?

 

[FurryOnTheInside]

I like what your doing with this as well. I also think the split plate for rigidity is a good idea with the 4 spoke alloy design. Is there any room between the back of the split plate and the spoke flange to get a nut on the M5?

I wish! Unfortunately no.
There's about 6mm room between the rotor flange and the spokes for the 5mm plate and perhaps a 1mm rotor spacer or washers.
If I was lucky enough to get the bolts lining up exactly between the spokes I think there would still be no room for nuts due to the diameter of the waist (and also possibly the shape of the spoke flange) and of course difficulty of getting even a very flat wrench in there to hold the nut.

 

[gary55]

After reading through your initial description I see you already addressed what I was wondering about. I'm thinking once you have assembled it you will have a better feel as to weather or not you want to ad another M5 through each of the 4 spokes just high enough abv. the spoke flange to get a tight sandwich. Looking forward to seeing how this one comes out. It's a hot topic these days.

 

[FurryOnTheInside]

After reading through your initial description I see you already addressed what I was wondering about. I'm thinking once you have assembled it you will have a better feel as to weather or not you want to ad another M5 through each of the 4 spokes just high enough abv. the spoke flange to get a tight sandwich. Looking forward to seeing how this one comes out. It's a hot topic these days.

Yeah definitely going to consider that.
Its all a bit fiddly to measure and speculate how it will come together, so I'm not even ordering the (m10 hole) spacers for the outer set of bolts until after i can see things in person.
Once I get the plates I can see the exact size of spacers I need and I'll be able to see if a third set of bolts will help. I am expecting that I'll want them just for a bit of extra security.. it might be overkill idk.

 

[gary55]

Yeah definitely going to consider that.
Its all a bit fiddly to measure and speculate how it will come together, so I'm not even ordering the (m10 hole) spacers for the outer set of bolts until after i can see things in person.
Once I get the plates I can see the exact size of spacers I need and I'll be able to see if a third set of bolts will help. I am expecting that I'll want them just for a bit of extra security.. it might be overkill idk.

The more I think about it I have to ask since I don't know your exact set up. I believe the split plate will stop you from getting enough offset on the sprocket. Most I have seen need the sprocket inboard of the back of the rotor flange. Yours will be almost directly over it.