Beisan S54 Exhaust Sprocket Hub Solution

[ethan]

I wonder for people that have been using Beisan hubs: is it mating to the smaller hole disk or anyone using it with the stock larger hole disk?
Of course the re-drilled smaller holes by itself would eliminate the tab breakage even of using with the "weak" OE hub, in theory.

Beisan says that you shouldn't buy their hub and use it with stock holes, so hopefully nobody is trying that. There isn't a tab breakage problem with either stock or Beisan hubs when used with redrilled disks. What's the concern here?

[sapote]

Given that a decade in we’ve seen zero failures with the Beisan solution, it seems sufficient

I wonder for people that have been using Beisan hubs: is it mating to the smaller hole disk or anyone using it with the stock larger hole disk?
Of course the re-drilled smaller holes by itself would eliminate the tab breakage even if using with the "weak" OE hub, in theory.

[cobra]

I hate to be that guy but what's the relevance here? If there were issues in BS hub design, we'd hear about it .... I think we are safe so far.

No issues, just interesting discussion.
Raj was a very conservative guy that did insane amounts of research. He made it a point to understand why BMW did things the way they did, and learned that there is quite a lot of thought that went into every little part on our cars. He didn't want to diverge too much from the original design and accidentally compromise something else, so he just addressed the issue enough to stop failures and that was it.

[Stilt]

I hate to be that guy but what's the relevance here? If there were issues in BS hub design, we'd hear about it .... I think we are safe so far.

[Obioban]

I look at Beisan and OE hub design and they all have the sharp 90* corners at the base of the driving tabs. This causes stress raiser and crack. The tab corner should have radius which is common practice in metal making.
with radius base, to fully mate with the disk which should have chamfer holes. Even without chamfered holes the radius tabs still can insert but there is a gap in between hub and disk. The chamfered holes will have zero gap and less cantilever on the tabs.
Don't know if VAC hub has radius tabs or not.

Given that a decade in we’ve seen zero failures with the Beisan solution, it seems sufficient

[ethan]

OK, so Beisan new hubs don't have larger tabs to reduce clearance on the stock disk holes. It is very much the same result - tab to hole clearance - as stock hub on stock disk.
IOW, don't use Beisan hub on stock disk to reduce the holes clearance. Use VAC hub in this case.

But why wouldn't you just have Beisan drill your stock disk at the same time you purchase their hub? I can't imagine willingly giving VAC money at this stage in the game. The Beisan combination is even $50 cheaper.

[sapote]

One area I disagree is you don't know where in the fatigue life of the original hub you are. It could be 10 miles from cracking when you install the new oil pump disk. I would feel more comfortable replacing both parts, unless it was a super low mileage hub.

I look at Beisan and OE hub design and they all have the sharp 90* corners at the base of the driving tabs. This causes stress raiser and crack. The tab corner should have radius which is common practice in metal making.
with radius base, to fully mate with the disk which should have chamfer holes. Even without chamfered holes the radius tabs still can insert but there is a gap in between hub and disk. The chamfered holes will have zero gap and less cantilever on the tabs.
Don't know if VAC hub has radius tabs or not.

[cobra]

One area I disagree is you don't know where in the fatigue life of the original hub you are. It could be 10 miles from cracking when you install the new oil pump disk. I would feel more comfortable replacing both parts, unless it was a super low mileage hub.

[sapote]

OK, so Beisan new hubs don't have larger tabs to reduce clearance on the stock disk holes. It is very much the same result - tab to hole clearance - as stock hub on stock disk.
IOW, don't use Beisan hub on stock disk to reduce the holes clearance. Use VAC hub in this case.

[karter16]

This brings up more confusion.
1. Do Beisan new disks have smaller holes than OEM disk? I assume so as people bought then to fix the loose OEM holes.

2. He said the new hub works with OEM new disk which has the larger holes. This means the new hub has larger tabs to reduce the hole clearance, and this means his hub with larger tabs won't fit his small holes disk.

I don't see how Rajaie could have been much clearer in his posts in this thread:

The Beisan exhaust hub tabs are thicker than the BMW hub tabs to improve strength.
The Beisan hub tabs are the same width as the BMW hub tabs. Thus the Beisan hub tabs fit the Beisan oil pump disk with smaller holes.

The Beisan exhaust hub should always be installed with a new Beisan oil pump disk.

Although the Beisan hub tabs are thicker and thus look and are bigger, they are the same width as the BMW hub tabs, and thus fit the Beisan disk with smaller holes.

If your hub tabs are not broken, there is no need to replace your hub. Once you install the Beisan oil pump disk with smaller holes, there is a 7 year 100% statistic that you will not experience a broken tab.
But if you insist on installing a new hub, you are correct that the Beisan hub, although with thicker tabs, does not have wider tabs, and will not remove the play with the OE disk large holes, and there will be hitting and possible rattling.

In my opinion, you should always install a new hub with a disk with new holes. This is needed to allow the hub tabs to mate and embed evenly into the new disk holes.

[sapote]

They're made to work with the Beisan oil pump disc so the tabs are slightly thicker but not wider.

This brings up more confusion.
1. Do Beisan new disks have smaller holes than OEM disk? I assume so as people bought them to fix the loose OEM holes.

2. He said the new hub works with OEM new disk which has the larger holes. This means the new hub has larger tabs to reduce the hole clearance, and this means his hub with larger tabs won't fit his small holes disk.

[DJAM3]

They're made to work with the Beisan oil pump disc so the tabs are slightly thicker but not wider.

[sapote]

[
The Beisan exhaust hub is a replica of the BMW exhaust hub, but incorporates a thicker wall and tabs
The Beisan hub tabs are the same width as the BMW hub tabs. Thus the Beisan hub tabs fit the Beisan oil pump disk with smaller holes.

The Beisan exhaust hub should always be installed with a new Beisan oil pump disk.
Used oil pump disks have indentations in the holes sides from embedding exhaust hub tabs. Due to the increased width of the Beisan hub tabs, new non-indented disk holes are best for allowing proper tab matting and embedding in the disk hole sides.

I'm confused:
1. a thicker wall and tabs
2. The Beisan hub tabs are the same width as the BMW hub tabs.
3.increased width of the Beisan hub tabs

In (2) he said the tabs have the same width, but in (3) he said the tab width was increased. Can someone verify that the tabs have thicker wall, or wider width?

[Maxima SE]

Excellent product at an affordable price. Wish it was around when I bought a new hub from BMW about 5 years ago for twice the price of this. Thank you for everything you've done for this platform.

[terra]

Guys I really appreciate the comments. And my Vanos is a top priority for me. I know it needs to be addressed. But can anyone answer my original question. Is their a Vin number or a build date when BMW switch their hub making process

I’m sure there is but only bmw knows what the exact cutoff is. Either way it doesn’t buy you that much extra time, so just order the disc and get down to it.