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Steering Stem Ram Ball--Why Not?


JZH

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There are several ways to mount a 1" RAM ball into a steering stem, and I've probably tried most of them! The most obvious, perhaps, is to use RAM's own offset mount:

RAM-B-342.jpg

Unfortunately, in RAM's infinite wisdom, they have manufactured the rubber/plastic insert in such a way that it is both too big (the cylindrical top part) and too small (the tapered part) to fit snugly into a VFR's steering stem hole, which measures 19mm (3/4"), so it is fairly useless as delivered. I'm sure I could eventually find an appropriate 19mm OD hard rubber cylinder with a 6mm hole through the middle, but where's the fun in that?

So I decided to try something else. The big problem with a steering stem mount, btw, is keeping the ball from rotating once you've attached something like a heavy GPS unit onto a big lever (which is what a RAM arm essentially is) fitted to the ball. Things I've stuck into the stem hole in the past have tended to un-screw at inopportune moments, but my solution is admittedly another variation on that same theme: I bought a Pro-Bolt Aluminium Top Yoke Nut, which replaces the top steering stem nut on most Hondas (M24x1.0 thread), including my VFR750FP, VFR800FiY, RVF400RT, CBR250RRR and CBR400RRN:

PRO%20BOLT%20ALLOY%20HONDA%20TOP%20YOKE%

This same nut does not fit my VFR400RN NC30 (more about that later, perhaps), but does fit a huge number of modern Hondas. It's not cheap (£13/$18), but it helpfully already includes a nicely centred 7mm hole. The same nut (but without the hole) is also avilable in titanium from Pro-Bolt and TitanClassics, but I'm happy to use aluminum.

The OEM chrome top nut takes the same 30mm socket as the Pro-Bolt alloy one, so swapping the two is a doddle. Although the correct drill size to tap an M8x1.25 threaded hole is 6.8mm, the 7mm hole should be sufficient. (I used a centering tap holder from McMaster-Carr, I believe it was--helps keep the tap perpendicular to the surface of the work.)

20150315_152832x.jpg

 

I decided to use an A2 stainless steel socket cap screw and tightened it into the now-threaded M8 hole in the top yoke nut:

20150315_153146x.jpg

Which got topped with an M8 stainless steel lock washer and looks like this:

20150315_153230x.jpg

The RAM ball I'm using is a pn. RAM-B-273-M6 (about $8):

RAM-B-273-M6U.jpg

Ram does make a 1" ball base that can be used with an M8 socket cap screw (pn. RAM-B-367, about $13):

RAM-B-367U.jpg

But, it doesn't have any kind of flange on it, so I decided to drill out the thread on the M6 version (which I've done in the past--there's plenty of metal) using a 6.8mm drill bit and my drill press. (Individual metric drill bits in the appropriate metric tapping hole sizes are available at McMaster-Carr):

20150315_153311x.jpg

After a bit of "one-grunt" torquing, I had this:

20150315_160830x.jpg

 

Which, 105 Nm later, looked like this:

20150315_152637x.jpg

And, with a RAM arm attached, like this:

20150315_183434x.jpg

The RAM ball is fairly solidly mounted to the top nut, so I hope it stays put! If it doesn't, I suppose I could try using Loctite, or even fitting a tiny rolled pin or two? However, I am sure that the top nut itself will not loosen (105 Nm!)...

I want to fit one of these to each of my bikes (except for the RC46, as it has a tank-bolt mount already), so keeping the cost down was a consideration, and my total investment turned out to be about $25-28 each. As mentioned above, the NC30 has a different steering stem size, which I think is the same as the RC30 and a bunch of Kawasakis, but is unlike any other Honda, so neither Pro-Bolt nor anyone else seems to make a similar domed nut to fit that bike (I think the thread is M32x1.0). So if I want to do the same for that bike I will be looking at very expensive custom machining, unfortunately.

As I had enough parts, I made two of these today and will probably make some more soon. Now all I need is to test them... :wink:

Ciao,

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+1 on the RAM one sucking big time....

Yours looks very solid indeed, as well as a factory option.

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I bought one of those, gave up on it and bought a Telferizer mount which was simple to fit and looks great.

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Top yoke nut came in today. Just ordered a Ram Mount 1-Inch Tough-Ball with 1/4-20 X 0.25 inches male threaded post. Almost perfect fit to the hole in the top yoke nut. No drilling required. Less than $20 for the nut and the Ram Ball.

41RK0haBwhL._SX425_.jpg

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  • 5 months later...
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Top yoke nut came in today. Just ordered a Ram Mount 1-Inch Tough-Ball with 1/4-20 X 0.25 inches male threaded post. Almost perfect fit to the hole in the top yoke nut. No drilling required. Less than $20 for the nut and the Ram Ball.

41RK0haBwhL._SX425_.jpg

This may be a better option! I have now tested my idea and unfortunately, it doesn't work. :wacko:

Well, it does work, until a little extra leverage is applied to the RAM ball in a counter-clockwise direction, and then it unscrews--lockwasher be damned. This was just going to happen regardless of torque or threadlock, as leverage can easily overcome that.

So, as I've got a little adventure planned for the weekend, I have expediently pinned mine using a short length of 2mm steel brad. As this is now necessary to keep the ball from unscrewing from the yoke nut, it would have been better to use an M6 screw, as the M8 takes up space I could be using for the pin(s). However, as the Pro-Bolt cap I used comes with a 7mm hole, that is probably too loose to fit an M6 screw snugly. The 1/4-20 thread on this one is approximately 6.35mm OD, which is closer to the 7mm ID of the Pro-Bolt cap, but still too loose for my liking (it does have a lot of extra flange into which a pin could fit--however, it is plastic, rather than aluminum).

Which means that v2.0 will use the Pro-Bolt yoke nut WITHOUT the hole, and I will simply drill my own M6 hole (5mm for tapping, 6.2mm for clearance), use the same M6 RAM ball, an M6 screw and pin it from the outset.

And if that doesn't work, I can always weld them together! :wink:

[Edit: I managed to find an alloy NC30/RC30 top yoke nut after all. It only comes non-drilled, which turns out to be a good thing! The manufacturer was Lightech.]

Ciao,

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See a post by huntinggunns. He has a very slick unit that works perfectly.

I have one installed on mine and he graciously donated several to the SUMSUM3 prize pool.

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If anyone could think of a way to adapt a bicycle stem wedge style anchor for the RAM ball, that should be the strongest way to mount it to a motorcycle steering tube, because by design those will strongly resist turning because of the very high pressure, metal to metal interface between the stem wedge and the steerer tube.

Somethng similar to this?:

http://www.ebay.com/itm/Stem-Adaptor-22-2mm-to-28-6-mm-For-1-Threaded-Forks-Alloy-L-150mm-/131467365412?hash=item1e9c10cc24

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rmi-5083_ml.jpg


RAM Attwood/Fish-On Wedge Base with 1" Ball

Estimated Ship Date: 10/6/2015 (if ordered today)Would you rather pick it up? Select Location


Purchased and mounted . Pic's if anybody interested .


http://www.summitracing.com/parts/RMI-5083

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JZH, hail to you! I like it, a lot.

The little rubber insert RAM sold a few years ago drove me to writing them a email about their absolute Mickey Mouse design about two years ago.

I kindly pointed out how almost all bicycle mount their steers in my native Holland with a simple cone, showed them a picture of what my 84 year young dad in Holland machined for me in his workshop.

Finally, years later, RAM came out with two cones types 17-21mm and 22mm and up and they both work.

I wish to commend you for your good work, very elegant solution, and for not accepting the absolute crap RAM made at the time.

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