New order, new colors!! Redesign Rocky Mountain tilted seat clamp.

No problem. But we're in a retrobike forum. We need to protect old designs sonetimes. This is a had design, but identifies the RM in early 90's. Im used to solve problems modifying things, but retro engineering needs to keep the design (changing materials, and only slightly the design keeping the essence). What Im looking to do. When you restore a retro bike, old car, etc you can not change to best design. Different objectives. No worries.
Perhaps you could make two? One for display like the original and a redesigned one for riding?
 
Perhaps you could make two? One for display like the original and a redesigned one for riding?
I need to do 5 or 10 identical to get a fair price in China. But not less than 25 €/each. If I had my own workshop, I will do several prototypes. I can't afford two different designs at this stage. Thank you for the idea. I will keep broken one.... And I will produce the last one I sent I think....
 
Thank you @Apparition_Cycles for the idea about Thompson. For all interested in using one of this. If you are not interested, please avoid to put commentaries without added value. As example "It is not going to work" has not added value. All the rest welcome. Here we have almost 11 mm of cilindric surface and extra at both sides. And estetics I think that match better with original ( despite all haters aroubnd here).
Now I need to see if CNC has same price. New bewel can be a handicap.View attachment 768909View attachment 768904View attachment 768905View attachment 768906
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Any thoughts? Would you agree in thi design if price is not increasing a lot?

@NigelFinnighan
@Carge
@Star12
@Apparition_Cycles
@jonnymcenroe
 
Hi, if it was me, I'd just replicate the original design.
It's not going to break that easily for the riding done on these.
My two 1993 Altitude ones have not snapped nor have they ever moved, but then I've never over-tightened it to cause the front to pinch together and that is with plenty of decent post out and in.
That over tightening is also a known problem with Marzocchi crowns cracking over time.

The two 1993 US and UK race bike had not snapped I looked at a few years back.
For me, the look and original design is the major thing, not ultimate strength.

It's a small part in a much flakier over all bike build with worse parts that will bend and snap somewhere (Syncros post and cradles, Syncros top caps, dodgy sus forks, lightweight rims, Alu nipples,..😂)

I get the feeling the others just want a replica for the same reason?

None of what Guinessisgoodforyou matters with these bikes.

BUT I'm not buying, as mine are fine.



(I have enjoyed reading about the process though, it is interesting :) ).
 
Thank you. very constructive post. I have some question for you @FluffyChicken :

Yes, I remember I had to overtight mine because my seatpost (Syncros Hardcoe 27.2mm) was moving all the time. I tight the bolt until the point that now I've seen that the bolt in my broken clamp is bent (bad sign which confirms your idea) . I broke it after only 30 km of standard riding on the woods. And my frame was new (NOS). It was not fatigue.
My concern is:

My unit broke because of overtight but mainly because seems a casted unit?
You experience with non broken units is with CNCd units?
On my experience, a 6061 or 7075 T6 machined should be 20-30% stronger that casted units. Only this should be enough to have an extra safety factor.

There are many points of view about improving the design, doing an hybrid design, or keeping the same, but this, yours, has a lot of perspective with your experience with same clamps in same frames.

I think that I will manufacture an almost identical one. I got a new price from China and maybe I can get them for 20-22$ each.

Thank you.
 
If I were you I'd say I'd improved the design vastly and made it strong like an ox, then I'd get them manufactured extra flimsy, but as the bikes never get ridden they'll never know. And you'd be able to buy a larger bulk of the clamps, so should someone be silly enough to ride their bike, you could have plenty of spares for them. Could be lucrative.
 
My bikes are not built and maintained to be hung on the wall so I like the idea of improving. But a stronger version of the original could work for me, if it’s possible. Mine did not crack but was missing from my Altitude frame when I found it so I stole the one from my Équipe frame and was about to cut the top tube of the later to solve the problem.

Here’s a sketch I made yesterday to see if the Thomson-like idea could work when inverted. I don’t want to impose it and I don’t think it’s better but might be explored. I think this one puts the bolt at the right place to reduce stress while keeping *some* of the angle. It’s only a contribution to the design options and it adresses some of the critics. The original angle could also be betrayed with non-parallel lines.

I think that we are spending 100x the time that has been spent in the nineties about this but, hey, it’s fun so why not. Congrats to you @Fatboy1974.

I have an architecture background so to me, options, critics, meetings and discussions are all part of a good design route and all feel natural.
 

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Would be nice if raceface or brodie or thomson would help us too.

If the redesign is faithful, the tolerances are tight and the materials thicker cut and premium, i'm all for it. Colour isn't a problem.

My local shop agrees 17mm should be enough and also recommends us to remove the step entirely. If you must make a step the ensure there is clearance from the post to avoiding binding to that instead of the frame itself.

Besides, who's to say the angle cut and finished on each bike is perfect. It will vary and the tolerances are of prime importance.

I remember my wanted ad for help finding a suitable clamp for my 95 hammer.
I needed a size which didn't exist and had to find a larger clamp and clamp it down tighter which is less than ideal.
 
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I thought about this and I did both options.

1.- A standard one, very similar to the original, but 15 instead of 13 mm thick.
2.- A mix of all ideas. Improved but not destroying the design, using Thomson idea to hide a wider design , lokking thiner that it is. I installed two bolts M5 ( instead of M6) to split the tension, and apply higher tension in lower ring of the clamp. A displaced only hole was ugly.
Last thought and I'm launching a 20 units order. Seems that I can get under 20-22 $ each so I'll take the risk and I will get 20.

In my opinion , option 2 is stronger (maybe 20-30%), tension is splitted , but it's not like the original. Divided hearth.

Maybe I would go for 1. At the end I willd ecide, but I like to know your thoughts (again), as potential customers ( customer always is right!).


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