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

[Apparition_Cycles]

your “intermediate option” looks better to me

otherwise you could explore this :



maybe a beveled option derived from the likes of Thomson could be explored (the original angle could be integrated in the bevel)

 

[Guinessisgoodforyou]

@novocaine has already told you what you need to do. You need the clamp opposite some material to pull against.

 

[Fatboy1974]

I know. But if we want to preserve the essence, this is the way. The easiest, cutting the seat tube at 90°. A lot of ways on the middle and none if that will be good enough for all. Ive been designing bikes and components as freelance during 18 years, so I hve some experience. With Fea analysis i expect to gain around 25% less tension, and 7075T6 also has 20-30% extra strenght. So will be enough maintaining the essence

 

[Guinessisgoodforyou]

I know. But if we want to preserve the essence, this is the way. The easiest, cutting the seat tube at 90°. A lot of ways on the middle and none if that will be good enough for all. Ive been designing bikes and components as freelance during 18 years, so I hve some experience. With Fea analysis i expect to gain around 25% less tension, and 7075T6 also has 20-30% extra strenght. So will be enough maintaining the essence

Good luck.

 

[Imlach]

It's a wholly faulty design and trying to recreate something shit just because it looked cool is a bad idea

 

[Woz]

Going way back in bike history .... deliberate gouging and pinching has been used. See little red parts very crudely drawn that is formed in the clamp which effectively have the aim to score and create an indent in the frame. There's no way it would move. The tolerances would need to be very exact to balance scoring vs actually putting it over the seat-tube, hardness of material fully understood, would be totally concealed from view, you get 100% "essence" from an outside appearance if that is your main goal.




Inspired from these. 1950.



Likewise, this was a totally daft, senseless, ill thought out design. Exactly like this frame and seat clamp you are wrestling with.

 

[Woz]

Another alternative is a shallow groove in the clamp, and a steel split O-ring inserted in it to help create a score in the seat-tube.

 

[Fatboy1974]

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.

 

[Guinessisgoodforyou]

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
View attachment 768907View attachment 768908

There is absolutely no hating here. All I said was you had been informed what you needed to do. Yet you are continuing with a flawed design. When as an engineer you should be putting it right and re designing the clamp to work properly. Just my opinion and if it offended you in anyway my apologies, that was not my intention.

 

[Fatboy1974]

There is absolutely no hating here. All I said was you had been informed what you needed to do. Yet you are continuing with a flawed design. When as an engineer you should be putting it right and re designing the clamp to work properly. Just my opinion and if it offended you in anyway my apologies, that was not my intention.

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.