this...or am i too naive???
i dont know if you will be able to find a manufacture that will do a one off proto with the possiblity of no production. Might look for a smaller custom builder or somone like zen. If you do find somone, it will be expensive probally around 8-10k for the frame, if you have everything speced out for the builder. Engineering drawings, cad files for the machined parts, tube profiles, ect. If you dont have any of that, your cost will go up. If you got the cash and the want go for it, ride it, learn from it, and have another go at it.could i maybe come in contact with some factory in far east to build one for me?
it that possible? how expensive would it be?
1. It doesn't have to be progressive. I know it's preference but looking at many designs it is very progressive (and they use springs too) Also why it is progressive right after sag point to get linear only later? Unless you want it to run more than 33% sag.it is 267 x 90mm (10.5” x 3.5” as most dh bike companies use nowadays. it offers more adjustability and higher shock longevity.
it is progressive as it should be, cause of the linear nature of the springs.
in the end the lr regresses to ensure that the shock won't bottom out harshly.
i had many issues to overcome in the design, such as chainstay length, shock-wheel clearance, bb height, rocker arm low pivot-bb clearance, centralized and low centre of gravity.
i have some detailed cad drawings and started also to work on solidworks.
don't know if i can move forward producing it myself, maybe giving it to a company and sell it.
or am i too naive???
didnt see the pulleywith the pulley as shown, i have a very low pedal kick back, and a chain growth of only 12mm.
so no problem and no gearbox needed.
View attachment 112228
1. as you said it is preference. linearity for me suits better with progressivity. mostly dh bikes now choose progressive lr.
2. yeap, english is not my native language, especially technical terms.
3. i know, but i believe that 10.5'' is the best suited here. i can adjust it though for an 9.5 spring. preference thingy again.
thank you for the feedback! jeep it up!!!
1. take a look:
NOW look at mine:
View attachment 112237
i guess that's enough...
2. 10.5 is used by wilson and the new gambler. more to come i guess! preference though as i said before.
i am an engineer, i'll make a finite element analysis, although i am not sure i'll go that far.
That's actually not true, a higher leverage ratio in a given part of the travel will allow the wheel to move more easily (eg. out of the way of a bump) in that part of travel - thus a more progressive early stroke will generally give better bump absorption characteristics. This is actually quite handy, as you can build lower pivot bikes that have better bump absorption characteristics than their pivot location would otherwise allow.1. It is not true that most dh bikes are progressive. Not that progressive. Some went a bit more progressive but for example Trek made the carbon session a bit less progressive for it to behave better on the rough tracks. Demo is very linear even if it got a bit progressive in the last iteration. Most plowy bikes are more linear than progressive. My legend is even a bit regressive at the end.
Linear leverage rate is better for the rough but it is also better for shock setup imho. You can easily make the design much much more linear and still have a bike that bottoms out very rarely. Also a linear shock + a fairly linear bike(very few are a total flat line that doesn't change) doesn't mean the bike will be easy to bottom out.
you mean regression. when the lr is progressive, in a certain amount of travel, the leverage is lower than that in a regressive, which means that less force is exerted to the shock and thus, less compression.The downside of increased progression is that you also use up a lot of travel very easily, and this can result in a somewhat wallowy and unstable ride. However with that said, I don't see the need to go very progressive on a high pivot bike, as bump absorption characteristics are already excellent.
That's actually not true, a higher leverage ratio in a given part of the travel will allow the wheel to move more easily (eg. out of the way of a bump) in that part of travel - thus a more progressive early stroke will generally give better bump absorption characteristics. This is actually quite handy, as you can build lower pivot bikes that have better bump absorption characteristics than their pivot location would otherwise allow.
The downside of increased progression is that you also use up a lot of travel very easily, and this can result in a somewhat wallowy and unstable ride. But there are clever ways around this, as linkages allow the L/R curve to change shape at different positions in the travel. Shock setup can be a bit more difficult but it hasn't really been an issue in my experience. However with that said, I don't see the need to go very progressive on a high pivot bike, as bump absorption characteristics are already excellent.
Nah, I meant progression. I believe if you have a straight LR curve where the LR number is high at 0mm of travel (say 4:1) and is low at 200mm of travel (say 2:1) then that bike would be defined as progressive - even though the LR is getting lower as travel is used.you mean regression. when the lr is progressive, in a certain amount of travel, the leverage is lower than that in a regressive, which means that less force is exerted to the shock and thus, less compression.
Don't really agree with that either, as you end up with a frame that is heavily dependent on a progressively valved damper to work correctly (unless you want to run an air shock, which comes with its own set of drawbacks). The Legend for example would struggle to function well without an RC4, same story on the Sunday.I'm stupid, you are right. should have remembered that. Still the frame has some progression after sag. I'm not really a believer that dh frames should be very progressive in the latter part of the travel.
Don't really agree with that either, as you end up with a frame that is heavily dependent on a progressively valved damper to work correctly (unless you want to run an air shock, which comes with its own set of drawbacks). The Legend for example would struggle to function well without an RC4, same story on the Sunday.
Take that shock away from either of those frames, and you end up having to compromise between maintaining bump performance and maintaining acceptable travel usage.
But even with the appropriate shock, I think there are other concerns, for example damper progression is unidirectional (for lack of a better descriptor) so you don't get the 'pop' on the return stroke that you would from a bike with mechanical (LR) progression - because in that case the spring would return the stored energy as opposed to the damper dissipating it. I think that's part of the reason these particular bikes (when sprung and damped correctly) are less poppy than more progressive alternatives - and personal preferences for pop/plow aside, this results in the bike requiring more rider input and energy to clear obstacles.
my mistake, ****ing english terminology...Nah, I meant progression. I believe if you have a straight LR curve where the LR number is high at 0mm of travel (say 4:1) and is low at 200mm of travel (say 2:1) then that bike would be defined as progressive - even though the LR is getting lower as travel is used...............I believe our understanding is the same, perhaps you are just defining it differently.
this is a characteristic of the regressive lr, not the progressive. (for about the same starting leverage value-that is in 0mm wheel travel)The downside of increased progression is that you also use up a lot of travel very easily, and this can result in a somewhat wallowy and unstable ride.
Nope. Udi is right on that right. Don't think of it in terms of - progresive/regressive but in leverage ratio alone. A progressive bike at the end is hard to bottom out because the ratio goes to low numbers and you need more force to compress the shock but with progressive begining you get a high leverate ratio in the fist part of travel.my mistake, ****ing english terminology...
this is a characteristic of the regressive lr, not the progressive. (for about the same starting leverage value-that is in 0mm wheel travel)
in the progressive you have a more strict use of travel, cause for a certain amount of travel you have less leverage, than on a linear or a regressive lr.
A progressive bike will start soft and end firm. A degressive bike will start firm and end soft.the santa cruz (regressive) can reach eg 50mm of travel, quite more easily for the same bump, compared to the rocky mountain (progressive).
this means that the regressive lr uses easily a lot of travel...
unfortunately i think you are wrong.the progressive bike will have the tendency to use the initial travel more easily than the regressive bike, as the LR is higher at that point.
That is untrue.unfortunately i think you are wrong.
the regressive lr uses more travel for the same bump. the mechanical advantage gets higher through the travel, this is why.
in a progressive lr the mechanical advantage reduces...
and for ****s sake, we are talking about leverage rate, NOT bike rate (shock rate related to wheel travel) which is the inverse (opposite relationship) of leverage. (in bike rate we use the terms rising rate and falling rate)
the diagrams that i put show the Leverage Rate.
THIS IS WHY regressive LR use the initial travel more easily than progressive, FOR A CERTAIN BUMP/.A degressive bike as it was pointed out starts hard and ends up blowing through travel at the end. Progressive is the other way around.
Nope.unfortunately i think you are wrong.
Agreed, but I think it's understood now.I think the confusion of terminology of progressive/regressive is because:
The leverage rate curve is an inverse of what people normally find intuitive.
I haven't really apart from a brief carpark test, but I think the LR curve on that bike looks very reasonable. If we believe the linkage file, heavy ramp-up only starts after the 200mm mark. I'd ride the Devinci quite happily, I think it would be an excellent bike. The 951 you mentioned on the other hand has a ridiculously progressive curve (it apparently drops below 1.5:1 in 8" mode, insane given a 3" shock).Though can't we get back on topic. Udi have you tried devinci? I really wonder how progressive is too progressive for linear shocks like ccdb? I'm not a fan of super progressive bikes but yeah, legend is too linear (it is regressive at the end too) but unbottomable bikes are silly.