Author Topic: My 4500 mod unvailed. (Read 6649 times)

Ionit · « **Reply #15 on:** January 17, 2006, 06:18:02 am »

I tested if the swingarm will in any way impede with the drive train and so far I would say it won't cause any problems. Thanks to Colin for bringing that to my attention.
During my test I attached everything to the frame that would possibly interfere and shifted from large gear to small without any problems. But I realize this is just a mock up and does not have any conclusive evidence the new swing arm will not cause problems.

I found that the drive side bushing sticks out closer to the tallest ring. If this causes problems during prototype testing I can either used a smaller ring or find a way to reduce the bushing length and permanently eliminate any problem.

I will post a picture when I have it.

Oh Simon do you still have the link to the second linkage simulator. I accidentaly deleted it during instalation of the first linkage sim and lost some newer files. I looked all over and could not find it.

Simon · « **Reply #16 on:** January 17, 2006, 08:31:04 am »

Quote

.

Oh Simon do you still have the link to the second linkage simulator. I accidentaly deleted it during instalation of the first linkage sim and lost some newer files. I looked all over and could not find it.

Does this help

http://www.bikechecker.com/

http://fs-kinematics.igorion.com/index.jsp

Simon.

kiwi · « **Reply #17 on:** January 17, 2006, 04:46:10 pm »

small chainring large cassette...... [smiley=coolfrown.gif]

shovelon · « **Reply #18 on:** January 18, 2006, 02:57:46 am »

Last night I checked the geometries of my Oz and 957. Although the fitup seems perfect, there is a leverage difference.

Both my bikes are large size. The distance between the upper shock mount and swingarm pivot is approximately 1 inch shorter on the Oz.

My conclusion is that there will be a big increase in rear wheel travel by putting the x57 swingarm and strut on the Evo frame.

Given the increase in leverage also, there is quite an increase in tensile load on the bonded joints, as well as compressive load on the strut and shock. But given the strudiness of the strut and swingarm, my belief is that they can handle it.

Terry

Simon · « **Reply #19 on:** January 18, 2006, 06:44:44 am »

I make it the other

Quote

My conclusion is that there will be a big increase in rear wheel travel by putting the x57 swingarm and strut on the Evo frame.

Terry

Are you sure Terry

I make it the other way round
due to the strut located at the rear of the s/arm,
now if this was brought forward then the travel will be increased.
the simulator gives Ionits setup at 69mm travel with a 1.5
stroke shock,this gives a ratio of about 1.8 : 1
the Evo is about 2.7 : 1
I could be wrong but thats how I see it.

Simon.

shovelon · « **Reply #20 on:** January 18, 2006, 08:05:34 am »

Simon,

You are right in regard to the ratios. But he is putting the strut on the Evo. The distance between the upper front pivot and lower front pivot is narrower on the Evo thereby increasing the amount of travel when the shock is compressed. This increase in travel also increases the leverage on the shock.

As I recall, the distance is 11 inches on the x57 as opposed to 10 inches on the Oz. Since the strut is somewhat more horizontal and the wheel is still traveling in a vertical direction, leverage has no choice to increase. But that will yield more travel.

Don't get me wrong, I like what I see, and am fascinated by what mayl emerge from this project. Stiffer rear end, and nice travel is what I am hoping for(and light as hell). And the old strut bikes were rock solid. This may be the best of both worlds, rock solid rear end on a carbon triangle.

One thing that does come into play is that the evo front pivots are lower not only between each other, but closer to the BB. However the rear axle remains the same. This is one more reason that I feel the way I do.

All this could become mute if the upper plates are modified to some extent.

Terry

Ionit · « **Reply #21 on:** January 18, 2006, 04:42:25 pm »

Ok so the picture doesn' help much but you can make out enough that the space for the chain is ok. I cycled the chain form the tallest ring to the smallest and kept the chain on the 11 tooth cog and nothing came in contact.

By the Linkage symulation I can modify it from 4" to 3" and get a fairly good ramp up.
Simon is right for the ratio. I would like to squeeze out a little more then 1.5" to 3" but I guess at base it would sufice. It would probably be more comprehensive if you see it in the symulator. Here is the file I am using for the demo Linkage modifier http://www.alexlori.ca/Proflex999.LTX that Simon posted a link to (http://www.bikechecker.com/ )
I am not processing anything in my head that is beyond my thought capabilities like leverage ratio's. I can imagine the differences one pivot point has over another. What I cannot imagine its relative itineration or proportion of force applied to the frame. After all I don't want to shear bolts and pivots.
And I hope I don't make a mute feeling as Shovelon expressed. He is right though, as you bring the pivots closer together theoretically I would need to use a exponentially stronger spring. Maybe I can tune it by changing the pivot location. I've already done that in the simulation with good results I believe.

Simon · « **Reply #22 on:** January 19, 2006, 06:02:55 am »

Very impressive,
I think you need to use a 1.75" stroke shock, this will yield around 81mm (3 3/16")travel more than
enough for a fast XC bike,
with the shock ratio at 1.8 : 1 you can use a softer spring if you leave the mounting points in there current position, this would give better small bump compliance
without running much sag,basically higher the travel to shock ratio
stiffer the spring needs to be (think I got that the right way round,anyway I know what I mean [smiley=laughing.gif]),
I can see this turning into a very light weight, fast,stiff,
XC trailblazer,maybe Proflex should of stuck to the prototype design.
Simon.
PS your simulation looks just like the one I did [smiley=laughing.gif]
though you have the shock stroke set at 42mm I have it set at 39mm.

Carbon_Angus · « **Reply #23 on:** January 26, 2006, 03:08:07 pm »

finally read this thread....fascinating!!!!

I can check some stuff on my Team Bike for anyone interested....won't be till Sunday though....

[smiley=beer.gif]

Ionit · « **Reply #24 on:** January 27, 2006, 01:21:17 am »

First congratulations on the new frame Carbon Angus. That offer is as good as it gets. It is not often you are able to purchase a brand new Proflex in this day.

Even though your new frame (being size XXL) I presume that all pivot bolts are in the exact same position and configuration in relation to one another as other strut bar Proflex's.
Do you know what I mean? The designer of this bike used a 3000, 4000, 5000 frame because it provided a base to accommodate tall people without changing the proven mechanics of the production smaller frames. The distance between the pivots are all in the same place proportionally.

I would be happy to check it on the linkage checker. All I need is an orthographic photo of the bike. But a side view is probably the best that will come. Note taking side shots for dimensional trueness is best when standing away from the bike several meters leaving allot of border around the bike. This ensures that the camera is receiving more parallel light from its focused object. If your to close objects tend to distort.

But again that is a great bike. If it was only available in a small size. You are the envy of every one on the forum.

Carbon_Angus · « **Reply #25 on:** January 29, 2006, 01:09:16 pm »

check my other post about the bike...I can get a better straight~on photo for you in a few days..send me a PM if you want and I can measure it for you anyway you want.

[smiley=beer.gif]

Ionit · « **Reply #26 on:** January 30, 2006, 04:03:54 am »

The one you have in your gallery is good. Don't worry about the new photo.
Re measuring: sure why don't you measure it. I wonder how diffrent it is from the others types built at the time.

Thanks.

Oz-SUB · « **Reply #27 on:** February 03, 2006, 02:23:18 am »

My Christmas present to myself was a Fox DHX Air 8½" i2i / 2½" stroke (gives 6 -6½" travel).

However, the main air charge shrader valve and its locating body material, means that a slot has to be cut into the frame pivot plate on the chainring side and a lump cut out of the frame's central rib!!!

I was going to risk milling the carbon thermoplastic to suit, as it does seem very strong in this area (with the plates and all).

I see from your photo that you have removed these plates, excellent, as I thought they may be bonded and riveted onto the frame. Anyone - comments and where would it be possible to buy the correct rivets and carbon / Ti plate to make new but modified plate with slightly moved (backwards) shock pivot holes?

regards Oz-SUB

Oz-SUB · « **Reply #28 on:** February 03, 2006, 02:51:11 am »

Ionit, from the photo of your frame, were the frame pivot plates bonded on as well as rivited?

What size drill did you use and what rivets do you intend to put back in?

Anyone know where similiar thickness plates could be purchased in the UK?

I'm asking, because I'm taking the brave step of trying to mod my Oz frame to take a Fox DHX Air shock.

shovelon · « **Reply #29 on:** February 03, 2006, 02:51:35 am »

Hey Sub,

I see what you mean with clearance. Just a thought, but if you want to keep the carbon, can you use the existing plates? Could you redrill a hole somewhat away from your existing hole to gain the clearance on the frame backbone? Could you then cut a slot into the old mounting hole?

Otherwise, aluminum plates would work too. 7075 alloy plate is the bomb for strength and lightness. It has mechanical properties close to steel, and is 1/3 the weight. And is stupid easy to fab, using woodworking tools. Looks good polished.

As far as rivets, as long as you are destroying the old ones, you could drill them out, ream, and install steel rivnuts. That way you could remove the plates when desired.

I am interested how your endevors turn out. Very fun.

Terry

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Author Topic: My 4500 mod unvailed. (Read 6649 times)