Author Topic: Why I want an old 856 frame (Read 3848 times)

Simon · « **on:** February 02, 2005, 08:56:51 am »

Thought I'd post what I was (roughly)proposing to do with an old 856 frameset(if I can get hold of one) and would be interested in any comments or suggestions,its nothing new and I've noticed a guy called called Caltimiras has posted something similar for an 857 in the files section,mine differs in the refabrication and repostioning of the strut and using lower link arms from a Vector2 fork,you may ask why,firstly I will now have the option of many types of shock as the i2i will be around 160mm with standard type eyelets,increased travel but I haven't investigated what sort of travel would be achived,may be lighter with some air shocks the shorter strut should compensate for the link arms and any strengthening,loads more mud clearance at the strut shock end,but mainly because I can,always loved the 856, exceptional climber with that short shiney no flex s/arm,this is why I want an old one to experiment on I don't want to mess up my wifes 856 I've had it a long time. [smiley=beer.gif]

Simon

shovelon · « **Reply #1 on:** February 02, 2005, 09:47:36 am »

Nice,

Lenthening the lower strut mounts located on swingarm would spread out compressiion forces in middle of swingarm if you have room.
Do you know what alloy is used on swingarm. I would reckon 6061 on this earlly model. 1996 model year Proflex was not produced in high volumes to use 7005 unless speced with Easton material. The box tube and blocks were rare in 7005 at that time.

Terry

jinder · « **Reply #2 on:** February 02, 2005, 12:16:03 pm »

Simon... Here is a 856 Frame for sale on ebay. Its $50 right now - good luck mate!

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=22679&item=7131500871&rd=1

Or a complete 856 in excellent shape ($100)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=27948&item=7132133346&rd=1

will · « **Reply #3 on:** February 03, 2005, 12:56:01 am »

Simon,

This is cool. I hadn't thought of using an old Vector link. Beautiful idea and elegantly simple.

I'm working on a threaded insert for the old cantilever brake bosses. This is an ideal reinforced spot to connect the lower link on either side of the wheel.

I'm inspired to move ahead on this project!

Will

Simon · « **Reply #4 on:** February 03, 2005, 03:59:33 am »

Thanks Shovelon,haven't got around to getting all the alloy info yet,all still in my head at the moment,you had adviced me in a previous posting about spreading the strut load when mounting the pivot centrally and have taken that on board,I will be contacting you for more advice should things actually progress, [smiley=beer.gif]

Will, think I just had one of those inspired moments regarding using the Vector2 lower link,I've got a spare set of old Vectors lying around so I'm partly there [smiley=nod.gif],I hadn't thought about using the threaded insert for the strut mount,I'm going to completly remove the rear strut mounting and the canti threaded mounts,then I intend to weld on new strut mounts (with a longer base) at the old canti mount area,good luck with your project just hope I can get mine going. [smiley=beer.gif]

Jinder,thanks I'm on it so hopefully something will come of it. [smiley=beer.gif]

Simon.

kiwi · « **Reply #5 on:** February 03, 2005, 08:16:03 pm »

if you are going to puta mount through the seat tube i hope you are going to strengthen the frame by blocking the gaping hole already there.(Ihave a genius for stating the obvious)

will · « **Reply #6 on:** February 04, 2005, 12:17:15 am »

Simon,

Spent some quality time staring at the 856 last night and holding my old vector link up to the frame. A few things came clear.

You're right about the swingarm mount. As simple as the brake bosses would be for a mounting point, even with their masive weld, the point loading would be massive. (But, can you TIG weld thin walled aluminum? Yikes!)

On my medium frame, this would be a very compact installation. There isn't much room for error.

Since the cable pass through is heavily reinforced, it might be good to mount the pivot to a "bridle" that's anchored in that recess. Maybe by inverting the Vector link, the frame pivot could be drilled through that area and keep the shock i2i short enough.

NOW, the only hesitation is that I got my 856 down to 25 pounds... With a tubeless conversion, a lighter rear shock, and my Formula B4 brakes, she's headed for < 22 pounds. At this point, I hate to add more parts.

TTFN,
Will

Simon · « **Reply #7 on:** February 04, 2005, 02:06:42 am »

Kiwi and Will
Yep I share your concerns,hence why I want an old 856 style frame,I tend to come up with an idea and just do it, then if or when (as in the floating brake design) things don't work out I redesign and modify,as I don't have access to stress loading programs etc (doubt I'd no what to do with it even if I did) [smiley=laughing.gif] I tend to do what I feel will work,
as for the stress loading on the down tube I may add in a small gusset on the inner triangle on the down tube post along with a tube running through the frame for the swing link to mount on to,as this is a swing link and not a rocker link I don't think the stresses will be that great after looking at some other swing link bikes,
the mount on the swinging arm will just have small long(ish) tapered vertical beam to spread the load,remember Proflex have mounted the strut in this position in the past all be it on a cromo s/arm,
as for welding thin aluminium tubeing, I can't but I know a man who can [smiley=nod.gif],
as for the weight the swinglinks are only around 100g for the pair plus a little bit of aluminium added,ie through shaft,gusset,s/arm beam,
now I'm hoping to make a considerably lighter strut plus a light weight air shock and Ti bolts, I'd be very disappointed if it didn't come out lighter than origional,what I've also failed to mention is that while I'm at it I'm going to convert the s/arm pivots to sealed bearings an add a welded on disc adaptor,having said all this I don't recommend anyone to try the same (this is my disclaimer),mind you I'm talking all about this and I haven't even got a frame yet [smiley=laughing.gif].
Simon.

kiwi · « **Reply #8 on:** February 04, 2005, 11:29:03 am »

perhaps simon the link may have to be inboard of the seat tube.I try to imagine the curve of the back wheel,and i dont tink you will have any clearance problem but the inboard mounting of the link willl be a way around that issue

Simon · « **Reply #9 on:** February 05, 2005, 07:09:57 am »

Kiwi,should I ever get a frame and around to this I think your right and I will have to mount the swing link on the down tube and not through it,exactly where I'm not sure but it will be around the same area as I intended to mount it through the frame,probabaly using a welded on mount on the outside as the link is quite short (the drawing is not exactly to scale), if I mounted it on the inside of the mainframe triangle the swing links shock mount fouls the down tube,though I could make some custom links to suit,something to work on in the future.
Simon.

jinder · « **Reply #10 on:** February 07, 2005, 09:33:14 am »

Simon.. did you win that 856 frame on ebay?

Simon · « **Reply #11 on:** February 08, 2005, 04:45:49 am »

Quote

Simon.. did you win that 856 frame on ebay?

Yes I did [smiley=nod.gif],many thanks for the link Jinder [smiley=beer.gif] [smiley=beer.gif],
Its just been posted and I should get it in around 10 days,
this could be a longish project but things are coming together,sorted my welder and aquired some suitable materials to work with.
Simon..

jinder · « **Reply #12 on:** February 09, 2005, 09:13:51 am »

Quailty! I can't wait to see it!

I might be in England this spring...who knows...maybe I can come over and help out?

Simon · « **Reply #13 on:** February 10, 2005, 06:16:02 am »

Quote

Quailty! I can't wait to see it!

I might be in England this spring...who knows...maybe I can come over and help out?

Thanks,You'll be more than welcome.
[smiley=beer.gif]
Simon.

tmaybee · « **Reply #14 on:** February 10, 2005, 06:32:45 am »

Quote

what I've also failed to mention is that while I'm at it I'm going to convert the s/arm pivots to sealed bearings

Hopefuly the frame you just bought has the axle holes drilled in the center of the main pivot. I remember you saying your wife's bike did not. Both my 955 and 856 are drilled in the center.

Cheers,
Trevor [smiley=beer.gif]

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Author Topic: Why I want an old 856 frame (Read 3848 times)

will

will