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PostPosted: Mon Feb 13, 2012 9:01 pm 
Old School Hero

Joined: Mon Dec 05, 2011 1:05 pm
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Location: Wales
Interesting frame and story.

It's 100% certain alu/alloy. It just hasn't been polished. Aluminium looks pretty rough unpolished, just like that.


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PostPosted: Mon Feb 13, 2012 9:56 pm 
Old School Grand Master
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Location: Antwerp, Belgium
racer x wrote:
Probably was being built a downhill racer 8) what if there was going to be disc specific for some of the first disc brakes at that time :roll: pro stops or something :D


eek ! Early disc brakes? :shock:
Please no !

However you might be on to something. It could be a downhill racer after all.
I just took the 828's swingarm off, and was surprised by what I saw.

Image

Image

No bearing at all, only a pair of huge bushings. So despite looking more refined on the outside, the production models appear to be rather prehistoric underneath.

The only pictures I've seen so far of Sbike swingarm pivots, were from the carbon model, which perhaps needed a more advanced pivot mount to reduce the stress on the rest of the frame.
The 828 I just took apart was one of the highest spec models you could get, so it stands to reason that the other alu Sbike fullys utilized bushings as well.
If the production models didn't have bearings, this is either a prototype or a downhill model that was never built.

I'm still not too sure on its age. It could be an early fully prototype that was never completed because it was too ugly. I mean ... Look at the first pic in this thread, and you'll see that the main spar was smaller than the swingarm. It certainly would have been difficult to get the Sbike name on the sides as well.
Even I have to admit that it's not a good looking frame, so I wouldn't be surprised if they ditched it before it was completed and moved on to the flat-sided designs.
It could also be a late prototype that was never completed. The slots in the proto's swingarm are identical to those on the 828's swingarm, but the proto's covers/cups don't have the bits that lock into those slots. So maybe this was intended to be an evolution of the fully models rather than a predecessor.

It's interesting and intriguing either way. I hope that someday I can get answers to all those questions.


Last edited by Raging_Bulls on Thu May 31, 2012 12:02 pm, edited 2 times in total.

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PostPosted: Mon Feb 13, 2012 10:06 pm 
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Hay what if that rear end works on you Prototype it mite only need spacing with some spacers or none at all 8) you could spray the front end up silver to match to rear end or vise versa polish it all :D

Are the brake and gear cable stops any good for the proto are they the same widths


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PostPosted: Mon Feb 13, 2012 10:34 pm 
Retro Guru

Joined: Sun Jun 19, 2011 9:44 pm
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Location: wirral
wondering if it wasnt cleaned up/neater welds as its a prototype maybe one of a few?
poss one for the following season,but if you see new models of cars(bmw/audi/merc nearly all car makers) try to desguise the new model from photographers and the competition so are quite low key in apperance b4 they go on public view. :?


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PostPosted: Mon Feb 13, 2012 10:37 pm 
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Very nice find, especially wtih the matching stem. 8)


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PostPosted: Wed Feb 15, 2012 5:53 pm 
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8)


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PostPosted: Wed Feb 15, 2012 7:09 pm 
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So you bought it in the end! That's cool mate! Very glad it's in good hands now!

Love to follow this build!


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PostPosted: Wed Feb 15, 2012 11:22 pm 
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Quote:
Why does the outside look so different in colour and structure than the bare alu of the 828?


The 828's been polished and lacquered. The proto is raw aluminium (plus a bit of oxidation). That's what it looks like :)

About the bearing/bushing thing: The lack of bearings in the 828 doesn't necessarily mean that your proto doesn't predate the 828. It's entirely possible that protos were made with bearings but production used bushings on cost or weight grounds. It's not as peculiar as it seems to use bushings -- suspension pivots move in a small arc at relatively low speed and take a lot of load, which bushings (especially big ones like those) are good at handling.

And +1 for not worrying about the shock mount -- that's more weld than most shock mounts have.


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PostPosted: Thu Feb 16, 2012 12:16 am 
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Sorry for multiquoting, but I'm not going to submit 4 posts in a row.
The topic will become long enough anyway.

racer x wrote:
Hay what if that rear end works on you Prototype it mite only need spacing with some spacers or none at all 8) you could spray the front end up silver to match to rear end or vise versa polish it all :D

Are the brake and gear cable stops any good for the proto are they the same widths


The 828's rear end fits the proto frame if I really want it to. The pivots are the same width. As long as I use the caps that came with the proto, it should be fine.

However the 828's swingarm has a few (minor) dents in it, and that's enough to ruin it for me, especially for this bike. I'm really not going to cut corners on this kind of build.
Also, the clean welding on the 828's rear end doesn't match the rough welding on the proto frame.

As for the cable stops, those do fit. The main spars are exactly the same width, so I can drill out the rivets on the 828 and use that one's cable stops on the proto.
The 828 frame is broken anyway, so it'll be cannibalized completely and then scrapped.

As for the paintjob, the most common colour for the full suspension Sbikes is the red frame with aluminium-coloured rear section.
Unless I get information about prototype-specific colours, I'll probably go with that.

-----

mtbdave wrote:
wondering if it wasnt cleaned up/neater welds as its a prototype maybe one of a few?
poss one for the following season,but if you see new models of cars(bmw/audi/merc nearly all car makers) try to desguise the new model from photographers and the competition so are quite low key in apperance b4 they go on public view. :?


Low key in appearance ... I'm afraid that'll be rather difficult for an Sbike.

There's no real reason why they would build the proto to look different than the production model. I've been measuring a bit, and it has the exact same geometry as every other Sbike fully I have data on.
In fact the geometry is the one thing they never really changed throughout the years and models (except for the differences between rigids, hardtails and fullys)

-----

stumpjumper1990 wrote:
So you bought it in the end! That's cool mate! Very glad it's in good hands now!
Love to follow this build!


Yup. I bought it with the intention of selling the fork and hanging the frame on my wall.
However once I started comparing it to the 828, I realized that it might be the real deal and decided to build it.

-----

MikeD wrote:
The 828's been polished and lacquered. The proto is raw aluminium (plus a bit of oxidation). That's what it looks like :)

About the bearing/bushing thing: The lack of bearings in the 828 doesn't necessarily mean that your proto doesn't predate the 828. It's entirely possible that protos were made with bearings but production used bushings on cost or weight grounds. It's not as peculiar as it seems to use bushings -- suspension pivots move in a small arc at relatively low speed and take a lot of load, which bushings (especially big ones like those) are good at handling.

And +1 for not worrying about the shock mount -- that's more weld than most shock mounts have.


Thanks, Mike. That could explain the difference indeed. Looks like I'll have to look for a good polisher then. I really don't want a mirror finish, but something similar to the 828's swingarm.

As for the bushings, I was thinking the same thing today. While a ball bearing might be smoother, it needs to handle a lot of stress and will not rotate much.

It could indeed predate the ones with the bushings. Perhaps it was the first one they made, and was never finished because there was "an issue with the styling" and/or because the bearings pushed the price up too much.
However right now that's just speculation. I hope to get an answer soon.

I guess I can stop worrying about the shock mount indeed. The 828 is only welded on the outside too, and the welds were strong enough to withstand whatever hit tore the seat tube in half.

Image

Still is scary though. I really want to lose 20lbs before I get on the proto, just to avoid the above picture.


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PostPosted: Thu Feb 16, 2012 12:48 am 
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Are you not going to bolt that rear end on just to see what she rides like as a mock up at least you can try it all out be for you have brake bosses welded on the other, i would just to see if it all works 8)

the proto would look good in black gloss with red decals :D what was you thinking of 8)


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