Project Diamondback...

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Ajax Bay

Guru
Location
East Devon
Altus hubs
Maybe, but more probably (going on the first image in thread (which shows rim) and see linked image):
Hubs: Shimano STX Parallax
Rims: Araya TM-18
How about this servicing video
 

Ajax Bay

Guru
Location
East Devon
The 'Parallax' concept is spread across a lot of the Shimano range, instead of the hub being full width they made it narrower and stuck spacers on the NDS just to even up spoke tension between the 2 sides.
I can't see that makes for a stronger wheel. Effectively you're dishing (with its weakening effect) the left side of the wheel. Why would evening up the tension between left and right side spokes be a 'good thing', I wonder?
 

raleighnut

Legendary Member
I can't see that makes for a stronger wheel. Effectively you're dishing (with its weakening effect) the left side of the wheel. Why would evening up the tension between left and right side spokes be a 'good thing', I wonder?
Bear in mind that a bike is effectively 'hung' from it's axles in that the weight is taken by the spokes at the top of the wheel, the more 'even' the tension on the spokes then the less lateral deflection occurs.
 

Ajax Bay

Guru
Location
East Devon
the weight is taken by the spokes at the top of the wheel, the more 'even' the tension on the spokes then the less lateral deflection occurs.
Well, if we assume spoke tensions of 1000N (left) and 1400N (right) at 'rest' and a 32 spoke wheel, and then add 600N of rider + bike weight as a load on the hub, using your 'hanging' model, the top 8 spokes (say - the other 8 in the top half will take a bit but much less) will have to take that extra 600N. I haven't done the maths but the top two (ie almost vertical ones) will each take an additional 100N (less actually). But won't they take that load equally? The wheel doesn't say to the right spoke 'oh you've already got 1400, I'll give your left side oppo who's only got 1000, more than you'. So there will be no lateral deflection. And if the 'Parallax hub' means that the spoke tensions left and right are closer, it still won't have any beneficial effect (other than allowing all the spokes to be the same length, perhaps, but now I'm clutching at spokes). Forgive if I have this wrong.
 

Ajax Bay

Guru
Location
East Devon
Another glorious 80's product

1990s - 1996 or 1997, I think.
 
OP
OP
RegG

RegG

Über Member
Location
Nottingham
Thanks guys for the help on the hub service question - all done and running nice and smooth. Surprisingly, the bearings were both in good order with no corrosion or marks etc.

Next problem is the seat post - it is simply seized in the seat tube and doesn't want to move! Any suggestions? I have sprayed GT85 around the top of the seat tube, so far, to no avail. Do I need to heat it up?
 

Ajax Bay

Guru
Location
East Devon
Do some searching on Cycle Chat. Seized seat posts have been done to death and there is lots of good advice (with decent scientific foundation).
Edit: @Yellow Saddle will likely help. In a different thread he said:
"Aluminium seatposts regularly get stuck in all sorts of frames, especially if they are greased.
The mechanism by which this happens is galvanic corrosion. that produces hard aluminum salts which you can see as a white substance with the consistency of salt. The oxide molecule is many times larger than the parent aluminium molecule and thus swells the seatpost to a point where it is stuck. It is very, very common, even with carbon frames or aluminium frames with carbon posts. . . . Water enters by dripping down the seatpost and moving via capillary action (and even gravity once it is past the clamp) . . . it will still get stuck and should therefore be removed periodically. Once it is really stuck, it requires hacksaw surgery to remove it, no chemical can undo the damage in there."
 
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OP
RegG

RegG

Über Member
Location
Nottingham
For anyone who may have taken an interest in this little project, heres a pic of the frame and forks on their return from the powder coaters.....
DSC04036.JPG


Very pleased with the result and the colour (chosen by the bikes owner, not me!). I used a firm called M & R Refinishing in Nottingham (http://mandrrefinishing.com) who explained everything they would do to the frame beforehand and gave me an excellent quote. They also powder coated the cranks and handlebar stem in black for me.

Just awaiting some new decals which I will apply before getting onto rebuilding the bike.
 
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