Rear disc on 756?

[Thunderchild]

Anyone ever contemplate putting a disc brake on the short swingarms like on the *55s *56s, etc.  

Thunderchild
www.urmb.org

[shovelon]

Check out the rear of this beauty.

http://idriders.com/proflex/galleries/Simon/856_XC_faux_bar.jpg

[Simon]

Okay I must admit I am pretty proud of that bike
even if my brother is now using it, Lol it is still mine.

here's a link to apic of my 856 disc adaptor.

http://idriders.com/proflex/galleries/Simon/Phtocaliper.jpg

Simon.

[Thunderchild]

Simon,
That is one sweet piece of functional art.  Can I send you my swingarm for a similar upgrade???  I want to bless my 756 (rear stratos equipped) with disc.  See the pic(mislabeled as 755) at http://idriders.com/proflex/galleries/thunderchild/755_rear_shock.JPG

I will trade you a large 855 frame and vector fork for parts for the work (frame has a small crack), and that is not all.  I will throw in a Utah Rocky Mountain Bikers T-shirt.

Thunderchild
www.urmb.org

[shovelon]

Oh my gosh!

I never knew such a shock exist. How well do you like it? Did you graft it?

While you are at it, check the drive side front swingarm mount to see if it is gusseted. Later swingarms had this. May as well do this at the same time.

Terry

[orange]

I have a Stratos Stratashock like this too, but sadly not for my Proflex, but my Orange X1 (different adapter). Bought back in '96 it has remote lockout - something in its day! In fact I can see the lockout on the one in that photo too.

Never been serviced in all that time and believe me I have used it plenty!!

[Simon]

Simon,
That is one sweet piece of functional art.  Can I send you my swingarm for a similar upgrade???  I want to bless my 756 (rear stratos equipped) with disc.  See the pic(mislabeled as 755) at http://idriders.com/proflex/galleries/thunderchild/755_rear_shock.JPG

I will trade you a large 855 frame and vector fork for parts for the work (frame has a small crack), and that is not all.  I will throw in a Utah Rocky Mountain Bikers T-shirt.

Thunderchild
www.urmb.org

Thats tempting however finding the time these days
for such projects is getting difficult,also its hell of along
way to send a swingarm just for a disc adaptor that I
couldn't guarantee would fit your prefered disc system,as you can see mine is specific for that caliper,

however if you were in no hurry and sent me the swingarm I think I do something that would suit most caliper types or better still send your intended caliper with the swingarm,

I wouldn't want your frame and forks (I have too much stuff as it is)though a XL shirt would be very nice (go with the one Willem gave me) plus return postage cost and a little for the welder (a mate is a better welder than me)

anyway think it over something for the new year.

Simon.  

[Thunderchild]

Thanks for the response, I am not in a hurry and will think it over.  Might be able to find a local welder which brings up a few questions.  Did you have any concerns about warping or deforming the swingarm when it was welded?  Any other precautions, tips, alignment, etc.?  

As for the questions about the shock.  I got the entire bike on ebay with a matching shock with lock out on the Girvin fork for a pretty good deal.  THe previous owner did not know much about the bike.  When I got it the shocks had no air in them.  My guess is that Stratos did not make many of these shocks or we would have seen them.  I have contacted Stratos and they said that they DO NOT service the shock.  Amazing .  Both shocks work and hold air, but the front shock was short on travel(earlier Girvin too).  I had to air it up so high to avoid bottoming out that it had no rebound control.  If you have ever ridden a shock with out rebound control, you know what I mean.  It would snap back pretty fast after hitting a ravine or dip.  IT was all I could do to not go over the bars when it bottomed out.  It would be fine for smooth single track and maybe someone lighter than me.   Needless to say it was a scary ride on the downhill side.  The fork with front shock went on ebay.  I did have many second thoughts about separating the two shocks.  On the rear, the shock works great.  The lock out is as solid as I have seen.  Not bad for a shock that is 8-9 years old.    

Thunderchild

www.urmb.org

[Simon]

I didn't have any problems with distortion,
maybe because I made up a solid jig bolted at the
dropout and bolted to the adaptor, then had the welding done with this all in place.

Simon.

[shovelon]

Thanks for the response, I am not in a hurry and will think it over.  Might be able to find a local welder which brings up a few questions.  Did you have any concerns about warping or deforming the swingarm when it was welded?  Any other precautions, tips, alignment, etc.?  

As for the questions about the shock.  I got the entire bike on ebay with a matching shock with lock out on the Girvin fork for a pretty good deal.  THe previous owner did not know much about the bike.  When I got it the shocks had no air in them.  My guess is that Stratos did not make many of these shocks or we would have seen them.  I have contacted Stratos and they said that they DO NOT service the shock.  Amazing .  Both shocks work and hold air, but the front shock was short on travel(earlier Girvin too).  I had to air it up so high to avoid bottoming out that it had no rebound control.  If you have ever ridden a shock with out rebound control, you know what I mean.  It would snap back pretty fast after hitting a ravine or dip.  IT was all I could do to not go over the bars when it bottomed out.  It would be fine for smooth single track and maybe someone lighter than me.   Needless to say it was a scary ride on the downhill side.  The fork with front shock went on ebay.  I did have many second thoughts about separating the two shocks.  On the rear, the shock works great.  The lock out is as solid as I have seen.  Not bad for a shock that is 8-9 years old.    

Thunderchild

www.urmb.org

Stratos will not service your shock? A-HOLES!!!!!!!!!!!!

I don't think that you will have any issues with the welding. Simon will know, but I think the alloy is 6061. Just don't overheat the part when welding, and have a bucket of cold water nearby to cold water qwench directly after the arc stops. This will ensure that you bring the weld affected zone back up to T2, and the grain structure can progress with natural age hardening. If your welder is competent enough to weld cooly, then the rapid dissipation of heat from the heat affected zone will in itself be enough to strain harden it back to T2, thereby inducing the natural aging process. Just make sure that you weld with 5356 filler, as it is hardenable, and aids in the strain hardeneng during cooling.

Remember this. If you cook the 6061 too much, and the heat affected zone stays at T0, then the natural aging process will never happen. T2 is the minimum hardness to achieve the grain structure to age harden. If the alloy is 7005, then you have nothing to worry about anyway, as it will be self hardening.

As far as warping the dropout, I would not worry about it. The swing arm is very stout.

That's it, go knock yourself out.

Have fun,
Terry

[Thunderchild]

Thanks Terry for the welding info.  What is the T0 and T2 referring to.  Temperature?  

Thunderchild

[shovelon]

Thanks Terry for the welding info.  What is the T0 and T2 referring to.  Temperature?  

Thunderchild

Temper(or hardness)

[jeffhop]

i made a disc mount for my xpx out of steel that is still going strong after 2 years abuse, not sure if there are any pix of it in my folder in the galleries cos i dont know how to look in them now!

[Simon]

i made a disc mount for my xpx out of steel that is still going strong after 2 years abuse, not sure if there are any pix of it in my folder in the galleries cos i dont know how to look in them now!

Here's a link to your pic's Jeff


http://idriders.com/proflex/galleries/jeffhop/


Simon.