Author Topic: Risse shock and x57, does it change the travel? geometry? (Read 4340 times)

Akagi · « **on:** April 11, 2009, 05:39:14 am »

Looking into rear shock replacement on my proflex 2000, don't need it yet, but looking into my options. I hope Callum will make the Fox RP23 kit a reality by the time I need it, but I am also interested in Risse as well.

I was checking out there website and it seems to list travel on all proflex models as 2.5 inches.

http://www.risseracing.com/proflex.shtml

which got me thinking. Have any of you Risse owners out there noticed any travel reduction or geometry change, or is it a perfect match?

whisperdancer · « **Reply #1 on:** April 11, 2009, 11:37:03 am »

Is Callum making a kit for strut bikes?
I have a Swinger 3 waiting to go into the '97 Animal, but I believe it's too long (210mm i2i)...

Akagi · « **Reply #2 on:** April 11, 2009, 03:03:00 pm »

Quote from: whisperdancer on April 11, 2009, 11:37:03 am

Is Callum making a kit for strut bikes?
I have a Swinger 3 waiting to go into the '97 Animal, but I believe it's too long (210mm i2i)...

That is what he was indicating in the "NOS kits Ebay" thread.

Also I dug up an old post a few years back indicating a member here had already fitted hte previous fox floats on his proflex front and rear, perhaps he can help also.

http://idriders.com/proflex/smf/index.php?topic=2752.0

bolting one of those up to the front shouldnt be that hard should it, as long as the eye to eye and stroke match up. Just need to figure that out when i have time.

kiwi · « **Reply #3 on:** April 13, 2009, 01:17:55 pm »

210 is the nominal eye of the strut bikes,that is eye to end

whisperdancer · « **Reply #4 on:** April 14, 2009, 05:52:02 am »

Yes, but with the adapter I will have to make, it will extend the shock by 25-30mm.

shovelon · « **Reply #5 on:** April 14, 2009, 08:42:18 am »

Yes, so try a shock with an i2i of 190mm x 50mm (7.5" x 2") stroke. Like this.

http://cgi.ebay.com/manitou-swinger-3-way-air-shock_W0QQitemZ250405632738QQihZ015QQcategoryZ158996QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Or you could go for a much shorter shock like this.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=150338707028

Carbon_Angus · « **Reply #6 on:** April 16, 2009, 10:01:50 am »

the actual rear travel for those *57's was under 3" anyway, i am pretty sure.

i have a genesis /cone adapeter on a strut styled k2 and love it. i guess it would depend on the style of riding you will do.

rapiddescent · « **Reply #7 on:** April 21, 2009, 04:47:57 am »

yes, I'm starting at the carbon bikes and working backwards - the idea is to have kits to allow a modern airshock to be used. I've nearly finished the 5500c and next in line is the x57.

It's harder than it looks - I'm not worried about the cone shape (done it before with the COR spring) but what I am worried about is that modern shocks have a standardised 12mm bushing based attachment for the lower part of the spring, i.e. they assume that its a pivot. Obviously, on a x57 there is no pivot there and the shock has to lock against strut. So my designs are based on a simple system of pinch bolts that will lock the shock in.

My prototype version had a pivot point CNC that fixed into the cone - but you could push the shock with your finger and it would move up and down. not ideal and would cause significant torsional stress on the shock.

The other idea I had was to mount the shock 90' rotated so that the shock could lock onto the strut using some CNC'd system - but then that causes problems for the top of the shock and would have to have a custom mount built and there's not an awful lot of room up there.

so .. there are challenges but I'll figure them out. If anyone wants to contribute ideas then I'll make sure you are rewarded suitably! I'll be looking for testers once I've got something workable.

rapiddescent · « **Reply #8 on:** April 21, 2009, 04:56:22 am »

==> extending the shock

don't worry about that. The x57's typically had a 2.9:1 ratio so if you use a modern airshock that's a bit longer then you will get extra travel, perhaps closer to 4.5 inches which is pretty standard nowadays. The modern airshocks can cope with a smooth and progressive travel over a longer distance than the nr-2.

however, you have to watch for clearance issues and might have to chop the bottom off the seat tube (I had to do this for the LTK9798ex long travel kit).

I'm working on the principle that an 857 will have +4" of travel and be lighter than it is now.

whisperdancer · « **Reply #9 on:** April 21, 2009, 05:38:44 am »

Won't it change the geometry of the bike (using a longer shock)?
I'm more worried about the "over the bars" feeling with the crosslink fork (that I really don't want to change), as it will raise the rear end of the bike. One advantage is that I can use lower pressure for the shock, but it will have more sag.

I've been thinking on an adapter for the Swinger 3 that touches the shock body, and with an excentric tightening system so it makes pressure between the shock body and the shock adapter...

Colin · « **Reply #10 on:** April 21, 2009, 07:19:35 am »

Quote from: rapiddescent on April 21, 2009, 04:47:57 am

The other idea I had was to mount the shock 90' rotated so that the shock could lock onto the strut using some CNC'd system - but then that causes problems for the top of the shock and would have to have a custom mount built and there's not an awful lot of room up there.

Just rotate the lower mount of the shock 90', leaving the upper one as normal, i.e. rotate the piston shaft in the shock body.
I have heard rumours that you have to be careful with some shocks that you don't undo something or foul something internally, but I'd be suprised if a single 90' turn woud bu**er anything up?

Col.

rapiddescent · « **Reply #11 on:** April 21, 2009, 01:28:32 pm »

just tried that on some of the shocks in the workshop and after a bit of leverage the GShox did turn so that the bottom bush was 90' to the top one. Will try it with a fox RP23 later. My plan is to use the Fox as the standard because they are easy to find.

orange · « **Reply #12 on:** April 21, 2009, 01:46:42 pm »

but then you don't you get a reasonable degree of sideways flex? I found that with my home made adapter.

Akagi · « **Reply #13 on:** April 29, 2009, 01:22:04 am »

I think i may have some solutions to get rid of the extra unecessary pivot and unecessary flex.

1)What if you used a tap and die kit to thread the unecessary pivot hole on the shock itself?
That way some part of the adaptor can be screwed in securly

That should be enough in my mind, as long as the Eye is rotated 90 degrees. Splines would work as well, but that seems way more complicated.

2)My other idea is filling in the eye with a closely matched diameter aluminum rod secured with some sort of automotive grade epoxy and then machining your own cone right out of the shock body... but that sounds even crazy to me, albeit lighter weight.

Also, I would glady participate in your beta test of your adaptor.

jeffhop · « **Reply #14 on:** April 29, 2009, 11:54:00 am »

i thought about making an adaptor for the strut type of bike when i had one, basically both ends of the shock are turned then milled to give them the flats which are then drilled for the mounting points. if you take one end and measure the diameter without any hardware in it, get someone with a lathe to turn a piece of ally with a hole slightly bigger (no more than a couple of thou`) and deep enough to be able to put a bolt through the shock hole to keep it solid (may need a bush machining for this) with a taper machined on the end, the whole thing could be achieved by only being 10mm bigger on the o/all length. ill print off a pic of your swinger and draw on it and post it back up to show you what i mean.

unfortunately i dont have the drawing i did on my comp anymore but im convinced this is the best way to mount a modern shock onto a strut bike, i could probably write a program for a fanuc controlled lathe if anyone has one lying about, once you got one done it would be a piece of cake to machine dozens and even alter it for different types of shock.

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Author Topic: Risse shock and x57, does it change the travel? geometry? (Read 4340 times)