Author Topic: Shock Ramblings 856 (Read 5108 times)

oldschoolbikr · « **on:** February 09, 2007, 09:47:58 pm »

I have been trying to convert a cone from a NR1 to a GDT.

Reaming out the threads and getting the correct shaft depth has been an issue but I haven't given up yet. The NR1 is pretty much shot, needs a rebuild, small scratches on the shaft, so this is a must do conversion as I only have the dampener from the GDT.

The shaft length of the GDT is much longer (even taking away the NR1 outer diameter thread length there is still about 3/4" of length).

After boaring the hole of the NR1 Cone the GDT dampener fits inside to a depth of about 3/4". The measurement from the center of the eyelet to the tip of the cone is 8 1/2" for the new GDT assembly. For the old NR1 it was 8". It seems to compress smooth, but I am reluctant to ride it because of the 1/2" shaft increase. Not to mention I have to go back and reposition my F. Der. because of the strut angle difference.

I have also contacted Risse Racing to see if they would be willing to fabricate some sort of stock 6.5" adapter and they very pleasantly told me no fwiw.

Does anyone have any thoughts on that extra 1/2" overall length change?

shovelon · « **Reply #1 on:** February 10, 2007, 08:25:21 am »

Can you ride it? The extra half inch will raise the height of the BB, but I can't see why it won't work.

So, I think everything is working as intended. Adjust the front Derailluer if needed, go for it. You may want to shorten that bumper a bit.

Good ridin'
Terry

oldschoolbikr · « **Reply #2 on:** February 10, 2007, 12:42:33 pm »

Thanks Terry, Everything else seems to be cool. The change in angle made me worry about how the dampener shaft was compressing into the unit as well as any other strut /stress related issues. I am probably making a mountain out of a mole hill.

orange · « **Reply #3 on:** February 10, 2007, 07:04:05 pm »

well, go find a mountain and a molehill and test out the bike!! ;-)

oldschoolbikr · « **Reply #4 on:** February 11, 2007, 12:07:39 am »

Well it looks like the extra 1/2" is going to be too much. The chainline for my small front ring is too low for my F. Der because of the angle the new unit puts it at. If I pull the Der. down, then it wont shift over my big ring teeth.

Suggestions?

Does anyone have the cone end of a GDT dampener that they would be willing to trade for a leaky NR1 dampener unit minus the cone? (Not to be insulting, I think that Noleen is still rebuilding these, so the right case might be a win/win.)

Thanks for looking.

rapiddescent · « **Reply #5 on:** February 11, 2007, 01:35:12 am »

strange - 10 years ago (crikey that sounds like a long time) I was selling long travel kits for the proflex 856 and we relied on pushing the shock out a bit to have room for the extra travel.

0.5 inch will only drop the rear wheel less than 1.5". You should investigate getting a mordern front mech that has more vertical tolerance - which they do to cater for long travel freeride bikes.

Of course, the 856 doesn't give you much room to play with for the front mech so it may be a bit hit and miss getting a front mech.

callum
rds

shovelon · « **Reply #6 on:** February 11, 2007, 05:55:26 am »

Get rid of the big gear. Honestly I rarely use mine. Either grinding up in small, or coasting at breakneck speeds down.

Go ride that mother!:-)

Terry

oldschoolbikr · « **Reply #7 on:** February 11, 2007, 08:07:33 am »

Thanks for the replies. Waiting on one more possible option. The Der. is 9 speed Deore XT so I guess it is fairly recent. I might invest in a newer one to see if the clearance matches. BP Mechs are always selling on eBay for dirt cheap.

I may also go with a 2x9 setup and invest in 38 to 40t ring.

You guys rock! Where else can you get first hand insight for a 10 year old bike?

Ziggy · « **Reply #8 on:** February 11, 2007, 08:45:48 pm »

Quote

strange - 10 years ago (crikey that sounds like a long time) I was selling long travel kits for the proflex 856 and we relied on pushing the shock out a bit to have room for the extra travel.

Any pics / details?

oldschoolbikr · « **Reply #9 on:** February 12, 2007, 09:37:41 am »

Wow, I just measured the height of my front der.s and the one on my other bike is 1/2" longer than the 9 speed XT on the Proflex.

Daddy's in business!!!

shovelon · « **Reply #10 on:** February 12, 2007, 09:57:58 am »

Quote

the 9 speed XT on the Proflex.

Daddy's in business!!!

Pimpin the Proflex. You go big daddy!

rapiddescent · « **Reply #11 on:** February 13, 2007, 04:11:02 am »

Quote

Any pics / details?

yeah - check out the rds website http://www.rapiddescentscotland.co.uk in the about us section. there's a picture of two of the test bikes at one of the big races in the UK. I'm sure I've got more somewhere...

callum
rds

Ziggy · « **Reply #12 on:** February 14, 2007, 01:34:42 am »

Quote

yeah - check out the rds website http://www.rapiddescentscotland.co.uk in the about us section. there's a picture of two of the test bikes at one of the big races in the UK. I'm sure I've got more somewhere...

callum
rds

If you come across any, be sure to show us

Wish you still sold em... I'd love to get another 856 & set it up like that!

rapiddescent · « **Reply #13 on:** February 14, 2007, 04:26:34 am »

if you really really want one, then I'm sure I can scrounge enough parts to make one up. I'll have a look in the workshop.

it doesn't work with disk brakes. I never sat down and figured out how to do that although I'm sure it isn't difficult.

You'll need a seriously beefy spring though. i rode the 5" travel setup in a DH series in the Uk for a while. i was utter crap but my junior sponsored rider was quite good. I'm probably best known for riding through the tapes at high speed and straight into the crowd.

callum
rds

Ziggy · « **Reply #14 on:** February 14, 2007, 05:02:18 am »

Quote

if you really really want one, then I'm sure I can scrounge enough parts to make one up. I'll have a look in the workshop.

it doesn't work with disk brakes. I never sat down and figured out how to do that although I'm sure it isn't difficult.

You'll need a seriously beefy spring though. i rode the 5" travel setup in a DH series in the Uk for a while. i was utter crap but my junior sponsored rider was quite good. I'm probably best known for riding through the tapes at high speed and straight into the crowd.

callum
rds

I would certainly be *very* interested! I've currently got one of the original GT I-drives with some of the original Bomber Jr-Ts, beefy wheels & XTR etc but I just don't like it that much! A long travel 856 would be sweeeeet. Would probably want to work out some way of getting disks on there, but how difficult can it be? :-S (Just checked - my rear wheel's rim brake compatible anyway, so it wouldn't be a big issue...)

Did you take the chance to convert to a standard shock?

Cheers
Jon

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Author Topic: Shock Ramblings 856 (Read 5108 times)

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