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Will 2.8 spring work on 3.0 shock???

Hydraulicman

Monkey
Sep 25, 2001
133
0
Belgium
I can maybe get an 400lbsx2.8 tit spring for my 3.0stroke dhx.
But will it fit

I already looked a bit with the search function and I found this

Originally Posted by Udi:
followed by manitou which have seriously low winds and nice big spacings. They look cool and save a heap of weight. On top of that, because of the low winds, a 2.75" spring will work on a 3" shock. I weighed a 350x2.75 manitou ti at 255g!

Originally Posted by Daver:
You need a spring with at least 3" of travel (before the coils will bind) to work properly on a 3" stroke shock. I have used 2.75" RCS, 5th and Manitou ti springs on 3" stroke shocks in the past with success, although i did need a spacer to get the RCS to work properly.

According to them it should work, but I wanted to be sure, because a ti spring isn't that cheap, so will a 2.8/2.75 ti spring fit a 3.0 dhx?

Daver is talking about a spacer??? Does someone have a pic of this

thx
 

preppie

Monkey
Aug 30, 2002
379
0
Europe
I can maybe get an 400lbsx2.8 tit spring for my 3.0stroke dhx.
a tit spring ? :monkeydance: You've been away for too long, you need to come back soon.

I tried to fit a smaller spring on my 5th.
When your shock (almost) bottoms the spring compresses too much and the coil binds
...this is very bad for your frame shock mounts and shock.

EDIT (after reading Udi en bdc's post)
I used a shorter steel spring with the same space between the coils as the correct sized spring.
 

Hydraulicman

Monkey
Sep 25, 2001
133
0
Belgium
hehe, my bad, just saw my mistake:poster_oops: , you know me always care more about the women then my bike...

I know i've been away for too long. Preparations to go to afghanistan, then now at the moment in afghanistan. But i'll be back in the beginning of july and I will be back better then ever.

New frame is lying in customs as we speak...

So it won't work:banghead:

Ps: aren't you never on msn anymore?
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
no it will not work. don't do it.
Why won't it work?

If the distance the spring can compress is larger than or equal to the shock stroke, then it'll work fine. The labelled travel ratings are hardly accurate...

Ti springs tend to have far larger coil spacing (manitou and progressive anyway) therefore you can most certainly get away with a 2.75" stroke spring on a 3.0" shock (as in people have tried it and it's worked fine).
 

ÆX

Turbo Monkey
Sep 8, 2001
4,920
17
NM
Why won't it work?

If the distance the spring can compress is larger than or equal to the shock stroke, then it'll work fine. The labelled travel ratings are hardly accurate...

Ti springs tend to have far larger coil spacing (manitou and progressive anyway) therefore you can most certainly get away with a 2.75" stroke spring on a 3.0" shock (as in people have tried it and it's worked fine).
agreed, if the measured space between the coils is greater than the shock stroke................run it!
 

ChrisKring

Turbo Monkey
Jan 30, 2002
2,399
6
Grand Haven, MI
Like Udi and BCD said, if there is enough distance so that it doesn't hit solid height before 3", you can run it. That said, I don't know how that will effect the fatigue life. Basically, you will stress it beyond where it was designed for. It could possible break after a while.
 

khoolhandz

Chimp
Jul 27, 2006
89
0
I LOVE SURREY
Springs get fatigued when compressed to within 10% of becoming solid.

Springs are manufactured such that the rated stroke has a built-in minimum 10% tolerance when compressed (at the rated stroke).

You probably can compress the 2.75 spring to 3", but it will be outside its rating.

Worst is, if the spring go solid before the shock bottoms out, you might end up breaking the collar or your shock, or even worst your frame.
 

Transcend

My Nuts Are Flat
Apr 18, 2002
18,040
3
Towing the party line.
Worst is, if the spring go solid before the shock bottoms out, you might end up breaking the collar or your shock, or even worst your frame.
Coilbind can cause immediate shock failure as well by destroying in the internals from passing along the shocks to them the coil didn't take up while coil bound, as well as the possibilities you mentioned. Stripping the shock body, breaking the retaining ring, cracking frame mounts, bending shock bolts etc.
 

DHS

Friendly Neighborhood Pool Boy
Apr 23, 2002
5,094
0
Sand, CA
Coilbind can cause immediate shock failure as well by destroying in the internals from passing along the shocks to them the coil didn't take up while coil bound, as well as the possibilities you mentioned. Stripping the shock body, breaking the retaining ring, cracking frame mounts, bending shock bolts etc.
thank you. people just cause you believe it MAY work. doesn't mean it will work all the time.

please get the correct length spring
 

alexchannell

Chimp
Jul 23, 2005
63
0
Springs get fatigued when compressed to within 10% of becoming solid.

Springs are manufactured such that the rated stroke has a built-in minimum 10% tolerance when compressed (at the rated stroke).

You probably can compress the 2.75 spring to 3", but it will be outside its rating.

Worst is, if the spring go solid before the shock bottoms out, you might end up breaking the collar or your shock, or even worst your frame.
Thats not true. You can't lump all springs under your 10% theory. Most any spring can be fully compressed with no material damage. This is a case by case basis. You need to look at thickness of coil, #of turns, distance compressed, material of coil.
 

ZUMBI

Chimp
Mar 22, 2007
67
0
Myslenice, Poland
a manitou 3" stroke spring has less stroke then a 2.75" stroke Ti spring from progressive.They differ in lenght by maybe 5mm but the coil spacing is a lot bigger in th Ti spring.One of my racer uses a 2.75" stroke Ti spring in a 3" stroke shock and it works great.Its not a perfect world.Just need to know the tricks I guess...
cheers
 

dh-noob

Chimp
Sep 17, 2007
34
0
Germany
Haha, I´ve to warm this thread up.:D
I´d have the perfect setup for my dhx rc2 (3" stroke). The 300 lbs spring is to soft, even with maximum airpressure. The 350 lbs spring is already to firm with minimum airpressure.
The only way to have a perfect setup is a 325 lbs spring.
A friend offers me a progressive suspension 325x2,75 ti spring. Theoretically the spring would fit because of less windings. Can anybody help (technically correct)? Do I overbend the 2,75 spring in my 3" shock?

The backup solution is a bos spring 325 (steel)
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
The progressive suspension springs generally have a little more stroke than they claim, so you should be fine. The spring's lifespan may be a little shorter, but it's not very common for them to break anyway.
 

MinorThreat

Turbo Monkey
Nov 15, 2005
1,630
41
Nine Mile Falls, WA
I'm looking at a 2.75 titanium spring myself right now for my 3"-stroke DHX. As long as the spring's free-length (L) minus the number of coils (N) x the wire size (D) of the spring is greater than 3", you should be fine [L - (N x D) > 3.0]

So, for example, if you have a DSP 2.75 x 400 spring, its free-length is 5.98. If the wire size for its 7 coils is 10mm (rounded up for a margin of error), then the space left — the available stroke — should be 5.98 minus 2.75 (70mm) = 3.224: plenty for a 3" stroke shock.
 
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Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
MinorThreat -
While that is correct in terms of not reaching coil bind, it's worth keeping in mind that springs are made with significantly more stroke than the stroke of the shock they are designed for (likely in consideration of durability / material limitations) - for example a DSP 300x2.5" Ti spring has an actual stroke of just over 3.5" - but that doesn't mean you should run out and throw it on a 3.5" shock.

I think in reality it's fine to milk an extra 0.25-0.5" out of a quality, widely spaced Ti spring, but it's obviously a calculated risk rather than a completely legitimate application. :)
 

MinorThreat

Turbo Monkey
Nov 15, 2005
1,630
41
Nine Mile Falls, WA
^^ Your caveat is appreciated and noted. In my case, I'm taking that calculated risk because: 1) I'm hoping to snag this spring at a significant savings; and 2) it will save me a little more weight.
 

dh-noob

Chimp
Sep 17, 2007
34
0
Germany
I just saw, that the k9 race (steel) spring, (made by eibach) 3" has just a lenght of 14 cm (5.5")


My original 350x3,25 Fox spring: 17 cm (6.7")

EDIT: The lenght of the ti 325x2,75 is 16 cm (6,3"). I´ll buy it! (just under 300g, not the best, but I save ~200g)
 
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dh-noob

Chimp
Sep 17, 2007
34
0
Germany
Here you can see 2 original Fox springs (300x3,25 and 350,3,25) plus the progressive suspensions 325x2,75 ti spring. almost the same lenght!

 

tacubaya

Monkey
Dec 19, 2009
720
89
Mexico City
Do the math bro.

Solid length of a squared and ground end spring is D*Nt where Nt is the total number of coils and D is the coil diameter in inches. Nt for squared and ground end springs is equal to the active coils plus 2.

I have here an X Fusion spring, labeled 450x76. It has nt=9 and 0.335 inches of coil diameter. That means the Ls (solid length) is 3.015". The spring is 6 inches long. That means it can compress 2.985" before biding.

76mm = 2.99" of stroke, and I got 2.985"