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Discussion Starter · #1 · (Edited)
I really want to try a coil shock in the back, but the space in my frame is very limited. The problem is clearance to the seat tube. The frame takes a 185x55 trunnion shock.

Which shock uses the smallest diameter coils? So far all I know is that DVO springs are supposed to be 53.30mm OD according to their support. Anything smaller than that? Also, the more distance between the lower bushing and the spring collar, the better. I printed out a DVO Jade to scale on paper and "installed it" in the frame, I think it MIGHT just fit. 馃榿
What if I used an offset bushing turned sideways to gain a tiny bit of clearance? Would that impact the kinematics a lot, or would it even work at all, or would the bushing rotate on it's own?
I know all of this might seem really stupid, i'm just super curious about coil shocks (and want to try just a new shock in general), but I don't want to buy a new frame yet. :)

Bicycle Wheel Bicycles--Equipment and supplies Crankset Bicycle frame
 

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I really want to try a coil shock in the back, but the space in my frame is very limited. The problem is clearance to the seat tube. The frame takes a 185x55 trunnion shock.

Which shock uses the smallest diameter coils? So far all I know is that DVO springs are supposed to be 53.30mm OD according to their support. Anything smaller than that? Also, the more distance between the lower bushing and the spring collar, the better. I printed out a DVO Jade to scale on paper and "installed it" in the frame, I think it MIGHT just fit.
What if I used an offset bushing turned sideways to gain a tiny bit of clearance? Would that impact the kinematics a lot, or would it even work at all, or would the bushing rotate on it's own?
I know all of this might seem really stupid, i'm just super curious about coil shocks (and want to try just a new shock in general), but I don't want to buy a new frame yet. :)

View attachment 1963087
As a reference point a Fox steel spring (500x3.25) measures 53.4mm, the 550x3.25 I have on my bike measures 54.8mm...

These were/are fitted to a Fox DHX RC4 9.5x3.0
 

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I really want to try a coil shock in the back, but the space in my frame is very limited. The problem is clearance to the seat tube. The frame takes a 185x55 trunnion shock.

Which shock uses the smallest diameter coils? So far all I know is that DVO springs are supposed to be 53.30mm OD according to their support. Anything smaller than that? Also, the more distance between the lower bushing and the spring collar, the better. I printed out a DVO Jade to scale on paper and "installed it" in the frame, I think it MIGHT just fit. 馃榿
What if I used an offset bushing turned sideways to gain a tiny bit of clearance? Would that impact the kinematics a lot, or would it even work at all, or would the bushing rotate on it's own?
I know all of this might seem really stupid, i'm just super curious about coil shocks (and want to try just a new shock in general), but I don't want to buy a new frame yet. :)

View attachment 1963087
The Fox SLS is the smallest diameter spring as far as I know.
 

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The Fox SLS is the smallest diameter spring as far as I know.
Is that right? I thought the Fox X2 stuff, SLS included, was a significantly larger diameter than the Bomber CR stuff. I have a Bomber CR and several springs for it. The springs are pretty tiny compared to the spring for my Jade and EXT, both of those are larger diameter.
 

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Discussion Starter · #9 · (Edited)
Thanks everyone.

Radon will say no for sure. But their customer service is poop to begin with. For example someone asked if they could use a 160 fork instead of 150 in a Slide Trail, and they said the frame is only rated for a 150. Yet they have a Slide Trail model which comes with a 160 stock... :rolleyes: From what i've experienced and heard the customer service is mostly made up by trained monkeys, if you ask a technical question you pretty much always receive some nonsense answer (2-3 weeks later).
According to a Linkage X3 model the frame has 20% progression, the leverage curve is almost a straight line from 2.89 to 2.29. I think that should work okay with a coil?
So lighter springs tend to be a smaller outer diameter?

Is that right? I thought the Fox X2 stuff, SLS included, was a significantly larger diameter than the Bomber CR stuff. I have a Bomber CR and several springs for it. The springs are pretty tiny compared to the spring for my Jade and EXT, both of those are larger diameter.
Could you measure the Marzo springs please? Interested in that shock since it's on the cheaper side, and if the coils are that skinny that's even better.
 

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What if I used an offset bushing turned sideways to gain a tiny bit of clearance? Would that impact the kinematics a lot, or would it even work at all, or would the bushing rotate on it's own?
I once asked the guys at offsetbushings.com if it was possible to install the offset bushings the wrong way to increase bb height. They said it won't work as the bushings tend to rotate to the slackest position
 

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I once asked the guys at offsetbushings.com if it was possible to install the offset bushings the wrong way to increase bb height. They said it won't work as the bushings tend to rotate to the slackest position
I used an offset bushing to move a shock clear of the toptube once. was on a kids bike though. Never moved but I'm guessing it would if it was used a lot.
 

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Discussion Starter · #13 ·
I once asked the guys at offsetbushings.com if it was possible to install the offset bushings the wrong way to increase bb height. They said it won't work as the bushings tend to rotate to the slackest position
Yeah that's what I thought. I'm guessing it would be even worse with the bushings turned "sideways", especially on the bottom bushing with a vertical shock.

Might just go with a Topaz... :rolleyes: I think I could possibly try to fit a coil shock very carefully and return it if it doesn't fit, but it's a bit of a gamble and not a small amount of $$$.
 

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20% progression won't be enough for a coil shock. In fact I'd even avoid larger air cans, you'll need to make sure you get something you can either stuff with tokens or that has a small air can to begin with.
I disagree with that. my bike has an 18% progression (2.6 to 2.15) and the 2022 model COMES WITH A COIL. The team riders on the EWS circuit have been coiling my frame since 2018.
20% is fine for a coil, OP.

My advice is to get a 'cheap' one used from PinkBike (sell it if it doesn't work) or beg a favor from a local shop to test fit if possible.
 

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A quick google of linkage rates of bikes I commonly see coil shocks on:
Transition sentinel: 25%
Ripmo: 20.8%
Orbea Rallon: 20%
Yeti SB150: 15%
Marin Alpine Trail XR: 18% (comes with a RS super deluxe coil)
 

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FWIW I tried the 'offset bushing in the wrong direction' thing for about 6 months and it didn't rotate on me. I also put it on the joint at the pivot that barely moved, rather than the one that was in the linkage and moved quite a bit. Never fully trusted it however, so that was always in the back of my mind during rides.
 

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A quick google of linkage rates of bikes I commonly see coil shocks on:
Transition sentinel: 25%
Ripmo: 20.8%
Orbea Rallon: 20%
Yeti SB150: 15%
Marin Alpine Trail XR: 18% (comes with a RS super deluxe coil)
My bad, you're right-- but it does matter what size shock we're talking about too.

Example: my Tallboy 4 has a stock progression of 26% but is not recommended for a coil because of the size of the shock (190*45). I thought that was because of the progression rate but apparently it's just because of the shock size. I guess I don't know how that works.
 

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Discussion Starter · #20 ·
I checked two fox steel springs I used for Bomber CR - 550lb at ~52.5mm and 600lb at ~53.5mm.

Currently I have Avalanche spring and that is larger at ~55-56mm for 500lb

Sent from my ONEPLUS A6003 using Tapatalk
Hmm, 52.5mm is pretty skinny! So it sounds like lighter springs might have a smaller OD, which is nice because i'm around 65kg so i'd need something light. I'm fairly sure something in the 52-53mm range would clear most of the seat tube, the problematic area is the lower part.

Automotive tire Bicycle tire Automotive lighting Bicycle frame Bicycle part


The part where the red line is is at an angle, which limits space there a ton... 馃槧

BTW I can't find Marzocchi springs, do they come stock with the cheaper, black FOX springs like this?

 
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