Which frame?

 

2021 Radon Slide Trail. Probably not a lot of people have experience with it here.

 

Personally, I would email or call Radon and see what they say. Most brands I know of have something to say about fitting different shocks to their frames.

 

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. [emoji16]
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

 

The frame has to be designed for a coil shock. The leverage curve may not be progressive enough. Your best bet is to ask Radon if you can install a coil shock.

 

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.

 

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

 

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.

 

Cane Creek Valt spring is 53mm in diameter

 

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.

 

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.

 

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.

 

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.

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

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

https://www.bike24.com/p2184602.html

 

Yeah, that doesn't look too good. The spring collar/perch is quite wide and relatively close to the eyelet. Maybe upside down would work better, the top of the shock is usually not as wide. But it all depends on the specific shock.
Things like this are really hard to say just from pictures, you must also test during compression all the way to bottom out, your best bet is to discuss with local shop if they have some coil shock to try. Or depending on the return policy you can always order, check for fitment and return if it doesn't work.

And yes, the black foxshox spring are the cheap option for Bomber CR. Stock the shock comes with no spring so you get to choose.

 

Yeah, that doesn't look too good. The spring collar/perch is quite wide and relatively close to the eyelet. Maybe upside down would work better, the top of the shock is usually not as wide. But it all depends on the specific shock.
Things like this are really hard to say just from pictures, you must also test during compression all the way to bottom out, your best bet is to discuss with local shop if they have some coil shock to try. Or depending on the return policy you can always order, check for fitment and return if it doesn't work.

It's a trunnion mount so I can only mount the shock in one direction. Luckily as the suspension moves through it's travel the shock rotates forward, away from the seat tube. So if the shock clears fully extended, i'm golden (unless there are clearance issues with the reservoir).
The shops around me are absolute garbage (or most shops in general here in Hungary). If you need a 6spd freewheel you're set, but testing a coil shock on your bike? Yeah, nah... 😁

Since no one in my group rides a coil my only option would be to buy new and return it. I guess I could slightly sand down the OD of a center sleeve/reducer that would easily slide in the bushing on the shock and leave no marks, and check the fitment that way. But it's risky for sure.

 

Sounds like lot of issues just for coil shock. Maybe well tuned air shock is better solution.
I don't see a great difference in performance between good coil and good air shock. Yeah they feel a bit different back to back, but both usually work pretty well while riding.

I love coil for lower maintenance and no need to check pressures. That's why I have it front and back, every time I take the bike out its exactly the same as last time i rode it. Even if it feels different (many possible reasons) I don't have to chase the "maybe the pressure changed?" rabbit. But you loose a bit of adaptability to terain/style of riding.

In the end, when setup right, air and coil are both great, and seems like for your bike coil just isn't meant to be, unless there is a specific shock with workable dimensions for you.

 

Found this DHX2 drawing, printed it out to scale, "mounted" it in the frame.

In the spring collar area at the bottom the clearance is pretty decent, but at full extension the spring JUST contacts the seat tube. This spring is 54.6mm according to the drawing tho, so with something in the 52-53mm range I might have like 1mm of clearance...
So i'm most likely staying air. Bummer!

 

I know this is an old thread but it's the only one that comes on Google.

I have contacted Radon and here's what they told me:
"the frame does not have enough clearance for a rear shock with piggy bag, so in my eyes a coil shock with piggy bag is not an option in the Slide Trail AL. You can mount a 160mm fork with no problem. "

 

I've seen someone on FB shoehorn an X2 in a Slide AL. It does have more clearance at the seat tube, but I guess less clearance at the down tube for the reservoir.
But honestly if you want to experiment with different shocks and increase the front travel, get a different bike. I should have sold mine a long time ago.

 

Old skool (imperial) coils from the 1990s to 2000s) are a bit narrower than modern metric springs I have a 500lb that is less than 50mmMany lighter weights are 48mm. The inside diameter is also smaller, so they won’t fit on the shock collar (you’ll need to Fab an adapter, I used a 3d printed part for my adapters

I’m running a cc dbil coil on a frame that has roughly 52mm in the shock pass thru using the old skool spring.

more details in the Hightowur 2 link in my signature

 

Old skool (imperial) coils from the 1990s to 2000s) are a bit narrower than modern metric springs I have a 500lb that is less than 50mmMany lighter weights are 48mm. The inside diameter is also smaller, so they won’t fit on the shock collar (you’ll need to Fab an adapter, I used a 3d printed part for my adapters

I’m running a cc dbil coil on a frame that has roughly 52mm in the shock pass thru using the old skool spring.

more details in the Hightowur 2 link in my signature

Thanks, but i've given up on the idea a long time ago. Bought an air Super Deluxe about ~2 years ago. It works fine, the rebound is a bit weird, I was thinking about a custom tune but i'm a bit over this bike.

 

I'd have taken a Dremel and cut out the down tube so the reservoir didn't hit anything. Then I'd ride it like I stole it and throw it away when tired of it.

 

My solution was less drastic, reducing the stroke by about~0.8mm.