Shortening eye to eye length on Fox CTD?

Nautonier

Nautonier

Eats Squid
I have a Fox CTD (running a Corset) that is 215.9 x 57.2mm. It's a on a Spesh Enduro and when at full travel isn't using all of the shaft length. I'm wondering if there is any way to internally change the eye to eye length without changing the stroke. Ideally I want to shorten the eye to eye to 214mm, which will lower my BB height by ~ 10mm.

Can this be done?

The alternative is to chop off 2mm from the shock yoke and mount, but this is a bit of a last resort and could be a one way ticket to the Fuckwits thread...
 
Boom King

Boom King

downloaded a pic of moorey's bruised arse
Have you let the air out and cycled the shock? Maybe that's where the compression stroke finishes.
 
S

schred

Likes Bikes and Dirt
Not sure, sounds tricky. No ability to use an offset bushing, and you sure about the 2mm ->10mm relationship?

Thinking about hacking at shock or mounts is like putting a deposit on that thread. Do it.
 
Nautonier

Nautonier

Eats Squid
Boom King said:
Have you let the air out and cycled the shock? Maybe that's where the compression stroke finishes.
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Yes, the compression stroke finishes about 8mm before the end of the shaft. I'm wondering if I can use more of the shaft, but less of the internals, resulting in 2mm less overall length.

NSD reckon they can do it, but only if they reduce the stroke from 57mm to 55, which, doing the maths, will reduce my travel from 165mm to 160mm, which I'd rather avoid if possible.

Cutting the yoke and the mount can be done without damaging anything and there is still plenty of thread for the bolt, the only thing I need to be careful with is damaging the thread in the end of the mount.

Anyone know the maths for how much a 10mm drop in BB height will slacken my HA?
 
Nautonier

Nautonier

Eats Squid
mitchy_ said:
Use an offset bushing in the top mount, common mod among the endurbro fraternity.
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I thought about that, but that will only give me ~1mm less. Where do you get them from?

Also, I know you've been experimenting a lot with different configurations and their resulting BB heights, how did you notice riding the bike at ~355mm vs ~345mm?

I know that tyre sizes etc affect BB height bit, but what's worrying me is that since I installed the 170 Lyriks, my BB drop has gone from -5 to +5. It might be in my head, but the bike does feel like it's riding too high - especially in the corners.
 
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shmity

Likes Bikes and Dirt
Keep in mind the corset (and all aircans) have a dimple that allows exchange of air between positive and negative air chambers during the stroke of the shock, on the corset this is much closer to the sag point of the shock. Setting the shock to naturally sit further into the stroke will have an effect on the way the shock rides becaause you're changing the location of this dimple relative to the sag point (making it sooner, which is one of the things the corset corrects) and thus affecting your negative spring volume in relation to the shock stroke. Its going to take away a lot of the advantages the corset brings.
 
Nautonier

Nautonier

Eats Squid
IMG_1581.jpg

Is it the inner bit (inside line) or outer (outside line) that punches out and can be replaced with the offset shim? If it's the outer I can see how you might get 2mm out of it.
 
mitchy_

mitchy_

Llama calmer
Inner, Proshox is where I got mine I think...



Keep in mind, offset bushes (or any shock mod) will slacken off the seat angle. Mine is dropped to 340ish, but that is purely from smaller wheels which keep the angles the same.

I can't really comment on it with the 650 link in mine, as I only used it with the fox/corset setup which kept blowing through its travel.

It definitely feels more planted with the lower BB, they are already pretty high at 351 standard.
 
Nautonier

Nautonier

Eats Squid
Sounds like the way forward, unfortunately with the Spesh shock mount design you can only run the offset bushing at one end, which will give me about 5mm of BB drop. I'm thinking of doing that as well as my 'dodgy mod' at the other end, which will probably be OK if I only hack 1mm off it, giving me the other 5mm I need.

IMG_1579.jpg
IMG_1580.jpg
 
Nautonier

Nautonier

Eats Squid
Any other votes for hacking? I guess the worst case scenario is that I'll ruin my shock and have to buy a Cane Creek IL coil... Shock yokes are replaceable as well.
 
Nautonier

Nautonier

Eats Squid
Ok chaps, I'm going in for surgery. I've ordered an offset bushing that will give me 5mm drop and my plan is to take 1mm off the yoke/mount to give me the other 5mm drop.
 
S

schred

Likes Bikes and Dirt
Nautonier said:
Ok chaps, I'm going in for surgery. I've ordered an offset bushing that will give me 5mm drop and my plan is to take 1mm off the yoke/mount to give me the other 5mm drop.
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I'd consider having a small machining/engineering type place do the work for you.

Also, you still haven't said how 2mm = 10mm at the BB, at face value it doesn't sound right e.g. extrapolating the full 57mm of shock compression puts the chainring nearly 28.5cm lower, no?
 
Boom King

Boom King

downloaded a pic of moorey's bruised arse
Flow-Rider said:
Hack it, take your time and get everything square.
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schred said:
I'd consider having a small machining/engineering type place do the work for you.

Also, you still haven't said how 2mm = 10mm at the BB, at face value it doesn't sound right e.g. extrapolating the full 57mm of shock compression puts the chainring nearly 28.5cm lower, no?
Click to expand...
Bahahahaha..... You guys.....

Just cut the damn thing off with whatever comes to hand. I've got an angle grinder I can drop off on the way home if you like?
 
Nautonier

Nautonier

Eats Squid
schred said:
I'd consider having a small machining/engineering type place do the work for you.

Also, you still haven't said how 2mm = 10mm at the BB, at face value it doesn't sound right e.g. extrapolating the full 57mm of shock compression puts the chainring nearly 28.5cm lower, no?
Click to expand...
When measuring my BB drop I pushed down on the suspension and used the travel indicator ring to show me how much shorter the shock needed to be to give me 10mm BB drop. Not sure how you get 28.5cm, that would render the bike unable to pedal.
 
Boom King

Boom King

downloaded a pic of moorey's bruised arse
schred said:
Also, you still haven't said how 2mm = 10mm at the BB, at face value it doesn't sound right e.g. extrapolating the full 57mm of shock compression puts the chainring nearly 28.5cm lower, no?
Click to expand...
Suspension doesn't generally work that way given multiple linkages etc.
 
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