Bottoming Coil Shock - ideas

you seem to have covered the bases and have a good grasp of your bike and the suspension.

I'd be going back to the manufacturer and asking for their thoughts on coils and setup.

At the end of the day with HSC and LSC and the coil, you've got all the options, but you may be asking for something that doesn't exist within those parameters on your frame.

forget about sag it is not actually going to help you. Have you used the CC tuning sheet to help? TF tuned calculator doesn't work very well. If the compression tuning (remember LSC will help with drops etc) doesn't work I would go for the 450-580 spring. I have a 400-480 spring on my mk1 transition patrol. It does bottom out but I don't feel it. For what I ride it is pretty spot on.

See if you can find a secondhand progressive spring, they usually go for £50ish.

As you say the bike shouldn't really need one, but it does sound like it might solve your issue.

Or a Sprindex spring would allow you to tweak the spring rate and also provide a bit of progression.

remember LSC will help with drops etc

This is interesting - I’d assumed drops would have high speed shaft speeds - but maybe they don’t - in which case lsc could help?

Progressive spring is probably higher on my actual list of things to try than the 500lb spring. Shame the CC ones are white!

I’m pretty sure from a riding perspective whilst I keep my weight on the front wheel enough for grip that I spend too much time with my legs very bent in a crouch so that probably means the rear of the bike gets a lot of my weight. Also means my back leg gets pumped up quickly on long runs so I’m consciously spending as much time as possible stood up tall which helps.

Interesting. I've had fairly similar issues. I'm on a ripmo af, and using dvo jade x coil. Originally 400lb spring, but changed to 450lb. I then bought a cascade link after last summer. It's been a lot better, but do feel like it's a little too easy to get through the travel. It doesn't bottom nearly as much, but I wanted more support on the big stuff. I've sent mine to sprung suspension, asking for custom tune with more HSC. Hoping this will be sufficient as the shock itself hasn't got any adjustment

The Ripmo af was another bike I considered coincidentally - as was the Jade X! Will be interested to see how you get on when the shock comes back.

Additionally, I'm not saying progressive springs are the perfect answer or that they don't have any downsides... but they can have a surprisingly big effect on how a bike feels to ride.

It's like night-and-day and a massive positive improvement in the case of one of my bikes, while on the other it made it sit up a bit too much and it felt skittish on very rugged trails.

Which is why I'd suggest trying it secondhand so you can sell it on at minimal loss, if need be.

You get used to the white BTW.

I have the cascade link on my V1 sent and it’s brilliant - the V1 was more linear though and from what I understand it needed the additional progressive spring curve to run the coil unlike the V2. Or so I thought. Jtech do an advanced spring calculator for a nominal fee, which is then deductible from an order if you go ahead and order a spring from them. I did that just to make sure before I ordered my ext spring due to the extra cost of the superlight spring. I have also used the Reverse components travel checker thing, decent bit of kit just for the confirmation that you’re on the correct spring rate.
I’m on a 550 spring fwiw, sitting at about 90kg kitted up, on a V1 sent with CC link 205 x 57.5 shock giving 146mm of travel, I hit decent sized stuff on it and have never had a harsh bottom out but use the majority of my travel.

Whilst you have the theory number from a calculator, how much ‘actual’ sag are you running?

I have an ohlins coil on my sentinel, running 383lb coil i think (or what ever slightly random number around that!!) I’m probably around 80kg kitted up. Haven’t had any harsh bottom outs that I can recall, maybe the odd one landing flat accidentally but I expect that!
Not much help but come over nibley and have a bounce on mine to compare!

Whilst you have the theory number from a calculator, how much ‘actual’ sag are you running?

It’s not fully accurate but somewhere around 16-18mm out of a 62.5mm stroke. So between 25.6% and 29%. Hoping to get a more accurate measurement with the reverse components thing when I put the coil back on the bike

@marksnook - I might take you up on that - although I’ve never bottomed out at Nibley 🤷‍♂️

Prime places for bottoming out are Staunton (Bridget drops almost blew my right foot off the pedal)and Bourton Combe. BPW I would 100% have bottomed out loads - drops everywhere.

If a bike rides well with an air shock, it will need a progressive spring. Bit of an over simplification, but if you are looking for the progression you get from your Float X, just buy the Vault in the rate you are currently on. Floating around 30% sounds perfect. If you like it, take it to a car place and get it powder coated any colour you want.

Yeah I think I’ll try and pickup up a 2nd hand 450/550 Valt progressive spring. If I get a chance this weekend I’ll go out and find a drop to session with hsc changes to see if that helps on the current spring. There’s a trail at Bourton Combe with log jumps and one of those at least tends to have a harsh landing on the current spring / damping settings

@superfli how much is the custom tune costing?

Nothing to lose by fully increasing HSC but if you're bottoming out regularly (blowing through the travel) then I'm not sure lsc/hsc adjustment will help enough so you probably need to go up a bit then adjust HSC etc. otherwise progressive spring... springdex?

I’d say with the 450lb it’s not regularly blowing through the travel - in the mid range it’s perfect- sits up better than the air. Just on drops it’s blowing through the travel.

Found a progressive 450-550kb spring for £40 delivered so taken a punt on that. It’s a bit tatty but if it works well I think I’ll get the local powdercoaters to dip it then powder coat it red to match my Lyriks.

@doomanic £45 on top of the std service (£120). Paid for Dyno graph too - not sure why you have to pay £15 for a print out TBH.

I'd get the shock tuned for the bike before buying any more products.

I’d get the shock tuned for the bike before buying any more products.

It’s a Cane Creek Kitsuma with hsc / lsc / hsr / lsr plus preload adjustment. So as long as you’re within the upper and lower limits of the damping adjustment I don’t think there’s a need for a custom tune internally. It’s just a case of working out what the correct settings actually are - which is what I’m grappling with - whether it’s the spring or the damping adjustments that need to change.

is your suspension in balance front to back. what i mean is are the forks and the frame both doing the work they need to? if your shock is bottoming too readily, perhaps your forks aren’t doing enough to absorb the impact.

i recently moved to a place with very different terrain. i softened my fork to take up the looser and more chattery nature of the trails.

after this adjustment i found that my rear was far too hard by comparison even though i liked the way i’d set it up previously, i didn’t like how it was working with the new fork settings.

i fitted a lighter spring and reduced the high and low compression damping and i’m pleased with the way it performs.

shortly after this revelation i read an article on setting up suspension for off road vehicles which spent time discussing the problems you can experience if the vehicle isnt balanced front to back. i think it was on the Fox website.

That’s a good thought - I.e if my fork was too hard then maybe that pushes my weight back further and onto the shock more.

At BPW I had about 10-15mm of the 160mm travel on the fork not used. I did have a couple of big impacts but not ones where I nearly died (if you know what I mean) so I’m kind of happy that’s still in reserve to potentially save me if I really mess up.

I think I did actually bottom them at Staunton off a drop that had a really flat landing - so it feels like the forks are probably about right - in which case the rear (somehow) needs to have some more resistance to the bigger impacts. Which probably comes back round to my initial options to try and achieve this - I think.

I do massively overthink some things though 🤷‍♂️

Someone please idiot-check my maths and assumptions

You have 24% progression, and 27% sag

With no progression, bottoming out requires 1 / 0.27 = 3.7 times your body weight
With 24% progression, that increases to 3.7 x 1.24 = 4.6 times your body weight

That seems like a lot to happen on a 1.5 foot drop even to flat.

You're not doing something like setting/measuring sag in a really agressive attack position and then landing dangling over the rear wheel?

I’ve been measuring fork sag stood upright in an attack position - think that’s got 25% ish sag.

Been measuring rear sag sat on the saddle with the dropper post down.

I’d say I probably am landing perhaps a bit back wheel heavy.

I thought that shaft speed at the end of the stroke was a low speed thing as most of the energy has been absorbed... so LSC increase to help bottoming out harshly? adding HSC will be likely to compromise the shocks ability to track high speed chatter.

Get a cheap spring with a higher rate, dont worry about sag too much, when you are riding along the rebound settings will be more important to stop the shock packing up and keeping it in the mid stroke area than static sag measurements.

might feel nice or might be horrible, the bum-dyno is the best judge IMO

do you land the drops on your front or back wheel?

though you may like the fork’s settings, they may not be working with the rear. if it is compressing at a lower rate than the shock then the back will need to deal with more of the impact. soften the fork and the and damper in the fork will be absorbing more energy,so there is less energy for the rear to absorb.

(i think, i’m not an engineer)

you may as well, as suggested above, wind the hsc fully in. that way the rear shock will resist more of the impact, putting more of the energy through the fork.
ah
as i’m sure you know, like everything, setting up suspension is a compromise. want it plush, it will bottom out or vice versa.

push used to make heavy duty bottom out bumpers. this may be your answer.

and springs aren’t 100% accurate with their ratings

Been measuring rear sag sat on the saddle with the dropper post downBeen measuring rear sag sat on the saddle with the dropper post down

If anything I'd say you are overdoing it there. As in, your actual riding sag will be quite a bit less than that.

Have you ridden it with that sag check tool on it? Possible dumb thought, are you sure you are actually bottoming it out?

and whar LAT said, you can get bottom out bumpers that are less squishy to give you some progression in the last 15% of the stoke.

On drops I used to just hoik the front wheel in the air and land back wheel first - but on the last coaching session I had I was told it’s fine to land front wheel first and in a lot of cases on slow speed drops / on tight turns it’s better to do that (within reason) so you have your front wheel back on the floor ready to turn. So I’m working on that at the moment. I’d say on faster / bigger stuff (say 3’ or a touch bigger) I probably am landing more rear wheel slipping into old habits. That said the most horrible drop of the weekend was the qualifier on Bonneville @ BPW (worse than the ones on Root Manoevres) - there’s something about that drop I just don’t like - first time was ok - 2nd time I landed a bit too much front wheel first for my liking.

I don’t 100% know I’m bottoming it out - but that’s my assumption. I can see it looks like I have been hitting the bottom out bumper. The reverse components thing should confirm either way when it’s bottoming.

On spring rating consistency I’ve been sticking to one brand - Cane Creek. Technically Nukeproof do inbetween ratings (425 / 475lbs) but with variable tolerances it seems best to avoid those.

I thought HSC was but hits and LSC was small hits as it relates to the shaft speed and not bike speed.

I thought HSC was but hits and LSC was small hits as it relates to the shaft speed and not bike speed.

That’s my basic understanding too.

Coil is back on the bike with the measuring tool in place - 17mm of sag - so 27%. Seems about right. Going to give it a test on the weekend hopefully - if I’m allowed out on my bike after 3 days away last weekend.

Got the progressive spring on way whilst I could get it at a good price (£40 delivered) if the hsc increase doesn’t do the job.

Why are you dropped the Qually? Doesn't need to be dropped any more.

We're there on 9th if you fancy it.

I thought HSC was but hits and LSC was small hits as it relates to the shaft speed and not bike speed

better to think about shaft speed in terms or "square edge" or "rounded" hits not big or small.

running into a 2" kerb is small yet a very high speed event.

also things slow down at the end of travel

have fun with the tuning!

What's the widest difference in spring rate before the shop needs to shim the shock so the rebound/compression is in the right range for the replacement spring?

Way back I had a DH rig that i needed a heavier spring on, and when buying the shock and going through details the supplier sourced me a spring and said they shimmed the shock to cope with the new heavier spring. Just think about ng that if you're moving through springs, maybe you'll go past the point the internals can cope without custom shimming?

Have you checked the Cane Creek website/owners groups? They were all pretty helpful when I was setting up my CCDB on an Orange Alpine several years ago. Love those shocks.

Have you checked the Cane Creek website/owners groups? They were all pretty helpful when I was setting up my CCDB on an Orange Alpine several years ago. Love those shocks.

I haven’t checked any owners groups - will have a look and see if I can find one on Facebook. Good thought.

What’s the widest difference in spring rate before the shop needs to shim the shock so the rebound/compression is in the right range for the replacement spring?

That I don’t know - think it’s meant to be pretty wide so not many need to be custom tuned. Would have thought 400-500lbs would be right in the middle of the range. If I turn lsc up to its strongest it’s really slow to return but if I turn it the other way it basically feels like it’s got no damping at all. So based on just that one adjustment I’d think I’d be ok.

I'm glad someone in the universe over thinks more than i do 🙂

I don't feel such a cabbage now 😉

I’m glad someone in the universe over thinks more than i do 🙂

I don’t feel such a cabbage now 😉

I wouldn’t go as far as overthinks more than you weeksy 🤣🤔

wasn't there an issue with the TF calculator churning out wrong numbers for springs a while back, or am I miss-remembering

wasn’t there an issue with the TF calculator churning out wrong numbers for springs a while back, or am I miss-remembering

I’m not sure but on this bike it has recommended a way lighter spring than I need - suggested 393lbs. I’d say it’s a bit too generic - not asking enough stuff about the bike and leverage curve etc perhaps.

Out of curiosity I put through the detail of my last bike that I ran with a coil on a Fox DHX2 and it came out almost bang on the spring I used and no issues with bottoming out. So perhaps the calculator suits certain bikes more than others. Just checked the aether and think it’s 30% leverage vs the 24% of the sentinel - so more resistant to bottoming out.

The Cascade Link would take the Sentinel to 30% but I’d also have to shorten my shock stroke to keep a similar amount of travel and it’s £337 😳

Shortening the stroke on a Kitsuma is only a case of adding a clip on spacer under the bottom out bumper.

wasn’t there an issue with the TF calculator churning out wrong numbers for springs a while back, or am I miss-remembering

I’m not sure but on this bike it has recommended a way lighter spring than I need – suggested 393lbs. I’d say it’s a bit too generic – not asking enough stuff about the bike and leverage curve etc perhaps.

I'm not sure that this tells you anything (and I think I've already said it in response to your pinkbike forum question) but I believe I'm heavier than you (85kg kitted up) and I'm running a 434lbs spring with my Ohlins shock on a v2 Sentinel with the standard link and no bottom out issues on drops up to around 5ft vertical drop. It's interesting that I'm happily on a lighter spring despite weighing more than you do 🤔

Just think of bottoming out as being the start of you using your god given suspension 😁

Maybe you’re focusing on one thing on an entire loop of riding and if you set it up to not bottom on that single feature then it’ll be worse for the main bit of riding. But if you’re sag is correct and you want more resistance I’d go with damping over spring rate change. Try closing low and high speed compression all the way, ride you’re drop 5 times trying to do it same speed/technique each time and take an average of the stroke used, if it’s not all of it then you can use the damper to tune out from.

I’m not sure that this tells you anything (and I think I’ve already said it in response to your pinkbike forum question) but I believe I’m heavier than you (85kg kitted up) and I’m running a 434lbs spring with my Ohlins shock on a v2 Sentinel with the standard link and no bottom out issues on drops up to around 5ft vertical drop. It’s interesting that I’m happily on a lighter spring despite weighing more than you do 🤔

That does suggests it’s a damping thing with the shock rather than the spring as your 434lb is probably near enough the same as my 450lb give or take with tolerances.

If I turn lsc up to its strongest it’s really slow to return

thats because you've adjusted rebound and not compression. full compression should lock out the shock and make it hard to compress. it shouldnt affect the extension of the shock at all.

Sorry - I meant lsr but my phone corrected it.

There’s a very firm platform and lockout setting on the shock so I’m pretty sure compression damping has the range it needs to control compression - I think I just need to try whacking a load more hsc on first and see how that goes off drops and then how that effects other things like big compressions or hard impacts in rock gardens

New progressive 450-550 spring arrived today - bargain £40 delivered from Pinkbike. Going to fit it this weekend whilst I’m down in the garage doing a lower leg service on the pike from my hardtail.

Currently in a bit of a bad way with a spasm in my lower back - so hoping to do an easy / mild ride on the new spring next weekend. In the meantime it’s loads of stretching and swimming + the physio said to try a few easy / short zone 2 rides on the turbo just to keep my back stretched out a little.

I don’t like the white so if the spring works well it’s definitely getting stripped and powdercoated. Thinking as close a red colour as I can get to my Lyrik ultimates.

[url= https://i.postimg.cc/KY6T20bJ/B2B619EE-6146-432E-94F0-8589630D9CF1.jp g" target="_blank">https://i.postimg.cc/KY6T20bJ/B2B619EE-6146-432E-94F0-8589630D9CF1.jp g"/> [/img][/url]

what is it's weight ?

Do you mean the weight as if I put it on some scales?

hope this fixes your issue.

this thread has me pondering putting a stiffer spring and winding back the compression

The CC shocks were odd for me in terms of spring rate. Had to increase the stiffness against recommended weight twice before I had something I was happy with (from 450lbs to 550lbs). I’m 75kgs.

Think I started with the TF calculator recommendation too.

Do you mean the weight as if I put it on some scales?

Yeah wondering how heavier it is compared to my 400-488 spring.

Will weight it for you later - might weigh the standard 450 Valt that comes of too just for good measure

Realised the coil was still sat in the window sill in the kitchen. 444 grams for the 65mm x 450-550 Valt coil.

Probably not a lot lighter than the entire float x shock that came off the bike 😳

my 400-488 is 429g, my 450 is 352g.

Rode my bike after getting the JadeX shock back from Sprung Suspension. I had asked for more HSC as well as the service. They replaced the shaft as it was a little worn as well. Not sure how much is down to the service, but shock feels fantastic! Very pleased. I've not noticed any less sensitivity, yet it feels more supportive and I'm sure its ramping up further into the stroke.
Dyno graph doesnt appear to have a legend to tell me what is before and after. I presume the blue is after:

Excellent service. Really hoping I dont have any issues with it in Verbier in a weeks time 🙂

100 points to everyone for massively overcomplicating this. Put a 500lb spring on. It's that simple.

100 points to everyone for massively overcomplicating this. Put a 500lb spring on. It’s that simple.

Go 550 just to be safe 😂

100 points to everyone for massively overcomplicating this. Put a 500lb spring on. It’s that simple.

I’m not sure about that - I think it might be too harsh on bumps - I’m 75kgs. Guess I’ll see how the progressive 450-550 spring goes - only paid £40 delivered to the door 🤷‍♂️

the correct way to setup your shock is to put more air in the coil.

then add lots of HSC to give nice trail feedback through your wrists.

when your collar bone has healed after a front door exit you should then experiment with the rebound damping.