As above I’m on a 2022 alloy Transition Sentinel which is said to be good for either coil or air. Progression is 24% according to what I can find online so should indeed work with an appropriate coil shock. Standard it comes with a Fox Float X performance elite – to get it to give enough mid stroke support (I.e not too soggy) I’m running 26% ish sag and it has lost a bit of small bump but is great on the rest.

I’ve got a Cane Creek Kitsuma coil which the tf tuned calculator suggested needed a 400lb spring for my weight (75kgs ish – probably nearer 78kgs kitted up I’d imagine) and riding style.

The 400lb spring was clearly too soft so I picked up a 450lb one and it’s a lot better – but still bottoms on anything around a 1.5 foot drop upwards.

For this last weekend where I was visiting BPW / Afan Masts / FOD off piste I ran the air and didn’t bottom at all – but in comparison to the coil it loses sensitivity over roots / rock gardens / has less grip. That said I pb’d everywhere at BPW cs my last trip a few years ago – took more than 2 mins off my roots manoeuvres pb/ a lot of that is improved technique on janky stuff but the bike is monsterous down there too!

So I’m trying to get the coil to a place where it’s got all the grip but isn’t bottoming. I figure I have the following options in ascending cost order:

Increase HSC to hold the shock up more on big hits (cheapest and first thing to try)

Increase spring weight to 500lbs – although this seems very high for my weight

Change to a progressive spring so I’ve got the sensitivity of the 450lbnto start with but stiffer as I get near the end of the travel

Cascade link which ups the progression to 30% / I’d have to decrease my shock travel by 7.5mm and would end up with 5mm extra travel vs now. Flipping expensive option though.

To help with sag measurement and working out how much travel I’m using I’ve picked up a reverse components travel tool thing.

Any comments / experiences / observations anyone has had with something similar would be very welcome to sense check my thoughts!

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