Mountain Biking

So, anyone got any knowledge of coil shock springs? The stock coil on my frame is 550lb, which according to the calculator on TFTuned is a bit low for my weight. My optimum spring rate for the sort of riding I do is around 620lb, so I was looking at the Cane Creek Valt progressives. Assume 550-670 would be about right, keeps it very supple for small bumps but then ramps up to above the required weight for bigger hits to about bottoming?

From what I've read, you want a progressive coil spring to be softer than a linear initially, then harder than linear as it ramps, so seems like the ideal one for my setup.
 
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Invertigo said:
So, anyone got any knowledge of coil shock springs? The stock coil on my frame is 550lb, which according to the calculator on TFTuned is a bit low for my weight. My optimum spring rate for the sort of riding I do is around 620lb, so I was looking at the Cane Creek Valt progressives. Assume 550-670 would be about right, keeps it very supple for small bumps but then ramps up to above the required weight for bigger hits to about bottoming?

From what I've read, you want a progressive coil spring to be softer than a linear initially, then harder than linear as it ramps, so seems like the ideal one for my setup.
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Check a couple of spring rate calculators, they will give different results. sag should be around 25-30%.

As for if you need a progressive spring, that will depend on the leverage curve on your bike. Yours is an Occam right? Which seems to have a progressive ratio, so you probably won't need a progressive spring, as you'll find it'll be hard to get full travel with both.

You wouldn't want a progressive spring to be softer initially as that would mean more sag. Sag is set by the spring rate alone. Progressive springs are really for frames without the leverage ratio to suit a coil. What coil is it? CC coils tend to have a fairly large bottom out bumper too which ramps up the last 20mm of travel.

You can always buy a couple of cheap steel springs and then but a lightweight valt spring once you've found the right spring rate. Have you ridden a coil before? You don't need to worry about going lighter to get better small bump sensitivity. I can start to move my rear suspension with my little finger pressing on the saddle.
 
TallPaul_S said:
Check a couple of spring rate calculators, they will give different results. sag should be around 25-30%.

As for if you need a progressive spring, that will depend on the leverage curve on your bike. Yours is an Occam right? Which seems to have a progressive ratio, so you probably won't need a progressive spring, as you'll find it'll be hard to get full travel with both.

You wouldn't want a progressive spring to be softer initially as that would mean more sag. Sag is set by the spring rate alone. Progressive springs are really for frames without the leverage ratio to suit a coil. What coil is it? CC coils tend to have a fairly large bottom out bumper too which ramps up the last 20mm of travel.

You can always buy a couple of cheap steel springs and then but a lightweight valt spring once you've found the right spring rate.
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It's a Stumpjumper Evo, so comes stock with a coil but also a very linear linkage, so much that bottoming out seems to be a regular complaint with the stock DHX2 coil. Of course the issue of then using a heavier spring is you compromise the small bump sensitivity that coils are seemingly coveted for :p

The other alternative I see online is an aftermarket linkage that adds progression, but that's a whole lot more expensive than a coil spring.
 
Invertigo said:
It's a Stumpjumper Evo, so comes stock with a coil but also a very linear linkage, so much that bottoming out seems to be a regular complaint with the stock DHX2 coil. Of course the issue of then using a heavier spring is you compromise the small bump sensitivity that coils are seemingly coveted for :p

The other alternative I see online is an aftermarket linkage that adds progression, but that's a whole lot more expensive than a coil spring.
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Oh wow yeah that is very linear. Deffo go for a progressive spring in that case. But keep the initial spring rate correct for your weight.
 
TallPaul_S said:
Oh wow yeah that is very linear. Deffo go for a progressive spring in that case. But keep the initial spring rate correct for your weight.
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Cheers, will have a look, only issue I seem to find is finding one with a high enough starting weight. Valt springs seem to go up to 550 starting. MRP do some 600+ ones, that might be the one to hit.

Edit: so using the Fox calculator, both 550 and 600 can work using preload (CC say their springs can take 6 turns of preload). 3 turns gives a 28.5% sag on a 550 and 26% with a 600, so I'd expect the 550-670 will do the job nicely?
 
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Invertigo said:
Cheers, will have a look, only issue I seem to find is finding one with a high enough starting weight. Valt springs seem to go up to 550 starting. MRP do some 600+ ones, that might be the one to hit.

Edit: so using the Fox calculator, both 550 and 600 can work using preload (CC say their springs can take 6 turns of preload). 3 turns gives a 28.5% sag on a 550 and 26% with a 600, so I'd expect the 550-670 will do the job nicely?
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You really only want the minimum preload to keep the spring in place. All Preload does is increase the force it takes to start the shock moving, it doesn't increase the spring rate.

 
TallPaul_S said:
You really only want the minimum preload to keep the spring in place. All Preload does is increase the force it takes to start the shock moving, it doesn't increase the spring rate.

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Well, even with the recommended minimum 1 turn of preload puts a 550 spring at 30.9% sag. Fox recommend 30% in their setup, appreciate a bit firmer is preferred for trail riding though. I don't seem to be able to find any progressive coils that start any higher than 550, even the MRP 600+ is actually 550 at the start and ramps up to near 700, pretty much the same as the Valt 550-670.

The same fox calculator also suggests if you have progression of 7-15% you should be dropping 50lbs from the linear spring rate, but not sure if a progressive spring follows this same guidance?

I am also working on shedding some pounds from myself too :p
 
Looks like the 550 one should be good then, I run around 30% sag on mine are never notice any bottom outs, but then my drops etc are max 2-3ft.

You can always buy a cheap 550 normal coil and test that to see if the sag is right and if you need a progressive spring.

Don't forget to include riding gear, water etc in your weight, can easily add another 10lbs.
 
Stock coil is 550 so that'll hopefully show me what I need. Yeah I've factored in riding gear into the weight, which is fortunately decreasing on a weekly basis still too :rolleyes:

Just need to get the missing parts delivered and I can throw it together!
 
TallPaul_S said:
Not had any creaking, but both BB's I've had the bearings have lasted 6 months, then a year before getting play in them. A 24mm or Dub crank is probably fine, but mine is a 30mm crank in a PF41/92 BB, so that leaves 5.5mm for the outer race, bearings and seal, and inner race. You can't get away from physics, there just isn't enough room to have decent bearings and a good seal. Hence I'm moving to a 24mm crank with a Hope PF BB when I finally manage to remove this one.
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Are your current cranks e13? Mine are, with 30mm axle. Maybe I've been lucky but mine have been running smooth now for over 18 months with lots of wet rides over the winter.
 
SpudMaster said:
Are your current cranks e13? Mine are, with 30mm axle. Maybe I've been lucky but mine have been running smooth now for over 18 months with lots of wet rides over the winter.
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Yep, E13 carbon TRSR - first BB started to feel a bit grindy after 6 months, was the E13 one - replaced with an expensive cane creek solid oil one, which a few weeks back started getting some play on a lakes trip. Neither have gone completely but both have had play in them which would only get worse.
 
Invertigo said:
It's a Stumpjumper Evo, so comes stock with a coil but also a very linear linkage, so much that bottoming out seems to be a regular complaint with the stock DHX2 coil. Of course the issue of then using a heavier spring is you compromise the small bump sensitivity that coils are seemingly coveted for :p

The other alternative I see online is an aftermarket linkage that adds progression, but that's a whole lot more expensive than a coil spring.
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its a problem with the DHx2, on my rallon i had to run it over sprung and use to much compression damping, after swapping to the newer linkage which is much more proggesive i was able to back way of on the damping. the shock died eralier this year so i got a ext storia for it and it is miles better, also was able to go from a 550 to 475 spring.
 
Last bits of the bike due for delivery tomorrow, with the exception of the progressive coil spring, so looks like Saturday is build day.

Pretty hyped, I have to admit!
 
So, just had a realisation. I don't think a 116 link chain is going to be quite enough on this new setup. 440mm chain stays, 51t cassette and 32t chainring. Might have to look at grabbing a 120 link one, or a 12spd chain (assume there's no issues there as my chainring is specced for 10/11/12spd apparently)
 
SpudMaster said:
Just checking :p I used a press to install mine and never had an issue but you see so many people knock in headsets and bbs with mallet and wood
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I've always used a hammer and wood to do headset, take your time and it's easy.

Done my first Zwift training session today, can see it being brilliant over the winter months.
 
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