Tech Tuesday - Coil Spring Swap

May 30, 2011 at 13:35

Your bike's suspension plays a key role in allowing you to ride faster and farther. The proper setup lets your wheels track the ground better, giving you more traction and confidence when you're pushing your limits on the trail, but it can take time to reach the ideal settings. The first and most important step is to have your suspension sagging into its travel the correct amount when you are fully geared up and on the bike. It is not until you have your spring rate dialed, which determines your sag, that you can start to fully take advantage of your shock's rebound or compression adjustments. While changing the spring rate on an air shock is relatively simple, the job is slightly more complicated on a coil-over model, although it can still be done in only a few minutes.

Unsure of how to setup your bike with the correct amount of sag? Check out this previous Tech Tuesday where we explain suspension sag in detail.

It is very important to be sure that the spring you're installing has enough free space between its coils to keep them from coming into contact with each other before the shock bottoms. There are two numbers on the coil spring pictured above - the "350" refers to the spring rate, meaning that it takes 350lbs to compress this spring one inch. The "3.0" means that there is enough free length, or space between the coils, to use this spring on a shock with 3 inches of stroke. If you were to put a coil designed for a shock with 2.5 inches of stroke on this 3 inch stroke shock the coils are likely to bind, resulting in either a damaged shock body or broken spring clip.

What you'll need:

• Hex keys (usually a 5mm or 6mm)
• Open ended wrench
• Your replacement coil spring

Helpful pointers:

• Always take note of your shock mounting hardware's orientation before removing it, and if need be lay it out on the counter top in order to make re-installation easier.
• Applying a small amount of grease to both the spring clip and preload collar where the coil spring rests can help reduce the chance of creaking as your suspension cycles. Excess amounts will only attract dirt and grime - be sure to wipe away any and all surplus grease.
• A thin layer of grease applied to the shock bolts will make removal down the road much easier, while a touch of blue Loctite on the threads will keep them from coming loose.
• Reinstalling your bike's rear shock is just as easy as removing it. Making sure to install it in the same orientation that it was originally in to keep the shock's reservoir from coming in contact with the frame or swingarm, bolt the shock to the frame before reinstalling the swingarm or linkage bolt. Doing it in this order, especially with the rear wheel removed, makes it far easier to align the shock bolt with the rest of the mounting hardware.

How to swap out a coil spring:

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38 Comments

Score Time

+ 10

mountguitars (May 31, 2011 at 0:13)

i was actually looking for a softer spring for my demo but i don't actually know how to swap the springs in case i do find one. this will definitely help and i don't have to bring the bike to a bike mechanic to do the job. thanks PB!

B-STOCK (May 31, 2011 at 5:49) (Below Threshold) show comment

hey its milke

socalshredder (May 31, 2011 at 7:08)

same thanks TT

DH-Til-I-Die (May 31, 2011 at 12:22)

Mike Levy is the GOD!

Davidsym (May 31, 2011 at 20:04)

exact same thing as what mountguitars said but stiffer couldent be better timing. Smile

[Reply]

akozz (May 31, 2011 at 5:36)

That's a piece of cake with bike like glory PB Razz

I have to disassemble some of the rear triangle linkage just to get acces to the shock in my demo. Not that i'm complaining Big Grin

[Reply]

rockyguy97 (May 31, 2011 at 18:47)

I really need to know if there is any way to sub a rock shox, manitou or marz spring for my fox vanilla. Also, with a 2.5 stroke, the tech page on foxshox says i need an 800 lb spring, (yeah, Im a fatty) but was wondering if a longer length spring in a lower spring rate would do the same thing; i.e. mine should be an 800x2.8 but would a 700 by 3.5 work. Got lots of space on the threads of the shock body for a long spring.

[Reply]

JubaBabaci (May 31, 2011 at 0:15)

Haha i watch these mainly for the Outtakes! Nah awesome video for those who want to learn!

[Reply]

boylagz (May 31, 2011 at 7:31)

Even if this job is pretty easy/straightforward, some riders would actually want to see it done properly, rather than strip any nut or hex slots in the shock bolts. Sweet TT Mike, appreciate it! Salute

[Reply]

jawzzy3 (May 31, 2011 at 0:54)

Is there any leeway at all with free-length on a spring and shock stroke? I got a new shock and spring installed on my bike at a suspension shop and they put a 2.25 spring on my 8.75x2.75 shock. Haven't noticed any problems yet but I don't wanna destroy my new CCDB Frown

allenrotstein (May 31, 2011 at 6:39)

Yup, there is a problem, your shock will bottom out pretty hard damaging the bushings and possibly the frame.

It's okay to get a longer stroke spring, like a 3.0 in your specific case, never never ever a shorter one!

mikelevy Mod Plus (May 31, 2011 at 8:55)

allenrotstein is correct, that isn't good. The coils could easily bind, pushing the preload collar right off the shock and ruining the body. Springs are cheap, spend the money and get the right one.

[Reply]

tony1j (Aug 2, 2011 at 12:13)

Hey Mike I got a RS vivid that I can't take the spring off because there is not enough free-play to remove spring clip any suggestions?

[Reply]

abonativ10 (Jun 2, 2011 at 21:24)

ok i no this is a wee bit of the subject of "how to remove a spring" but does any body no if rockshox or any componey makes a taperd steer tube and bottom crown for the 2011 boxxer ?

fitz-randolphdavid Plus (Jul 31, 2011 at 14:27)

risse racing has made some i believe

[Reply]

skippy888 (May 31, 2011 at 1:56)

Cheers PB, never done it before but seems simple if you got the right parts. Thanks

[Reply]

RaleighVoid (May 31, 2011 at 4:46)

hi mike. gonna swap coils with my friend, his stroke is 2.3, mine is 2.37, will these springs be ok to swap over? thanks, arthur.

pbuser102331 Plus (May 31, 2011 at 5:13)

Check the free length of both i,e just measure them with a ruler and so long as the difference isn't huge it will fit,also compare the internal diameters too as vivids use a fatter spring than fox and even some of the fox internal widths are different.

RaleighVoid (May 31, 2011 at 10:00)

well mines a dhx 4 and his is a van r, soo should be ok. and yeh we'll do that cheers.

[Reply]

p-romano (May 31, 2011 at 0:14)

This almost seems like a waste of a tech tuesday. I swear this is one of the easiest and most self explanatory things out there.

+ 20

mikelevy Mod Plus (May 31, 2011 at 0:47)

It certainly isn't the most involved job, but keep in mind that there are a lot of riders out there with new bikes, possibly their first mountain bikes, who don't know how to do this. There are also 52 weeks in the year... lots of time for more advanced Tech Tuesdays.

Mike.

fantaman (May 31, 2011 at 1:00)

On the marzocchi rocco you need to take out the rebound adjuster in order to change the spring,while with the other shocks you don't have to do that.

p-romano (May 31, 2011 at 1:05)

I want to see fork damper service. Most intimidating thing for sure because of how easily things can be broken.

mikelevy Mod Plus (May 31, 2011 at 5:51)

@p-romano

Check the TT list at the bottom of the article. You'll find ones for Fox lower leg removal, Motion Control service, Manitou Dorado and even a Circus rebuild. There are more to come, they just take quite a bit longer to put together. Leave a suggestion for which fork model that you'd like to see in the comments section.

gnarbar (May 31, 2011 at 7:12)

@mike you're spot on with your first reply, there's loads of riders who've never taken a coil off a shock or removed a shock from a bike, now they know how to do that if they want to change spring rate......which gives people incremental increases in their ability to look after their own bike and to be more self reliant, also worth mentioning, some bikes you have to take the rear wheel off to pull out the shock......good luck with that fun and games !!

p-romano (May 31, 2011 at 10:06)

The fox lower leg removal and service was a very good video and a similar one would be great for a Boxxer. But it would also be nice to see the damper removed and serviced.

stefan-ram (May 31, 2011 at 10:25)

yea, service of motion or mission control damper
i had problem with my MoCo damper and i couldn`t find anywhere on the net about servicing it
so i`ve been forced to experiment by myself, luckily i didnt broke anything :S

p-romano (May 31, 2011 at 10:35)

tech tuesday #25 shows motion control service but skips a lot of steps

the-freerider (May 31, 2011 at 11:07)

mike is it possable to make one on how to service a 888

Bjammin (May 31, 2011 at 16:18)

Mike, You're too helpful!!!!!!!!!!! You're Putting all the LBSs out of Business!!!!!!!!!! (sarcasm intended, except for the "helpful" bit)

stefan-ram (May 31, 2011 at 23:34)

@p-romano
skips all the steps of servising the damper itself

saso (Jun 1, 2011 at 3:22)

stefan the damper has manny small pieces and seals that you probably don't have at home... so you are better of by sending it to a bike shop were they have all the parts and know-how to doo it correctly.

[Reply]

fantaman (May 31, 2011 at 0:22)

i've been experimenting with 3,5'' stroke springs on 3'' stroke shocks for about 3 months,i head not a single issue with them

p-romano (May 31, 2011 at 0:38)

a longer coil will always work as long as there is space to fit it on the shock

mikelevy Mod Plus (May 31, 2011 at 0:48)

That is something that I forgot to include... there is always something! This it totally true, thanks p-romano!

[Reply]

tea-addict (May 31, 2011 at 16:31)

Spring rate isn't measured in 'inch-pounds'; that's a unit of torque. Spring rate is force/distance, hence pounds per inch (or more properly, N m^-1).

[Reply]

fatlarry (Jun 1, 2011 at 11:04)

I watch this just for the outtakes...

[Reply]

jedras (May 31, 2011 at 13:56)

geee ! that's so helpful. THANK YOU

[Reply]