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A little assistance setting up / adjusting front shocks.

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A little assistance setting up / adjusting front shocks.

Old 05-03-15, 03:22 PM
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GZ99
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A little assistance setting up / adjusting front shocks.

Hello,

My new bike is the fist bike I have ever owned with adjustable front shocks. I had a box-store rig with garbage suspension forks that I hated with a passion.

My new rig has the Rockshox Recon TK GOLD solo front shock forks with lockout.

I do mostly road / maintained trail riding with the occasional foray into more off-the-beaten-path trails. I bought my current bike as a one-bike-does-all kind of deal because I don't have the capital to invest in multiple bicycles (i.e. Road / comfort / etc).

Now... Onto my issue... The suspension fork on my bike has 100mm of travel with a lockout system. I was under the assumption that the lock would prevent suspension travel when I am riding on the road or on a smooth trail. It would seem that the lockout only stiffens the fork and when it moves makes a PFFTTT sound, like air escaping from a badly fitting air chuck.

Now... As I stated earlier... I have no experience with suspension forks... Is this normal? And is there an adjustment where I can further stiffen the suspension fork to give it more of a rigid type ride when I am on the road?

Thanks in advance
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Old 05-03-15, 08:33 PM
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From SRAM's page:
TurnKey™This exclusive technology works a lot like the Secret Service. If you happen to hit a big rock when you have your fork locked out, TurnKey’s patented blow-off design takes the bullet for you, absorbing the unexpected hit instantly. When you think about it, it’s kind of noble. Compatible with both PushLoc and PopLoc remotes.
The main reason for suspension lock-out is to prevent wasted energy due to pedal bob and weight transfers. If you hit a big impact, you're not wasting pedaling energy. You may even want to consider riding regularly with the fork not locked out. If you're a relatively smooth pedaler you'll find that the lock-out doesn't actually do much and the suspension is nice for potholes and curbs.
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Old 05-03-15, 08:54 PM
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Originally Posted by gsa103 View Post
From SRAM's page:


The main reason for suspension lock-out is to prevent wasted energy due to pedal bob and weight transfers. If you hit a big impact, you're not wasting pedaling energy. You may even want to consider riding regularly with the fork not locked out. If you're a relatively smooth pedaler you'll find that the lock-out doesn't actually do much and the suspension is nice for potholes and curbs.
Well. That explains the PFFTT... Thanks for that... I don't know how I missed that when I was perusing the literature. TBH. I only ever notice it when pedaling hard (off saddle). I haven't attempted to climb a hill with this bike yet... So I don't know how it will feel then... I don't like hill climbing.

Thanks for the info.
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Old 05-03-15, 10:47 PM
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Originally Posted by GZ99 View Post
Well. That explains the PFFTT... Thanks for that... I don't know how I missed that when I was perusing the literature. TBH. I only ever notice it when pedaling hard (off saddle). I haven't attempted to climb a hill with this bike yet... So I don't know how it will feel then... I don't like hill climbing.

Thanks for the info.
I don't know the fork, but I'm a bit surprised that you can hit the blow-off point pedaling out of the saddle. Did your bike shop help you adjust the air pressure when you purchased the bike? You should probably check the sag, you normally want 15-25mm for a 100mm fork. It seems like you might want just slightly higher pressure. That's really more of a feel thing though. Personally, I like a plush fork, and tolerate a bit of bob as a necessary evil.
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Old 05-03-15, 11:03 PM
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Originally Posted by gsa103 View Post
I don't know the fork, but I'm a bit surprised that you can hit the blow-off point pedaling out of the saddle. Did your bike shop help you adjust the air pressure when you purchased the bike? You should probably check the sag, you normally want 15-25mm for a 100mm fork. It seems like you might want just slightly higher pressure. That's really more of a feel thing though. Personally, I like a plush fork, and tolerate a bit of bob as a necessary evil.
I purchased the bike directly from airborne and assembled it myself. I am mechanically apt and got the bike set up pretty well. Front and rear derailleurs shift like butter and she rides well... I haven't the slightest clue on what needs to be done to adjust the shock.

It has the lockout on the right post and an adjustment knob on the left. But there is also a metal tube with a hex socket sticking out the bottom of the one post.

I figured I'd err on the side of caution this time around and ask.

The other option is spending a day tearing down the fork and seeing how it works. lol
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Old 05-04-15, 01:24 AM
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If you have the Solo Air version (there is also a coil spring version) of Rock Shox Recon Gold TK fork, then you have a Schrader valve (car tyre valve) for adjusting the air pressure in your fork (using a fork/shock air pump). The valve is on the top of the left fork arm, under a screw-on cap. More air pressure equals to stiffer fork. You adjust the air pressure according to your weight and to the desired feel of the fork.

Always remove all the air from the fork before disassembling the air chamber part (when servicing the fork or if you are curious to see how the fork is made).

If you have a knob marked "Preload" there (instead of the Schrader valve), then you have the coil spring version of that fork. Use that knob to adjust the pre-compression of the coil spring. More pre-compressing the coil spring equals to stiffer fork. For some coil spring forks you can also buy different coil springs (for lighter cyclists or for heavier cyclists).

On both versions (air and coil spring) you also have a rebound damper adjustment knob on the bottom of right fork leg. It has a label with a rabbit and a turtle. From here you adjust the rebound damper (adjust how fast the fork will extend after it is compressed). Be careful not to lose that rebound adjuster knob (it can be pulled out - necessary when disassembling the fork).

The TurnKey compression damper is not adjustable (unlike the Rock Shox's Motion Control compression damper for instance). You can only lock it out or leave it in normal position.

Last edited by Seb71; 05-04-15 at 02:09 AM.
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Old 05-04-15, 02:18 AM
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Hmmm. So it's as easy as adding pressure via a Schrader valve... As soon as I have a moment, I am going to check that out.

Thanks
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Old 05-04-15, 11:59 AM
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http://www.veloplus.ch/pdf/artikelde...chart_2015.pdf

That document contains the recommended pressure based on rider weight (remember to include pack weight). The recommend pressure is a good starting place, but you'll likely want to go up or down a few psi depending on feel (lower = plush, higher = not bottoming out).

You may also need a shock pump, assuming one didn't come with the bike.
Something like:
Amazon.com : RockShox High-Pressure Shock Pump (300 psi max) : Bike Suspension And Accessories : Sports & Outdoors

Brand doesn't really matter. The main thing is shock pump are optimized for low volume, high pressure, while most floor pumps are high volume and lower pressure.
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Old 05-04-15, 12:13 PM
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Originally Posted by gsa103 View Post
http://www.veloplus.ch/pdf/artikelde...chart_2015.pdf

That document contains the recommended pressure based on rider weight (remember to include pack weight). The recommend pressure is a good starting place, but you'll likely want to go up or down a few psi depending on feel (lower = plush, higher = not bottoming out).

You may also need a shock pump, assuming one didn't come with the bike.
Something like:
Amazon.com : RockShox High-Pressure Shock Pump (300 psi max) : Bike Suspension And Accessories : Sports & Outdoors

Brand doesn't really matter. The main thing is shock pump are optimized for low volume, high pressure, while most floor pumps are high volume and lower pressure.
Thanks for the info. I have a single stage, 150psi, 60 gal air compressor (with moisture filtration). I also have access to a two stage, 250psi air compressor... So I think I will be able to get by.

Once again, much obliged.
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Old 05-04-15, 03:33 PM
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NO No NOoOOo no compressor, you will blow your fork...

Get a fork specific shock pump,, a hand pump with a puff bleeder for making tiny very tiny pressure releases...

Here is mine,,works like a charm, a Giant, the guage is removable for better back pack fit.
You don't need the guage if you know how to use your sag ring or to add a tie strap for a sag ring...:


NOTE: it moves small amounts of air, will take 23 years, 4 months six days and five hours to fill a flat tire..
Not really but a cheap $20 larger volume air pump will fill a 29er tube to 30 psi in about 100 pumps..
this one,,LOL I dunno, don't wanna know,,I guess 250.

Carry Co2 ,,,

The fork lock out gives up a bit of air, so you don't blow the seal on a surprise sudden/hard hit...

Last edited by osco53; 11-29-16 at 06:31 AM.
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Old 05-04-15, 04:01 PM
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I don't understand why I couldn't use a compressor? It seems to me that I would regulate pressure around where I wanted the fork and let it equalize. I do realize it would take very small amounts of air to adjust the fork pressure...

Perhaps it's best if I just drop by Broken Spoke and let them adjust the pressure for me.
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Old 05-04-15, 04:03 PM
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Originally Posted by GZ99 View Post
I don't understand why I couldn't use a compressor? It seems to me that I would regulate pressure around where I wanted the fork and let it equalize. I do realize it would take very small amounts of air to adjust the fork pressure...

Perhaps it's best if I just drop by Broken Spoke and let them adjust the pressure for me.
If you think using a compressor is ok then yes you better go to the Spoke..

It's a volume thing,, a comp hits hard with each piston stroke, It will simply beat your seal silly..

You will understand after they show you a proper shock pump in action.
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Old 05-04-15, 04:22 PM
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Originally Posted by osco53 View Post
If you think using a compressor is ok then yes you better go to the Spoke..

It's a volume thing,, a comp hits hard with each piston stroke, It will simply beat your seal silly..

You will understand after they show you a proper shock pump in action.
I completely understand the relationship between pressure and volume. That's why I would use my compressor with an accurate regulator to control pressures by equalization.

Either way, you are correct... I don't understand the mechanics of the fork fully, that's why I posted this thread. I am most definitely taking your advice and not using my compressor, and this isn't an argument for using a compressor... It is simply a statement of my understanding of the mechanical relationship of volume and pressure and pressure regulation... and the gap (lacktherof) in my understanding of how the fork stores and uses that pressure.

Thank you for the advice, it is much appreciated.
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Old 05-04-15, 11:56 PM
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Another advantage of a shock pump over an air compressor: it is easier to take with you on a trail (so you can test how the fork behaves with various air pressures and make adjustments on the field).
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Old 05-05-15, 05:02 AM
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Originally Posted by osco53 View Post
NO No NOoOOo no compressor, you will blow your fork...
You could blow a fork seal if put the wrong pressure into the fork.

If you set a regulator to 50psi then you will only put 50psi into the fork, it won't magically put a large volume of air at 300psi into the fork and blow the fork to pieces.

I've used a compressor with a tire inflator to put air into a fork and it has never looked like blowing up.





I do recommend getting a shock pump.

Last edited by cobba; 05-05-15 at 08:56 AM.
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Old 05-05-15, 02:25 PM
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I took the bike over to broken spoke today and had them adjust the pressure with a suspension pump. I will be purchasing one, but not at the moment... $$$ is tight while I am overhauling the motor for my car.
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Old 05-05-15, 07:59 PM
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Using an air tank compressor with a regulator would be fine. A compressor/regulator directly into the fork could be bad. A regulator alone might not be able to respond fast enough to prevent the fork from over-pressuring, hence the need for an air tank volume. If the compressor is feeding an air tank, the air tank acts as a volume reservoir, in which case you could easily use it to pressurize the fork.

Back on topic, how did the fork respond after setting the pressure.
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Old 05-06-15, 10:48 AM
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Originally Posted by gsa103 View Post
Using an air tank compressor with a regulator would be fine. A compressor/regulator directly into the fork could be bad. A regulator alone might not be able to respond fast enough to prevent the fork from over-pressuring, hence the need for an air tank volume. If the compressor is feeding an air tank, the air tank acts as a volume reservoir, in which case you could easily use it to pressurize the fork.

Back on topic, how did the fork respond after setting the pressure.
Beautifully. The ride is no longer soft and I feel more power going to the ground and not being eaten by the suspension. The lockout is more effective and the ride is much nicer. I also adjusted the rebound to a bit slower setting and it handles the bumps well enough. It's now set to 170psi. My compressor will only pump to 130psi max (single stage) so I would have never been able to reach that point anyhow.

Now I am looking for a nice, small, suspension pump that I can add to my kit.
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