# Truth or hype: Zertz inserts?



## alexedge (Jul 13, 2007)

Just bought a new aluminum frame, love the feel of aluminum the way it rides, accelerates, everything except the slight road buzz. In my experience, carbon or Ti seatpost typically transmit slightly less of this vibration to your backside than an aluminum post, so I'm in the market for a new seatpost.

My question is, do the Specialized seatposts with the Zertz 'vibration damping' inserts really make a difference? Not looking to start a "Specialized rocks!/Specialized is the Evil Empire" argument here - please only reply if you have personal experience with using both a standard (non-zertz) seatpost and a specialized post.

Thanks!


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## dbassi (Sep 30, 2006)

alexedge said:


> My question is, do the Specialized seatposts with the Zertz 'vibration damping' inserts really make a difference?
> Thanks!


Not the seatpost for me, the frame does.


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## iliveonnitro (Feb 19, 2006)

Agreed. I noticed a little bit with the fork and frame (very little), but not on the seatpost.

Granted, these were on 20min rides.


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## kbiker3111 (Nov 7, 2006)

I had one for two years. It was a fine seatpost, relatively lightweight and as comfortable as any carbon post. The zertz did nothing that I could percieve though. I noticed it in the handlebars, but not the seatpost.


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## tubafreak (Apr 24, 2006)

An insert like zertz will dampen some (very little) of the road buzz. You can feel the buzz through your 3 contact points (handlebars, seat, pedals). With the handlebars and pedals, the damping provided by the handlebar, frame, and fork inserts. With the seat, your chamois should provide the damping through the seat. Because of this, the seatpost insert is redundant and doesn't seem to have an effect.


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## Plank (Apr 23, 2006)

I agree with everyone here I don't think it makes much difference. I have one bike with and one without and I can't say one is more smoother that the other.


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## Rubber Lizard (May 10, 2007)

I removed the zertz inserts in my seatpost and packed the space with bacon. That made a huge difference.


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## Kerry Irons (Feb 25, 2002)

*5 psi*



alexedge said:


> My question is, do the Specialized seatposts with the Zertz 'vibration damping' inserts really make a difference? Not looking to start a "Specialized rocks!/Specialized is the Evil Empire" argument here - please only reply if you have personal experience with using both a standard (non-zertz) seatpost and a specialized post.


You will probably get more impact from dropping 5-10 psi tire pressure. You'll never notice any increase in rolling resistance but you will notice the comfort. If that causes pinch flats, then move up to the next tire size.


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## Forrest Root (Dec 22, 2006)

Kerry Irons said:


> You will probably get more impact from dropping 5-10 psi tire pressure. You'll never notice any increase in rolling resistance but you will notice the comfort. If that causes pinch flats, then move up to the next tire size.


No way. I just read in Air & Space Technology that when the Russian Soyuz capsule return to Earth and land out in the plains, the capsules actually land on giant zertz cushions. The parachutes are just for show.


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## dagger (Jul 22, 2004)

Walk away from the zertz insert unless you like carbon fiber splinters up your arse. I have seen at least 3 broken zertz seatposts at my LBS. They were all broken at the insert.


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## acid_rider (Nov 23, 2004)

i had a zertz post on my Specialized Roubaix and it was nice. I then bought a Madone with carbon Bontrager Race-X-Lite post and it was just as comfortable overall. Then I bought a Time with first a carbon and then aluminium posts and it was just as nice! I then tried aluminium FSA SL220 post on two frames - Madone and Time and I did not notice any difference to carbon posts - all were nice. I therefore think that the seatpost material (carbon or alloy) will not make noticable difference to ride quality unless it is not very stiff in the first place. I think it is the frame+forks and saddle and wheels+tyres+air that will make the most ride difference, not seatpost, not stem, not bars. Now I have a Thomson Elite post in a carbon frame and it is as comfortable as any carbon post I have tried.


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## rbart4506 (Aug 4, 2004)

I've got an 04 Roubaix (aluminum/carbon mix) with zertz in the frame and in the seatpost/fork. I've also got an 07 Roubaix Expert with the full carbon frame with zertz in the fork and seatpost. The 07 Roubaix is much nicer riding, but I'm guessing that is way more the frame then the zertz.

Now to really answer your question. I've used the Pave SL (stock 04 post), the Pro SL (stock 07 post) and a Thompson Elite on my 07 Roubaix. Currently the Thompson post is the one that I ride. The Pave SL has the most flex, ride quality between all three posts is pretty comparable. I honestly find that the ride quality was better with the Thompson. So do the zertz do something?? Who knows, but if I was shopping for a seatpost I would skip the Specialized and spend you money on a Thompson...


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## dagger (Jul 22, 2004)

*Don't agree....partly*



acid_rider said:


> I think it is the frame+forks and saddle and wheels+tyres+air that will make the most ride difference, not seatpost, not stem, not bars. .


The one single item that dramatically improved my ride quality on my aluminum bike was the FSA KForce Light seatpost. Key factor .....the frame is a compact geometry. With a traditional frame without much seatpost exposed to allow it to flex...then the seatpost will not affect the ride quality. If you have a compact frame and no carbon seatpost...go get one and you will be amazed.


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## rbart4506 (Aug 4, 2004)

dagger said:


> The one single item that dramatically improved my ride quality on my aluminum bike was the FSA KForce Light seatpost. Key factor .....the frame is a compact geometry. With a traditional frame without much seatpost exposed to allow it to flex...then the seatpost will not affect the ride quality. If you have a compact frame and no carbon seatpost...go get one and you will be amazed.


Look below vvv 

I have a Thomsom Elite on my full carbon compact Roubaix and I don't notice any degradation in ride quality. I actually found the opposite, I found the ride to be better with the Thompson.

I highly doubt I will ever be looking at getting a carbon post in future...


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## acid_rider (Nov 23, 2004)

*you misunderstood my reply*



dagger said:


> The one single item that dramatically improved my ride quality on my aluminum bike was the FSA KForce Light seatpost. Key factor .....the frame is a compact geometry. With a traditional frame without much seatpost exposed to allow it to flex...then the seatpost will not affect the ride quality. If you have a compact frame and no carbon seatpost...go get one and you will be amazed.


I was referring to choice of seatpost material (alloy versus carbon) in a modern *carbon* frame. if you have a poorly riding aluminium frame then i would not be surprised if a carbon post improved the ride. aluminium frames ride so poorly that almost anything would improve the ride. Oh, oh, now I hear the aluminium frame bigots flaming me for saying that. Ok, I take it back, aluminium frames ride great! They ride best! (not). Modern Carbon frames can be made to ride any which way you like - from very bad to very best and the seatpost material wont make any difference to the ride quality.


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## rellimreeb (Jul 29, 2007)

*+1 for hype*

I had a Roubaix for a couple of years. 

I don't want to quibble with the fine engineers at Specialized, but I think my Excalibur rides better than my Roubaix did. And in small high-frequency stuff, I can't tell any difference. 

There are other variables at play here (seat, stem, bars, fit, etc), but I don't feel as fatigued on my Ridley after long rides.


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## kgg (Apr 28, 2003)

Rubber Lizard said:


> I removed the zertz inserts in my seatpost and packed the space with bacon. That made a huge difference.


Yeah - but I'll bet you have more problems with dogs.


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## capt_phun (Jun 14, 2004)

+100
I used to ride a S-works Tarmac with the zertz & the seatpost has a stupid zertz as well. It did nothing for comfort. My Look is smoother, whatever that is worth, with a Thomson post. Like was mentioned before, drop your tires 5 psi & that makes more a difference. Plus that old zertz post was a pain in the arse to adjust with the 8mm nut in the front instead of a hex head. stupid! There is only 1 post, Thomson.


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## Mr_Snips2 (Jun 26, 2006)

This comes up alot. But in my honest opinion the biggest difference in ride i've made to my bike was to put a quality full carbon bar on it. Not specialized, but still, i ride a CAAD 8 which is about as buzzy and stiff as it gets. And the bars made a world of difference. I got the Easton EC90 bars.


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