anyone familiar with headshoks?

[Cirkustanz]

On my new Cannondale F4 that has an HeadShok Super Fatty Ultra DL, if I lift up the bars to do a wheelie there is a feeling that reminds me of when I was riding one of the crappy bikes I had as a kid with a loose stem.

That stem eventually broke on me, and I had a nasty fall while dropping off a porch.

I weigh 235, and at first I would only notice this when actually lifting the front tire up to go up a curb, or whatever. But as it became more apparent, I paid more attention to it and realized that I felt it on a lesser level if I was pedaling hard while standing up.

I had only rode the bike once since I bought it, and I took it back to the shop. The service guy is headshok certified supposedly, and I described my fear to him, so he checked the shock out.

He did not get on the bike, he just pushed down on the fork about 10 times and verified the suspension worked.

On MTBR, a couple of people mentioned the possibility of having the weight of the oil changed from a 5 weight to a 7.5. The service guy said the holes in the shocks were finely tuned to work with a certain type of oil, and using a thicker oil impedes how the shock is designed to work. So I clarified and said "so you're saying that changing the weight of the oil is a bad thing?" and he did not respond either way.

I told him I feared eventually breaking the stem/fork/shock or injuring myself if I got more adventerous in doing wheelies or whatever.

Other people have mentioned that the sensation is mostly because this shock does not have a rebound adjust. Green light went off in my head, since the first sales guy described rebound to me when looking at another bike, although his description was absolutely wrong.

So I inquired to the service guy about how much it would cost me to get an upgrade to a shock with rebound adjust, known as the DLR. (D for headshock, L for lockout, R for rebound) He said something they retail for something around $140.

When I first rode the bike on a test ride I was very careful with it since I did not own it, and while I rode it for a good 15 minutes, I didn't do much with it really, I'm sure I would have noticed this.

I'm also wondering if lowering the PSI on the shock will effect the scenario any. The sales guy set the shock PSI based on my weight, to a percentage that he said was recommended. Honestly it feels pretty firm to me and I would not mind lowering it a bit, especially if it would have any impact in rebound.


Sometimes I wish bikes were more like computers. With a computer you KNOW if something is wrong.

[soupboy]

Have you checked to see if your headset is pre-loaded correctly. "Loose stem" sounds more like "loose headset". "Loose stem" does not really describe the fork topping out when unweighted. If that is the issue it should be addressable by more/heavier oil and/or a stiffer negative spring.

OE forks are notorious for low oil levels - have you had this checked?

You are not unusually heavy for any modern MTB fork. Take your bike back to the shop you bought it from and demand that they set it up properly for a rider your size. If there is indeed something wrong they should fix it immediately.

Riding a new bike you're concerned about ain't cool.

[Cirkustanz]

I wouldn't know how to check to see if my headset is preloaded correctly. (it's all greek to me) That's the trouble with bike shops and noobies like me. There is an inherent translation problem, and honestly I want to be upset with the shop for not RIDING the bike when I describe it but they are so nice about it. And I am overly aware that I don't know what I'm talking about, and they are nice to me about it.

Which makes my demanding that they set it up correctly very awkward.

I have thought about bringing it into another shop but it seems that Erik's has an exclusivity agreement or something, and no one else stocks Cannondale mountain bikes, except for REI. I have reservations about REI being able to give feedback on the matter, but that is another matter.

Now I know how some of my customers at my old job must have felt.


Have you checked to see if your headset is pre-loaded correctly. "Loose stem" sounds more like "loose headset". "Loose stem" does not really describe the fork topping out when unweighted. If that is the issue it should be addressable by more/heavier oil and/or a stiffer negative spring.

OE forks are notorious for low oil levels - have you had this checked?

You are not unusually heavy for any modern MTB fork. Take your bike back to the shop you bought it from and demand that they set it up properly for a rider your size. If there is indeed something wrong they should fix it immediately.

Riding a new bike you're concerned about ain't cool.

[soupboy]

Rich - please PM me. I'm happy to look over your bike and show you how to check for certain basic mechanical maladies that befall most bikes.

There is no reason that the shop you purchased it from can't help you. I know Erik's pretty well. If you want, I'm happy to visit the SLP location with you to make sure your needs are addressed. Their SLP team is excellent.

Sean

[nigel]

Rich check your PM's I'll get you squared away asap.

D

[Cirkustanz]

I found this video of shock rebound is on Youtube. It certainly makes me really wish I would have received a correct explanation of this when I originally purchased the bike.

http://www.youtube.com/watch?v=dk0cJMcDLJ0

I honestly don't know if rebound adjustment has anything to do with the concern I have over the fork. My goal in making this thread was to get advice on that.

Since the original bike I was looking at had it, I would have asked about it on the upgrade had I understood what it was. I might have purchased a different bike.

Ah, the frustrations of having a wine taste and a beer budget. :laugh:

[Digger]

Contact Shockspital (www.shockspital.com) - A great local suspension shop.

[GreySquirrel]

I have rebuilt my Fatty D and my son's Ultra Fatty head shock many times. Red Squirrel's needed rebuilt at least once a season and always after Leadville. All the headshocks are of similar design. That is an Air Spring that the user can set by how much air pressure is put in. The damping or rebound control also know on a car as shock absorbers is accomplishes by a piston in a cylinder filled with oil. The small orifice in the piston controls the damping. This assembly can be damaged easily if not taken apart with the proper (special) tools. If the damper is not bled of air after assembly it will not function as a damper. That said heaver or lighter oil will change the damping factor. However this will be a trail and error exercise that could take up most of the summer.

[Cirkustanz]

However this will be a trail and error exercise that could take up most of the summer.


Interesting to hear you say about the adjustment taking a long time to get down. I talked with someone at Erik's with more thorough knowledge of the headshoks and he told me that because of the higher PSI in the shock, that replacing the oil to the heavier weight is the correct thing to do, and he is taking care of that for me tomorrow.

His explanation of it was very clear, and based on what I know now, I don't see how it would take you that many attempts to get the shock to perform as it should. If that were the case, people would stop buying bikes with that shock system.

I'm bringing the bike into the SLP store tomorrow and he is going to replace the 5 weight oil for 7.5 and is confident that is the cause of the problem.

[GreySquirrel]

Rick
He is probably right. I have never tried to adjust the damping on a headshock. I have replaced the oil with the same as what was in there.
My son is about 155 and I'm 20 pounds heaver. The shocks always worked OK for both of us. I think there probably is a range of weights that a oil will handle fine. I know Dave at Erik's used to set up Cannondale forks for their team so your right he has more experence in this area. Good luck. Let us know how it works out.


Interesting to hear you say about the adjustment taking a long time to get down. I talked with someone at Erik's with more thorough knowledge of the headshoks and he told me that because of the higher PSI in the shock, that replacing the oil to the heavier weight is the correct thing to do, and he is taking care of that for me tomorrow.

His explanation of it was very clear, and based on what I know now, I don't see how it would take you that many attempts to get the shock to perform as it should. If that were the case, people would stop buying bikes with that shock system.

I'm bringing the bike into the SLP store tomorrow and he is going to replace the 5 weight oil for 7.5 and is confident that is the cause of the problem.

[Cirkustanz]

I dropped it off this afternoon and I just got a call back from Dave.

Funny thing is, the wrong air pressure was used in the shock when it was setup since Cannondale had just updated the chart for the 08 shocks.

It was set at 165 and it was supposed to have been set at something like 100-110 (can't remember what he said).

Makes sense to me, since even around town I just set the shock all the way to the left and left it there. :P

Its all done though and I am picking it up tomorrow morning.

[Cirkustanz]

I have to wonder though, if every Headshock Erik's has sold since last year has been set at incorrect PSI as a result of their chart being wrong.

[wokerhopper]

I know the one on my bike has the right PSI, we will be making sure that all headshocks are checked to be at a proper PSI and that all employees are aware of the settings. Thanks for the heads up on this one!