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Discussion Starter · #1 · (Edited)
The seat post clamp on my R3 failed catastrophically and damaged my carbon post.
The clamp is a flawed design.

Here's what happened:
My seat post kept slipping on a ride. I weigh 198 pounds. The clamp looked fragile and I did not want to over tighten it. When I got home, I pulled out my torque wrench. I am a airplane mechanic so I know about torque. The clamp torque specs max 4.5nM on the clamp itself. So, I begin to torque it to that setting and BEFORE it got there, there was a loud bang. The bolt failed. There was no damage to the frame but it cracked my $200 Deda Superzero Post.

Here is why:
The seat clamp nut has NO pivoting nut for the bolt. So, when the bolt is tightened, the clamp bends and the bolt holes are not parallel. This causes the bolt to bend inward towards the seat post like a bow thus --putting a tremendous force directed to the back of the post INSTEAD OF AROUND the post. It also side loads the bolt causing it to fail.

The fix:
For $25, I found a KCNC Clamp in a 30.7mm size at Fairwheel bikes. It has a pivoting nut and a titanium bolt. It's black and looks great. It fits perfect and only weighs 12g ( only 4g more than Cervelo's poorly designed clamp ) Also, I used a carbon friction paste to keep the post from slipping. This worked like a charm. SALSA makes a 30.0mm one which works too.
http://fairwheelbikes.com/kcnc-sc9-road-seatpost-collar-p-1227.html
This is a carbon safe clamp and won't damage your post unlike the stock one if you go to 4.5nM. Most all of the bikes with a 27.2 post have this similar design. ( Specialized, Giant,..etc.)

Conclusion:
In the last month, I have purchased a new Cervelo S2 AND an R3. I REALLY would like Cervelo to credit me $25 for the new clamp and a new seat post or at least throw me a nice jersey or something. I followed Cervelo's torque specifications perfectly.
Last week, I sent them an email with an explanation of this issue and also notified my LBS where I purchased the frames new.
So far, I have not heard back from either.

Opinion:
Cervelo makes the best frames I have ever ridden. Their engineers are brilliant but they overlooked this very minor issue. I know they are busy with the Tour of Spain so that's perfectly okay. I am posting this thread so you don't perform the same mistake.
I hope this goes okay since I don't want a huge headache if I experience a major warranty issue. I am fairly certain that it will be fine.
 

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skygodmatt said:
The seat post clamp on my R3 failed catastrophically and damaged my carbon post.
The clamp is a flawed design.

Here's what happened:
My seat post kept slipping on a ride. I weigh 198 pounds. The clamp looked fragile and I did not want to over tighten it. When I got home, I pulled out my torque wrench. I am a airplane mechanic so I know about torque. The clamp torque specs max 4.5nM on the clamp itself. So, I begin to torque it to that setting and BEFORE it got there, there was a loud bang. The bolt failed. There was no damage to the frame but it cracked my $200 Deda Superzero Post.

Here is why:
The seat clamp nut has NO pivoting nut for the bolt. So, when the bolt is tightened, the clamp bends and the bolt holes are not parallel. This causes the bolt to bend inward towards the seat post like a bow thus --putting a tremendous force directed to the back of the post INSTEAD OF AROUND the post. It also side loads the bolt causing it to fail.

The fix:
For $25, I found a KCNC Clamp in a 30.7mm size at Fairwheel bikes. It has a pivoting nut and a titanium bolt. It's black and looks great. It fits perfect and only weighs 12g ( only 4g more than Cervelo's poorly designed clamp ) Also, I used a carbon friction paste to keep the post from slipping. This worked like a charm. SALSA makes a 30.0mm one which works too.
http://fairwheelbikes.com/kcnc-sc9-road-seatpost-collar-p-1227.html
This is a carbon safe clamp and won't damage your post unlike the stock one if you go to 4.5nM. Most all of the bikes with a 27.2 post have this similar design. ( Specialized, Giant,..etc.)

Conclusion:
In the last month, I have purchased a new Cervelo S2 AND an R3. I REALLY would like Cervelo to credit me $25 for the new clamp and a new seat post or at least throw me a nice jersey or something. I followed Cervelo's torque specifications perfectly.
Last week, I sent them an email with an explanation of this issue and also notified my LBS where I purchased the frames new.
So far, I have not heard back from either.

Opinion:
Cervelo makes the best frames I have ever ridden. Their engineers are brilliant but they overlooked this very minor issue. I know they are busy with the Tour of Spain so that's perfectly okay. I am posting this thread so you don't perform the same mistake.
I hope this goes okay since I don't want a huge headache if I experience a major warranty issue. I am fairly certain that it will be fine.
Haven't heard of a lot of failures of this clamp. If there really is an engineering problem I can't imagine they won't rectify it- remember this is the company that recalled a huge number of forks because they decided they were engineered wrong and could break if installed incorrectly.
 

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California L33 said:
Haven't heard of a lot of failures of this clamp. If there really is an engineering problem I can't imagine they won't rectify it- remember this is the company that recalled a huge number of forks because they decided they were engineered wrong and could break if installed incorrectly.
Not to be snide, but if you haven't heard doesn't mean it doesn't happen. My collar cracked in half, JUST RIDING ALONG. As with the OP, mine was torqued to spec. Two other teammates that weigh less than me (I'm 175 lbs) also have had the same thing happen.

Their little weight weenie collar is totally inadequate and I would highly recommend throwing it away out of the box and putting on one of the two above mentioned collars. I personally bought the Salsa b/c that is what my LBS had in stock.
 

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Hum a few bars and we'll sing you a tune...

I agree that because it hasn't been blogged to death, doesn't mean that it isn't an issue...

Same thing happened during a fitting... the tech was tightening the seatpost after making an adjustment and pop .. the collar bolt caused the thread to fail.

I had just ordered a campy record post to replace the oem FSA post that had really poor seat angle adjustment and luckily Campy includes a new clamp with the seatpost.

I too added the FSA paste and haven't had any problems.

If you want another R3ism ... turn your bike upside down and follow the cable routing ... makes contact with the paint before the cable guide... most bikes are set up this way ... actually a carryover from the R2.5 ... this may have since been resolved but I just added a strip of clear body tape ( like I do on the headtube to prevent housing rub through).

I doesn't affect the ride but it does differentiate themselves from some of the more boutique brands.

JH
 

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otoman said:
Not to be snide, but if you haven't heard doesn't mean it doesn't happen. My collar cracked in half, JUST RIDING ALONG. As with the OP, mine was torqued to spec. Two other teammates that weigh less than me (I'm 175 lbs) also have had the same thing happen.

Their little weight weenie collar is totally inadequate and I would highly recommend throwing it away out of the box and putting on one of the two above mentioned collars. I personally bought the Salsa b/c that is what my LBS had in stock.
We could rename this the bi&*ch and moan forum- not saying it's a bad thing, quite the contrary. You tend to hear about any problem. I had a mountain bike frame crack. I posted my problem on MTBR, RBR's sister forum, and found that not only was I not the first to have a problem with that model, I wasn't the 21st. We've had three people say they've had this problem, though I'm not sure if the tech jh talked about overtightened the collar (it sounds like it if a tube of friction paste solved his problem). I've seen way too many shop wrenches work around CF components without torque wrenches. I think every CF maker should put a sticker next to the collar saying, 'Don't over tighten. You MUST use friction paste or the post will slip.'

So is it a problem? When another ten people join in I'll say, 'probably.'
 

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I thought I am the only one who got this problem. Of course, I used torque wrench and I weighted only 138 lbs. This happened only a few trips on my new R3 SL. Luckly, I noticed it and replaced with a new clamp before any incident. I dont' care about replacement costs, but care about accident that might happen to others. So, make sure that you check R3 clamp before your trip.
 

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Discussion Starter · #8 ·
...any frame will have very minor issues from time to time such as mine. Still the best frame I've ever had.

Cervelo requested that I don't post details of this situation. So, I will oblige.
I am sure this minor issue will turn out just fine.

Ride safe!
 

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So I'm curious, what did Cervelo do for you in return for your silence on the matter? Surely that is not part of the gag order too? Did you get the $25 back, or the nice jersey you were hoping for?
 

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campy has the right size

I killed two birds with one stone by ordering a campy record seatpost that came complete with the right size seatclamp for my 07 r3. nice carbon seatpost, alloy cradle with good setback & carbon top plate for a little panache. Micro adjustment did away with the lousy FSA SLK seatpost that came with the frame and the new clamp ( though similiar to the oem clamp) got a fresh new life c/w FSA carbon paste. No issues.

Good luck.

JH
 

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seat clamp

I had the same problem with my 2011 R3. I was tightening the seat post clamp with a torque wrench and the threads in the seat post stripped. I didn't overtighten. I was thinking maybe the threads were so sensitive maybe to protect from overtightening. I bought a new seat post clamp a month ago. So far so good.
 

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Happened to me too

I have had an 09 R3 for a year and a half and my seat post clamp developed a crack after about 6 months. I noticed it on a ride, looking down, and took it straight to the shop where they sold me a new one. I had been fitted on the bike after I bought it and so they claimed the guy must have tightened it too much, though he claims he used a torque wrench. I don't remember if he did, but I understand from here that others have broken before the max torque. Mine cracked several months after the fitter changed my saddle height and I hadn't touched it since. It wasn't a huge amount of money, but it was annoying to have this happen to a pretty new bike. The picture is out of focus from my phone, but it gives you an idea of the crack.
 

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Carbon assembly paste

Mu understanding about seatpost slippage isn't just about torque, it's the inaccurate mating of two cylindrical objects?
not enough surface area between the OD of the post and the ID of the seattube. the carbon paste fills in the minute gaps and provides more friction?
I had this problem on an alu post into ti, but not on my R3 (and I *ahem* weigh more than you do) :p
 

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I've not had THIS problem before, but I learned my lesson pretty quickly about titanium bolts and making sure that they don't bend like what happened to the original poster here. And based on his description I'd feel exactly like he does as well. I'd be annoyed.

Edit: Didn't realize this thread was so old!
 
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