Creaky Superleggera
05-17-13, 09:23 AM
#1
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Creaky Superleggera
Sorry for not putting this in the mechanics sf but I thought it would probably be best answered here.
I'm having a saddle/seatpost interface issue with a Concor Superleggera (alloy rails) and a Camp. NR seatpost (the kind with 2 bolts under the saddle.
The saddle was making all sorts of creaking noise, and when I went to tighten the clamps, I found that I could see light under the rails, although the bolts were quite snug. Also, the rails seemed to be sitting too far toward the outside of the clamps, rather than in the contour where they should be. (Sorry but I didn't think to snap a picture.)
I compared the rails on the Superleggera to a Supercorsa with steel rails, and here's what I found:
SL rails are 13mm
SC rails are 12mm
OD of the SL rails where they clamp is 52mm
OD of the SC rails where they clamp is 49mm
I was thinking that maybe the rails would compress together slightly as I tightened the seatpost clamps, but I had them pretty tight and started to worry about breaking a clamp, and it still didn't look right. So at least for the present I'm using a different saddle.
Has anyone else encountered this? Is there some trick? I already have doubts about alloy rails, so filing them down is a non-starter. I've thought about trying to squeeze them together slightly with a wooden hand screw, but I have a feeling they'd just bounce back.
Thanks.
I'm having a saddle/seatpost interface issue with a Concor Superleggera (alloy rails) and a Camp. NR seatpost (the kind with 2 bolts under the saddle.
The saddle was making all sorts of creaking noise, and when I went to tighten the clamps, I found that I could see light under the rails, although the bolts were quite snug. Also, the rails seemed to be sitting too far toward the outside of the clamps, rather than in the contour where they should be. (Sorry but I didn't think to snap a picture.)
I compared the rails on the Superleggera to a Supercorsa with steel rails, and here's what I found:
SL rails are 13mm
SC rails are 12mm
OD of the SL rails where they clamp is 52mm
OD of the SC rails where they clamp is 49mm
I was thinking that maybe the rails would compress together slightly as I tightened the seatpost clamps, but I had them pretty tight and started to worry about breaking a clamp, and it still didn't look right. So at least for the present I'm using a different saddle.
Has anyone else encountered this? Is there some trick? I already have doubts about alloy rails, so filing them down is a non-starter. I've thought about trying to squeeze them together slightly with a wooden hand screw, but I have a feeling they'd just bounce back.
Thanks.
05-17-13, 10:48 AM
#2
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Firstly, the rails should sit right in, centered in the clamp grooves. As you noted, the pressure from the rail clamp on the seatpost should usually pull the rails into the clamp grooves
It would be unusual if the one on yours isn't doing so. Maybe the reason you are seeing daylight under the rail Can be just attributed to the bigger OD of the aluminum rails, which the saddle maker found neccessary to make them strong enough to bear the weight of a rider. The resulting less contact with the seatpost clamp is likely causing the rails to maybe twist as you ride and the slippage between the clamp and rail contact points are the sources of the squeaking.
I'm not sure, but this slipping and flexing of the aluminum rails may actually cause eventual cracking and failure, so maybe it would be a good idea to minimize it. Maybe you can provide more friction at the clamp grooves by putting pieces of sand paper in them. If that does not work, youmight just want to find a different seatpost that will have a clamp that can fit and grip those bigger than usual rails.....or vice versa.......
It would be unusual if the one on yours isn't doing so. Maybe the reason you are seeing daylight under the rail Can be just attributed to the bigger OD of the aluminum rails, which the saddle maker found neccessary to make them strong enough to bear the weight of a rider. The resulting less contact with the seatpost clamp is likely causing the rails to maybe twist as you ride and the slippage between the clamp and rail contact points are the sources of the squeaking.
I'm not sure, but this slipping and flexing of the aluminum rails may actually cause eventual cracking and failure, so maybe it would be a good idea to minimize it. Maybe you can provide more friction at the clamp grooves by putting pieces of sand paper in them. If that does not work, youmight just want to find a different seatpost that will have a clamp that can fit and grip those bigger than usual rails.....or vice versa.......
05-17-13, 12:26 PM
#3
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alu seat rails problem
I'm having a saddle/seatpost interface issue with a Concor Superleggera (alloy rails) and a Camp. NR seatpost (the kind with 2 bolts under the saddle.
... when I went to tighten the clamps, I found that I could see light under the rails, although the bolts were quite snug. Also, the rails seemed to be sitting too far toward the outside of the clamps, rather than in the contour where they should be.
...
Has anyone else encountered this? Is there some trick? I already have doubts about alloy rails, so filing them down is a non-starter. I've thought about trying to squeeze them together slightly with a wooden hand screw, but I have a feeling they'd just bounce back.
Thanks.
... when I went to tighten the clamps, I found that I could see light under the rails, although the bolts were quite snug. Also, the rails seemed to be sitting too far toward the outside of the clamps, rather than in the contour where they should be.
...
Has anyone else encountered this? Is there some trick? I already have doubts about alloy rails, so filing them down is a non-starter. I've thought about trying to squeeze them together slightly with a wooden hand screw, but I have a feeling they'd just bounce back.
Thanks.
The saddle in question was planned to be sitting on what's meant to be my lightest bike, and it's still below 10 kg (in 63cm with clinchers), but I'd rather have the other saddle on it. The [red] one on it now may look flashier, but it's a lot less comfortable than the Supperleggero (which admittedly looks a bit boring in comparison, kind of a marbled brown. Anyway, you can't see that when my ass is on the thing ...).
Still have no valid explanation and would like to hear some (real) experts about this issue ...
05-17-13, 02:55 PM
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Over time I have found a number of saddles that had rails that did not mesh well with the seat post clamp. Sometimes one can manhandle things into submission, sometimes not, a later Campagnolo two bolt seat post with alloy lower cradle yokes just does not have the clamping power of the earlier steel parts.
I have manipulated the rails on occasion, one must be mindful to not spring the saddle frame from the shell, I can advise that they are a challenge to get back together. On that one, once the rails and shell were apart the alignment of the rails went pretty easily, the reinstallation was a two man job.
I have manipulated the rails on occasion, one must be mindful to not spring the saddle frame from the shell, I can advise that they are a challenge to get back together. On that one, once the rails and shell were apart the alignment of the rails went pretty easily, the reinstallation was a two man job.
05-17-13, 03:13 PM
#5
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What a coincidence - I've just (say about 2 weeks ago) experienced exactly the same problem, with a Selle Italia Superleggero saddle on a SR Royal Extra Light seatpost. And I really couldn't explain it to myself, was wondering the same as you do. I didn't measure anything, but more less instantly decided that the rails would break [too] soon - and those saddles are d6mn expensive, so I used another one that was 80 grams heavier.
The saddle in question was planned to be sitting on what's meant to be my lightest bike, and it's still below 10 kg (in 63cm with clinchers), but I'd rather have the other saddle on it. The [red] one on it now may look flashier, but it's a lot less comfortable than the Supperleggero (which admittedly looks a bit boring in comparison, kind of a marbled brown. Anyway, you can't see that when my ass is on the thing ...).
Still have no valid explanation and would like to hear some (real) experts about this issue ...
The saddle in question was planned to be sitting on what's meant to be my lightest bike, and it's still below 10 kg (in 63cm with clinchers), but I'd rather have the other saddle on it. The [red] one on it now may look flashier, but it's a lot less comfortable than the Supperleggero (which admittedly looks a bit boring in comparison, kind of a marbled brown. Anyway, you can't see that when my ass is on the thing ...).
Still have no valid explanation and would like to hear some (real) experts about this issue ...
repechage, mine is the older steel yoke variety post and the upper clamp piece is steel as well. It's the upper piece I was worried about as it tapers down pretty thin on the ends. I don't know how likely it would be to break that piece but I'd feel foolish if I did it forcing an ill-fitting saddle when I have other options.
05-17-13, 05:19 PM
#6
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I have two Sella Italia Superleggeras, one assembled quick and easy, the other I just looked at closely today after this thread, there are some marks on the saddle from a previous mechanics clamping onto a Campagnolo or equal form factor post, the rails are slightly curved as seen in from the side, I put it together, not as easy as the other, but it obeyed with some effort.
I happen to like these saddles, more "give" than the Cinelli saddle and of course lightweight. The do not show up often. I discovered them in 1976 and lament selling the bike it was attached to.
I happen to like these saddles, more "give" than the Cinelli saddle and of course lightweight. The do not show up often. I discovered them in 1976 and lament selling the bike it was attached to.
