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Discussion Starter #1 (Edited)
I recently noticed that I have broken my third seat in 18 months:madman: What is that all about? Usually the left bar of the seat is cracked or snaps while I am riding. Am I just putting too much pressure on my seat some how. I am 170 on a rigid SS. Im not even sitting that much! The only seat that I haven't broken yet is my Brooks Pro. I would hate for that to happen. Help! I can't afford too much more of this.
 

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Vaginatarian
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is the seat too far forward or rearward? ideally you should be in the middle of travel
do you have Ti rails? try steel
are you tightening the seat clamp too much (could crack or waeken the rails)
 

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Discussion Starter #3
dan0 said:
is the seat too far forward or rearward? ideally you should be in the middle of travel
do you have Ti rails? try steel
are you tightening the seat clamp too much (could crack or waeken the rails)

I am all the way forward on the seat rails. My setback for my post is 20mm. Should I just get a longer stem so that the seat can be properly positioned on the rails? I am also riding ti rails so that may have something to do with it. I like the weight savings though.
 

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sjhopeiu said:
I am all the way forward on the seat rails. My setback for my post is 20mm. Should I just get a longer stem so that the seat can be properly positioned on the rails? I am also riding ti rails so that may have something to do with it. I like the weight savings though.
there you go, if the seats all the way up or back the rails dont have much flex so they bend and break easier
Ti rails are weaker than crmo and more expensive, I usually bend mine rather than break them though
if you can get your seat in the middle the Ti rails will probably be ok
 

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Get a seatpost with more setback. 20mm is already a fairly good amount, but there are several options out there with 25mm, and you can always go with the Titec seatpost which has 37mm (1.5"), but it weighs about 350 grams.
 

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bad mechanic said:
Get a seatpost with more setback. 20mm is already a fairly good amount, but there are several options out there with 25mm, and you can always go with the Titec seatpost which has 37mm (1.5"), but it weighs about 350 grams.
I think that will move him back the wrong way since his seat is all the way forward (I could be misunderstanding his setup). Unless you need the setback post because of cockpit geometry, I would suggest ditching it for a straight post. Then your seat doesn't need to be all the forward to properly align you above the pedals. If I'm backwards in interpreting your seat alignment, go with bad mechanic.

EDIT: I think bad mechanic's got it right since OP is also mentioning a longer stem. I'd go with the proper seatpost first since they say your seat over pedal alignment should be dialed in before you mess with the stem. I suppose that what is comfortable is what is most important, but have you checked your alignment with the whole plumbob from kneecap(ish) over pedal spindle w/ cranks at 3/9 o'clock?
 

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I had the same problem. I calculated the stress in the rails and it is high enough to cause fatigue failure ( I am 170 lbs. and run with the seat all the way back). It looks like standard mountain bike seats use the same rail diameter as road bikes. Thin rails flex so they soak up some of the shock from bumps. The downside is weakness.

You can get "downhill saddles" with heavier rails. You might need to change the seatpost to accept the thicker rails.
 

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dan0 said:
there you go, if the seats all the way up or back the rails dont have much flex so they bend and break easier
Ti rails are weaker than crmo and more expensive, I usually bend mine rather than break them though
if you can get your seat in the middle the Ti rails will probably be ok

update
you can also spin the setback seatpost around and make it a setforward seatpost, and its free
 

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Discussion Starter #10
I appreciate everyone adding to this...So far it has been helpful. Allow me to clarify a bit more. My seat is actually as far back toward the rear wheel as it can go. Not forward. My cockpit needs to be a bit longer because the seat post is clamping down on the rails at the very front part of the seat.

That said, I agree that I want to fix the seat over BB position before going to the stem to make adjustments. I am using a 20mm setback post now and feel like maybe a bit more would do the trick to clamp the rails more toward the middle. I did the bob string off my knee cap and the position of the bob was right on at 3 and 9 oclock. My concern is that anymore than 20mm and I would really need a larger frame. But I am barely 6 foot on a Niner large steel frame. They usually fit smaller anyway.
 

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You sure there aren't any burrs on the seatpost where the rails sit? Any roughness?

Weird you only break one side of the seats. :skep:
 

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larger frame?

sjhopeiu said:
...I did the bob string off my knee cap and the position of the bob was right on at 3 and 9 oclock. My concern is that anymore than 20mm and I would really need a larger frame. But I am barely 6 foot on a Niner large steel frame. They usually fit smaller anyway.
If achieving this position requires a setback seatpost and pushing the seat all the way back, then maybe you need a bigger frame. But you're on a large already? I am not claiming to know all about this stuff! I'm just trying to regurgitate what the LBS guy said to me. Not sure where the recommended spot is to place the end of the string from the plumbob, but with me they dropped it from the tendon under the kneecap as apposed to off the tip of the kneecap.
 

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sjhopeiu said:
I appreciate everyone adding to this...So far it has been helpful. Allow me to clarify a bit more. My seat is actually as far back toward the rear wheel as it can go. Not forward. My cockpit needs to be a bit longer because the seat post is clamping down on the rails at the very front part of the seat.

That said, I agree that I want to fix the seat over BB position before going to the stem to make adjustments. I am using a 20mm setback post now and feel like maybe a bit more would do the trick to clamp the rails more toward the middle. I did the bob string off my knee cap and the position of the bob was right on at 3 and 9 oclock. My concern is that anymore than 20mm and I would really need a larger frame. But I am barely 6 foot on a Niner large steel frame. They usually fit smaller anyway.
as long as the knee position is fine a little more setback wont make any difference for frame size, the seat will be in the same position but the clamp will be more in the middle.
the problem is the clamp is too far forward now.
I have the same issue, same size ,niner rip 9 large
 

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Discussion Starter #14
No burrs...Actually the first time it happened it was on my Cannondale and now twice with my Niner. Different posts for each. DanO and I are on the same page. More setback would do it...or maybe just move the seat a bit more forward without the setback. that would be in line for dropping a bob from the back tendon rather than the knee cap.

It is kinda wierd. After having a seat for a month or so I can always look at it from behind and see that it is bent down to the left. I wonder if it is from the pressure I am putting with my left leg when descending. right foot forward of course for a right hander. Don't you guys do that? Use your leg for control. I also come down on my seats really hard with a rigid bike. So much so that my seat has slipped up during races. I could be coming down on one butt bone really hard over and over again. Thanks for everyone's help so far.
 

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This just sounds cattywompus.

Can you get behind your seat?
Do you ride with your arms bent?
How long is your stem?
How tall are you?
What is your inseam and sleeve length?

I would hate to suggest that both bikes do not fit but what size are they?

Could you post a photo?
 

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sjhopeiu said:
I recently noticed that I have broken my third seat in 18 months:madman: What is that all about? Usually the left bar of the seat is cracked or snaps while I am riding. Am I just putting too much pressure on my seat some how. I am 170 on a rigid SS. Im not even sitting that much! The only seat that I haven't broken yet is my Brooks Pro. I would hate for that to happen. Help! I can't afford too much more of this.
First, if you like the seat position relative to the pedals, then going to a bigger frame of the same brand is not going to change anything, because the seat tube angle is probably the same. I weigh more than you, have often run seats nearly all the way back, rode geared fs for years so I was sitting more than you, and the only time I broke one was an accident that tossed the bike 10 feet, landing on the saddle. I never had a problem with ti rails, either. I am wondering is the problem is not with the seat clamp.

Like others have suggested, a seatpost with more lay back may help, even if the problem is not the layback, but a screwy seat clamp.
 

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Discussion Starter #17
Berkeley Mike said:
Can you get behind your seat?
Do you ride with your arms bent?
How long is your stem?
How tall are you?
What is your inseam and sleeve length?

I would hate to suggest that both bikes do not fit but what size are they?

Could you post a photo?
I will give you what I know.
My arms are always bent especially because of the rigid setup. Without bent arms I would have no shox.
My stem is 110mm...already a pretty good length
I am 6 foot even
I have a 33/34 sleeve length and I wear a 34 inch pant
I no longer have the Cannondale...had to sell it to build the ss niner
And yes, I can get over the back of my seat pretty comfortably. In fact I prefer to sit on the very back of the seat.
I would post a photo but I don't have any good ones of me on my bike from the side.
Don't forget I am 170 and sometimes 165 during the heat of the season.
 

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Thanks for the feedback

What is the distance from the center of your bar to the back of the seat?
What kind of bar?
How long have you been riding?

Thanks for your patience with this. I am interested.
 

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Discussion Starter #20
Berkeley Mike said:
What is the distance from the center of your bar to the back of the seat?
What kind of bar?
How long have you been riding?

Thanks for your patience with this. I am interested.
The distance from the center of my bar to the back of my seat is 32.75 inches or 83 cm.
I have a Easton EA70 flat bar with very little bend
I have been riding for nearly 3 years. This will be my 3rd season.
My patience is good...also very curious. Thanks for the inquiry. :thumbsup:
 
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