Dmac
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- Canada
Ah yes that might work!
New rider confession: my butt hurts
- Thread starter FrankR
- Start date
AHicks
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- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
bolt....
6zfshdb
Well-Known Member
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- Northeast Pennsylvania
I solve the slipping problem with my QR clamp by tightening the bolt a couple of turns AFTER I push the lever in.
Djangodog
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- Claremont, NH
If everything is sized properly 5 Nm of torque should be adequate. Over-tightening the seatpost collar can cause damage to the frame and seatpost. It can also cause the binder bolt itself to fail. If the seatpost isn’t staying put after applying 5 Nm of torque to the seatpost’s binder bolt, there is something that is incorrect. The “Assembly Lube”, that @PedalUma suggested is a good option, but first, be sure that seatpost and collar are sized properly to the frame.
AHicks
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- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Speaking from experienced gained with several bikes, I'm here to tell you the advice in bold is going to totally depend on the rider's weight. Heavier riders (like me) can often find that getting the seat post to hold it's position can be pretty challenging. Something like this, even if you are not working with carbon fiber, if properly sized, can often be a solution. Just pay attention to the sizes. They are NOT universal....
6zfshdb
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- Northeast Pennsylvania
At 230#, I could never get my post to hold using 5 Nm of toque on the clamp. The grit paste helped a bit but I wound up buying high quality clamps and tightened them well beyond 5 Nm. Still not perfect but the best I could do until I saw this in another thread:
I added a second seat post clamp. I ground off the lip and slid it farther down the seat tube. The double clamp scheme allows me to tighten both to 5 Nm and it holds perfectly:
I haven't tried it with QR clamps but the principle is the same so it should work.
I can't find the thread where I saw the idea so I can't credit the original poster.
I added a second seat post clamp. I ground off the lip and slid it farther down the seat tube. The double clamp scheme allows me to tighten both to 5 Nm and it holds perfectly:
I haven't tried it with QR clamps but the principle is the same so it should work.
I can't find the thread where I saw the idea so I can't credit the original poster.
Djangodog
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- USA
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- Claremont, NH
As a “general” rule, the slot in the collar, (clamp), is aligned with the slot in the frames seat tube. There are exceptions, but they generally, (not always), apply to carbon seatposts. If you have an alloy seatpost, the collar would be more effective with the slots aligned, (unless the manufacturer instructs you to have them as shown above).
fooferdoggie
Well-Known Member
There is a easier way to do it. you need to find a clamp that fits the seat post its self. you put that around the seatpost where you want it to stop and use the regular seatpost clamp. problem solved.
6zfshdb
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- USA
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- Northeast Pennsylvania
You can't see it well in the pictures but the slot in the post IS aligned with the clamp. That seatpost has 2 slots. That alignment "rule" also applies to the slot in a shim (if used).
6zfshdb
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- Northeast Pennsylvania
This works but while it keeps the post from dropping, it can still swivel which is almost as annoying for me anyway.
fooferdoggie
Well-Known Member
it sounds like a poor fit. I used to weigh more and never had the seat post move. How tight does the seat post fit without the clamps? if its a little loose I would try making a shim from a pop can. I had to do that to one bike.
PedalUma
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- Petaluma, CA
It needs to be a beer can according to Zen and the Art of Motorcycle Maintenance. I will need to reread it. It is interesting how it is a bit like Fight Club. The main character has duel personalities with different names.
Djangodog
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- Claremont, NH
If I remember correctly, the shim was used to prevent movement of his friend’s BMW handlebars. It’s been a long time since I read it so I could be way off. You almost have to study that book in order to keep it all straight. It was amazing how he pulled the whole thing together in the last few pages.
6zfshdb
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- USA
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- Northeast Pennsylvania
The bike has a 28.6 mm seat tube and the OEM post is rock solid. The problem is, I use Redshift, Thudbuster and Kinekt suspension posts which are all 27.2 mm. They aren't available in 28.6 mm so I have to use a 27.2 to 28.6 shim. I've tried several but get the best result with this one from Cane Creek:
It's a snug fit and there is no room to use the beer can trick. Part of the problem is the thickness of the aluminum seat tube. it's almost twice as thick as any of my other aluminum frame bikes and requires quite a bit of clamp force.
The dual clamp idea works fine though so problem solved.
fooferdoggie
Well-Known Member
ok ya I see whats happening. the combo of the two is causing issue.
fooferdoggie
Well-Known Member
one thing you could use is the locktite for bearings on the seat post and shim so that does not rotate then your clamp is only having to hold one part in place.
