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How does everyone do this- with a dropper post in the bike I don't want to clamp that, and as far as I'm aware clamping carbon is a no no.
What do people use?
(a) why not clamp the dropper? Just make sure you do it on the bit nearest the saddle. Clean it and put a soft cloth around it before clamping.
(b) use the frame and just don't crank up the tension on the clamp too hard.
(c) you'd be amazed at how thin some aluminium frames are and you've probably not even considered damaging them in a workstand.
Expose more of the lower section of the dropper and clamp that
Expose more of the lower section of the dropper and clamp that
Is the wrong answer. You are MORE likely to damage the post that way.
Use the dropper - near the saddle so it can't slip down in the clamp and wrap a soft cloth round it.
Is the wrong answer. You are MORE likely to damage the post that way.
Unless something has changed, that is the way that Rockshox say to clamp it
I've used the dropper in the past, I now run a 170mm dropper slammed all the way in on my all mountain bike. It leaves just the collar and its fallen out twice whilst working on it. Another time I put the seat down and it slipped pulling the seat up and ended up having to re-bleed the post.
any other ideas?
Carbon frames are not that flipping fragile. Clamping force of a bike stand is not going to affect the frame in any way!
Re clamping the dropper: forces on the post are similar in direction to those experienced with a fat MTBer sat on it, but far smaller.
any other ideas?
you're clamping the uppy downy shaft of the dropper, yes?
Do your seatclamp up a bit tighter so the post doesn't pull out with the weight of a bike on it or just clamp around the frame.
depends on the clamp.
i use the dropper. got my bike back yesterday from the bike shop and it had marks in the invisiframe where they had clamped the frame.
just be careful.
molgrips
Subscriber
Carbon frames are not that flipping fragile. Clamping force of a bike stand is not going to affect the frame in any way!
Some tubes are wafer thin, I've seen one crushed with my own eyes and it didn't take that much force. There is no reason for all tubes to be designed to withstand a crushing force
Clamping force of a bike stand is not going to affect the frame in any way!
I've seen 2 carbon frames cracked from being put in workstands.
Get this type of workstand?
Dropper all the way up and clamp just under the saddle. Use a cloth if you are worried about it.
Just clamp it round the dropper shaft with a rag. Or round the TT. Never been an issue in what must be nearly 10 years of various carbon bikes.
Usually clamp my carbon road bike on the top tube. It then needs minimal clamping force as gravity is holding it in place. You wouldn't think twice about picking the bike up by the top tube.
Usually clamp my carbon road bike on the top tube. It then needs minimal clamping force as gravity is holding it in place. You wouldn’t think twice about picking the bike up by the top tube.
No problem just hanging it there.
Start doing things like fixing a BB in, or other amusing torquey things and see what happens.
Very comprehensive video from Park Tool about clamping a dropper:
Basically: clamp the lower part if there's enough exposed, if not raise to full height, make sure jaws and stanchion are nice and clean and clamp away. As usual, clamp just enough to keep it there. don't go cranking away on it.
All of what Scotroutes says.
Basically: clamp the lower part if there’s enough exposed
Weird
scotroutes
Member
Expose more of the lower section of the dropper and clamp that
Is the wrong answer. You are MORE likely to damage the post that way.
I’ve seen 2 carbon frames cracked from being put in workstands.
I hope I never end up with a carbon frame with tubes that thin. I do my workstand up finger tight, in fact sometimes it's not even tight. I could exert more force with my fingers, so that would mean a top tube that I could crush in my hands which seems implausble. I think you lot are doing them up too tight.
If however you are leaning full force on the bike with it in the workstand then you have no mechanical sympathy. That's what the floor is for - most people have one.
I think you lot are doing them up too tight.
If however you are leaning full force on the bike with it in the workstand then you have no mechanical sympathy. That’s what the floor is for – most people have one.
Ooft, full patronising mode there
My solution was to use a piece 45mm x 45mm x approx 300mm length of timber and screw in two large hooks, secure this into the clamp and lower the top tube into the hooks.
If however you are leaning full force on the bike with it in the workstand then you have no mechanical sympathy. That’s what the floor is for – most people have one.
molgrips wins at STW for the day!
Why not just put an old standard seatpost in and clamp that as tight as you want. Thats what I do.
Because that’s a ball ache with a stealth post
So, to summarise,
Don't want to clamp the frame.
Don't want to clamp the dropper.
Don't want to pop a standard post in.
Think that just leaves you with get a shop to fix it.
Think that just leaves you with get a shop to fix it.
And what do you think the shop will do?
mashr
Member
Because that’s a ball ache with a stealth post
Fair point, as you can probably tell, mines external.
I clamp my carbon frame by the top tube and never had a problem - as mentioned above you need minimal force unless doing something really heavy duty. It comes down to common sense really - just don't clamp the sh*t out of it.
Swap on a crusty old saddle and clamp it on the nose or between the rails and the top
Think that just leaves you with get a shop to fix it.
And what do you think the shop will do?
Whack it in the workstand, but the OP wouldn't be there to get precious about it! ,😁
Got a cheap old seatpost in the spares bin? Use that.
Good thread. I've always struggled with this and just thought it would be a really bad idea to clamp on the shaft of the dropper. I've clamped over the collar, gently, but that never seemed great. Quite often clamp the seat tube right under the junction with tt so some of the weight is spread. Sometimes just clamped the top tube (sort of hung the bike). Depends on teh frame and shock position.
If i'm doing anything high torque, like a bottom bracket, I do it with the bike out of the stand.
Having read all this and watched the vid above, I reckon clean jaws, and clamp the shaft. When you actually think about it, I think even they are making far too much fuss about stresses on the dropper - by all means let the bike find its natural postion but you sure as hell don't do that when you're riding it. Cranking up a steep hill with your 80+kg body bouncing up and down on the saddle and post at a nasty angle. Surely the bike hanging under it's own weight is nothing compared to that? Even when you're working on it.
I do what others have suggested. Clean the dropper (don't like working on a dirty bike anyway), soft cloth round the dropper and then clamp it round the exposed bit of the dropper. Usually let the bit with the seat rails drop down to rest on the top of the jaws before I finally do it up tight (and even then, just tight enough to keep it in one place.
Anything torquey and the bike is either on the floor or partly on the floor (e.g. front wheel taking the weight to undo cranks) to avoid forcing the dropper in the jaws.
I used to obsess about it (and the rag is probably a throwback to that) but having done it lots it's fine.
The innards of a dropper are not going to be designed with high pulling-up forces in mind. So best way is to clamp on the dropper shaft but with the bike upside-down. 😉
and on the subject of super thin carbon frames. Unlikely to be an issue with the 'all mountain' mountain bikes most of us ride but I did some work on top end Trek Road bikes and the top tubes were so thin you could distort them by pressing with your fingers....
Well I watched the video simon_g posted. Which has plenty of info from [b]expert[/b] mechanics. good enough for me.
clean jaws, and clamp the shaft
I just hang the nose of the saddle over the clamp.
It moves under about the same force id be willing to put through a clamped carbon tube.
Any further force I stick it on the floor.
Bet them I have funcy wing profiled frame and seat post on both my road bikes so not gonna be clamping anywhere anyway
Well I watched the video simon_g posted. Which has plenty of info from expert mechanics. good enough for me.
There's at least one qualified and experienced bike mechanic already posted on this thread.
