Dropper Posts with Integrated Seat Clamps

iLukeKendall

So I’ve just installed a new Fox Transfer dropper post to my Whyte 29-C. The Whyte uses a wedge-style integrated seat clamp, applying pressure to the front of the post to secure it in place. It’s rated at 6Nm maximum torque.

My problem, is that tightening the clamp is preventing the dropper post from operating. Specifically, it struggles to go down, and then will only return half way. I know it’s the clamp causing the issue as if I loosen it right off, the post operates fine.

It seems I can’t even tighten the clamp to 2Nm without the post being affected, and whilst I know I can use carbon grit paste to reduce the torque required, I’m a bit concerned this won’t be tight enough given my old carbon post was tightened to 5Nm? Is it normal for them to have to be so loose? Is this an inherent issue with integrated clamps? TIA.

The Rookie

I have a Whyte with the getagrip seatpost clamp, it causes no problems with my Giant dropper, but yes all you can do is use ways to minimise the compression. I’d first off try with to find the maximum bolt torque it will work with.

steve_sordy

I have a Whyte T130 C-RS with a Reverb dropper and I have no problems. But I use Finish Line fibre grip assembly paste. This is designed for carbon fibre components and for seat tubes that have to clamp onto dropper posts. It increases the grip so you don't have to tighten the screws so much.

http://www.chainreactioncycles.com/fini ... rd|93292UK

02gf74

Not seen that design before but it applies force to a smaller area than the band type which squeezes the top of the seat tube.

Depending on the design of the dropper, clearly yours is different to rookies, there may be problems, I suspect the tube wall thickness on yours is thinner so it deforms to stop the inner tube from sliding.

Try carbon paste but my gut feeling is that the low clamp clamping torque to allow the dropper to drop will be too low to keep the post from sliding down.

I assume you can't fit a conventional seatpost clamp.

iLukeKendall

Thanks for the replies all.

I've tried tightening it as far as possible before the movement of the post is affected, and when checking with a torque wrench it's only around 1Nm which seems like it's not going to be strong enough to prevent the post from slipping. That said however, surely if it's tight enough to deform the post, it must be gripping it?

I'm waiting for some new wheels before I can properly test ride, however applying weight and sitting on it doesn't appear to cause it to slip, although this will no doubt change when being ridden properly.

I'm a bit reluctant to apply assembly paste yet in case I do have to return it - there's more hope of them authorising a return without a scratched up post from grit paste!

For reference, here's a photo of the setup/clamp.

02gf74

iLukeKendall wrote:

Thanks for the replies all.

I've tried tightening it as far as possible before the movement of the post is affected, and when checking with a torque wrench it's only around 1Nm which seems like it's not going to be strong enough to prevent the post from slipping. That said however, surely if it's tight enough to deform the post, it must be gripping it?

It may be griping it but with how much force? Is it enough to support your weigh, statically and dynamically when you are being bounced about.

I'm not familiar with that clamping arrangement so making a torque comparison to regular seatpost tclamps my not be applicable. Those I find, for my weight, tend to be at least 3 nm.

My money is on it will slip at 1 nm, may be not immediately but after some time.

iLukeKendall

Just as an update, I returned the post to Evans this afternoon and got a refund, as after ensuring the clamp was correctly applying pressure to the post, I still couldn't get past 1Nm before the function of the post was affected.

It looks like Whyte spec Rockshox Reverb's on their bikes with the same clamp that come with a dropper from stock, so looks like I may have to consider one of those as an alternative...

The Rookie

Have a look at the Giant dropper as well, while mine is the older 'getagrip' style integrated clamp it works just fine.