I have an SDG I-Beam on my BFe and it is all pretty good other than that during a ride the head rotates backwards. At the start of a ride it is in a nice comfortable level position but at the end my balls are getting squashed because the nose has come up.

What can I do to stop this from happening? I don’t want to have to buy a new saddle and post.

Tighten it up?

Honestly if it’s tight it shouldn’t rotate, I’ve been using them since they first came out and have never had a problem with them rotating, that’s a weird one ❓

Its about as tight as it will go without rounding off the bolt.

Sounds like something is faulty, I use I-beam seat posts on all my bikes and haven’t had this problem (and I’m a fat knacker). Is your seat positioned with the clamp very far forward on the rail? That would cause greater leverage and if so it might be worth looking at a lay-back I-beam post.

2 bikes here with I-beam posts and absolutely no problems, but then mine are Kore (one carbon and one alloy) and they have different twin bolt fixings rather than the single one of the SDG – which is why I chose them.

The saddle is quite far back, I might slide it forward before the next ride. Would carbon paste work?

Take it apart, and put it back together – maybe you’ve done something wrong.

Been using them for years and not had any problems.

yep take it apart, clean and try again. maybe a bit of grease in there making it slip?

I’ve had a clamp components not mesh very well with themselves (badly moulded). Silicon spray lubed the parts before tightening them seemed to work.

I took it apart yesterday and found out why it has been rotating. Its made of cheese!

The head is bending and there are a few very small cracks, you can see the bump in the rail where it has bent upwards. Needless to say I have sent off a warranty form to CRC and have every confidence that they will send me a new post.

It seems like a very strange failure and I hope that it is a one off. There are no weight limits listed on the SDG site and while I might be a little overweight I’m not a total biffer and wouldn’t normally expect this kind of failure.

P1010826 by i_ache, on Flickr