Thomson Seatpost problem.

The top of my Thomson Seatpost seems to have worn down. Had it 6 months and its on my everyday ride. But it only gets used for 15 miles a day at the most. It looks like I’ve been riding with a grinding disc sewn into my baggy legs. Is it normal? Or should I speak to CRC (where I got it from)

That’ll be down to your saddle sagging and rubbing on the top clamp. Not a fault of the post, but your flexy saddle.

Im pretty sure you can get replacement clamps, but it’s just going to happen again with that saddle.

Yeah, think you need to change the title of your post, up there 😉

EDIT DUE TO STUPIDITY ON MY PART I think you needed an inline rather than a layback post. Not sure what’s caused the wear as the saddle looks ok but the clamp looks too far forward on the rails to me. I expect CRC will say that it’s user error

[edit]
My first thought was that it must have been the saddle causing the problem, but I would have expected the leather to show more signs of wear than it does.

Is the clamp made from silvery cheese?!

I think you needed an inline rather than a layback post…. the clamp looks too far forward on the rails to me.

Isn’t it about as far back as it could possibly be?

Check the inside of the saddle. I expect when the saddle sags, it also widens and at a guess you’ll see an nice shiny staple where the clamp is being rubbed.

Isn’t it about as far back as it could possibly be?

Yes 😕
edited above.

Yeah it’s a bike fit fail, def doesn’t want an in-line. Has to the be the saddle base though else you’d have a worn a whole in your leg

A whole what in his leg?

The saddle has been changed from a Flite saddle which wasn’t worn on the sides either. This one’s only been on a week as the nose on my flite was torn. But there’s no wear on the inside of either saddle :S Must just be my shorts rubbing 🙁 Just thought it would last longer than it has done.

I expect when the saddle sags, it also widens and at a guess you’ll see an nice shiny staple where the clamp is being rubbed.

That seems more likely than your shorts tbh.

That’s fab, amazing how metal can wear.

I’ve looked up the rota and apparently, today I’m the designated dick, so- get a bike that fits! Sorry about that, I don’t make the rules.

IMHO, if it was your shorts the leather would have gone before the seatpost clamp.

The grain of the wear is vertical, so does look like its from the saddle moving up and down as you put your weight on it.

Its not a great idea running your saddle that far back for lots of reasons, most saddles have guidelines on the rails.

I’ve looked up the rota and apparently, today I’m the designated dick, so- get a bike that fits! Sorry about that, I don’t make the rules.

biggest frame On-one do. Can never find a frame with enough reach. And its in the saddle guidelines too.

By the looks of it the saddle is way to far back on the clamp and has exposed the clamp to being rubbed by your shorts.. what they made of? sandpaper? 🙂

Posts with more layback than Thomson are out there, plus bigger bikes than On-ones.

plus bigger bikes than On-ones

Wish I hadn’t got rid of my Ali Scale

its in the saddle guidelines too

Really? It looks to me like the leading edge of the clamp is clamped onto the bend at the front of the rails.

http://www.chainreactioncycles.com/Models.aspx?ModelID=20501

There’s no way your shorts are wearing through metal!

I’d say it’s because the edge of your saddle is flexing down and rubbing the clamp – just look at the downward striations, plus the shape of the wear is following the saddle edge.

I’d say it’s caused by your saddle being too far forward on the rails. Further back and the saddle sides are further out where they shouldn’t foul. A Flite is fairly low profile to the rails in that forward position, as is your current saddle apparently, and saddles are designed to flex to various degrees.

If you need that position your choice may come to a higher profile saddle, a post with more layback, or most drastically a correctly sized frame!

Edit: too slow

Yup, it’s your saddle. I’ve had a Flite do this to a reverb clamp. It’s not the actual leather that does the work, its the grit that gets all over your saddle that does it. It doesn’t wear the leather as the leather is soft and the grit becomes slightly embedded and stuck on so it moves with the leather and all the relative movment happens against the metal. Its the same mechaninsm that allows plastic cable outers to wear a notch into an aluminium frame. Once you wash the bike all the grit goes and evidence of what happened is gone.

Is it safe? Or should I buy the new clamp as above?

It’ll be absolutely fine!

Totally fine, the part that’s missing wasn’t really carrying any load.

It was just there to make it look tidy!

If you are bothered, give it a wee rub down to smooth it off and paint it black. It’ll only rub off again though so best just look on it as the kind of patination that shows you actually use your bike.

portlyone – Member

Is the clamp made from silvery cheese?!

Us in the business call it “aluminium”, it falls somewhere between Brie and Camembert wrapped in tinfoil.

what material are the rails? Flexy rails could also give increased rubbage on the inside of the saddle.

As said above, saddle to far back (frame too small?, use a longer stem?) so has been rubbing under flex. As for wearing the clamp and not the saddle it might have been from grit catching under the saddle and acting as a grinding paste, found that with cable rub on frames after a few wet gritty rides when I’ve not bothered fitting helitape.

Edit:\all mentioned above. D’oh 🙄