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Item # THP0008

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  • Black, 28.6mm ($30.00)
  • Black, 31.8mm ($30.00)
  • Black, 35mm ($30.00)
  • Silver, 28.6mm ($30.00)
  • Silver, 31.8mm ($30.00)
  • Silver, 35mm ($30.00)
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Item # THP0008

A functional piece of bling to top off your Thomson cockpit.

Thomson has a fitting reputation for reliable, functional and lightweight components. In the same vein as Chris King, they take their time before releasing a product -- when they do, they've done it right. The Thomson Seatclamp is no different. Granted, most of us don't consider a seatclamp a performance component -- that is, until it's not performing. There's not much worse than being on a ride when your seatpost is gently easing its way down into the seat tube.

The Thomson Seatclamp represents the Thomson values in a sleek, simple, lightweight package. While they admit you probably won't win a race because of it, Thomson engineered this beauty to perform -- the bolt is threaded at an angle, about 1.5 degrees off-center, to help provide awesome clamping force -- they say just 20 inch-pounds on the fastener will suffice. It's available in anodized black or silver in 31.8 or 35.0mm sizes.

  • Aluminum with anodized black or silver finish
  • 1.5-degree off-center threaded bolt
  • 18-gram weight

Tech Specs

Claimed Weight:
18 g
Recommended Use:
road cycling
Manufacturer Warranty:
5 years

Reviews & Community


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Thomson....Nuff said

  • Familiarity: I've put it through the wringer

I rock Thomson stems and seat post on all my bikes. This is the first time using their seat collar. As all of their other products it has beautiful craftsmanship. Just can't go any better for performance and price.

Avg. ride time: 5h 39m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

It Works

  • Familiarity: I've put it through the wringer

It is a seat post clamp. It looks nice, it's light and my post hasn't slipped. About all you can ask for from a clamp.

Solid Clamp

  • Familiarity: I've used it once or twice and have initial impressions

I'm amazed at the low torque needed to get such a solid hold. I'm guessing this will lessen the chances of ever having to replace it. The last clamp I had popped at 5nm torque. The threads pulled out of the clamp body. This Thomson clamp specs only 2.8nm torque, and it is holding really strong! This is a great seatpost clamp!

Thomson Seat Post Collar

  • Familiarity: I've put it through the wringer

I swapped my factory clamp for this. It really cleaned up my bike and the quality is unbeatable. Great product!

It's the little things...

  • Familiarity: I've used it several times

Seat collars are simple and only have one job-keep your post from slipping. It is surprising how often something as simple as a seat collar is done badly. Either the collars don't keep the post in place or the collar itself is susceptible to breakage.

The Thomson collar will not let you down. It is light, it is dependable and elegant. I would say that this simple collar design and finish boards on usable art.

Upgrade your bike now!

is the measurement referring to the inside...

is the measurement referring to the inside diameter? my bike seat tube is 31.8 internally so the seat post clamp should be the larger diameter?

The measurement does refer to the inside diameter, which is the outside diameter of the seat collar.

Avg. ride time: 2h 56m per week
  • Average ride time is based on Strava activity over the last 3 months. Give your reviews credibility by connecting your account.

That added bling

  • Familiarity: I've put it through the wringer

Thomson Post?-Check

Thomson Stem? Check

Thomson Bars?-(YEP they make bars!) Check

Thomson Seat Collar?- NO?!?! What is this, amateur hour? Add that added bit of bling, you know you want to, your bike will thank you.

Solid piece, set it and forget it

    Would have given this a 5 if it was a little lighter or a little more economical.

    Lets be honest, the only reason 95% of us upgrade from stock is to save weight or add bling. This part is anti-bling but lighter than your average QR factory clamp, but I replaced it on my latest build with a titanium unit weighing 10g that was half the price, so.....

    Unanswered Question

    If my frames seatpost size is 27.2mm ,what...

    If my frames seatpost size is 27.2mm ,what would be the normal clamp tube size?

    I need a clamp for a 63CM Serotta (road...

    I need a clamp for a 63CM Serotta (road bike) w/ a Ti frame - 31.8. I’m using a Thompson 30.9 seatpost, will this fit the fame and clamp down the post?

    Is there a return policy?

    Hey Doug. I don't think the 31.8 will fit your bike. I think you need a 34mm but you could measure the outside diameter of your seat tube if you have calipers and it will give you a number close to what size you will need. Bear in mind we are work in very small increments so you will need to be precise. Aluminum frames with 31.6 seatposts usually run the 35mm clamp but since you have a Ti frame and a 30.9 seatpost you are going to need something in the 44mm range.