Hello,

I know that diameter for seatpost clamp for tarmac would be 32.6mm but the offer for this part is very limited(only carbon ti has them I guess) so I would like to ask if anyone is using 31.8mm seatpost clamp and if works fine as well

Thank you

I asked a similar question a while back and didn't get too many positive responses. The Specialized clamp weighs 20g or so which isn't the lightest by a long way but replacing it will only save 10-15g so not sure it's worth the hassle

are you sure it weights only 20gr? I have the S works clam of the SL2 and look much more massive than that.

I also ride a S-Works Tarmac (2007). I never found a decent replacement for the stock 32.6 seat clamp. My scale showed 21 grams and I quickly realized that trying to find something to only lose a few grams wasn't worth the money or time. About the only thing I decided to do, if the time and situation came up over the next winter, was to lighten it through drilling or grinding/removing some of the existing material. I could live with bringing it down to under 20 grams and never think about it again...

Good luck on your quest...

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Thanks...

Rick
Somewhere south of Chicago IL, USA

carbon ti is decent but pricey.
i just think that a 31.8mm clamp would fit anyway.

I looked at the Carbon Ti 32.6....and the price.

Yes, the grams per dollar ratio is quite high...Looks like around $50 US without shipping to drop to 8.8 grams from 21 grams..

($50/12.2gr) $4.10 per gram....better savings elsewhere I would imagine...but if it the last 12 grams you need to lose to hit a weight thresh hold..go for it!

_________________
Thanks...

Rick
Somewhere south of Chicago IL, USA

or a 31.8mm one for 20Usd and less than 10gr...

Let us know how it works for you..

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we are talking about 0.8mm less. let's see, let's see...

I am looking forward to hearing from you regarding the outcome on using the 31.8 seat post regarding fit and function. For those of us that are saddled with the 32.6 size requirement, knowing if will work or not will be helpful.

I personally think that if using the 31.8 sized clamps worked acceptably specialized would have used it in some form...

The only way to know for sure it to test the theory and find out... if you can get access to a cheap used 31.8 carbon band style clamp, the investment wouldn't be bad if it didn't work...

keep us updated...

_________________
Thanks...

Rick
Somewhere south of Chicago IL, USA

also very true!

A seatpost clamp off an SL3 or SL4 would work and be lighter. The clamp on my SL3 has way less material than my SL2. But I haven't weighed the clamps

The clamp on my SL3 weighed in at 16g with a ti bolt.

Correct, but there is a 2.5mm difference in circumference - potentially half the width of the bolt hole.


KCNC do 33.0 dia clamps that are relatively light and reasonably priced which would probably be a better fit

http://www.kcnc.com.tw/old/Web/NewWeb/rdpost3.htm

The only problem is that the 33.0 size appears to be (or is going to be) discontinued but is still available as old stock.

question is why 33mm and not 31.8 that is lighter?