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Saddle Rail Diameter - fit problem!

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Saddle Rail Diameter - fit problem!

Old 06-24-09, 11:12 AM
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RichBenn
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Saddle Rail Diameter - fit problem!

I just got a new Terry Fly Ti saddle. I put it into a Bontrager X-lite carbon seatpost, and found out the rails are too small for the Bontrager. With the clamp torqued to spec, the Terry slides forward and back and rocks up and down a bit.

I had a Terry Fly Carbon in there before, which did fit. Out come the calipers. Battery was dead, but could tell that of the three Terry saddles I own, of different generations and compositions, they all have different rail diameters. The Fly Ti I just got is the smallest.

So, what to do?
1. cut some thin aluminum and make shims
2. Get another seatpost (which one? will it fit?)
3. Send the seat back, it's defective?

I'd jump on #2, as I hate the Bontrager adjustment mechanism, but I hate spending yet more money on the seat issue. I just bought it (a new, old stock item), unfortunately.

Suggestions?
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Old 06-24-09, 11:14 AM
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DieselDan
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I'd shim it first, but you seem to have your mind made up regarding a new post.
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Old 06-24-09, 11:17 AM
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RichBenn
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For making shims, is it best to make them so they don't overlap when wrapped? Anything I need to watch out for?
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Old 06-24-09, 12:38 PM
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Carbon-railed saddles are typically 8mm with metal (steel/titanium) rails being 7mm. This explains the looseness. The good news is that any seatpost that is not specifically designed for a carbon railed saddle will fit your new saddle just fine.

If you are going to shim, I would use 0.5mm aluminum with no overlapping and make sure the gap is lined up with the gap in the clamp.
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Old 06-24-09, 01:41 PM
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RichBenn
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Originally Posted by joejack951 View Post
Carbon-railed saddles are typically 8mm with metal (steel/titanium) rails being 7mm. This explains the looseness. The good news is that any seatpost that is not specifically designed for a carbon railed saddle will fit your new saddle just fine.
I'm not aware that this seatpost is supposed to be designed for carbon rails only; however, that appears to be the case. Interestingly, my wife has an older Terry Fly saddle with ti rails, and it's rail diameter is even LARGER than the carbon. Go figure!

Originally Posted by joejack951 View Post
If you are going to shim, I would use 0.5mm aluminum with no overlapping and make sure the gap is lined up with the gap in the clamp.
Thanks for the tip! Makes sense.
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