seat rail size

[Dude_Here]

I found a Thomson seatpost on ebay for $50 (pulled off a Gary fisher bike). The only thing I'm not sure about is that it says "41mm saddle rail clamping area for use with 7mm saddle rails
". I tried to measure my seat rails but with just a measuring tape it's pretty hard to differentiate btwn 7 and 8 mm round tubing. I guess my Q is: look for a diff seatpost or will this 7mm rail clamp work for pretty much any seat out there. BTW my seat is a Oryx Freeride seat. I couldn't find any info on it's rail size...

[johnathan]

8mm rails are normally only used for extreme saddles and so yours might be. It probably will fit but depnds on how the clamp works i looked on the tompson site and there is no mention of 8mm rails, it will fit i would say but i would not be comfortable with the set up in case the bolts worked loose becuase of them not clamping into the upper clamp enough due to the rails being 8mm.

[Dude_Here]

Hmmmm, Thx Jonathon. I just had another thought. Last year my wife bought me a saddle - it was a nice big super gel couch saddle and was obviously designed for X-country use. It fit fine in the seatpost I have and my current seat fits fine into the same post so I'm thinking the one I have is likely 7mm if that seat fit into it and my current seat fits in the same post. Any other thoughts are welcome...

[johnathan]

Judging by the saddle (i went on the oryx site) it looks like they use the same saddle across most of the range and as 8mm saddle are usually reserved for higher end dh and fr saddles i think it is probably safe to conlude that its a 7mm rail system.

[Bryce]

I had an 8mm saddle on a standard post - no problems. I dunno if I'd recommend it though

[johnathan]

depends upon clamp design and bolt lengths but it should be ok i think as long as the bolts are long enough to get a good hold on the upper clamp.