Seatpost width for specialised hardrock??
 

Hi there,
I got this old hardrock off ebay with the intention of putting various newer parts on it including a new seat post. Trouble is, the original post is well scratched so I can't see the right size and haven't got a fine enough measuring tool to measure in 0.1s of a mm. I did see on some other posts that 26.6mm was a common size around this era? the drivetrain and mech are Altus C20 if that helps...
Any help appreciated...

Get a Vernier Caliper and measure, its a useful tool to have when working on bikes.

I would have thought it would eb 26.8 but 26.6 is a common size too. i agree get some metric calipers or head to you bike shop.

Try and match the components with Bikepedia to get the year. You'll see some components change year to year so should be able to get a match.

Here's 1995 that says 26.6. 96 says 26.2.
http://www.bikepedia.com/quickbike/B...e#.UJrLGIXfY4Q

Or read the date codes from the Shimano parts.

http://www.sheldonbrown.com/shimano.html#date
bottom of the page

Stop by your LBS and make sure you ask before trying to stuff a seatpost into the hole.
They might have a seatpost sizer or a set of scratched up posts you can try before you start putting a new seatpost in for a test fit.

I have a specialized hardrock from '88 or so, and it takes a 26.6 mm post.

I found that Specialized MTB seatposts are all over the map and they switch from year to year. Even bikepedia is wrong on occassion. Take the old seatpost down to your LBS or hardware store and let them measure it for you. You can get digital calipers at amazon for less than $15.00.

Hi guys,
thanks for the advice. I did go to my LBS and they said it was 26.5mm which seems really odd...may have to get a second opinion. Also looked at bikepedia but there were inconsistencies regarding the various frame sizes and spec on each model compared to mine: think mine might be 1993 but it's only 6speed (not 7) and is a 17" frame (and not 16.5). Anyway, I guess ur all right - I need a proper caliper.

Well if they measured it at 26.5 my guess would be it actually takes 26.4or 26.6 which are lot more common and would be consistant with a older Specialized seatposts typical go by .2 difference. 26.5 just doesn't seem right for seat post. While a real good set of calipers will get you close I have often found the only way be sure is to try several seat posts to be sure. Did the shop actually stick a post in there to verify the size.