RodTi Posted July 24, 2007 Share Since today seems to be the day for silly questions... Here goes... Just how big a difference does ,2 of a mm make with regards to seatpost sizing? Thanks to a fellow hubber, I tried my luck with a 26,8 seatpost on my 27,0 bike. And it fits.Well.As in - you have to twist it left and right to work it in deeper, or pull it out.It occasionally slips down after a rocky descent, but not so much that I notice it while riding, but only when I get off, and see that my marker line has shifted. I am a heavy rider though - so this is probably to be expected. Point though, is that my bike is old - and only source of information is on the web.Numerous sites confirm it to be a 27,0.People who own the same frames confirm it to be a 27,0.But the Thompson Elite very clearly states that it is a 26,8. Now yes - the quickest way to settle this, would be to go home, load the bike in the car, and then schlepp off to a different lbs in a different town, which might actually have one of those thingies that measures the width. But I haven't yet remembered to do that.So I thought I'd try my luck here. A 27,2 seatpost is definitely too big. Is it possible that the 26,8 is too small, and yet the ,2mm deviation is so insignificant that the seatpost fits well enough so as not to shift around?Would this then mean that a 27,0 would fit even snugger? Should see some interesting answers to this.Or none at all. Such is life. Ta Link to comment Share on other sites More sharing options...
dirtrider Posted July 24, 2007 Share I also could not get the exact size post for my bike . And went the -2 route . Works perfectly . Does not even go down . Link to comment Share on other sites More sharing options...
HANSIE SLIM Posted July 24, 2007 Share It slips down becuse it has to be 27.0 mm. To make the 26.8 fit tightly you are probably over tightening it. Get a 27.0 mm seatpostHANSIE SLIM2007-07-24 08:35:01 Link to comment Share on other sites More sharing options...
MichH Posted July 24, 2007 Share Yeah, but like someone else said today DR, you have to be careful not to fall through your own poepol you're so maer! Erm, regarding the OP, sorry can't help!! Link to comment Share on other sites More sharing options...
ewep Posted July 24, 2007 Share Yeah' date=' but like someone else said today DR, you have to be careful not to fall through your own poepol you're so maer![/quote'] Thanks hey, now I'm only SOMEONE!!! Link to comment Share on other sites More sharing options...
NotSoBigBen Posted July 24, 2007 Share MichH - was thinking the same about what ewep said but I aint talking to or about DR at the moment cause he said my bike is ugly! Have an old Specialized FSR retro I've built up and had the same problem, -2 hasn't given any trouble! HANSIE SLIM - maybe 'Get a 17.0 mm seatpost' not so slim? Link to comment Share on other sites More sharing options...
NotSoBigBen Posted July 24, 2007 Share ewep - NOT! Link to comment Share on other sites More sharing options...
MichH Posted July 24, 2007 Share Hehehehe, ewep, I was trying not to remind him who it was who said it in case it got you into more trouble!! Link to comment Share on other sites More sharing options...
Mudsimus Posted July 24, 2007 Share I'll get the right size. I rode a 27.0 seatpost in a 27.2 frame...and well I f uped the frame. Link to comment Share on other sites More sharing options...
dirtrider Posted July 24, 2007 Share Not to worry . I will not feel save going around in circles at the Tswane race ! Will be witing for him ! Link to comment Share on other sites More sharing options...
RodTi Posted July 24, 2007 Share It slips down becuse it has to be 27.0 mm. To make the 26.8 fit tightly you are probably over tightening it. Get a 17.0 mm seatpost Ja.That might be.And I suspect I am way heavier that Dirt-rider, who apparently does amazing biological feats by falling through himself ... Seriously though - how easy is it to overtighten a seatpost with a cheap old quick-release? Link to comment Share on other sites More sharing options...
dirtrider Posted July 24, 2007 Share How u do that Mud Dee ? Link to comment Share on other sites More sharing options...
Mudsimus Posted July 24, 2007 Share Rode it for a year with the 27.0 seatpost, but it kept slipping. I broke two clamps in the process. When I replaced the post with a 27.2 the frame cracked just below the clamp. Link to comment Share on other sites More sharing options...
dirtrider Posted July 24, 2007 Share ouch . Ok hopefully I will get away with my setup since I get no slip and as you may have gathered don't weigh much over 75 Link to comment Share on other sites More sharing options...
RodTi Posted July 24, 2007 Share Mud - don't want to get into semantics here - but what do you mean by slipping? As in every 5 minutes, get off because it's moved say 10cm's? If I adjust mine once/maybe twice in a 3 hour ride, and then because of a gradual shift of about 5 cm's? Hangon - anyone out there who is large to heavy, with a correctly sized seatpost that does NOT slip at all?? Link to comment Share on other sites More sharing options...
Mudsimus Posted July 24, 2007 Share I must add..it happened on a road bike. And I did fool around with it quite a few times and thus I may have weakend the alloy of the frame. if you are worried just use a piece of alloy from a cooldrink can(fanta pref..) around the post, it works great. Link to comment Share on other sites More sharing options...
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