In a message dated 7/3/05 11:49:53 AM, email@example.com writes:
>My 753s bikes are a 90s RON COOPER and a recently acquired , mid 80s , RALEIGH TEAM bike.
>The COOPER came with a damaged seat lug as it had been used with
>a 27.2 seat post ,this was corrected with a 27.4 reamer and it now fits
>a 27.4 post beautifully Close examination of the RALEIGH shows the same condition a 27.2 post and binder eyes pinched down so it will also get the 27.4
>reamer and another post. I beleive WATERFORD has consistently used 27.4 posts even with
>531. So whats up here?
>inquiring mind wants to know BOB FREITAS
sunny MILL VALLEY,CA
I've refrained from chiming in on this but I just talked with Bob so what the hey, here goes. And I'm discussing non-metric tubes here. Almost all 531 and 753 bikes with the nominal 0.9/0.6mm seat tubes are happier with 27.4 seat posts. I reamed Bob's Cooper and I only took the high spots caused by the heat distortion off with a 27.4 reamer. The nominal 0.9/0.6 Reynolds tube actually measures closer to 0.55 mm wall thickness and I've measured plenty of virgin tubes. I believe this is the reason for the crushed seat bolt ears on so many 531 and 753 bikes. I know my 531 bikes are much happier with 27.4 posts and they require only a light pass with the reamer. I do not know why the 27.2 post is so often used foir these bikes. However a Columbus 0.9/0.6 seat tube is often slightly thicker than 0.6 and really needs to be reamed out to 27.2. Thus endth the lesson for the day. Phil Brown Just finished riding a 531 frame with a 27.4 post and has returned to San Rafael, Calif