1981 Raleigh Grand Prix Canada marker seatpost size
05-11-21, 02:33 PM
#1
Senior Member
Thread Starter
1981 Raleigh Grand Prix Canada market seatpost size
I've done my measuring with the seatpost sizer and I've come up with 25.8mm but the seatpost clamp ears are a bit deformed from the undersized 25.4 that was in there so it is a bit tricky to measure. 26.0 doesn't go past the ears. Can anyone confirm the size if they've got one? Thank you in advance.
05-12-21, 09:50 AM
#2
Senior Member
Join Date: Nov 2004
Posts: 23,223
Mentioned: 654 Post(s)
Tagged: 1 Thread(s)
Quoted: 4722 Post(s)
Likes: 0
Liked 3,036 Times
in
1,874 Posts
I can't confirm the size but 25.8mm was a common size and typically the next step above 25.4mm.
Take a wide, flat bladed screwdriver and insert into the top of the cinch slot at the back of the seat tube. Gently pry it open until the slot itself is slightly wider at the ears than the bottom. With the top opening wider than OEM spec, you will be able to test fit the 25.8mm and 26.0 posts and see which will insert past the bottom of the cinch slot, where the diameter hasn't been distorted by cinch bolt tightening on an undersize post.
Take a wide, flat bladed screwdriver and insert into the top of the cinch slot at the back of the seat tube. Gently pry it open until the slot itself is slightly wider at the ears than the bottom. With the top opening wider than OEM spec, you will be able to test fit the 25.8mm and 26.0 posts and see which will insert past the bottom of the cinch slot, where the diameter hasn't been distorted by cinch bolt tightening on an undersize post.
Likes For T-Mar:
05-12-21, 02:15 PM
#3
Senior Member
Thread Starter
I can't confirm the size but 25.8mm was a common size and typically the next step above 25.4mm.
Take a wide, flat bladed screwdriver and insert into the top of the cinch slot at the back of the seat tube. Gently pry it open until the slot itself is slightly wider at the ears than the bottom. With the top opening wider than OEM spec, you will be able to test fit the 25.8mm and 26.0 posts and see which will insert past the bottom of the cinch slot, where the diameter hasn't been distorted by cinch bolt tightening on an undersize post.
Take a wide, flat bladed screwdriver and insert into the top of the cinch slot at the back of the seat tube. Gently pry it open until the slot itself is slightly wider at the ears than the bottom. With the top opening wider than OEM spec, you will be able to test fit the 25.8mm and 26.0 posts and see which will insert past the bottom of the cinch slot, where the diameter hasn't been distorted by cinch bolt tightening on an undersize post.
05-12-21, 04:48 PM
#4
WGB
Join Date: Jul 2017
Location: Niagara Region
Posts: 2,917
Bikes: Panasonic PT-4500
Mentioned: 46 Post(s)
Tagged: 0 Thread(s)
Quoted: 1800 Post(s)
Liked 2,334 Times
in
1,378 Posts
I'm not sure either way but the 1981 American Raleigh Catalogue shows the American Grand Prix variant at 26.4mm. I could've sworn my sons Canadian GP is 25.4mm but not sure what year his is.
https://www.kurtkaminer.com/TH_Ralei..._81_24n25.html
Doesn't cudak888 keep the old catalogues? Might be someone else but thought it was him.
Spelling error! That was 25.4mm
https://www.kurtkaminer.com/TH_Ralei..._81_24n25.html
Doesn't cudak888 keep the old catalogues? Might be someone else but thought it was him.
Spelling error! That was 25.4mm
Last edited by WGB; 05-16-21 at 06:32 PM.
