Recently purchased used an "old school" Diamondback Topanga, it has a 25.4mm seatpost but has a shim inserted down the seat tube and there is no gap at the pinch point, obviously, the correct size is NOT 25.4.
Is there a simple way to find what it should be? I am thinking of prying the gap open to say, an eighth of an inch and putting a micrometer in there? or would there be something stamped on the frame somewhere? the only date I can find on it indicates April 95 but that might not be the date of manufacture. Any ideas?
"me" <[email hidden]> wrote in message news:PMrJh.15168$zU1.11334@pd7urf1no...
Quoted message said:
Hi All,
Recently purchased used an "old school" Diamondback Topanga, it has a 25.4mm seatpost but has a shim inserted down the seat tube and there is no gap at the pinch point, obviously, the correct size is NOT 25.4.
Is there a simple way to find what it should be? I am thinking of prying the gap open to say, an eighth of an inch and putting a micrometer in there? or would there be something stamped on the frame somewhere? the only date I can find on it indicates April 95 but that might not be the date of manufacture. Any ideas?
Why not just take it to a bike shop and ask them to try a few seatposts. It is going to be cheap to buy it there I would think too.
Is there a simple way to find what it should be? I am thinking of prying the gap open to say, an eighth of an inch and putting a micrometer in there? or would there be something stamped on the frame somewhere? the only date I can find on it indicates April 95 but that might not be the date of manufacture. Any ideas?
You could measure the tube's diameter lower down and subtract twice the wall thickness.
"me" <[email hidden]> wrote in message news:PMrJh.15168$zU1.11334@pd7urf1no...
Quoted message said:
Hi All,
Recently purchased used an "old school" Diamondback Topanga, it has a 25.4mm seatpost but has a shim inserted down the seat tube and there is no gap at the pinch point, obviously, the correct size is NOT 25.4.
Is there a simple way to find what it should be? I am thinking of prying the gap open to say, an eighth of an inch and putting a micrometer in there? or would there be something stamped on the frame somewhere? the only date I can find on it indicates April 95 but that might not be the date of manufacture. Any ideas?
Why not just take it to a bike shop and ask them to try a few seatposts. It is going to be cheap to buy it there I would think too.
That doesn't work because I have no car and no close bike shops, however, your suggestion reminded me I have other bikes, one of which has a 26.6mm seat tube which fits nicely.
"me" <[email hidden]> wrote in message news:PMrJh.15168$zU1.11334@pd7urf1no...
Quoted message said:
Hi All,
Recently purchased used an "old school" Diamondback Topanga, it has a 25.4mm seatpost but has a shim inserted down the seat tube and there is no gap at the pinch point, obviously, the correct size is NOT 25.4.
Is there a simple way to find what it should be? I am thinking of prying the gap open to say, an eighth of an inch and putting a micrometer in there? or would there be something stamped on the frame somewhere? the only date I can find on it indicates April 95 but that might not be the date of manufacture. Any ideas?
Why not just take it to a bike shop and ask them to try a few seatposts. It is going to be cheap to buy it there I would think too.
That doesn't work because I have no car and no close bike shops, however, your suggestion reminded me I have other bikes, one of which has a 26.6mm seat tube which fits nicely.
Thanks for the idea.
Good luck. I have 5 bikes, all different brands and vintages, from an old French Motobecane, 1980's Schwinn Super Sport, to 3 newer 1994-200? MTB's and all 5 have different seat post diameters. Worse yet is the fact that they have 3 different types of seat mounts. I have about 9 seats and can't get the ones I really want on the seat post for the bike I want it to be on. It's a mess and there is apparently not (now) a standard. I would have thought the 1970's French bike and the Schwinn would be the same, but not even those two are close. The 3 later bikes, 1 Taiwan, 1 Japan, and 1 China are all different. You might be able to pry the top a bit but the diameter down in the tube is gonna getcha. Bill Baka
"Bill Baka" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
no said:
nash said:
"me" <[email hidden]> wrote in message news:PMrJh.15168$zU1.11334@pd7urf1no... > Hi All, > > Recently purchased used an "old school" Diamondback Topanga, > it has a 25.4mm seatpost but has a shim inserted down the > seat tube and there is no gap at the pinch point, obviously, > the correct size is NOT 25.4. > > Is there a simple way to find what it should be? I am thinking > of prying the gap open to say, an eighth of an inch and putting > a micrometer in there? or would there be something stamped on > the frame somewhere? the only date I can find on it indicates > April 95 but that might not be the date of manufacture. > Any ideas? Why not just take it to a bike shop and ask them to try a few seatposts. It is going to be cheap to buy it there I would think too.
That doesn't work because I have no car and no close bike shops, however, your suggestion reminded me I have other bikes, one of which has a 26.6mm seat tube which fits nicely.
Thanks for the idea.
Good luck. I have 5 bikes, all different brands and vintages, from an old French Motobecane, 1980's Schwinn Super Sport, to 3 newer 1994-200? MTB's and all 5 have different seat post diameters. Worse yet is the fact that they have 3 different types of seat mounts. I have about 9 seats and can't get the ones I really want on the seat post for the bike I want it to be on. It's a mess and there is apparently not (now) a standard. I would have thought the 1970's French bike and the Schwinn would be the same, but not even those two are close. The 3 later bikes, 1 Taiwan, 1 Japan, and 1 China are all different. You might be able to pry the top a bit but the diameter down in the tube is gonna getcha. Bill Baka
never the less tell us if my suggestion worked out OP already said he had one that was close and may find out it was.
"me" <[email hidden]> wrote in message news:PMrJh.15168$zU1.11334@pd7urf1no...
Quoted message said:
Hi All,
Quoted message said:
Quoted message said:
Recently purchased used an "old school" Diamondback Topanga, it has a 25.4mm seatpost but has a shim inserted down the seat tube and there is no gap at the pinch point, obviously, the correct size is NOT 25.4.
Quoted message said:
Quoted message said:
Is there a simple way to find what it should be? I am thinking of prying the gap open to say, an eighth of an inch and putting a micrometer in there? or would there be something stamped on the frame somewhere? the only date I can find on it indicates April 95 but that might not be the date of manufacture. Any ideas?
Quoted message said:
Why not just take it to a bike shop and ask them to try a few seatposts. It is going to be cheap to buy it there I would think too.
That doesn't work because I have no car and no close bike shops, however, your suggestion reminded me I have other bikes, one of which has a 26.6mm seat tube which fits nicely.
I agree that you should try to find a bike shop and have them measure it with a seatpost sizing rod.
If you don't have a shop near you, well you could always buy one:
Good luck. I have 5 bikes, all different brands and vintages, from an old French Motobecane, 1980's Schwinn Super Sport, to 3 newer 1994-200? MTB's and all 5 have different seat post diameters. Worse yet is the fact that they have 3 different types of seat mounts. I have about 9 seats and can't get the ones I really want on the seat post for the bike I want it to be on. It's a mess and there is apparently not (now) a standard. I would have thought the 1970's French bike and the Schwinn would be the same, but not even those two are close. The 3 later bikes, 1 Taiwan, 1 Japan, and 1 China are all different. You might be able to pry the top a bit but the diameter down in the tube is gonna getcha. Bill Baka
never the less tell us if my suggestion worked out OP already said he had one that was close and may find out it was.
Merely stating something that is a pain to those of us with more than one bike. Bill Baka
