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Gt Palomar seat post question and repair question

rustyjustyrustyjusty Posts: 35
edited 26 June in MTB workshop & tech
A neighbour was throwing out a gt palomar that he doesnt use and has a rusty chain and missing seat post. and rusty derailleurs so i got it off him. See photos attached below, its missing a seat. Im a novice at repairs although have changed a cassette before.

Question 1: I tried a seat post that i had and it didnt fit, so i measured the diameter of the hole in the frame, the hole where the seat post goes, and it seems to measured 27mm. What diameter/width seat post do i need to buy for this and im guessing ill need the connector part that fits on to the seat or does that come with the post ?

Question 2: what would be a good reliable and not too expensive cassette to buy for this bike ? I think its got 6 speed on the back although the right shifter can accommodate 7 speeds, and front deraiileur, can i use any 3 speed thumb shifter ones ?

Has anyone any idea what year this bike is from from the photo ?






Posts

  • MattFalleMattFalle Posts: 10,096

  • rustyjustyrustyjusty Posts: 35
    MattFalle said:


    There have been different models of palomar over the years and im guessing different sizes of posts ?, i did measure the diameter of the hole where the seat post slots and it seemed to read 27mm. Is the post usually slightly narrower than the hole to allow it to fit and for the clamp to hold it? Coz ive seen 27mm posts and 27.2 ones etc.
  • whyamiherewhyamihere Posts: 7,571
    How did you measure? Vernier calipers are the only thing accurate enough really because seatposts vary by 0.2mm. 27.2mm is the most common, but 27.0mm and 26.8mm both exist. What size is the post you tried which didn't fit?
  • rustyjustyrustyjusty Posts: 35
    edited 27 June

    How did you measure? Vernier calipers are the only thing accurate enough really because seatposts vary by 0.2mm. 27.2mm is the most common, but 27.0mm and 26.8mm both exist. What size is the post you tried which didn't fit?

    The seatpost from another bike that i tried was about 28, though i didnt realise the size at first.

    I measured the hole in the frame with a metal ruler and tried to be as accurate as possible, it read 27mm, though as you say it may not be accurate, point 2 of a mm would be hard for it to detect.

    My question is, would point 2 make much difference so would 27 or 27.2 be ok as it has a clamp to close the gap? or would it be better to get slightly smaller than the hole in the frame so a fit is guaranteed ? So maybe i could get a 26.8mm seat post to fit the 27mm hole ?

    If i can find the year of my palomar then i can google it to get the official specs of seat post

    there was a number engraved underneath the bottom bracket that read D8B59353, though i dunno what this means ?
  • veronese68veronese68 Posts: 25,485 Lives Here
    This and also measure in different directions as I've found they can be slightly out of round.
  • rustyjustyrustyjusty Posts: 35
    edited 27 June
    If i could find the year my bike was made i could google it to be more accurate. The gt label on my bike is on the top bar and it has suntour forks and a sticker saying 6061 heat treated alumium, though im not sure when its made ? Will have another look underneath maybe theres a sticker with date on it. Googling a Gt palomar seatpost says 27.2 but thats not to say every years model is that ? I just wanna get the right seatpost and not be disappointed

    Im gonna be offline now till tomorrow. Cheers guys
  • MattFalleMattFalle Posts: 10,096

    How did you measure? Vernier calipers are the only thing accurate enough really because seatposts vary by 0.2mm. 27.2mm is the most common, but 27.0mm and 26.8mm both exist. What size is the post you tried which didn't fit?

    The seatpost from another bike that i tried was about 28, though i didnt realise the size at first.

    I measured the hole in the frame with a metal ruler and tried to be as accurate as possible, it read 27mm, though as you say it may not be accurate, point 2 of a mm would be hard for it to detect.

    My question is, would point 2 make much difference so would 27 or 27.2 be ok as it has a clamp to close the gap? or would it be better to get slightly smaller than the hole in the frame so a fit is guaranteed ? So maybe i could get a 26.8mm seat post to fit the 27mm hole ?

    If i can find the year of my palomar then i can google it to get the official specs of seat post

    there was a number engraved underneath the bottom bracket that read D8B59353, though i dunno what this means ?

  • MattFalleMattFalle Posts: 10,096
    Although tbh its a very basic level bike so i'd hazard s guess at 27.2 throughout the years it was made.
  • rustyjustyrustyjusty Posts: 35
    edited 28 June
    MattFalle said:

    Although tbh its a very basic level bike so i'd hazard s guess at 27.2 throughout the years it was made.

    I'll buy a 27.2 seatpost, should fit, cheers
  • rustyjustyrustyjusty Posts: 35
    edited 29 June
    Question : Also. it is an 18 speed (6 speed cassette) but the right shifter is a 7 speed one so im guessing id be ok to fit a 7 speed shimano cassette at the back without any difficulties ? Also would a 7 speed from Decathlon work just as well ?

    Would the chain need altering to accomodate etc ?
  • MattFalleMattFalle Posts: 10,096
    logically what you posted sounds like it should work all ok.

    yup - Decathlon, Amazon, Shimano whatever cassette all the same.
  • MattFalleMattFalle Posts: 10,096
    chsin may need adjusting, may not. give it a bosh and see.
  • whyamiherewhyamihere Posts: 7,571
    You need to check if it is a cassette or not. 6 speed cassettes are rare, so it's probably more likely to be a freewheel. If it is, you'd need to either fit a 7 speed freewheel (generally available from the same places) or change the wheel to allow fitting a cassette.

    It's fairly easy to tell which you have. This is a freewheel, note the wider bit in the centre which is built into it. This is a cassette, which has a separate lockring. Also, freewheels will generally have a smallest cog of 14 teeth as they have to be larger to accommodate the freewheel mechanism, while cassettes often start from 11 or 12 teeth, that's not a guaranteed way of working it out either way though.
  • rustyjustyrustyjusty Posts: 35

    You need to check if it is a cassette or not. 6 speed cassettes are rare, so it's probably more likely to be a freewheel. If it is, you'd need to either fit a 7 speed freewheel (generally available from the same places) or change the wheel to allow fitting a cassette.

    It's fairly easy to tell which you have. This is a freewheel, note the wider bit in the centre which is built into it. This is a cassette, which has a separate lockring. Also, freewheels will generally have a smallest cog of 14 teeth as they have to be larger to accommodate the freewheel mechanism, while cassettes often start from 11 or 12 teeth, that's not a guaranteed way of working it out either way though.

    I didnt realise mountain bikes from the last 10 years or so still used freewheels ? I thought they were all cassettes, i wonder if the previous owner fitted a 7 speed and left the smallest one off by mistake ? I willl have a look though, thanks for the info :)
  • MattFalleMattFalle Posts: 10,096
    its v v unlikely he left the 7th cog off by mistake if its all done up, adjusted and working - more than likely he put on a 7 speed shifter, 7 speed cassette and had to leave the 7th cog off as its a 6 speed freewheel.

    as you're tight for cash csn you borrow a 7 speed cassette to see if it fits before you buy one?
  • rustyjustyrustyjusty Posts: 35
    edited 30 June
    MattFalle said:

    its v v unlikely he left the 7th cog off by mistake if its all done up, adjusted and working - more than likely he put on a 7 speed shifter, 7 speed cassette and had to leave the 7th cog off as its a 6 speed freewheel.

    as you're tight for cash csn you borrow a 7 speed cassette to see if it fits before you buy one?

    I might have an old 7 speed cassette i can try, i just didnt realise that freewheels where still used on bikes as im guessing its less than 10 years old

    Question: if it turns out its a freewheel, can i buy a 7 speed freewheel to replace the 6 thats currently on without probs ?
  • Munsford0Munsford0 Posts: 206
    Yes, if you have the necessary freewheel remover
  • MattFalleMattFalle Posts: 10,096
    but, tbh, you're now ploughing money into a shed when you could be saving that for a new bike.

    and will you actually realise any difference between 6 & 7?

    factor in cost of new chain to mstch new cassette as well.....
  • MattFalleMattFalle Posts: 10,096
    Munsford0 said:

    Yes, if you have the necessary freewheel remover

    or, alts, for the cost and hassle of a 7 speed freewheel look for a decent 7 speed 2nd hand wheel snd change the gallah over in a one-r
  • rustyjustyrustyjusty Posts: 35
    MattFalle said:

    Munsford0 said:

    Yes, if you have the necessary freewheel remover

    or, alts, for the cost and hassle of a 7 speed freewheel look for a decent 7 speed 2nd hand wheel snd change the gallah over in a one-r
    This for £12.99 looks alright https://www.decathlon.co.uk/p/7-speed-14x28-screw-on-freewheel/_/R-p-288
  • MattFalleMattFalle Posts: 10,096
    if you have a freewheel, yes.
  • rustyjustyrustyjusty Posts: 35
    MattFalle said:

    if you have a freewheel, yes.

    Its a freewheel, i had a look. Ill buy a 6 speed to replace it and new chain. How much would a cheap reliable chain be ?
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