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Singlespeed/fixed gear ratios

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  • 09-10-2007 1:20pm
    #1
    Ghost Rider
    Registered Users Posts: 1,883 ✭✭✭


    I'm running a singlespeed freewheel at 42/16 and find it perfect for Dublin. Does anyone else use this ratio with a fixed gear and, if so, how do you find it?


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    #2
    peterk19
    Registered Users Posts: 2,278 ✭✭✭peterk19


    Im running the same ratio and find it perfect for my commute from Donaghmede to south city centre although im considering changing it to make it a bit harder


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    #3
    niceonetom
    Registered Users Posts: 4,833 ✭✭✭niceonetom


    i run 48:17 and find it grand. that's 76.25 gear-inches. 42:16 works out at 70.8 inches.

    the only time i've really struggled with it was getting from up knockmaroon hill, which if you know it is pretty bloody steep.

    for ratio comparison purposes this helps.


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    #4
    rp
    Users Awaiting Email Confirmation Posts: 1,227 ✭✭✭rp


    niceonetom wrote:
    i run 48:17 and find it grand. that's 76.25 gear-inches.
    That's a monster gear! I'd read the 72" was a good all round size.

    BTW, anyone got any fixed-wheel swaps? I've a frame to trade, and I'm looking for either a 42.5mm chainline crank *OR* a 135mm rearhub +- wheel.


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    #5
    niceonetom
    Registered Users Posts: 4,833 ✭✭✭niceonetom


    rp wrote:
    That's a monster gear! I'd read the 72" was a good all round size.

    BTW, anyone got any fixed-wheel swaps? I've a frame to trade, and I'm looking for either a 42.5mm chainline crank *OR* a 135mm rearhub +- wheel.

    i bought it off a courier who had it 48:15, that's 86.4 inches. that's monster.


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    #6
    rp
    Users Awaiting Email Confirmation Posts: 1,227 ✭✭✭rp


    niceonetom wrote:
    i bought it off a courier who had it 48:15, that's 86.4 inches. that's monster.
    Scarey. That'd mean you'd be doing 50kph at an easy 120bpm, nice, but getting started in the first place would be a challenge.


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    #7
    Itsfixed
    Registered Users Posts: 564 ✭✭✭Itsfixed


    oh dear i must be either a) a wimp or b)old and slow: I run a 42:17. This is for around dublin too.

    Mind you my tyres are 32mm, fairly thick.

    I do find myself spinning too much sometimes and thinking about moving to oooh, let me think, 41:16.

    I find sheldon brown's gear calculator useful for working all this ratio stuff out.


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    #8
    TinyExplosions
    Registered Users Posts: 6,860 ✭✭✭TinyExplosions


    I run 42/16m and find that I could maybe go a little higher, but am only learning :)


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    #9
    fish-head
    Closed Accounts Posts: 1,896 ✭✭✭fish-head


    rp wrote:
    That's a monster gear! I'd read the 72" was a good all round size.

    BTW, anyone got any fixed-wheel swaps? I've a frame to trade, and I'm looking for either a 42.5mm chainline crank *OR* a 135mm rearhub +- wheel.

    What's the frame?

    I was riding 42/16 before it all went to ****e. I found it good enough to be able to accelerate through holes in traffic and pelt it up hills.


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    #10
    rp
    Users Awaiting Email Confirmation Posts: 1,227 ✭✭✭rp


    fish-head wrote:
    What's the frame?
    New York Cycles, compact aluminium (black), with fork and possibly with BB + (black) chainset (30/12) and/or wheels (ambroiso's + mavic's, black), must go to make room for Il Pompino (rack & mudguard braze-ons...).


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    #11
    Itsfixed
    Registered Users Posts: 564 ✭✭✭Itsfixed


    rp wrote:
    New York Cycles, compact aluminium (black), with fork and possibly with BB + (black) chainset (30/12) and/or wheels (ambroiso's + mavic's, black), must go to make room for Il Pompino (rack & mudguard braze-ons...).

    Great choice! I have two of 'em. Are you getting the new black one?


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    #12
    rp
    Users Awaiting Email Confirmation Posts: 1,227 ✭✭✭rp


    Itsfixed wrote:
    Great choice! I have two of 'em. Are you getting the new black one?
    No, the traditional "Trigger's mums bathroom" blue (my last bike was black, time for a change); got it off Cliff at a good price (he doesn't deal with On-one anymore, cuz they sell cheaper on the web...).
    Trouble is, I forgot to check the dropout spacing, assuming it would be 120mm, but it turns out it's 135mm. Brant at On-one says it's OK just to pop in a 120 hub, wheel tugs (inside the fork) and tighten it up, but i don't like the sound of that...


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    #13
    peterk19
    Registered Users Posts: 2,278 ✭✭✭peterk19


    rp wrote:
    New York Cycles, compact aluminium (black), with fork and possibly with BB + (black) chainset (30/12) and/or wheels (ambroiso's + mavic's, black), must go to make room for Il Pompino (rack & mudguard braze-ons...).

    would you swap for money?


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    #14
    Itsfixed
    Registered Users Posts: 564 ✭✭✭Itsfixed


    rp wrote:
    No, the traditional "Trigger's mums bathroom" blue (my last bike was black, time for a change); got it off Cliff at a good price (he doesn't deal with On-one anymore, cuz they sell cheaper on the web...).
    Trouble is, I forgot to check the dropout spacing, assuming it would be 120mm, but it turns out it's 135mm. Brant at On-one says it's OK just to pop in a 120 hub, wheel tugs (inside the fork) and tighten it up, but i don't like the sound of that...

    No i don't either, to be honest. I have both a 135mm spaced one and a 120mm one. If you use a 120mm hub you might have to do a lot of messing around with spacers to get the right chainline. too much hassle, IMHO

    Brant sells a 135mm flip/flop hub for about 20stg but it seems to be out of stock. It's still going very strong on my machine nearly 3 years on.

    You could try a googling for a UK shop that sells Surly 135mm hubs. Try charliethebikemonger.com. Nice chap, very quick delivery.


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    #15
    flickerx
    Registered Users Posts: 1,234 ✭✭✭flickerx


    Ghost Rider wrote:
    I'm running a singlespeed freewheel at 42/16 and find it perfect for Dublin. Does anyone else use this ratio with a fixed gear and, if so, how do you find it?

    I got a fixed 48/14, never had any issue with it really, you get used to taking off with it at the lights.


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    #16
    niceonetom
    Registered Users Posts: 4,833 ✭✭✭niceonetom


    flickerx wrote:
    I got a fixed 48/14, never had any issue with it really, you get used to taking off with it at the lights.

    daaamn. i had to check what that was in inches (92.5!). too beau coup. probably fun on the flat but i think my knees would explode at the bottom of the first steep hill.


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    #17
    flickerx
    Registered Users Posts: 1,234 ✭✭✭flickerx


    niceonetom wrote:
    daaamn. i had to check what that was in inches (92.5!). too beau coup. probably fun on the flat but i think my knees would explode at the bottom of the first steep hill.

    Well, I'm using it for the commute from Broadstone to Blanchardstown, not really any serious hills along that way so no hassle...


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    #18
    Ghost Rider
    Registered Users Posts: 1,883 ✭✭✭Ghost Rider


    I live very near Broadstone too. How do you find stopping at the lights at the bottom of Constitution Hill? (Or do you head in the other direction?)
    flickerx wrote:
    Well, I'm using it for the commute from Broadstone to Blanchardstown, not really any serious hills along that way so no hassle...


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    #19
    flickerx
    Registered Users Posts: 1,234 ✭✭✭flickerx


    Ghost Rider wrote:
    I live very near Broadstone too. How do you find stopping at the lights at the bottom of Constitution Hill? (Or do you head in the other direction?)

    Where I live (near the top end of Dominick Street) I dont have to go any further south than the junction at Western Way, so I dont have to deal with that hill.

    I just go up the Phibsborough Road, then up the Old Cabra Road, all the way out the Navan Road.


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    #20
    Ghost Rider
    Registered Users Posts: 1,883 ✭✭✭Ghost Rider


    I hear ya. So your only hilly part is coming back down Phibsborough Road at the end of the day. Not too bad, I'd imagine.
    flickerx wrote:
    Where I live (near the top end of Dominick Street) I dont have to go any further south than the junction at Western Way, so I dont have to deal with that hill.


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    #21
    Wez
    Registered Users Posts: 1,747 ✭✭✭Wez


    Does anybody know how to measure chain thickness? I got a 17T sprocket for the rear, but it's chunkier than the original chain and so have to replace the chain and front sprocket to match, but I wanted to upgrade so I know it's not gonna brake.. I don't know how they are measured, so don't know what to look for as a replacement..


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    #22
    Morgan
    Registered Users Posts: 2,481 ✭✭✭Morgan


    It would be cheaper just to get a narrow 17t sprocket.

    But anyway, chains are either 1/8" (track, bmx, singlespeed) or 3/32" (derailleur). Assuming you've got a 1/8" sprocket you need to get a matching chain. The wider chain doesn't really do much for you though (according to Sheldon Brown) - the 3/32" is just as strong.


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