Singlespeed & Fixed Gear - change from 46/17 to 44/18 noticeable on hills?

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alleyooptroop
07-21-08, 12:54 PM
so i finished my ss conversion this weekend and went for a couple rides. i've mentioned here before on another post that there are a couple (what i now consider) major hills i have to negotiate before i get into any flat riding terrain. i tried my best but could not get up either hill and had to walk. so i'm considering changing from my current 46/17 (73.1 gear inches) gearing to 44/18 (66 gear inches). i'm not experienced enough to know how the difference in gear inches will feel so i'm hoping someone here will be able to give me some insight. as always, thanks in advance for any replies.
p.s. (warning, noob question) is it possible to change the chainring without having to remove the crank arm? i currently have a set of sugino rd's.
ZiP0082
07-21-08, 12:56 PM
I used to run around 66-68 gear inches on my old singlespeed and sorta wished i had closer to 70-71 for hills... i didn't have a super high max speed being under 70 gear inches.
I don't think the crank arm has to come off, if you angle the chainring around the arm to pull it off.
wearyourtruth
07-21-08, 01:00 PM
you should notice a pretty big difference... when i went from 42x16 to 42x15 it was quite noticable (i know that's the other way) i think it will help a lot.
and no, you don't have to take the crank arm off, just remove the bolts and slide the chainring around... the only time i could think of is if you are running a rocket ring or other solid chainring and running it on the inside of a road crank... it might not fit over the crank, otherwise shouldn't be a problem.
if 44/18 is too small then why not 44/17? keep your rear cog on, it'll be easier. i am at 44/15 now and wll change to 44/17 soon for hills and what not.
alleyooptroop
07-21-08, 01:27 PM
if 44/18 is too small then why not 44/17? keep your rear cog on, it'll be easier. i am at 44/15 now and wll change to 44/17 soon for hills and what not.
i'm actually at 46/17 right now so i was considering changing both the chainring and freewheel to 44/18. i probably should just change either or first and see how it feels. i'm assuming changing the freewheel would have more of an impact?
i tried my best but could not get up either hill and had to walk. so i'm considering changing from my current 46/17 (73.1 gear inches) gearing to 44/18 (66 gear inches). i'm not experienced enough to know how the difference in gear inches will feel so i'm hoping someone here will be able to give me some insight.
to answer this question, yes.. you should notice how easier it will be to pedal. the thing with gear inches is, it is the measurement you travel on one full pedal stroke. So every pedal with the new ratio, you will travel 66 inches, which is a pretty reasonable ratio for a hilly area.
i think that answers your question, unless i'm reading something wrong, which is quite often the case.
gfrance
07-21-08, 01:40 PM
You'll notice quite a big difference. If it is still too much to get up the hills, get a geared bike.
alleyooptroop
07-21-08, 01:44 PM
You'll notice quite a big difference. If it is still too much to get up the hills, get a geared bike.
do you think i should just change one of them first or go ahead and change both the chainring and freewheel?
alleyooptroop
07-21-08, 02:59 PM
one more thought. to save money, could i just change out the chainring to a 42t?
deadforkinglast
07-21-08, 03:32 PM
Try changing the chainring first. You can find a 42 or 44 tooth chainring for not much money at all, probably less or about the same as a decent freewheel, and they're easier to change.
visitordesign
07-21-08, 03:36 PM
that's a pretty substantial difference. it's going to have you spinning pretty hard on flats to sustain a speed that you might be familiar with--which is by no means a bad thing, but if you aren't up to working on your spin, you may feel quite a bit slower.
How long have you been using your current chain? If it has been a while, you might want to get a new one if you get both a new chainring and a rear cog. Chains "stretch" happens over time and the chain can cause noise when used with new gears.
PS: Yes I know the chain doesn't actually stretch, that is why I put it in quotes.
alleyooptroop
07-21-08, 04:49 PM
Try changing the chainring first. You can find a 42 or 44 tooth chainring for not much money at all, probably less or about the same as a decent freewheel, and they're easier to change.
that's what i was thinking. i even found a guy on a local fixed gear message board selling a 42t chainring for $5. will it matter if the chainring is made to be an inner chainring on a traditional road bike? or do i need to get something specifically for ss/fg?
How long have you been using your current chain? If it has been a while, you might want to get a new one if you get both a new chainring and a rear cog. Chains "stretch" happens over time and the chain can cause noise when used with new gears.
PS: Yes I know the chain doesn't actually stretch, that is why I put it in quotes.
it's actually a brand new chain. just finished the bike this weekend.
marqueemoon
07-21-08, 07:08 PM
if 44/18 is too small then why not 44/17? keep your rear cog on, it'll be easier. i am at 44/15 now and wll change to 44/17 soon for hills and what not.
44x17 is a beautiful gear.
I'm running 42x17 on my ss commuter but it's a tank.
thats what i like to hear
I'm in a hilly area and run 40x17. I just went to 42x17 and am having problems pulling my trailer now. I noticed quite a difference with that on hills even without the trailer too. 42x17 is what a lot of people seem to use in hilly area's though. I was reading in the touring forum and a guy road 4500 miles across the country with a 44x15 (I think) fixie and a 20 tooth freewheel on the flip side.
the thing with gear inches is, it is the measurement you travel on one full pedal stroke.
Huh. I never made that correlation. Learn something new every day. :)
the thing with gear inches is, it is the measurement you travel on one full pedal stroke.
Huh. I never made that correlation. Learn something new every day. :)
Well that's because he's wrong. Gear inches is not the measure of how far you travel per stroke, that is development. Gear inches is the size of wheel on an ordinary (or unicycle) that would give you the same resistance.
The development for 44/18 is actually about 200 inches.
alleyooptroop
07-22-08, 02:03 PM
Well that's because he's wrong. Gear inches is not the measure of how far you travel per stroke, that is development. Gear inches is the size of wheel on an ordinary (or unicycle) that would give you the same resistance.
The development for 44/18 is actually about 200 inches.
you guys are smart
mangpress
07-23-08, 02:17 AM
surely then, if you say that the gear inches is the circumference of the wheel on a unicycle that issues the same resistance, what snails said would be the logical progression from that.
with no ratio on a unicycle, purely the circumference of the wheel that is directly attached to the cranks to determine the work required for each whole pedal stroke (and furthermore: whole wheel rotation). gear inches must be the same measurement assuming that the cranks are the same length.
in the original example: if the ratio is 46/17 and 73.1 gI, then this would lead to the conclusion that (with the same size crank arms) a unicycle with a 73.1 inch (circumference) wheel would require exactly the same resistance to pedal, ceteris paribus.
so surely what you have labelled 'development' and gear inches are in fact the same thing?
http://www.sheldonbrown.com/gain.html
No, development is gear inches times pi. Try it for yourself.
They're linearly related but not equal, so they give you the same approximation of "difficulty" but GI is not how far your bike travels when you pedal.
mangpress
07-25-08, 11:35 PM
i see.
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