Fixed Gear Chainline

TinyExplosions

Raam wrote: »

Is something like this suitable?
http://www.chainreactioncycles.com/Models.aspx?ModelID=12164

I don't think you need a conversion kit, just a track cog, something like this as your spacing should be fine, and you've a lock ring already... what ratio you thinking of going too?

blorg

You positively don't want that conversion kit, it won't work (it is designed to fit onto a standard cassette freehub)- you need a track cog you screw on, like Tiny suggests.

Raam

Cheers lads. As it stands today, the chain does not run straight when on the fixed gear, so maybe spacers of some sort would be useful.

At the moment, I have 16 at the back, I was thiking of dropping it to 14.

Raam

Another question, my chain is currently 3/32, I think. It's a "regular" chain, as the shop thought maybe the other chain was making the noise.

I presume I can only get a 3/32 sprocket?

thesunwashot

Raam wrote: »

Cheers lads. As it stands today, the chain does not run straight when on the fixed gear, so maybe spacers of some sort would be useful.

At the moment, I have 16 at the back, I was thiking of dropping it to 14.

If you are adding spacers you are going to be adding them to the chainring as you want your rear cog to be screwed on fully.

So if the chain is further out from the center of the bike at the back than at the front you can add some washers or this sort of thing between the chainring and the cranks: http://hubjub.co.uk/etc/etc.htm#rs

If the chain is further out at the front then you probably need to change your BB unless you can switch your chainring to the other side of the crank spider.

Raam

Cheers, from memory, I think that the chain is further out at the front.

TinyExplosions

Raam wrote: »

Cheers lads. As it stands today, the chain does not run straight when on the fixed gear, so maybe spacers of some sort would be useful.

At the moment, I have 16 at the back, I was thiking of dropping it to 14.

That's a fairly large jump (bearing in mind that I don't want to tell grandma to suck eggs) -each tooth at the back is about 3 gear inches, as opposed to 1 for each tooth at the front -so your 48-16 at the moment would be equivalent to a 54-16 -you're jumping from about 78 gear inches to 91 -a big difference!

Raam

TinyExplosions wrote: »

That's a fairly large jump (bearing in mind that I don't want to tell grandma to suck eggs) -each tooth at the back is about 3 gear inches, as opposed to 1 for each tooth at the front -so your 48-16 at the moment would be equivalent to a 54-16 -you're jumping from about 78 gear inches to 91 -a big difference!

What would be a recommended change to make?

TinyExplosions

Raam wrote: »

What would be a recommended change to make?

I'd suggest going to 15 and seeing what it's like (they aren't all that expensive, so is worth trying out imo). Having said that, I've just checked, and I'm only running 42-15 (which I find possibly too easy), so you're already a fair bit bigger!

TinyExplosions

This may be of some use:

Hello All,

I have had a few questions regarding gearing etc and this is just info that might be of some use.

As a rule of thumb changing the back sprocket by one tooth makes a difference of approx 4 inches, while added a tooth to the front chainring increases your gearing by 2 inches.

It is usually advisable to have at least 2 front rings and a few back sprockets.

So say for example if you have a 48 & 49 front and a 14/15/16 for the back you would have a good choice of gears for most occasions.

48x16=81 inches (good warm up gear)
49x16=82.7
48x15=86.4 Race gear
49x15=88.2 Race gear (not windy)
48x14=92.6 Very fit & strong
49x14=94.5 Too high

A full chart below and based on that and what is on your bike already you may choose different array of sprockets & chainrings

If you also had a 50 front ring then with those back sprockets you would also have 84.4, 90 (useful) & 96.4

Remember that track chains are thicker and anyold from ring wont do! Also track rings can be changed quite quickly -5 allen keys that screw straight into the armiture.

Rear sprockets come in two basic types. 1. screw on -which will require a chain whip to remove, and 2 a handier version where the body screws on and the sproket just sits on this and is held by a lock ring which requires that head set open ring type tool (whose name i have no idea!!)


As recommended by UK outdoor track......
81" for novices and if you're not fit
84" if reasonably fit and experienced....also intermediate riders if it is windy
88" entry level race gear for FIT riders or super-fit riders on a windy day
90.6" Race gear for very fit or experienced riders ....will be too high for anybody if windy.

http://www.aboc.com.au/tips-and-hints/track-bike-gear-chart

Ring Cog Gear
56 13 116.3
55 13 114.2
54 13 112.2
53 13 110.1
52 13 108.0
56 14 108.0
55 14 106.1
51 13 105.9
54 14 104.1
50 13 103.8
53 14 102.2
49 13 101.8
56 15 100.8
52 14 100.3
48 13 99.7
55 15 99.0
51 14 98.4
47 13 97.6
54 15 97.2
50 14 96.4
46 13 95.5
53 15 95.4
49 14 94.5
56 16 94.5
52 15 93.6
45 13 93.5
55 16 92.8
48 14 92.6
51 15 91.8
44 13 91.4
54 16 91.1
47 14 90.6
50 15 90.0
53 16 89.4
46 14 88.7
49 15 88.2
52 16 87.8
45 14 86.8
48 15 86.4
51 16 86.1
44 14 84.9
47 15 84.6
50 16 84.4
46 15 82.8
49 16 82.7
45 15 81.0
48 16 81.0
47 16 79.3
44 15 79.2
46 16 77.6
45 16 75.9
44 16 74.3

Regards Hugh Byrne

Raam

Thanks Tiny.

Couple more questions...
is this tool correct for removing the sprocket (pic not very clear)?

blorg

No, you'll need a track cog lockring tool to remove the lockring and a chain whip to remove the sprocket. (Middle tool here has both and is the one I borrowed from fish-head.)

niceonetom

sprocket? no. lockring? yes. as long as it's a dura-ace lockring (or compatible one) which it does look to be from your pic.

a chainwhip is what you need to remove the sprocket. got one?

btw. does the genesis flyer have a sugino crankset? that's what i have and i get a better chainline with the ring mounted on the inside of the spider.

blorg

Personal experience trying to tighten a track cog lockring with a bottom bracket lockring tool was not positive- are you sure?

niceonetom

well i use the track tool in the middle of your pic blorg (lovely tool), but i think a six-splined tool would work too. but not on all lockrings (ie not on the ones with only two notches like most of 'em).

@raam- if you're buying a tool for the job this is what i'd recommend.

Raam

niceonetom wrote: »

sprocket? no. lockring? yes. as long as it's a dura-ace lockring (or compatible one) which it does look to be from your pic.

a chainwhip is what you need to remove the sprocket. got one?

btw. does the genesis flyer have a sugino crankset? that's what i have and i get a better chainline with the ring mounted on the inside of the spider.

I have a chainwhip, although a bit different from the one pictured earlier. I don't have any of those other tools. I guess I'll buy the middle one, if that's the only one I'm going to need

Yes, it's a Sugino crankset. It doesn't look like I can mount it on the other side of the spider as it is running mighty close to the chain stay as it is. I've had another look at the chainline, and it isn't really too bad. The noise has GOT to be the chain running on worn cogs.

thanks a million for all the advice.