carleton

It comes down to:

- Personal preference
- Chain issues


Most people can't feel the difference between small/small or large/large chainring combinations to make gears. Everyone experiences the issues that come with chainring/cog combinations taking or giving too much chain.

Eventually, you'll settle on a system whereby you won't have to change chains when you change gears. A lot of it is trial and error. But, I think both options above will keep the wheel on the dropouts...depending on your dropouts.

When you start using a 13t (i.e. 45/13) cog in the mix, you really run into issues with having too much chain.

queerpunk

there's all sorts of bro science about large/large combinations versus small/small combinations, and the rational part of my brain wants to reject it all. people talk about spinning up more weight with a larger chainring... bah! nonsense. people talk about chain angles and friction - but the chain still goes all the way around a cog no matter how big it is... nothing really seems to actually make sense.

except i have this one gear combo that just feels bigger than its actual roll-out, and i hate it. i feel like i can't modulate it or roll it properly. i don't know why it feels so wack. but it does.

so i don't know what to believe.

carleton

This touches on a key point.

Weavie, it's a fact that some people can feel the difference between small/small and big/big gear combinations that make the same gear. Some gears that are technically bigger will feel smaller on the legs.

It's up to debate why this happens. There are a lot of theories. Nay-sayers focus on the theories and poke holes in them to debunk the phenomena the people experience. This doesn't change the fact that those experiences exist.

The first time I experienced it was during my first year of racing. I was used to riding a 50/15 (90" / 7m) for race gears by that time early in the season. Then I bought a 14t and put on a 48/14 (92.6" / 7.2m) and did my first efforts on it. It felt so light that I came off the track mad thinking that I had forgotten to change the 15t out for the 14t. 48/14 (92.6") felt like a significantly smaller gear than 50/15 (90"). Not the same...smaller. I had no idea why, but that's what I felt.

I experienced such with other combos, like 45/13 (93.5") vs 52/15 (93.6"), as well. I *really* liked 45/13. The difference was night and day to me. Can't explain it. It just was. What sucked about running 45/13 was that because the combo used both a small chainring and a small cog, they didn't use up much chain and the wheel would extend off of the dropout, so I had to use a short chain (1 less link than my normal chain) in order to use that combo. This made using that gear a pain in the butt.

queerpunk

i wonder if we'd be able to tell the difference if we did it doubleblind.

carleton

Anna Meares' mechanic couldn't

Story Time:

Back in like 2009 or 2010, Anna Meares was in the World Championship 500M. As the story goes, she was scheduled to ride a 45/13 (from my bad memory of the story). So, the mechanic preps her bike, they hook up her bike in the start gate. She mounts it. 5...4...3...2...1...Go! Wooooosh! NEW WORLD RECORD!

After all of the festivities, the mechanic starts to break down the bike and notices his goof. He put on a 46t instead of the prescribed 45t chainring. Good thing she won (and set a world record)!

weavie

Granted this is all stemming from infield babble between intervals, but, my feeling is that I can do more jumps faster with a smaller chain ring.

I couldn't say if over a long period of time I would get more or less fatigue with either set up. My guess is it's about power (or lack of) and muscle makeup and some combinations just end up feeling more right than others.

JimiMimni

Allegedly, the smaller chainrings accelerate quicker than their larger brethren. I'm couldn't tell you if that's total bunk or not, but in my limited experience, that seems to have some truth. I feel snappier on a 49/14 than on a 52/16, even though it's a much larger gear. Consequently in a race two weeks ago, I was driving a group with a 52t, and found a rhythm really easily and it stuck there quite well. It's likely placebo, but eh, whatever. Experiment and see what you like!

Voodoo76

I'm starting over equipment wise so debating this too. The only measurable difference I can think of is chain speed (always going to be faster on a bigger ring for same rpm). Doesn't seem like moving 400g 10% faster would be a significant thing.

dunderhi

So what are all of the factors?

1. The linear speed of the chain speed
2. The amount each link must rotate
3. Aerodynamic drag
4. The flywheel effect
5. Total weight
6. What else?


IMHO, since the highly unusual 63-19 and 40-12 are equivalent options to the popular 47-14 & 50-15, that maybe the sweet spot lies in that 14-15t cog range and that significant differences might only be felt at the extremes.

markwesti

What is the reason most track cranks use 144 BCD ?

queerpunk

back in the day, ALL cranks were 144 bcd - track and road.

and then road changed because they wanted to accommodate smaller chainrings.

track never needed to do that.

and since it's not like track stuff really gets wholesale upgrades (ie, there's a new dura-ace groupset every three years, but nothing similar for track gear), sold in high volumes, nor do the demands of the equipment really ever change - then, well, there's no need to change.

and why would anybody change? every good chainring is 144bcd. why would somebody try to elbow a minority piece of equipment that's incompatible with absolutely everything else worth using?

Koogar

Placebo effect. Sorry, but it's real.

I guess it's also possible that, if you're using the same chain length, the difference in effective chainstay length and therefore wheelbase and weight distribution could change the way the bike feels.

markwesti

Thanks , Mr. punk . Hey while I have you on the screen , what do you think about this crankset ? I mean for entry level practice only .

https://www.planet-x-usa.com/i/q/CSS...-2000-crankset

queerpunk

It'll be just fine.

wens

Track and facility are really nice, had some really fast and hard racing that was tons of fun. The only tracks I've ridden are cleveland and indy, but it's easier to ride than either of those. Super smooth surface and transitions I pretty much only noticed when I would accelerate a little coming down hill out of the turn.

Things that are a bit less than ideal are lack of on track warm up time at all, and a high barrier to entry for out of town people to get on the track/do weeknight races outside of the oca track cups. My impression is the driver for those is whatever insurance arrangement the track/city has, and it seems like there's already more demand than available track time, so I'm not sure how much you can criticize there. If the local demand is already more than the track can easily accommodate it's kind of hard to argue that a big effort should go into making it easier for out of town guys.

Hida Yanra

sounds awesome - glad you got to go check it out!

wens

Now I just need to find a way to check out Burnaby, because I heard cool things about it.

And all the other tracks. I have a vision of re-writing the Pokémon theme song to got to ride them all.

taras0000

What about FCV? That's in your neck of the woods.

MarkWW

@wens, you must have been the other american I kept seeing on the big board from time to time. I was hoping to find you and introduce myself at some point.

Speaking of the racing this weekend, I was given a hard time by the officials doing bike check because of the UCI minimum handlebar distance rule, of all things. In UCI jargon, the handlebars have to sit within an area bounded "at the rear by the axis of the steerer tube (D)". Since my tk1 has a bayonet fork, they were measuring it as somewhere on the bayonet part in front of the headtube, but I had to explain to them that it should be through the center of the headtube. We came to a settlement that I would rotate my bars forward a touch. It still amazes me that you can have your bike checked X amount of times and come back with just as many different interpretations of the rules.

wens

I think one of two Americans not from new York. Gotta say UCI rules are a pain. I think it would be easier if they applied to all the us racing because shops would be used to checking bikes, but I can't imagine the value in telling a brand new racer their bike is too light or such.

I heard someone say bike check was more involved than usual because they're trying to train more people or some such, but I have no idea if that's wild rumor or truth.

queerpunk

what a drag.

the officials should understand what "axis" means.

wens

I mean, yeah. But as an engineer, I got chided several times in my early career for dimensioning to things that are very difficult to inspect, like the theoretical center of a tube. There's no way you're doing anything but eyeballing the centerline in a time effective manner unless you're bringing along a cmm.

Poorly implemented rule

gtrob

They must have had new people up there, as Andrew, the guy who checks every bike always, knows a TK1 lol. And a TK1 with scattos shouldn't be able to fail.


It is tough for out of towners, to do a tuesday race you have to take a cert B (or A and B if you are new to track), then a race cert, then try and get a spot for racing (they are sold out 3-4month in advance). Like you said, there is more demand than track right now. There is also never 'open' track, but at nationals/provincials they are better in having an hour or two a day of open.

In the summer I am hoping to see more camps and things for people as the demand eases a bit and makes room for racers. Like a 4 day where the first day is all the certs out of the way at once.

Dalai

@wens Even if the UCI rules were implemented for all racing in the US, it won't mean shops know or care about the UCI rules.

All racing in Australia is under UCI rules (including local club races) and the onus is on the rider to know and keep up to date with the constant rule changes. Bike shops don't know or care about UCI rules as racers comprise of only a small percentage of sales.

carleton

Yeah, remember, they are all volunteers.

I am (was a?) USA Cycling Official, even though we had to be versed on the rule book and pass a test. Nuances like those presented by the TK1's bayonet fork weren't covered.

If this happens, I'd raise the case to a higher level official who should probably have experience in such matters, and logic will prevail...hopefully.

If all else fails, simply say, "Sarah Hammer won several world championships and an Olympic silver medal on this bike...I'm pretty sure it's UCI legal." ... and see how far that gets you