Current Projects chat and miscellany

Too big isn't really a big deal. If you can ride comfortably with the saddle and bars as they are then by all means do, just bear in mind when/if you get another frame there should be some seatpost showing.

Generally this is due to smaller frames having a smaller toptube, which means less reach. So instead of having a small amount of seatpost and short stem, you have a loonger stem and more seatpost when you have a smaller frame.

That probably makes no sense. Tell me if I'm talking nonsense.

This shows that sizing on non-racing bike frames is not that critical/can easily be adapted to the rider.

No its fine, i am 5'8", the frame measures 55 from CC to top of tube, so long body short legs, its a bit tall, i stand over crossbar with no clearence in bare feet, my wife 5'5 1/2" and has 2" over the bar!
Short ass legs, its how i remember my first fixie being?

Like I said, if its comfortable. Ride it.

If you adjust gear ratio at the same time as you adjust crank length to maintain the same gain ratio, crank length selection becomes arbitrary over quite a large range, far larger than the range offered on mainstream commercial product in adult sizes. Some very small adults, or people with range of movement problems, need shorter cranks but nobody needs cranks longer than 175. They might select them based on preferred cadence, and Zinn might keep telling them they need them because he manufactures long cranks, but all the good science* on the matter points to crank length within a wide range having no measurable effect on overall biomechanical efficiency.

So crank length does make a difference, but only to what cadence is comfortably maintained, but not to actual power output?
Do longer cranks mean that hills are easier as more leverage, a bit like engines having higher torque level don't struggle so much up a hill, but won't necessarily have a higher power output (HP)?
i.e. - longer cranks = diesel land rover, short cranks = nippy hatch back? Or, the rider still has same power output, but crank length allows it to be used in different ways.
Or do other factors apply, optimal cadence for set ratio, or is it more that each person finds what works for them?

haha, ok, yeah quite a big fail, all turned up fitted it, did not line up with the rear cog and even with the chain ring on the inside it would need a narrower BB, so i'm being sent out another as there seems to be some trouble with the manufacturer?

see now the whole Saddle to bar drop thing, i was always shown that the saddle and headset should be the same, now i see on here its obviously changed since the dark ages, but as i say, the frame is mabie to big for me then, but wont know till the crank is on?

God, I remember my On One project, I got so much wrong on that build, I think I went through 7 stems till I got it right!
You're not doing that bad.
Any build is gonna be a bit of a learning process, hopefully less and less the more you learn (I hope...).

Yeah and i am sort of winging it with what i have, i got the frame forks and headset together, i've had to go budget on the rest, ive got 16t fixed and freewheel on it, so will be a good start back into it. I wont really know till i get out on it.

Thats what makes it fun!

I love designing and building bikes, cause you inevitably come across something you weren't expecting that gives the build a bit of character.

So crank length does make a difference, but only to what cadence is comfortably maintained, but not to actual power output?
Do longer cranks mean that hills are easier as more leverage, a bit like engines having higher torque level don't struggle so much up a hill, but won't necessarily have a higher power output (HP)?
i.e. - longer cranks = diesel land rover, short cranks = nippy hatch back? Or, the rider still has same power output, but crank length allows it to be used in different ways.
Or do other factors apply, optimal cadence for set ratio, or is it more that each person finds what works for them?

Surely the 'leverage' issue is just the gear ratio, which crank length contributes a bit to, but much less than chainring and cog size. So for the same chainring and cog size, longer cranks will be a slightly higher gear than shorter cranks. If you adjust for this with chainring and cog size, then crank length becomes irrelevant to 'leverage' - and (assuming tester is right about it not making any difference to human power output) the only thing it will make any difference to is comfortable cadence.

Just replaced the crankset on my Schwinn Sprint with a Dia Compe Gran Compe (http://www.iminusd.com/dia-compe-gran-compe/), loving it.

Sorry for rubbish phone-quality photo!

No its fine, i am 5'8", the frame measures 55 from CC to top of tube, so long body short legs, its a bit tall, i stand over crossbar with no clearence in bare feet, my wife 5'5 1/2" and has 2" over the bar!
Short ass legs, its how i remember my first fixie being?

I recon it could go up a bit more, i'm 2" shorter than you with short legs to and my 54cm beater fits me the same way, but the saddle is up about 2 or 3".

So crank length does make a difference, but only to what cadence is comfortably maintained, but not to actual power output?

Yes, but bear in mind that your self-selected preferred cadence will probably change if you change crank length, it turns out that people tend to have a preferred (and limiting) foot speed, not repetition rate. You can test the limit fairly easily by doing low gear spin outs on the rollers - you'll probably find that if you max out at 170rpm on 175mm cranks, you can jump straight onto 170mm cranks and hit 175rpm, i.e. you're not limited by ω itself but by the product ωr

Surely the 'leverage' issue is just the gear ratio, which crank length contributes a bit to

Exactly

Restraps and Easton flat boys FTW!

www.restrap.co.uk

Have you worked out how to get into them when on the move? I really like horizontal straps but just couldn't get on with them.

Ended up bodging a set onto some clips in the end.

I was in my local Evans yesterday, its one of these warehouse style ones with offices, so most stuff you have to look up on a screen and get them to send one down just to look at it, i wanted to try some bars.

I asked why they did not carry velcro straps, i was then talked down to by to young hipsters about the small buisness and the reason there are no small bike shops in our town anymore.

You should have seen their faces when i asked for an adapter for my 'old fashon' pump, "no you cant buy them anymore" am i really that old, you used to be able to walk into any hardware store on your local parade and they would have 2 types of plaid/cloth covered adapter that screw into any bike pump, now you can only get the car type and a little adapter for the smaller one on my new 700c's, oh, there are no hardware stores left round here because of b&q and the like.

If i ever win the lottery, i'm opening a local bike/skate/hardware/butchers/greengrocer/fishmonger/florist/bakers/offlicence,

oh bugger, thats a supermarket.

i feel old today, hahahahahahahaha.

So someone working at Evans had a go at you for not shopping in an LBS? I hope you pointed out the irony of that situation

oh no, there are no LBS anymore the last shut down last year, there are 2 evans!

He was puffing out his chest and giving it, "yes well they just cant hold the stock like us...." (while trying on oversize sunglasses and not being able to sell me some velcro straps because the only have large amounts of stock that small manufactures cannot supply....)
*unt

Surely the 'leverage' issue is just the gear ratio, which crank length contributes a bit to, but much less than chainring and cog size. So for the same chainring and cog size, longer cranks will be a slightly higher gear than shorter cranks. If you adjust for this with chainring and cog size, then crank length becomes irrelevant to 'leverage' - and (assuming tester is right about it not making any difference to human power output) the only thing it will make any difference to is comfortable cadence.

Yes, but bear in mind that your self-selected preferred cadence will probably change if you change crank length, it turns out that people tend to have a preferred (and limiting) foot speed, not repetition rate. You can test the limit fairly easily by doing low gear spin outs on the rollers - you'll probably find that if you max out at 170rpm on 175mm cranks, you can jump straight onto 170mm cranks and hit 175rpm, i.e. you're not limited by ω itself but by the product ωr

Exactly

Thanks guys, think I'm slowly getting it.

So, a smaller crank will still have the same foot speed, but a higher RPM as each rotation has less physical distance for the foot to travel than a longer crank?

But a longer crank with the same gearing will have the same power output, but a bit more leverage for hills and the like and a slightly slower speed?

So, basically, if you got two riders on a track with the same level of power output, one with longer cranks and slightly higher gearing, and another with shorter cranks and slightly lower gearing, basically having the same gain ratio, they would be doing the same speed?

oh no, there are no LBS anymore the last shut down last year, there are 2 evans!

He was puffing out his chest and giving it, "yes well they just cant hold the stock like us...." (while trying on oversize sunglasses and not being able to sell me some velcro straps because the only have large amounts of stock that small manufactures cannot supply....)
*unt

What a twat.
I loved those old school bike shops when I was a kid, emporiums of the interesting and fun, and still do today.
And although I do get a lot of components from Wiggle and CRC, as they are cheaper because of their huge stock, I still pop into my LBS for advice from the old boy behind the counter (although the mechanic ain't up to much) from time to time.

^ With the possible other benefits of the longer cranks make it easier to get up to speed, but the shorter cranks make it easier to maintain given speed?

(un)fashionably late to the 2012 slave party....

Those bars, my eyes, etc. Blame Spotter, I saw the wide bars on his Leader and loved it.

So many spacers. WAC.

Slam that stem. Moar riser

Oh and you need some plugs

Looks class.

Maybe you could melt some of those spacers down into bar-end plugs though?

Eurgh, being so needlessly anal in the CP thread is so Bike Porn. Sorry.

LOOOLLL. It was funny.

stemflip maybe? and glad to see my chainring found use:)

No plugs = dick move on any thread.

Get some.