Bike Mechanics Impart Their Wisdom On Vorb

shmoodiver · *by **shmoodiver** on Sat 4/Jul/09 2:33pm*

Wobbler wrote:
Mr_Bob wrote:
Wobbler wrote:hot glue will sort it out

[sarcasm] will Aralldite work too? [/]

no, but araldite might

or 4 bottles of some of the loctite retaining compound

thats a little retentive.

Astoria Paranoia · *by **Astoria Paranoia** on Sat 4/Jul/09 2:35pm*

you mean attentive

Wobbler · *by **Wobbler** on Sat 4/Jul/09 2:40pm*

shmoodiver wrote:
Wobbler wrote:
Mr_Bob wrote:
Wobbler wrote:hot glue will sort it out

[sarcasm] will Aralldite work too? [/]

no, but araldite might

or 4 bottles of some of the loctite retaining compound

thats a little retentive.

each bottle only does 0.25mm so you'll be needing four.

Mr_Bob · *by **Mr_Bob** on Sat 4/Jul/09 2:54pm*

So basicly what I'm thinking of doing, getting some steel tubing with a 18mm inside diameter, and a 20mm outside diameter, I know someone with a lathe, shave off a 1mm step from the tube, and problem solved.
yes, it's a lot of faffing around, it might cost a lot to get the piece of pipe turned down, but it'll be worth it to get the problem solved.

dented · *by **dented** on Sat 4/Jul/09 3:00pm*

Sort of, if its 18mm ID and 20mm OD, then the thickness of the tube will only be 1mm. So you will only be getting 0.5mm shaved off, to give it a new OD of 19mm.

shmoodiver · *by **shmoodiver** on Sat 4/Jul/09 3:04pm*

Wobbler wrote:
shmoodiver wrote:
Wobbler wrote:
Mr_Bob wrote:
Wobbler wrote:hot glue will sort it out

[sarcasm] will Aralldite work too? [/]

no, but araldite might

or 4 bottles of some of the loctite retaining compound

thats a little retentive.

each bottle only does 0.25mm so you'll be needing four.

of course

Wobbler · *by **Wobbler** on Sat 4/Jul/09 3:08pm*

make sure you get it cnc machined

Mr_Bob · *by **Mr_Bob** on Sat 4/Jul/09 3:14pm*

dented wrote:Sort of, if its 18mm ID and 20mm OD, then the thickness of the tube will only be 1mm. So you will only be getting 0.5mm shaved off, to give it a new OD of 19mm.

That's what I meant to say :blush:

Though the size of the larger part of the step won't matter.

shmoodiver · *by **shmoodiver** on Sat 4/Jul/09 3:52pm*

Wobbler wrote:make sure you get it cnc machined

by c and c music factory?

Spokes · *by **Spokes** on Sat 4/Jul/09 5:20pm*

Mr_Bob wrote:Ok, I've got an odd ball repair...,
need some advice.
I've got a customer running one of these Fsa bmx spyder adapters:
and I think that there may be a missing spacer on it. I'm after a stepped washer, something that looks like this:
Measurement on the Bb axle (from a free agent 24" cruiser) is 18mm
and the diameter of the hole in the Fsa spyder is 19mm - which means that the chainring isn't sitting straight, and is shifting under load which is throwing the chain.
Anyone got any advice on where I can get one of these washers?
(Or has anyone got one of these)?
or is it something that I should to talk to someone with a lathe?

I know a wee bit about Freeagents and the axles are 19mm. But keeping in mind some BMX gear is not that well made. Sounds like aftermarket cranks.

Mr_Bob · *by **Mr_Bob** on Sat 4/Jul/09 6:17pm*

thought it would be something unusual,
looks like getting something turned up might be the easiest option.

SamKnight · *by **SamKnight** on Sun 5/Jul/09 11:13am*

if your having trouble getting one made PM me, i'll talk to our machinists and see if i can get something turned down for you out of ali or steel (whichever you prefer)

Spokes · *by **Spokes** on Sun 5/Jul/09 11:26am*

musket wrote:Longer crank = more leverage, but the tradeoff is in acceleration and high cadence. Short arm is less leverage, but easier to wind up and spin at high cadence.

For example, track sprinters use 165s, Pursuiters use 180's.

Hey Musket, is this a general rule? leg length have any factor in it?

Oli · *by **Oli** on Sun 5/Jul/09 11:43am*

Spokes wrote:
musket wrote:Longer crank = more leverage, but the tradeoff is in acceleration and high cadence. Short arm is less leverage, but easier to wind up and spin at high cadence.

For example, track sprinters use 165s, Pursuiters use 180's.

Hey Musket, is this a general rule? leg length have any factor in it?

Oli wrote:Musket and XCrazy are on to it - but I would add that there is no absolute rule about crank length, no matter what anyone says. Many top cyclists have ended up running cranks the total opposite to what the many formulas have dictated because the theories didn't fit their style, and many of theories are contradictory anyway.

You've just got to try different lengths, and not just for a day or two - it has to be at least 6 months of all kinds of riding I reckon. Drags out the learning process a bit...

AFWIW, after extensive testing I discovered that I am happiest on 172.5s and have a 930mm inseam wtf!? I can push longer lengths (have tried 170s, 175s, 177.5s and 180s when I was fit(ter) for at least a year each, but my knees didn't like it (I think it's because I have a short femur in relation to my tibia) and as soon as I got tired my pedaling on climbs went to pieces. More than usual.

I can just turn shorter cranks easier even when I'm a sorry sack of shit.

HTH

Spokes · *by **Spokes** on Sun 5/Jul/09 11:47am*

Oli wrote:
Spokes wrote:
musket wrote:Longer crank = more leverage, but the tradeoff is in acceleration and high cadence. Short arm is less leverage, but easier to wind up and spin at high cadence.

For example, track sprinters use 165s, Pursuiters use 180's.

Hey Musket, is this a general rule? leg length have any factor in it?
Oli wrote:Musket and XCrazy are on to it - but I would add that there is no absolute rule about crank length, no matter what anyone says. Many top cyclists have ended up running cranks the total opposite to what the many formulas have dictated because the theories didn't fit their style, and many of theories are contradictory anyway.

You've just got to try different lengths, and not just for a day or two - it has to be at least 6 months of all kinds of riding I reckon. Drags out the learning process a bit...

AFWIW, after extensive testing I discovered that I am happiest on 172.5s and have a 930mm inseam wtf!? I can push longer lengths (have tried 170s, 175s, 177.5s and 180s when I was fit(ter) for at least a year each, but my knees didn't like it (I think it's because I have a short femur in relation to my tibia) and as soon as I got tired my pedaling on climbs went to pieces. More than usual.

I can just turn shorter cranks easier even when I'm a sorry sack of shit.

HTH

Yes Oli.

Just trying to work out what ratio vs crank length to go for.

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