T50 - whatcha planning to build.....

[trapdoor2]

The effect is on the chain line and it depends on whose BB you buy, but 113 should always work; it may bias the chain to the right, 109 might be fine for a single ring but bad for a triple.

Everyone assumes Square taper is easy; rather it's more bomb proof; here's some reference to knowledge you need to pick and maintain a square taper without a bike shop.

Yah, the Origin8 site has no chain-line info on their cranks (that I could find). I read thru all the Sheldon Brown stuff this morning...good info but no specific help there. Same goes for figuring out the Alfine 8 chainline...which could be any of three combinations of drive gear (dished in/flat/dished out). I grew up with square taper BB, no issues there...and on this bike, don't care much about the weight factor.

I think I will go with the 113 and see what happens. I can always swap it out if it is somehow wrong for this build. I have a 109 on my V2/k single-speed but it has a different crank.

 

[Charles.Plager]

Doing some roll downs until my derailleurs arrive

Slow mo fun

Higher and steeper at the neighbor's

You really need to drink more of that coffee you roast.

 

[Eric Winn]

You really need to drink more of that coffee you roast.

That particular roll was after 2 1/2, maybe 3 cups of Sweet Marias Ethiopia Yirga Cheffe Araya Buna.

 

[Eric Winn]

T50 waxed chains waiting for assembly

Ratz is not allowed to make garage comments...

 

[ratz]

T50 waxed chains waiting for assembly

Ratz is not allowed to make garage comments...

you waxed it in a plastic pool; most excellent idea for volume work

 

[Eric Winn]

you waxed it in a plastic pool; most excellent idea for volume work

Not even. That pool would melt. That molten wax is hot!

 

[Bill K]

I think I will go with the 113 and see what happens.

One more consideration: I am using an old Ultegra triple crank with 170mm crank arms. The left crank arm touches the chainstay because the chainstays are designed for nice, wide tires (which I am planning to take advantage of). I have spacers on the drive side bottom bracket to adjust the chainline to the IGH which gives the crank arm plenty of clearance. I need to add a spacer to the left crank arm to get it to clear the chainstay.
So, a wider square-taper bottom bracket would be better, or shorter crank arms would be better so the crank arm clears the chainstay.

 

[trapdoor2]

One more consideration: I am using an old Ultegra triple crank with 170mm crank arms. The left crank arm touches the chainstay because the chainstays are designed for nice, wide tires (which I am planning to take advantage of). I have spacers on the drive side bottom bracket to adjust the chainline to the IGH which gives the crank arm plenty of clearance. I need to add a spacer to the left crank arm to get it to clear the chainstay.
So, a wider square-taper bottom bracket would be better, or shorter crank arms would be better so the crank arm clears the chainstay.

Yah, I'm running 155mm arms, so that helps. I went ahead with the 113. We'll see what happens when it all gets here.

The rims I'm getting laced to the Alpine are Velocity "Blunt", so mo' widah be mo' bettah.

 

[super slim]

http://www.bikesmithdesign.com/Short_Cranks/apex.html

Will the crank length be 113 mm?

 

[trapdoor2]

http://www.bikesmithdesign.com/Short_Cranks/apex.html

Will the crank length be 113 mm?

No. My cranks will be 155mm in length. With an old-school square-taper BB, you have to choose how long you need the axle to be to get an optimum chainline (between front chainring and rear gear). Because I will be running a single chainring, I don't need much axle width (would need wider if I was running a double or a triple). However, I do need enough width so that the crank arms clear the chainstay as they turn. So, the minimum available axle length is around 103mm and the max is around 120mm. A good SWAG is 113mm, so I went with that.

 

[Jeremy S]

However, I do need enough width so that the crank arms clear the chainstay as they turn.

Your heels will also need to clear.

 

[defjack]

I used a 118 with a triple

 

[McWheels]

113mm on a V2k with Sturmey Archer 33T chainset and SA 8-Sp IGH. It's really clean and straight, rubs nothing, but I must get round to buying those Nukeproof Electrons. Those might be my 2000 mile purchase. Cleared 1900 today. 2 more weeks ought to do it.

 

[McWheels]

I'm liking these Clarks CMD-17 disc brakes. Easy to install and adjust.

Here is Clarks reference for pads for the CMD-17: http://www.clarkscyclesystems.com/p...isk-pads/id-8389c.html?atrr_diskpad_style=620


Apparently these are the same pads used in avid BB5. Anyone have a preferred source for replacement pads?

Discobrakes, http://www.discobrakes.com/?s=0&t=0&
I've got the sintered pads and one of their rotors for a Promax 600, it's way better than whatever was there before.

 

[Rampa]

I wonder if we could get a frame/fork kit with steerer about 15 inches longer? I kind of want to mount my pivot clamp at handlebar level and use a zero reach stem attached to the top slider tube.

I was always curious why an extension tube was chosen instead? Wouldn't a tall steerer in the fork be stronger? And provide more options for the hobbyist?

 

[trapdoor2]

I wonder if we could get a frame/fork kit with steerer about 15 inches longer? I kind of want to mount my pivot clamp at handlebar level and use a zero reach stem attached to the top slider tube.

I was always curious why an extension tube was chosen instead? Wouldn't a tall steerer in the fork be stronger? And provide more options for the hobbyist?

This is a far weaker situation than the standard. The pressure from pedaling would likely bend the extension forward. You want to keep that force vector (top tube) as close to the head joint as possible to create the strongest link between pedals and headset.

 

[DavidJL]

I think the best bet is to do the emeljay mod discussed in the Adventure Series forums. It would be nice if there was a kit to do this. I have done this mod and it produces a very solid, stiff front end. With the extra fork steering tube length, this mod might even be good with the stock seat angle. If I mod the T50, I will post pix.

 

[Rampa]

Yes. But why is there is an extension tube at all? Why not a 2 foot steerer? Then we could do this.

 

[DavidJL]

I guess they could have made the steerer longer. A front derailleur would not work with the boom tube at such an open angle. Maybe they should just build in the emeljay mod from the get-go, making it like the Silvio of yore.

 

[trapdoor2]

First of all, the head-tube has to support the headset bearings. So, it shouldn't be painted (the bearings have to slip over the tube with the least possible clearance, etc.). You could paint the exposed portion after assembly, of course, but most people would prefer to slip an already finished extension over the head-tube. Secondly, I imagine head-tubes for bicycles are manufactured to a common length. Sure, you could order custom...but you pay for that, esp. if you are ordering less than a zillion units. I believe head tubes simply screw into the fork bridge, so presumably you could unscrew it and install your own custom tube if you wanted to. Alternatively, you could simply weld additional tubing to it to get the height you want.