Belt drive Sprockets on the Cheap!

[Miles]

It might be a good idea to work out a standard specification for pulleys?

 

[boostjuice]

Yes we could do this once we know the tooth profile wall thickness (not specified in the datasheet).

The first person who gets one of these in their hands, please measure it and let us know

 

[Miles]

Yes we could do this once we know the tooth profile wall thickness (not specified in the datasheet).

- 8mm pitch HTD tooth profile.
- Internal diameter = outer diameter minus 12mm
- 6 x 6mm holes on 5-1/4" (133.35mm) diameter circle.
- 4-9/16" (115.89mm) registration diameter.
- Web thickness 3mm?
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-
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[Miles]

but a 6inch rotor combo would fit from my quick measurements.

What is the max. clearance likely to be needed around the calliper when using a 6" rotor? Radial and lateral.

 

[boostjuice]

but a 6inch rotor combo would fit from my quick measurements.

What is the max. clearance likely to be needed around the calliper when using a 6" rotor? Radial and lateral.

For the following example, the 160mm caliper/rotor assembly could protrude ~15mm laterally into the cavity of a sufficiently large OD pulley, allowing a 2mm clearance between the caliper mounting points. This example would then fit radially inside 84>90T pulleys (84T: 212.53mm OD - [2 x 6mm wall thickness = 12mm] = 200.53mm ID, 2 x 98mm caliper radius = 196mm = 2.265mm clearance)

 

[Miles]

Thanks a lot bj. I'll model that up, later.

 

[recumpence]

Thanks a lot bj.

Hmm, "BJ" is not a nick-name that is, shall we say, desirable, here in the US. :wink:

Matt

 

[Miles]

It never occured to me

Better tell this guy: http://www.bj.org/about-bj/mission/

 

[boostjuice]

Rest assured, my true initials/nickname aren't BJ at all. 'Boostjuice' - It's a pretty crappy hangover username from my long past days of frequenting WRX forums ("Boostjuice" is an Juice bar franchise in Australia ). I just couldn't be bothered thinking up something new and equally lame when I migrated over here. :lol:

 

[recumpence]

It never occured to me

Better tell this guy: http://www.bj.org/about-bj/mission/

Now, now, Miles....... Are you daring to breech the religion topic here and in someone else's thread?! :wink:

I am just funnin with you Guys about the name thing. It just struck my funny-bone.

Matt

 

[Miles]

 

[katou]

Okay, I've spent some time looking at my bike wheel, and I can't figure out what the offset is for.

I know it's probably a dumb question, but why do we need an offset in the sprocket carrier?

Katou

 

[Miles]

I know it's probably a dumb question, but why do we need an offset in the sprocket carrier?

If there's room for the pulley and belt line within the frame, without an offset, and you're not using a disc brake as well, then you don't need one.

 

[katou]

Ah, so the offset moves the sprocket CLOSER to the wheel by taking advantage of the fact that the spokes are slanted.

On a non-dished wheel for example, there would be no need to have an offset. Correct?

Katou

 

[boostjuice]

Ah, so the offset moves the sprocket CLOSER to the wheel by taking advantage of the fact that the spokes are slanted.

On a non-dished wheel for example, there would be no need to have an offset. Correct?

Katou

Technically a 'dished' wheel just has differences between the lateral spoke angle LHS vs. RHS. So even 'non-dished' wheels have a lateral spoke angle that allows some inbound pulley offset to allow best placement for frame/tyre clearance.

 

[amberwolf]

Or maybe if you have a really fat tire and need to move it out the other way?

 

[Miles]

I've posted the model for this version.
http://www.endless-sphere.com/forums/viewtopic.php?p=396929#p396929

It's probably the most suitable one to use with the split pulleys.

 

[boostjuice]

So is this revision sized to fit around the 160mm rotor/caliper dimensions I posted?

 

[Miles]

So is this revision sized to fit around the 160mm rotor/caliper dimensions I posted?

No. I was more concerned about clearance on the other version. I haven't had time to properly check that out, yet. I thought I'd upload something to get some feedback. Is STEP format any good for you?

Free STEP file viewer: http://stpviewer.com/

 

[boostjuice]

I can convert it to DXF at work. Was just using 'STP viewer' here at home, but it doesn't show dimensions so I couldn't tell.

 

[Miles]

Here's a quick section view:

 

[boostjuice]

Thanks So this version has the same offsets as the 5x130mm BCD adaptor you sketched for Matt's production?

 

[Miles]

They're similar. This has slightly less minor offset because there are 2 x 2 offset positions.

We could probably reduce the diameter of the disc brake mount section a bit?

 

[boostjuice]

We could probably reduce the diameter of the disc brake mount section a bit?

Well it looks like the adapter ID around the hub interface is 59mm ID assuming i'm right in interpreting the wall thickness as 4mm inwards from the 67mm OD.

Of three different brand/model disc brake hubs i've measured, two of the ISO 44mm interfaces are 52mm OD, and one is 52.5mm OD. I'm guessing there could be a bit of variation out there amongst hub manufacturers, so it would be wise to leave a bit of extra clearance for the odd "freak" hub that a user may encounter. Is there any advantage to going smaller than 59mm? Other than the tiniest of weight savings, it doesn't seem to cause clearance issues the way its currently designed.

 

[Miles]

ID is 60mm (3.5mm wall). Unless you can envisage a situation where the OD might interfere, let's leave it as it is.

Did you ask Pfeifer if they supply any existing resellers with non-split pulleys?