Strong freewheeling crankset

[skyungjae]

I think another resource we should be looking into is what the EGO kit uses. From pictures, I can tell they use ECHO trial cranks, but the big mystery is the bottom bracket.

 

[full-throttle]

I think another resource we should be looking into is what the EGO kit uses. From pictures, I can tell they use ECHO trial cranks, but the big mystery is the bottom bracket.

In their promo video it looks like rider's foot slips off the pedal OR the spindle breaking on the big drop
/viewtopic.php?=23244

 

[flyinmonkie]

Maybe this got missed with the excitement about the flanged freewheel, so I'll post it again with a pic.



http://www.trialsaddict.com/special-offers/echo-isis-hd-bottom-bracket.html

Clay

 

[skyungjae]

I may try the TruVativ Giga Pipe Team DH 128mm spindle with one of the ISIS trials arms if I come about some spending cash in the near future. Until then, I'm just going to have to suck it up.

 

[wildharemtbkr]

Flyingmonkie, looks like a great bb, but notice the last line. :?

Echo IsIs HD Bottom Bracket Only £34.99

Echo IsIs HD Bottom Bracket Read More...

Price: £34.99

BUY IT Description
Echo IsIs HD Bottom Bracket

Echo's heavy duty machined aluminium bottom bracket features 128mm chromoly axle and outboard bearings inserted into specially machined cups.Outboard bearings are those which sit outside of the bottom bracket shell, which results in less load and stress on the bearings, prolonging the life of the bottom bracket.

Fits a standard 68mm bottom bracket shell.

IsIs fitment only.

Special tool required for fitting.

Available in anodised black only.

Supplied with stainless steel Echo crank bolts M15.

Weight:

355g (including bolts)


Please note:

This bottom bracket is not compatible with front freewheels.

 

[flyinmonkie]

Has that stopped us before? ha ha. I was just looking at pictures, and not reading descriptions. Doesn't mean it can be made to be suitable. Worth a shot.

Clay

 

[wildharemtbkr]

Haha good point! I like the outboard bearing, but I think the bearing and the freewheel would be trying to share the same space. I have a pair of Isis trials cranks I want to put on my norco, but I think I'll go with the gigapipe bb. I'll post up some pics when I get it going.

 

[skyungjae]

Haha good point! I like the outboard bearing, but I think the bearing and the freewheel would be trying to share the same space. I have a pair of Isis trials cranks I want to put on my norco, but I think I'll go with the gigapipe bb. I'll post up some pics when I get it going.

Looking forward to it. :wink:

 

[xadmx]

sorry if this is hijacking the thread, has anyone used a sprag bearing for the freewheel on the crank.
adam

 

[spinningmagnets]

Sprague/CSK-PP has been discussed, just that nobody has fired up a lathe to put one together for a beat-down test. I like the idea.

Flyinmonkie, the Echo ISIS heavy-duty BB you posted might be difficult to find a way to put a freewheeling pair of chainrings to, but they would be awesome for a full suspension frame that had a left-side chainring for a "crossbreak" style of drive, where a MAC motor was acting as a jackshaft. There would still be driveline "issues" to sort, but I am confident that it would be doable.

 

[spinningmagnets]

I don't know what BB cartridge AFT uses, but it has to at least a little better than the "lowest bidder" cartridge that the GNG comes with...

edit, they are $133, and the square shanks have no taper. They are used with very strong BMX crank-arms.

...Offset Bottom Bracket Cartridge 153 mm fitted with hybrid ceramic bearings that helps increase drivetrain efficiency...

http://www.af-tech.com.au/Products_Ebikes.html

 

[skyungjae]

I don't know what BB cartridge AFT uses, but it has to at least a little better than the "lowest bidder" cartridge that the GNG comes with...

...Offset Bottom Bracket Cartridge 153 mm fitted with hybrid ceramic bearings that helps increase drivetrain efficiency...

http://www.af-tech.com.au/Products_Ebikes.html

$133 Standalone price

Yeah... I don't know about that one.

Edit: Actually, for those who are planning to use GNG's chain rings it's not too bad.

 

[spinningmagnets]

From Chalo:

19-22mm bottom brackets come in both inboard and outboard bearing varieties

LightningRods found these 19mm diameter shafts, CroMo with hollow center, for $79. The longest model is 6-7/8 inch long (6.875, 174mm):

$79 ChroMo hollow shaft, 48-spline, 6-7/8-inch / 174mm long (also avail in: 5.2/133mm, 5.6/143mm, 6.0/152mm
http://www.profileracing.com/estore/product.php?productId=343

Here's a German 165mm wide BMX shaft that's similar, 36-spline, 23-Euro
http://www.bike-mailorder.de/Bike-T...komplett/Gusset-Pigmy-OKR-Achse-fuer-MTB.html

I like the idea of the outboard bearing cups allowing bigger bearings, but...the internal (smaller) bearings of common cartridges have not been a failure point yet, it has been mainly the shafts bending when a hardtail takes jumps.

The 19mm shaft link took me to these: $47 bearing cups from Profile for the 19mm CroMo shafts, and the bearing cups are the normal width (because the bearings are internal), so we might have enough shaft space to attach a FW adapter to the shaft instead of the crank-arm (like the crank-arm FW adapter listed nearby). Although these cups have the smaller internal style, they have 4 bearings to try and make up for it, plus, they DO include lockrings to hold the GNG-style bracket onto the BB-shell.

http://www.profileracing.com/estore/product.php?productId=64

$55 from Odyssey for the same. http://www.chainreactioncycles.com/Models.aspx?ModelID=51865

This site also has the bearing cups that use bigger outboard bearings, but as Chalo pointed out, that makes a 68mm wide BB into an 86mm wide, wasting 18mm of precious shaft space.

Good pics of installation http://www.parktool.com/blog/repair-help/bmx-three-piece-crank-service

Also, the same site has 48-spline spiders for 104-BCD sprockets (sprockets 32T-48T available)

Something like this would allow me to attach the FW to the shaft instead of a trials crank-arm.

 

[spinningmagnets]

On a completely different path: ES member elation was selling these from Australia for $250 using a CSK-PP clutch-bearing. Since it was the #35 size, I seem to remember it can take an adequate level of power?

http://endless-sphere.com/forums/viewtopic.php?f=28&t=21248&start=15#p310370

 

[skyungjae]

I emailed Kranked and ebikessf about the BB used on the EGO kit. Hopefully they'll be willing to give up the information whether it's proprietary or not. At the very least, the length of the spindle would be a great information.

IF, and that's a big IF, there is an off the shelf ISIS BB that'll work with the GNG mount and other mid drives, we'll be able to bullet proof the kit for off road use.

 

[Miles]

On a completely different path: ES member elation was selling these from Australia for $250 using a CSK-PP clutch-bearing. Since it was the #35 size, I seem to remember it can take an adequate level of power?

Well, there were several failures reported.... You shouldn't expect to be able to use a single CSK unit without further bearing support.

 

[skyungjae]

On a completely different path: ES member elation was selling these from Australia for $250 using a CSK-PP clutch-bearing. Since it was the #35 size, I seem to remember it can take an adequate level of power?

Well, there were several failures reported.... You shouldn't expect to be able to use a single CSK unit without further bearing support.

I think failures are going to be the end result without proper maintenance and replacement regardless of going with a clutch bearing or freewheel. Chains will stretch and wear down other drivetrain components long before they snap. I'm not sure about the clutch bearing, but the freewheel, like a chain/pads/fork oil/etc, should probably be changed out on a regular basis (annually w/ proper cleaing?) before a potential lock up and bruised shins/calfs.

 

[Miles]

I think failures are going to be the end result without proper maintenance and replacement regardless of going with a clutch bearing or freewheel.

Early failures are usually the result of design and specification by the clueless....

 

[skyungjae]

I think failures are going to be the end result without proper maintenance and replacement regardless of going with a clutch bearing or freewheel.

Early failures are usually the result of design and specification by the clueless....

Very true... not to mention poor quality control sometimes like budget chains. It is not fun when a chain snaps while pedaling uphill the on the first ride.

 

[gestalt]

couldn't you go extra long on the BB to provide space for the support bearing and the motor mounting sheets? your crank arms would be farther apart but that's usually the way we like to run them anyways. then you do have to worry about chain line issues like I am having with my gng that only allows me to use my top five gears. I plan on spacing out the chain ring closer to the center with longer bolts and stacks of washers.

 

[Miles]

Let's review the kind of idiot the guy at Elation was:
http://endless-sphere.com/forums/viewtopic.php?p=216640#p216640

 

[skyungjae]

no dice from ebikessf regarding the BB used in the EGO kit. They no longer carry that kit anymore. I emailed the EGO rep, but I doubt they'll respond since this could potentially hurt their sales. :lol:

 

[full-throttle]

Just installed the b.bracket. Will take photos and install the rest. I recently switched over to Linux, so may not be able to upload the photos till Monday. Hehe

 

[flyinmonkie]

couldn't you go extra long on the BB to provide space for the support bearing and the motor mounting sheets? your crank arms would be farther apart but that's usually the way we like to run them anyways. then you do have to worry about chain line issues like I am having with my gng that only allows me to use my top five gears. I plan on spacing out the chain ring closer to the center with longer bolts and stacks of washers.

It is a double edged sword. Space is needed for chainrings, freewheel crank, support bearing. But, the longer the BB shaft, the more leverage on the ends and the easier it bends. So for a stronger BB it needs to have a shorter shaft.

Clay

 

[spinningmagnets]

Part of the reason I posted the 19mm tube BB-shaft is that they are CroMo, and also in some ways, a tube can be stronger than a solid rod of the same diameter. I believe there is a good chance these will be as strong as anything else out there.

Good that several different avenues are being researched, never know ahead of time which one will pay off...