Tangent Giant DH Revival Build

[Balmorhea]

Your tensioner isn't cutting it. It's no substitute for actual fixed chain tension when you use a sprocket that small.

Figure out how to get the overall ratio you want while having at least 20 teeth on the wheel sprocket.

 

[amberwolf]

Mods/anybody, am I posting in the wrong place? Should I try creating a new thread in the "E-Bike Build Threads / Photos & Video" area?

Do you want it moved there?

I don't think it's going to make a difference where it is for the number of posts/replies. That's just up to whoever wants to follow this thread. Anyone that's already posted to it or subscribed to it will be getting notifications whenever a new post is added, regardless. Whether they reply is up to them.


I've probably got hundreds or more subscribed people on some of my threads...but almost never does anyone else post on them (even if I post a question there).

Just how it is.

 

[amberwolf]

Drive train converted to single speed with Chris King 14 tooth single speed rear cog and Surley chain tensioner (up-ward tension mode). KMC Z510 1/8 chain. Still skipping

I dont' have a direct solution, but some advice about the principles that might help you figure one out:

Skipping is about tension, and about number of teeth engaged (as well as shape of tooth vs shape and spacing of chain/rollers). The more teeth engaged, the less each tooth is stressed by the torque, and the less likely it is the chain will climb the teeth to skip.

More pull on the chain, with less teeth, means more tension is required.

More chainwrap (more teeth engaged) means less tension needed for the same pull on the chain.

The more the system skips the more it will damage the tips of the teeth, and the more worn the parts are the worse the skipping will be.


The simplest way to get good tension is not to use a tensioner, but to have just the right number of links in the chain to wrap the teeth you have, which will end up about half of each sprocket covered with nothing but chain and sprockets (no tensioners or guides).

Then use a slotted mount for whatever is at one end of the chain, either wheel or motor, to adjust the tension, and allow installation/removal of the chain.

 

[skidmark]

Thanks for the feedback everyone

Yep. Your cog is small and,
-check chain line alignment
-check for proper chain tensioner on the rear.

Chain alignment is good. 1/8" single speed chain is matched to Chris King 1/8" rear cog. Front chainring is a 36t Raceface N/W 104 bcd. It's a little sloppy on the front but overall not bad.

Your tensioner isn't cutting it. It's no substitute for actual fixed chain tension when you use a sprocket that small.

Figure out how to get the overall ratio you want while having at least 20 teeth on the wheel sprocket.

^This is where my brain is heading. Too small of a rear cog and not enough chain tension. the rear susp. movement is probably not helping either. I think my best move is to up the cog and chain ring sizes to increase the number of teeth engaged.

Do you want it moved there?
...
I've probably got hundreds or more subscribed people on some of my threads...but almost never does anyone else post on them (even if I post a question there).

Just how it is.

Thank you amberwolf. I guess I'm still a little green and overly optimistic on replies Thanks for the feedback I'll just stay here and keep chugging away. The last few replies were most welcome

 

[12-C]

Hey, 3220 motor here..... but it's sitting idle.....

GET YOUR CHAIN RIGHT!!!!

I dropped a chain a few times and had it bind DEAD STOP, it caused the internal aluminum cycloid gears to deteriorate quick.

so now my beautiful tangent drive is sitting as a useless lump...

Have you heard from Dave at all? I know hes up to other things in life.... But I could really use a spare part from him or the designs specs at least to have a new gear milled.....

I don't think I've seen peak W above 3k range on my bike. I've seen 5K range climing in gears that are far too low.... but realistically the bike itself wont last if you are pushing it that hard....imo. It's still a bicycle at the end of the day.

 

[skidmark]

Hey, 3220 motor here..... but it's sitting idle.....

GET YOUR CHAIN RIGHT!!!!

I dropped a chain a few times and had it bind DEAD STOP, it caused the internal aluminum cycloid gears to deteriorate quick.

so now my beautiful tangent drive is sitting as a useless lump...

Have you heard from Dave at all? I know hes up to other things in life.... But I could really use a spare part from him or the designs specs at least to have a new gear milled.....
...

Hey 12-C,
I hear you loud and clear. To answer your question, no, I have not heard from Dave. I have tried emailing but no use as it comes back un-deliverable. Guess he's out of the ebike game unfortunately

That is a real bummer to hear about your chain binding damaging the internal cycloid gears. Good luck finding a replacement (or the specs on the gears). I'm afraid us Tangent owners are left to figure things out for ourselves these days

 

[12-C]

With regard to the chain skipping, I experienced this too, and it turned out to be from the inner chain ring at the crank. The teeth were literally misshapen from the torque. Seemed to get worse and worse with more frequent skipping until finally I jammed my chain... give it a peek.

 

[MadRhino]

If you ride on a problem, you soon ride on a bigger problem, and if you keep going... well, you are the problem.

 

[12-C]

For the rear I went with a sram 990 cassette. The original cassette was a plain vanilla cassette where each cog engaged the freehub independently. This led to me sheering the teeth from the cog on several of the larger ones and damaging the freehub a bit.

The 990 has a solid billet carrier that has a massive surface area to engage the freehub so I don't have to worry about damaging the cog or hub. Also, there are not weak little plastic spacers between the cogs. I went with the 34-11

From what I could tell, I never had skipping from the chainring/cogs, only the drive chainring that the tangent was powering. It seems to be made of some form of soft cheese.

I also designed a spider to allow me to run a hardened steel 74BCD chainring instead of the mild steel 24T stock sprockets that SBP sells....haven't had it machined yet, its still just a file. I made it as close to the stock spacing that tangentdave provided.

 

[Balmorhea]

For the rear I went with a sram 990 cassette. The original cassette was a plain vanilla cassette where each cog engaged the freehub independently. This led to me sheering the teeth from the cog on several of the larger ones and damaging the freehub a bit.

The 990 has a solid billet carrier that has a massive surface area to engage the freehub so I don't have to worry about damaging the cog or hub. Also, there are not weak little plastic spacers between the cogs. I went with the 34-11

Keep in mind that the sprocket teeth on those things are not designed to withstand any more torque than the cassette splines are.

That aluminum carrier is not intended to transmit superhuman forces. It's designed not to chew up aluminum freehub bodies, which a lot of expensive hubs use even though it's a bad idea.

 

[12-C]

For the rear I went with a sram 990 cassette. The original cassette was a plain vanilla cassette where each cog engaged the freehub independently. This led to me sheering the teeth from the cog on several of the larger ones and damaging the freehub a bit.

The 990 has a solid billet carrier that has a massive surface area to engage the freehub so I don't have to worry about damaging the cog or hub. Also, there are not weak little plastic spacers between the cogs. I went with the 34-11

Keep in mind that the sprocket teeth on those things are not designed to withstand any more torque than the cassette splines are.

That aluminum carrier is not intended to transmit superhuman forces. It's designed not to chew up aluminum freehub bodies, which a lot of expensive hubs use even though it's a bad idea.

thats true, but the failure was within the splines, so the cog is obviously stronger. How much stronger? Not sure, but with my type of riding the splines were the weakest link, especially in the larger cog. I'm not expecting things to last forever , just fail less frequently.

 

[briangv99]

Decided to get my Tangent 3220 up and running too, but this time with a more conservative 2.5kW so I could use my EM3EV Jumbo Shark Samsung 35E battery that I use across a few of my bikes.

The Haro 357 NIne DH frame, that I had lying around for serveral years, seemed like a good match for the Tangent and left plenty of space to mount the battery.

At 2.5kW the Tangent is fairly conservative in the power it dishes out, and hopefully will be kinder on the derailleur components.

Even at the lower power level the little Astro 3220 still gets quite toasty. Fortunately the 3220 with its samarium cobalt magnet is apparently safe to 200c.

 

[Tommm]

Decided to get my Tangent 3220 up and running too, but this time with a more conservative 2.5kW so I could use my EM3EV Jumbo Shark Samsung 35E battery that I use across a few of my bikes.

Put another buckle and slide that battery down mate. You will get extra clearance and lower center of gravity.

 

[briangv99]

Put another buckle and slide that battery down mate. You will get extra clearance and lower center of gravity.

Yeah, could look at doing that. But may need to add another Rivnut.

The battery was in the lowest position I could get it when I had the motor raised to tuck in close to the frame. I hit problems with motor drive chain to suspension pivot clearance, so needed to clock the motor downwards, leaving the gap under the battery.

By the way, that strap is just there to take load off the battery cradle that is attached to the frame with Rivnuts/Nutserts. Shark pack are not normally intended to be mounted upside down, so the strap distributes some of the loads back to the frame.

 

[ichiban]

Decided to get my Tangent 3220 up and running too, but this time with a more conservative 2.5kW so I could use my EM3EV Jumbo Shark Samsung 35E battery that I use across a few of my bikes.

The Haro 357 NIne DH frame, that I had lying around for serveral years, seemed like a good match for the Tangent and left plenty of space to mount the battery.

At 2.5kW the Tangent is fairly conservative in the power it dishes out, and hopefully will be kinder on the derailleur components.

Even at the lower power level the little Astro 3220 still gets quite toasty. Fortunately the 3220 with its samarium cobalt magnet is apparently safe to 200c.

IMG_20201129_140835_copy_1152x528.jpg
IMG_20201129_140851_copy_1152x528.jpg
IMG_20201129_140958_copy_1152x528.jpg

briangv99

I really like your whole bike, especially the swing arm. Is it original or do you have it made ? What is the drop-out width ?

My current build is :

++Giant Glory DH build + GMAC + PhaseRunner
https://endless-sphere.com/forums/viewtopic.php?f=6&t=108610&p=1592541&hilit=glory#p1592541

In which the 8T GMAC, Phase Runner, CA3 display from Grin is about to be delivered anytime soon.

I also checked the Chinese QS205 H3 @300w non-geared rear hub with Sabvoton controller but found that it has some drawbacks I don't like personally. One major thing, it requires me to use only 1-speed free-wheel or have to heavily modify the swing arm. It requires a mininmum 150-mm drop-out clearance just to fit a single speed free wheel. Not to mention that the QS205 hub itself is not ready for 8/9/10-speed modern cassette mount. The QS factory probably think that the rider is not going to peddle much anyway.

So I chose the 8T GMAC route with considerably less power/speed but with reasonable amount of build works for me. Plus, may be a little better regen braking power (with some tweaks). But Grin's response is terrible, sometime I can have answers I need from emailing with them like 2-3 time a month !! Hopefully, when I need service or parts from them, their service will be improved. It is bad for business when customer think you can hugely improve. IMHO, this is one major thing the Chinese win trade battle, their response is very fast in general (hours or 1-2 days max).

My battery will be mounted under the downtube too. May be by custom FRP. But after seeing your mounting, I am kind of interested since it will be a whole lot easier than the custome fiberglass case. My 1st 27.5" BBSHD MTB (14S5P x LG 18650MJ1) also have the pack mount underneath the downtube, hung with 3 brackets - still going super strong after 10k kms.

My problem is, LG18650HG2 (planned 20S4P = 8xxwh) is not avail to me from my usual reliable supplier in China. They are 2018-era mfg lot and might be somewhat deteriorated from 2-3 year sitting. So I might have to go for Samsung 21700-40T (lot June 2020, planned 20S3P for 8xx wh) with slightly bigger, heavier and more $$ pack. This is for my usual ride of 50-60kms range max and won't stress the cells that much. I can mount a spare 2nd pack (may be 20S2P or 3P) above the front wheel, OR rear frog case, OR rear rack for extra range. Just have to get the build done asap. Covid-19 has delayed this build for over half a year already.

briangv99, do tell us more about your bike ride. Would like to hear how it performs, handles and all that.

 

[Tommm]

Put another buckle and slide that battery down mate. You will get extra clearance and lower center of gravity.

Yeah, could look at doing that. But may need to add another Rivnut.

The battery was in the lowest position I could get it when I had the motor raised to tuck in close to the frame. I hit problems with motor drive chain to suspension pivot clearance, so needed to clock the motor downwards, leaving the gap under the battery.

By the way, that strap is just there to take load off the battery cradle that is attached to the frame with Rivnuts/Nutserts. Shark pack are not normally intended to be mounted upside down, so the strap distributes some of the loads back to the frame.

Didn't know you had nuts holding it. I go under downtube and straps only. But my straps are quite beefy, cargo straps. The only thing I have to do is some zipties to stop it from going side to side.

 

[Xtr6]

Tangent is still awesome to drive. I also own a LMX-64 but the Tangent is more power al the way. The main problems are keeping the chain in one piece. :wink:

 

[Tommm]

Tangent is still awesome to drive. I also own a LMX-64 but the Tangent is more power al the way. The main problems are keeping the chain in one piece. :wink: WhatsApp Image 2020-04-10 at 21.26.04(1).jpeg

A matter of trading torque for rpm. Then use a big rear cog to multiply it back up to the same wheel rpm.

 

[briangv99]

briangv99

I really like your whole bike, especially the swing arm. Is it original or do you have it made ? What is the drop-out width ?

My current build is :

++Giant Glory DH build + GMAC + PhaseRunner
https://endless-sphere.com/forums/viewtopic.php?f=6&t=108610&p=1592541&hilit=glory#p1592541

briangv99, do tell us more about your bike ride. Would like to hear how it performs, handles and all that.

Hi Ichiban, apologies for the slow reply.

The bike rides and handles great as is, but I'm trying to refine some of the details to make the Tangent more or an all round package that I can pedal in unison with rather than just a full on high power dirt bike. That's why I've toned down the power from how I was running it previously at 6kW, attached my jumbo shark battery to the frame and added shiftable gears as opposed to the single speed setup I had before.

The swing arm is the original Haro part with no modification. The angular design just looks a little home made. The drop out width is 150mm with a 12mm through axle. The dropout are removable, so you could make your own and bolt them on to accomodate a GMAC.

Speaking of GMAC builds you might like my other bike here

https://endless-sphere.com/forums/viewtopic.php?f=6&t=109158&p=1602734&hilit=gmac#p1602734

I've gone with a Nucular 12F controller rather than a Phaserunner for a bit more grunt.