Voicecoils's 2nd build: Giant DH Team

[voicecoils]

Voicecoils's 2nd build: Giant DH Team (7" travel up front, 8" travel in the rear)

[EDIT] Save yourself the trouble of slogging through this thread and jump straight to the electrified DH Team's new home with Mark_A_W here:
http://endless-sphere.com/forums/viewtopic.php?f=6&t=15439


Here are the specs:
FRAME: 2004 Giant DH Team
REAR SHOCK: Manitou Swinger 6 way
FRONT FORK: 2002 Marzocchi Super T Pro
WHEELSET: 24" Alex DJ rims w/ novatec hubs
CASSETTE: 9spd Shimano LX (w/ rapid fire shifter)
CRANKS: Shimano Saint (38t chainring)
BRAKES: Hayes HFX-9 HD hydraulic rear (front brake and 8" discs yet to be bought)
(plus a seat, seatpost, stem, handlebars & pedals of course and a few more links in my chain!)

I'm building up this bike as the second bike I hope to electrify using the same batteries purchased (but waiting to receive) from John @ e-mtb.com.au for my red rigid project. If you're not into downhilling, the Giant DH Comp & Team were extremely popular race bikes for a good few years till the Giant Glory and Ironhorse Sunday World Cup got a foothold as the dominate weapons of choice.

The batteries are two packs of 36v 10ah each which can be wired in series or parallel and are capable of 40-50a discharge. With a cell voltage of 3.2v, total power available is therefore 3072-3840 watts at either 76.8v (72v nominal) or 38.4v (36v nominal). I mention this because of design considerations to be explored further on.

 

[voicecoils]

Battery Placement:

Using my mockups of the batteries I'm waiting on, here's some placement options I've tried that don't interfere with the forks or pedaling:

View attachment 2
View attachment 1

 

[voicecoils]

Motorising:

I'm tossing up between two options:

RC motor drivetrain with 2 stage reduction (all mounted on the rear swingarm) driving a sprocket mounted to the LHS of the rear wheel on the disc brake mount. Possibly using the Top Hat adapter http://search.ebay.com/_W0QQsassZandyinchville

OR

Crystalyte 5-series with a lot of hassle to get it to work with my 135mm wide 12mm hollow thru axle setup on the rear end. Essentially I would need to either cut off the current drop outs and weld standard vertical dropouts in place or cut down the 5-series axle length and weld plates to the axel ends that could then be bolted to the rear end with another adapter. (I'll try to do some sketches of what I mean)

Both would require a fair bit of work. I need to make a decision based on what will give me the most torque and speed for the 3.1-3.8kW of available.

Here's the rear swingarm, a decent amount of space (even with the pedal in the worst part of it's stroke):

 

[voicecoils]

I'm at the stage where the bike is almost ride able and so I need to make decisions on how to turn it in to a fun ebike

Any suggestions on components or design choices to get the most acceleration, top speed & hill climbing ability out of the power my batteries can provide is much appreciated. In otherwords, I wish to maximise system efficency to maximise performance.

If I go for an RC motor system, I'll need to either choose a motor & controller combo that can run at 38.4v (80-100a) or 76.8v (40-50a). Along with this, a 2 stage reduction gearing, likely with belt (first stage) to chain to wheel (second stage).

If I go for a xlyte 5-series, I need to decide which one for my 24" wheels, then figure out how the heck to get it mounted to the bike

Ideally I'd like to be able to accelerate briskly up to 65kph (40 mph) but don't see a real need to go any faster. And enough torque to pop wheelies off the line. Perhaps I'm dreaming

 

[voicecoils]

holding

 

[AussieJester]

Damn thats a SERIOUS MTB buddy :-| Themz the forks i would LOVE to have on my project...An R/C setup on this would be awesome albeit alot harder to do i think (technically wise...as you can't simply buy everything off the shelf and fit it it needs to be made) Best of luck anywayz

 

[voicecoils]

Damn thats a SERIOUS MTB buddy :-| Themz the forks i would LOVE to have on my project...An R/C setup on this would be awesome albeit alot harder to do i think (technically wise...as you can't simply buy everything off the shelf and fit it it needs to be made) Best of luck anywayz

Cheers! I think there is enough space to package it all in on the rear swingarm, and could get me quite a high power/weight ratio.

Want to help me put together a gearbox for it? (I don't have access to a workshop or even a garage, damn Sydney housing costs )

 

[AussieJester]

Want to help me put together a gearbox for it? (I don't have access to a workshop or even a garage, damn Sydney housing costs )

Would love to if i had access to the necessary machinery alas i dont anymore... the man you want to get on the good side of is Recumpence (Matt) he has mad skills and the ducks nuts machinery at his disposal .... Only other option for your particular bike i think would be to autocad the design your after and have a local machine shop knock it up for you hopefully reasonably cheaply, that bike definitely deserves something special don't it! best of luck mate fingers crossed for you

 

[johnrobholmes]

I have some ideas for the bike. Can you measure the triangle of the rear swingarm? My gearbox may fit into the side of one of your swingarm, or at worst mount on top. The top hat adapter will be your best bet for having both disc brakes and a separated gearbox design.

Realistically I don't think 40mph top speed and hill climbing will be available with the same setup without multi speeds. You can regear, but if you have it set for 40mph you will be pulling a ton of amps going up hill.

Very nice bike mate, very nice.

 

[lawsonuw]

I think the e-bikes.ca frame bag and triangular battery would fit in the front of your bike's frame.

I second the motion to put an RC based system it that bike. A 53xx would be way too much weight. I see space to hang the motor under the downtube of the bike in front of the cranks. Unfortunately the down tube is some funky shape so mounting would be a pain. The other good spot I see is mounting the motor on the left side of the rear suspension arm similar to an I-zip.

Marty

 

[recumpence]

Voicecoil,

VERY nice bike! My next build is a similar bike. :wink:

Obviously I am partial to RC components. However, the complexity is a bit high. But, you are rewarded with high power to weight ratio.

My recumbent is geared for 40mph top speed. It climbs very well, but, that is on pavement. You can achieve climbing and 40mph top speed with RC components, but it will be expensive.

The best controller for RC applications is the Castle Creations HV110. It goes up to 50 volts max. The best motor I hvae found is the Plettenberg I am running. But, it is $1,000 US! Super spendy. You can go with an AXI 5345 and get very good performance if you can deal with a touch of quirkyness at 1/3 throttle (odd back EMF issue with that motor). It is cheap and very powerful.

If you go with RC components, you really should go with lithium cells for weight savings. Again, spendy. But, that bike was not cheap either.

I think a 30mph top speed with good climbing would be a decent achieveable setup.

John's gearbox may be a good option for you considering the size requirements. My reduction may work too. Bear in mind, there will be a bit of fabrication (hand work) needed to get any RC system on that bike. It would be worth it, though.

Again, VERY nice bike!

Matt

 

[deecanio]

Hi voicecoils,

amazing bike, you have the choice of hub or rc setup which is exactly the same as me right now, very similair setup too.
Having watched matt,scott and miles i would say wait just a little longer (if you can) until matt has had some time to work in his shop on a gearbox that all rc adopters can try (by the way matt thats the best piece of news ever that your looking at this, sorry i havent had time to post recently to extend a big thank you). if matt comes up with something that is fittable to a lot of bikes (say seatpost mount) i think you'll see an exodus from hubs to rc because of the power to weight advantage and size of controllers.
however without the skills to build your own or buy from matt i think it will be a long long journey to engineer things just so from various places and get it all to play nicely together.
i have the same bike (dh) and i've chosen to go with another puma hub this time for the reasons above but mainly because i can put the hub in easily into 135mm drops, then thrash the crap out of it, then put it in the bin once matt answers all my prayers!! whats the size of your dropouts anyway? you have more choice of hub than an x5 i would think at 3kw also? less weight too - you dont say whether you plan to ride on or offroad?
If you dont mind me saying i would look again at your battery choice/ mounting more closely - it seems a shame to have a great triangle for them then mount them on the sides? im saying this because its exactly where i was with my two large blocks, not very nice and if you haven't committed to batt buy yet i would say at least look into a custom pack first?
Anyway just my 2 cents to try to help you avoid mistakes i made
bike looks cracking and looking forward to the build


Cheers,


D

 

[voicecoils]

Would love to if i had access to the necessary machinery alas i dont anymore... the man you want to get on the good side of is Recumpence (Matt) he has mad skills and the ducks nuts machinery at his disposal .... Only other option for your particular bike i think would be to autocad the design your after and have a local machine shop knock it up for you hopefully reasonably cheaply, that bike definitely deserves something special don't it! best of luck mate fingers crossed for you

no worries. "local machine shops" aren't much of an option in Sydney anymore (that I know of). If you can find one where they are able to speak English AND consider taking on small jobs / one offs then you're stuck paying monster set up and labour fees.

I'm looking into Matt's "gearbox for the rest of us" design. If it does fit, that would be great, otherwise I'll try to find a local solution.

 

[voicecoils]

I have some ideas for the bike. Can you measure the triangle of the rear swingarm? My gearbox may fit into the side of one of your swingarm, or at worst mount on top. The top hat adapter will be your best bet for having both disc brakes and a separated gearbox design.

Thanks for taking the time to post

I'll get the rear swingarm measurements and post them up here. I picked the frame because I've ridden models from a few years perviously & they still have one of the most uncluttered designs out there. The shock is quite out of the way but still gives a plush 8" of travel. I'm sure there will be a way to get something working on it. Going to 24" wheels has given me a bit more clearance too.

The top hat adapter looks good but I'd really like to se someone who's squeezed a #35 chain AND a hydraulic disc caliper in that space. If it does work though, that's fantastic.

 

[voicecoils]

I think the e-bikes.ca frame bag and triangular battery would fit in the front of your bike's frame.

I second the motion to put an RC based system it that bike. A 53xx would be way too much weight. I see space to hang the motor under the downtube of the bike in front of the cranks. Unfortunately the down tube is some funky shape so mounting would be a pain. The other good spot I see is mounting the motor on the left side of the rear suspension arm similar to an I-zip.

Marty

The triangular bag should fit, yes. I've already ordered and paid for the battery packs from e-mtb.com.au however. (shown mocked up in the posts above) I'm just waiting for them to arrive.

Thanks for your vote on the RC system. If so I think I NEED to have it mounted on the swing arm, otherwise I'll have a hard time dealing with chain-growth due to the long travel suspension.

 

[voicecoils]

My recumbent is geared for 40mph top speed. It climbs very well, but, that is on pavement. You can achieve climbing and 40mph top speed with RC components, but it will be expensive.

The best controller for RC applications is the Castle Creations HV110. It goes up to 50 volts max. The best motor I hvae found is the Plettenberg I am running. But, it is $1,000 US! Super spendy. You can go with an AXI 5345 and get very good performance if you can deal with a touch of quirkyness at 1/3 throttle (odd back EMF issue with that motor). It is cheap and very powerful.

If you go with RC components, you really should go with lithium cells for weight savings. Again, spendy. But, that bike was not cheap either.

I think a 30mph top speed with good climbing would be a decent achieveable setup.

Thanks for checking in with your ideas and suggestions I'm stoked to get this project off the ground.

Power to weight, and keeping weight off the wheel is what appeals to me. I want to mount RC drive system on the swingarm which will increase my unsprung weight, but hopefully not nearly as much as an ~11kg (~25lbs) Crystallite 5-series.

Ok, Castle HV110, I've seen that in your build & Karen's moped. Looks good and can be bought from castle's website direct. I could only feed it 38-39v and 80-100 amps however. So I would not be able to max out its potential.

What's your opinion on their Neu motors? Do their 1915 series have much street cred? They are rated a max 3.6kw which is about perfect for the power my batteries can output. I don't know how long that "surge" rating would last if run continuously.

I'd like to go for lithium poly cells but I've already paid for my Lifepo4 packs. Two 36v 10ah lifepo4 packs wasn't too cheep either :? :lol: Perhaps at some point in the future I can simply stuff the entire front triangle with a 1-wide stack of A123 cells. Quite a few could fit in there The bike hasn't been a "cheap" build so far, but everything bar the wheelset has been second hand. Very high quality DH equipment looses value quite fast as new year model equipment comes out.

I plan to use the bike probably 3/4 of the time on pavement, 1/4 of the time on trails. Until the system is running and proven stable I don't plan to ride it through and rough DH style tracks. 30mph would be fine I suppose, especially if acceleration was awesome, but on the road I can pedal up to 31-34mph (50-55kph) down small hills on my 8 kg road bike already. I'd hope my motorised system would be a bit better then pedal power alone

 

[voicecoils]

i have the same bike (dh) and i've chosen to go with another puma hub this time for the reasons above but mainly because i can put the hub in easily into 135mm drops, then thrash the crap out of it, then put it in the bin once matt answers all my prayers!!

whats the size of your dropouts anyway? you have more choice of hub than an x5 i would think at 3kw also? less weight too - you dont say whether you plan to ride on or offroad?

If you dont mind me saying i would look again at your battery choice/ mounting more closely - it seems a shame to have a great triangle for them then mount them on the sides? im saying this because its exactly where i was with my two large blocks, not very nice and if you haven't committed to batt buy yet i would say at least look into a custom pack first?

Puma sounds like a good hub motor, I'm setting up a Bafang PMGR on my commuter bike to run at 72v. I can't just drop a hub motor into my frame though. It IS 135mm dropout spacing, but uses a thru axel instead of a drop out of any kind.

What alternative hub motors do you think should be considered at 3-3.8kw?

As in the post above, I plan to ride 3/4 on pavement, 1/4 on trails. I won't be doing any DH riding on the bike till everything is proven reliable and sturdy.

Unfortunately I have already committed to the batteries (and their accompanying form factor). I'll look again though at how I could squeeze it all in more nicely.

Thanks for your input and suggestions. I'm learning lots as I go along

 

[johnrobholmes]

I have a Neu 1915 right here in hand. I am also a distributor for Neu and Castle products if you need some shipped out to you, I can do it in one box and save you some cash at least.


I can't say just how nice the Neu will work, but for the price and size it is a very fine motor for the task at hand. The gearbox I am working on is made just for the 1915. Judging by the power, I think it will be the PERFECT motor for the job. My only concern is how well the gears will hold up to the power!

 

[voicecoils]

I have a Neu 1915 right here in hand. I am also a distributor for Neu and Castle products if you need some shipped out to you, I can do it in one box and save you some cash at least.

I can't say just how nice the Neu will work, but for the price and size it is a very fine motor for the task at hand. The gearbox I am working on is made just for the 1915. Judging by the power, I think it will be the PERFECT motor for the job. My only concern is how well the gears will hold up to the power!

I will definitely be keeping this in mind. Let me know how you go with the gearbox.

Here are the rear triangle dimensions:

top member is ~340mm long
bottom member is ~300mm long
smallest gap between members: 16.8mm (at the wheel end)
largest gap: ~95mm (towards the bottom bracket)

the rectangular tubing is 32.3mm high and ~18.3mm wide.

the closest distance between the RHS and LHS of the rear triangles is ~95 mm wide and it's 135mm wide at the drop outs.

I will try to get the dimensions on to a photo of the bike later today.

 

[voicecoils]

here are some borrowed photos of the same frame, stripped:

View attachment 2
View attachment 1

From flicker member: http://www.flickr.com/photos/erikkellison/

 

[johnrobholmes]

VERY interesting suspension pivot. I like the sharply rising rate geometry of it, it would allow a simple shock with minimal valving.

 

[voicecoils]

VERY interesting suspension pivot. I like the sharply rising rate geometry of it, it would allow a simple shock with minimal valving.

You should check out the Giant Glory's virtual pivot point linkages if your interested in well executed suspension.

What are the expected dimensions of your gearbox? Perhaps I can make a cardboard/foam mockup of it and play around with potential placement possibilities.

from: http://www.flickr.com/photos/callumwalls/

 

[deecanio]

HI Voicecoils,

yes i see your dilemna with the straight through axle at the rear, i suppose maybe you could make up some suitably thick torque arms and mount them somehow? i find the brake side is easy as there's two bolts there already to provide support but the drive side is a bit more tricky, i only have a 20mm through axle at the front with bogo fitting at the back.
Sounds like both Matt and Rob are looking at the reduction box so fingers crossed we will be able to lose our hubs and have rc motors which would be amazing - it's all positive for making the switch not least the weight.
Very excited about the build and looking forward to seeing it all come together - this will be an awesome build
Keep us posted !!!!!


Cheers,


D

 

[AussieJester]

Damn Voicecoils, i soooo want them forks mate.... :: sigh ::

 

[deecanio]

Hi Kim,

have you looked on ebay for some forks, i found mine there and they were pretty reasonably priced, you'll find all the different types there, marzocchi,fox,etc and most are affordable especially if you go for 02's -04's - watch the steerer tube length though - a lot have been cut for a specific bikes.

Cheers,

D