PROJECT no 4 Doc's Giant DH comp 2003

[Doctorbass]

You've got your setup really stiff, DH bikes are often set to sag 20% just sitting on them. Think Dmitrii's bike. You're on 26" rims and the hookworms are a pretty tall, fat tyre. Basically your set up to be as far from the ground as possible.

I think you could make it work on 24", but I don't see massive benefits in using that size wheel to compromise other aspects of the bike just to use them. There are very strong 26" rims and if you want more "thrust" just increase the current limit on the controller instead of downsizing the wheel size... Just my opinions.

Dmitrii's was more like 80% sag...

He's now changed from a 300 to 450lb spring.

We aren't downhilling on these bikes, we're pissfarting about at high speed on ashphalt. I could go an ever stiffer spring


The ride is better on 26". 24" looks cooler.

But pedal strike is bad news, I'm staying with 26".


Doc, for perspective, I weight 90kgs and want my bike set up pretty stiff (think sportsbike rather than downhiller).

So if you weight less than me, a 600lb spring will be too much for you.


Mark

Thanks for that!.. I might just re adjust the air pressure on the manitou rear shock. it seem a bit low and have less damping.

 

[Seriousknot]

Doc, your bike doesn't look Giant, she only looks merely enourmous!!! A very small joke. But seriously, I was wondering how many cells you will be using? What voltage level and controller setup? I just realized that you and I are building similar projects. You, however, have much more experience than I do, so it might benefit me to pay attention to how you progress. I will do my best to assimilate your knowledge. Hope you don't mind.

 

[damcard]

I decided to go to 26", hence my rims being available.

 

[Doctorbass]

I want the look of the stealth bomber wheel size.. and also 24" offer a bit more torque and less stress to the rear dropout.

Doc

 

[Mark_A_W]

"less stress to the rear dropout"

That depends on the motor (volts and amps).

Not the wheel size.

 

[Doctorbass]

"less stress to the rear dropout"

That depends on the motor (volts and amps).

Not the wheel size.

Actually for the same trust, a X5 on a 26" wheel WILL offer more stress on the dropout than a 24" or 20 " wheel.

I confirm.. I tested... and also I saw twisted X5 axel on a 26" wheel with equivalent power trust than my 20" rear wheel setup that never twisted...

Today, CHXS shown me his twisteed X5 axel !! the first i ever saw!

look like Methods is not the only torture tester here!

 

[Mark_A_W]

For the same thrust, yes.


But the thrust is an output of the torque x diameter.


It is the torque that is the "driver". If you reduce the torque to maintain thrust, then yes, the stress will go down.


But if you leave the torque the same (as most would), then the stress is independent of wheel size.


Anyway, we are debating semantics now.

 

[Doctorbass]

Anyway, we are debating semantics now.

 

[Seriousknot]

Doc, I think I have found the rim I want to use. They are Arrow Racing DHX 24". The reviews on these hoops sound really good. Couldn't find a retailer so I just ordered directly from them. I spoke to Mary Jane at (541) 471-7212 . They have a limited number of 24" only, all 26" have been sold. I even have a calculated spoke length from Ebikes.ca, 115.9mm in a radial lacing pattern. MJ even gave me a discount $80 per rim. I decided to use this only on the rear. I can buy a front wheel with Halo Combat2 rim completed for about the same price at Ride-This. Now to get spokes for the rear. Got any ideas?

 

[Seriousknot]

Mary Jane just called me back and said she has a few rims with minor chips in the powdercoat.....and she dropped the price on these to $65.00!!!

 

[damcard]

Doc, I think I have found the rim I want to use. They are Arrow Racing DHX 24". The reviews on these hoops sound really good. Couldn't find a retailer so I just ordered directly from them. I spoke to Mary Jane at (541) 471-7212 . They have a limited number of 24" only, all 26" have been sold. I even have a calculated spoke length from Ebikes.ca, 115.9mm in a radial lacing pattern. MJ even gave me a discount $80 per rim. I decided to use this only on the rear. I can buy a front wheel with Halo Combat2 rim completed for about the same price at Ride-This. Now to get spokes for the rear. Got any ideas?

Really, they won't have 26 anymore or just out at the moment? I have 24 now, but was about to order some 26. I had to go directly to arrow too.-David

 

[Seriousknot]

According to Mary Jane, they are out of 26". The supplier that made the rims for them has gone out of business. How do you like your 24's ?

 

[Seriousknot]

Oh yeah, Damcard,
Where did you get your spokes?

 

[damcard]

Heh, I have not laced them yet. Guess I will go ahead and use them since I can't get the 26"rims. I was waiting on some other things. Sorry Doc, I didn't know. I am lacing them to a Hadley hub not a motor.

 

[Doctorbass]

Heh, I have not laced them yet. Guess I will go ahead and use them since I can't get the 26"rims. I was waiting on some other things. Sorry Doc, I didn't know. I am lacing them to a Hadley hub not a motor.

No prob.. I will buy tough rims with eyeslet.

Doc

 

[tapholov]

Hi,

just my little grain of salt here:

if you use a 24" wheel, you might want to lengthen the shock in the rear to correct the change in rake on the front suspension. Having done so myself, I ordered my rear shock from Yasusu and have been very satisfied. You can specify length and they'll provide the right spring according to your evaluation of the total weight of bike-rider. Cheap and very quick with the delivery.

Also, I don't think there's a lot of room for batteries in there. I'm also using A123s on my latest e-bike and if you're going your usual high voltage way, it'll be hell to situate.

However, once you'll get to high speed, we know you will, you'll really like the feel-soft suspension aspect of the bike. Aim and go, no worries, it'll save you rims also.

Can't wait to see what you do with this one. Have fun.

 

[Mark_A_W]

How good a shock can they make?

The Manitou swinger fitted to this frame is very high end, and worth about a grand new.

 

[Doctorbass]

UPDATE 17 July 2010

Still 3 things to do:

1- Solving the rear drop out problem and adding steel on the perfect way

I will probably decide to do that this way: I will install on each internal side of the arm of the swing arm a steal plate of 1/8" that will fix to the 2 arms rear end, then i will replace the actual thick aluminum dropout by a thick steal torque arm in egg shape that will be soldered to the larger 1/8 plate.

To do that i might need the help and skill of Turbobass to help me for the weld job That torque arm will be more than enough with like 12mm thick steal on each side


2- Finishing the battery box ( 12 lipo 6s 5Ah)

Pretty easy.. that will be made of 5 welded aluminum plate to make a box. The 6s Zippy pack will be in 4 row by 3 column. each of the 3 pack group will be paralleled and each of these trio will have a 1/32 thick plate between them to renforce the main box to resist to the cell internal pressure.


3: The most complicated: finishing the serie-parallel device for the X5 motor

That project became bigger than i expected!.. I decided to make a PCB inside the motor that will make all connections and support the 6 relay of 80A

I decided to make it so that if it really work nice.. i want to be able to replicate these pcb easy and make them availlable for the crowd. The most difficult thing is that none of our motor have exactly similar internal dimensions fo rthe centering of each of the 6 holes on the stator! So i need to find an average of all existing X5 motors and center each relay to that averaged position. By this way it will be easyer to fit the pcm with the relay on all X5. It also should be narrow enough to fit in both old and new X5 gen.

Right now, the PCB cad is almost done and i will build the first prototype with the CNC of my friend to cut the empty trace on the PCB. and the disk shape of it.

Still few days to wait that his load just decrease a bit and we will make that.


As for the X5 and wheel, both 24" x 3.0" wide bite tires and the Double track 24" 36 holes are arrived and the front wheel is assembled. All customs 13g spokes and nipples are also arrived and wait to be tested!

I had to wait until the X5 case was painted to assemble the wheel and check if the calculated spokes lenght is ok.

About the famous colling holes i added but that are all pointing in the wrong direction.. I decided that it will be just enough anyway... Ordering for 100$ of new side covers and drilling all them again.. will take too much time

I leave you some pics of the paint job on the X5 motor i just finished in the last hour. ( I used the new Rustoleum Black Hammered finish).. It look pretty nice!

 

[John in CR]

Doc,

I'd just fix the exhaust holes by tilting the drill in the other direction. You have plenty of metal strength there, so the longer holes will just mean better air flow. The exhaust holes see higher external velocity, so angled the wrong direction will fight strongly against the interior flow.

The intake holes are less critical on the shape and you've already reduced the structural strength there by about half, so I wouldn't do more than just round off the 2 sharp edges of each intake hole.

No internal vanes to help the air spin better and maximize centrifugal flow???

How about the series/parallel, have you done any test runs to see the effect? That is definitely something I want to try, because turning my motors into real hill climbers at lower current would be a great thing to have. Plus my motors have a lot more available space inside than the X5's, so I'm sure I'll want several of those series/parallel switching rigs.

John

 

[Doctorbass]

Doc,

I'd just fix the exhaust holes by tilting the drill in the other direction. You have plenty of metal strength there, so the longer holes will just mean better air flow. The exhaust holes see higher external velocity, so angled the wrong direction will fight strongly against the interior flow.

The intake holes are less critical on the shape and you've already reduced the structural strength there by about half, so I wouldn't do more than just round off the 2 sharp edges of each intake hole.

No internal vanes to help the air spin better and maximize centrifugal flow???

How about the series/parallel, have you done any test runs to see the effect? That is definitely something I want to try, because turning my motors into real hill climbers at lower current would be a great thing to have. Plus my motors have a lot more available space inside than the X5's, so I'm sure I'll want several of those series/parallel switching rigs.

John

Yeah. I was planning on puting some internal vanes to guide the airflow.. just like the turbine of a vaccum cleaner.. redrilling each holes is something i dont want to do beasue the case is already painted and also becasue i guess that i'll still have some airflow... anyway.. I want to try first and then i'll redrill them if i can't acheive good cooling results

I hope to try that serie parallle very soon. .. as soon as the PCB is finished.. but i need my frienf Martin availlable for the CNC...

Doc
:wink:

 

[Seriousknot]

ehT tniap skool yllaer doog coD. Oops, I mean The paint looks really good Doc. Hehe

 

[gwhy!]

Hi Doc,
Just thought I would give my input as regards 24" rims, I am currently using a 24" B.M.F rim ( very cheap, good and strong but now discontinued ) on the rear of my current bike ( 40mm wide with high side walls and very strong ( so far )) there are plenty of very good 24" rims, I run a 3" tire, This compo is a tad under the size of a 26" rim with a 2.5" tire The trouble I have had with my setup is the tire slips on the rim and pulls the tube which is not to good for me ( but I do run a low pressure setup ) so I put a dab of silicon on the bead before fitting and this have solved this problem. 24" rims are so much stronger than 26" ( this is from personal experience ). Another thing to look out for is that if you run a 3" tire on a 24" make sure it will fit in the frame/forks , some forks will not accept a 24" rim with such a big tire...

Cheers.

 

[John in CR]

My only problem with 24" rims has been finding good tires down here, because 24's aren't common. Ordering stuff like that online doesn't make sense for me due to the transport and duties and taxes down here.

 

[Doctorbass]

My only problem with 24" rims has been finding good tires down here, because 24's aren't common. Ordering stuff like that online doesn't make sense for me due to the transport and duties and taxes down here.

The Arrow Wide bite seem to have prooven their quality.. O nean the stealth bomber and the Motoped are using them.. 24 x 3.0.

i've put them on the Double track rim and they fit perfect.. and look realy strong!!



i've ordered 4 x Magicshine 900 today... i'll have more than enough light on the front of the bike for night dirt ride!!

4x

and a tail light.
Doc

 

[Seriousknot]

Will you be using the standard batteries that come with the lights, or will you connect them to the main battery?