Max comfortable width of pack mounted in triangle

General Discussion about electric bicycles.
Post Reply
wallywolf   1 µW

1 µW
Posts: 4
Joined: Dec 04 2019 9:25pm

Max comfortable width of pack mounted in triangle

Post by wallywolf » Dec 04 2019 9:47pm

I about to be building a new battery pack and it’s going to be a 20S10P pack mounted in the triangle of my 1999 rockhopper. Because of the number of cells and the shape of my triangle and to give me good options for keeping current flow healthy I think I’m going to need to orient the cells 5 across. This makes the pack at a minimum 5 inches wide if I honeycomb the cells. Any opinions on whether that is what too wide to be comfortable riding?

User avatar
amberwolf   100 GW

100 GW
Posts: 29076
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Max comfortable width of pack mounted in triangle

Post by amberwolf » Dec 04 2019 9:50pm

Everybody is different, so make a cardboard version and tape it in there, and ride a while; you'll know for sure. ;)

wallywolf   1 µW

1 µW
Posts: 4
Joined: Dec 04 2019 9:25pm

Re: Max comfortable width of pack mounted in triangle

Post by wallywolf » Dec 04 2019 9:59pm

Fair suggestion, thank you.

User avatar
E-HP   100 kW

100 kW
Posts: 1181
Joined: Nov 01 2018 9:20pm

Re: Max comfortable width of pack mounted in triangle

Post by E-HP » Dec 04 2019 10:37pm

wallywolf wrote:
Dec 04 2019 9:47pm
I about to be building a new battery pack and it’s going to be a 20S10P pack mounted in the triangle of my 1999 rockhopper. Because of the number of cells and the shape of my triangle and to give me good options for keeping current flow healthy I think I’m going to need to orient the cells 5 across. This makes the pack at a minimum 5 inches wide if I honeycomb the cells. Any opinions on whether that is what too wide to be comfortable riding?
Can you design the pack so it's wider further forward in the triangle, and narrower where your knees may have an issue?

rockstar195   100 W

100 W
Posts: 163
Joined: May 13 2019 8:33pm

Re: Max comfortable width of pack mounted in triangle

Post by rockstar195 » Dec 04 2019 11:27pm

Post pics of the triangle please.

User avatar
E-HP   100 kW

100 kW
Posts: 1181
Joined: Nov 01 2018 9:20pm

Re: Max comfortable width of pack mounted in triangle

Post by E-HP » Dec 04 2019 11:38pm

rockstar195 wrote:
Dec 04 2019 11:27pm
Post pics of the triangle please.
I had one of those. They were straight butted steel tubes, so the triangle is big, or bigger, depending on the frame size. I'd say this is a 17"/medium frame:
https://www.bikepedia.com/QuickBike/Bik ... item=88847

rockstar195   100 W

100 W
Posts: 163
Joined: May 13 2019 8:33pm

Re: Max comfortable width of pack mounted in triangle

Post by rockstar195 » Dec 04 2019 11:47pm

wallywolf wrote:
Dec 04 2019 9:47pm
I about to be building a new battery pack and it’s going to be a 20S10P pack mounted in the triangle of my 1999 rockhopper. Because of the number of cells and the shape of my triangle and to give me good options for keeping current flow healthy I think I’m going to need to orient the cells 5 across. This makes the pack at a minimum 5 inches wide if I honeycomb the cells. Any opinions on whether that is what too wide to be comfortable riding?
Post pics of the triangle please.

User avatar
amberwolf   100 GW

100 GW
Posts: 29076
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Max comfortable width of pack mounted in triangle

Post by amberwolf » Dec 04 2019 11:55pm

rockstar195 wrote:
Dec 04 2019 11:27pm
Post pics of the triangle please.
rockstar195 wrote:
Dec 04 2019 11:47pm
wallywolf wrote:
Dec 04 2019 9:47pm
I about to be building a new battery pack and it’s going to be a 20S10P pack mounted in the triangle of my 1999 rockhopper. Because of the number of cells and the shape of my triangle and to give me good options for keeping current flow healthy I think I’m going to need to orient the cells 5 across. This makes the pack at a minimum 5 inches wide if I honeycomb the cells. Any opinions on whether that is what too wide to be comfortable riding?
Post pics of the triangle please.
https://www.google.com/search?q=1999+ro ... 76&bih=594

User avatar
Hwy89   1 kW

1 kW
Posts: 431
Joined: Mar 03 2013 9:52pm
Location: Northern Arizona

Re: Max comfortable width of pack mounted in triangle

Post by Hwy89 » Dec 05 2019 2:30am

Are you using 18650 cells? I get 5 cells at ~3.75 inches in columns and 4.12 inches honeycombed. This is packing them tight without cellholders.

User avatar
dogman dan   100 GW

100 GW
Posts: 35418
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: Max comfortable width of pack mounted in triangle

Post by dogman dan » Dec 05 2019 7:14am

5 inches is wide, but should be tolerable. 6 inches can be stood by some, just depends on if you pedal, or faux pedal, or no pedal. At 6 inches, you will be pedaling quite noticeably bowlegged.

User avatar
DogDipstick   1 kW

1 kW
Posts: 447
Joined: Aug 19 2018 12:39pm
Location: Fleetwood Pa

Re: Max comfortable width of pack mounted in triangle

Post by DogDipstick » Dec 05 2019 10:10am

My pedals clear with a 122.5mm BB and 7" in between. Pedal clears by 5mm on each side. The cells are 6.5 in a box and there are 20 or them.

You get used to it. Its nothing like the spread have to do on my Ninjas. Ninja you are really humping a gas tank. You get used to it. Plus, I like to pedal squarly, not at an angle that hurts my knees. So the 7" in between are tehre whether the batt is or not. My hips are 7+ inches apart.

Still looks thin. Thinner than the forks in the front ( 8 inch apart tubes)
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

wallywolf   1 µW

1 µW
Posts: 4
Joined: Dec 04 2019 9:25pm

Re: Max comfortable width of pack mounted in triangle

Post by wallywolf » Dec 05 2019 10:56pm

Hwy89 wrote:
Dec 05 2019 2:30am
Are you using 18650 cells? I get 5 cells at ~3.75 inches in columns and 4.12 inches honeycombed. This is packing them tight without cellholders.
Yea I’m taking the honeycombed width and adding a little margin for padding and a case. Plan was to build an mdf triangle box to protect the battery.

Tommm   10 kW

10 kW
Posts: 718
Joined: Apr 03 2018 2:32am

Re: Max comfortable width of pack mounted in triangle

Post by Tommm » Dec 06 2019 6:26am

I have 4.25", (1row standing + assembly/box) which is fine, 5" would be ok too. Anything above and you won't be as flexible offroad flicking it around, you knees would be hitting it.
If you only ride street feel free to follow the others.

User avatar
DogDipstick   1 kW

1 kW
Posts: 447
Joined: Aug 19 2018 12:39pm
Location: Fleetwood Pa

Re: Max comfortable width of pack mounted in triangle

Post by DogDipstick » Dec 06 2019 8:54am

Tommm wrote:
Dec 06 2019 6:26am
I have 4.25", (1row standing + assembly/box) which is fine, 5" would be ok too. Anything above and you won't be as flexible offroad flicking it around, you knees would be hitting it.
If you only ride street feel free to follow the others.
I rip mine around off road. Drifting donuts, mud slinging 20 feet.

Still not as wide as most MC at 7". Looks thin. I flick that thing hard. My knees dont hit. IDK maybe Im just me, but I dont fear the 7 inches in my box.

Image
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

Tommm   10 kW

10 kW
Posts: 718
Joined: Apr 03 2018 2:32am

Re: Max comfortable width of pack mounted in triangle

Post by Tommm » Dec 06 2019 9:12am

DogDipstick wrote:
Dec 06 2019 8:54am
Tommm wrote:
Dec 06 2019 6:26am
I have 4.25", (1row standing + assembly/box) which is fine, 5" would be ok too. Anything above and you won't be as flexible offroad flicking it around, you knees would be hitting it.
If you only ride street feel free to follow the others.
I rip mine around off road. Drifting donuts, mud slinging 20 feet.

Still not as wide as most MC at 7". Looks thin. I flick that thing hard. My knees dont hit. IDK maybe Im just me, but I dont fear the 7 inches in my box.

Image
I think the difference is the top tube on yours might be slanted? My top tube starts almost from the base of the seat, so the battery starts really close to you and is always in line with my knees.

User avatar
DogDipstick   1 kW

1 kW
Posts: 447
Joined: Aug 19 2018 12:39pm
Location: Fleetwood Pa

Re: Max comfortable width of pack mounted in triangle

Post by DogDipstick » Dec 06 2019 9:35am

I say its "To WIDE" when the pack hits the ground if the bike falls over.

My bike has fallen over, and the pedal, bar and axle is on the ground, but I did not get any road rash on the battery box.

Image

Image
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

Grantmac   10 kW

10 kW
Posts: 680
Joined: Oct 22 2018 12:43pm
Location: Victoria, BC

Re: Max comfortable width of pack mounted in triangle

Post by Grantmac » Dec 06 2019 12:21pm

Keep in mind one person's "offroad" is another's walking path. So be careful which advice you follow.
Me personally I want it under 5" at top tube height, perhaps slightly more on the downtube but not much. Be careful to take into account suspension travel if you are going to do any real offroading. The pack design above wouldn't survive full travel of the front suspension so is best considered an onroad or gentle path option.

User avatar
DogDipstick   1 kW

1 kW
Posts: 447
Joined: Aug 19 2018 12:39pm
Location: Fleetwood Pa

Re: Max comfortable width of pack mounted in triangle

Post by DogDipstick » Dec 06 2019 1:20pm

Its 5" travel on a frame designed for 4 1/2". I havnt been able to bottom yet. Maybe you cannot see because of the angle.

I mean youare not the first to say that it might bottom. I cannot keep the front down with the pack anywhere else. I'll happily hit whoopdedoos at 35mph.

But yeah soft at first but havnt bottomed. 80lbs.

I'll bet it will throw mud 40'. Plus the Dave Weagal suspension eats bumps.

I should take the spring out and take a picture fully bottomed. I am not riding on walking paths. Heavy logging trails. Fast.

The wheel is smaller than a normal 26" too.. Its a 24". Remember you must consider that.

Grantmac wrote:
Dec 06 2019 12:21pm
Keep in mind one person's "offroad" is another's walking path.
Allota Watts @ 83.1v of raw QS power takes me everywhere on my Ironhorse DW link XC... :) Powered by Chevy. :D Broke 10 horses the other day. ( BTW; ...don't get hurt... :? )... (Currently building a battery datalogger.). :roll: Playin with (24) IRFB4115s now. :wink:

User avatar
dogman dan   100 GW

100 GW
Posts: 35418
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: Max comfortable width of pack mounted in triangle

Post by dogman dan » Dec 08 2019 8:41am

I had off road bikes set up much like Dogs. I did not pedal more than a handful of strokes a mile. Rode great standing up, pinching the saddle between my thighs. I rode it exactly like I used to ride my trials MC.

But sit down and try to really pedal, It was too bowlegged for me to do it for say, 50 miles. 5 inches worked for that for me. I had a half inch of frame bar between my battery and road rash, and did not drag my pants leg on the frame. The battery was one 18650 cell length wide.

miro13car   1 MW

1 MW
Posts: 1722
Joined: Mar 26 2007 1:30pm
Location: Calgary, Canada

Re: Max comfortable width of pack mounted in triangle

Post by miro13car » Dec 08 2019 2:04pm

as far as I know there are ways to "spread" your legs while pedaling.
change bottom bracket to wider
or
install extenders between cranks and pedals
such extender screws into crank and pedal screws into extender.
Eplus, Bionx

User avatar
amberwolf   100 GW

100 GW
Posts: 29076
Joined: Aug 17 2009 6:43am
Location: Phoenix, AZ, USA, Earth, Sol, Local Bubble, Orion Arm, Milky Way, Local Group
Contact:

Re: Max comfortable width of pack mounted in triangle

Post by amberwolf » Dec 08 2019 11:40pm

If you widen the cranks too much, you can injure yourself over time, especially if you're putting any serious power into the pedals.

How much is too much depends on your own hip width and knees, etc. Look up Q-factor; there's a fair bit of stuff out there (some of the opinions found may conflict with other stufff on the same subject, though).

I'm sure that a significant portion of my knee/etc problems I have to live with and work around now were caused by my bicycling with the wrong fit bikes all my life, between crank width and length and frame/seat height, etc. Probably some of my hand numbness issues are from that sort of thing, too (riding with too much pressure on the wrists, wrong hand positions, etc etc).

User avatar
dogman dan   100 GW

100 GW
Posts: 35418
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: Max comfortable width of pack mounted in triangle

Post by dogman dan » Dec 09 2019 8:13am

True enough, wrong fit bike will give you hand and wrist problems. But so does just getting old. :roll:

But yes good advice not to pedal hard much on bikes that are making you pedal bowlegged. That's why I couldn't, or at least wouldn't pedal much at all on those dirt bikes with 7 inch wide battery boxes. And,,, 99% of the ride there was no way to keep up. At 40 mph, no pedaling.

Post Reply