GT i-drive 2.0 Build

[GCinDC]

Looks like it tests OK and runs. Rim trued?

hunting for a rim now. my thinking is to get a strong and wide 24" rim and put as big as possible tire on it.

i'd love to put a trials quality tire on, like this:

obviously that won't fit, but what about the surly?


i'd like to be able to run as low a tire pressure as possible and still not get pinch flat for going over curbs...

i'd rather not go moped small tho. here's a 24 x 3 rim:

i'd rather get the double track profile but it looks like that's only 32mm?

[Sacman]

i'd like to be able to run as low a tire pressure as possible and still not get pinch flat for going over curbs...

You running lower pressure tires to avoid pinch flats? Looks like you're a good candidate for tubless and Stan's sealant so you're much less likely to get flats and avoid having to deal with removing torque arms and wires just to change your tubes.

Once I get everyting dialed in on my bike I'm gonna put Stan's in there too.

[GCinDC]

You running lower pressure tires to avoid pinch flats?

no, it's hard to avoid them w/ low pressure tires and jumping etc. but i generally prefer them lower...

stans sounds interesting. and messy?

hi res pics just uploaded..

hall surgery

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they caulk these halls in?

disgusting new motor...

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galvanic corrosion

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[full-throttle]

stans sounds interesting. and messy?

It doesn't have to be messy, but you got to have a track pump or a compressor and to take your time. There are a few good videos.

I just switched to tubeless on my MTB 'cause I pinch flat every 2nd ride. Nothing bad to report, it seem to work well. I don't expect it to seal every single puncture and do not mind to do extra maintenance AS LONG as it's at home and not on the ride!

The installation was easy once I found a decent pump. A bucket with some soapy water does the trick. Oh, and I'm using tubeless specific rims (Mavic XM819) and tubeless-ready tyres (Schwalbe Racing Ralph) Got to try normal rims with rim strips and normal tyres next.

[Sacman]

And you don't even need to have tubeless specific rims. You can run tubeless the "ghetto" or "gangsta" way by stretching a smaller 20" or 24" tube over your 26" rim and fillet it in half to make the liner to cover your spoke holes. Once you get your tire mounted and filled with Stan's you can just trim off the excess part. Here's a couple of videos showing you how.






And then here's a video showing how effective the Stan's sealant works.

[dbaker]

Make sure you "caulk in" the Halls with high temperature stuff. 100% silicone is good for high temps as is JB weld.

[GCinDC]

Make sure you "caulk in" the Halls with high temperature stuff. 100% silicone is good for high temps as is JB weld.

really? i can't use gelato??

IMG_4722.JPG (214.69 KiB) Viewed 713 times

[dbaker]

JB weld it is

[etard]

And you were worried that Stan's might make a mess...

Will the Large Marge fit your dropouts? It may be time to get a big boys bike Greg, something with a wide rear triangle?

[GCinDC]

And you were worried that Stan's might make a mess...

Will the Large Marge fit your dropouts? It may be time to get a big boys bike Greg, something with a wide rear triangle?

oops, i meant to post about the tires in my DH comp thread!

those would never fit in the GT

and i measured the Giant DH Comp and think 3" or just over might be about the max that'll fit. i doubt i'd be able to fit the Larry 3.5" wide..

nevermind the big fat larry at 4.7"

[GCinDC]

good fun:

[ambroseliao]

If you listen with headphones, you can hear his heart beating. Very cool!

[GCinDC]

hey guys, have you seen this?
count the number of tear-offs (as in goggle lens tear-offs)

fyi: 5.10 / Danny Hart: Hart and soul Trailer
gotta love the comments, too:

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[full-throttle]

Yeah nice mullet

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Here's another vid that's too good not to share

[Sacman]

Here's another vid that's too good not to share

Wow! I've seen many vids of guys doing bike tricks but they were all BMX or MTN bikes.
This is the first I've seen where a rigid, carbon fiber ROAD bike is used.

[GCinDC]

so i'm back on the idrive this week, since the dh comp is in repair. such a different ride. so high up now! tighter suspension..

anyway, i had a long errand after work yesterday and had to ride 21 miles! and without a CA!

i was late for an appointment at the end, so i got a good workout, going on speed 1 (15mph max) most of the way. considering normal driving uses about 1 to 1.5Ah per mile and the old pack had maybe 8Ah tops, i was asking a lot, pedaling hard, knowing i could hit the cliff anytime...

thankfully towards the end, i remembered that i had my lipo buzzers which hooks up to the pack db25 and it alerted me in the last 1/2 mile that one cell was hitting 3.2V under load.

that pack always had a runt cell, so i wasn't terribly surprised, and my balance charge cable hasn't been working, so it hasn't been balanced since 2011.

here are the no load voltages at the end:

unbalanced_cells_after_700cycles.jpg (52.29 KiB) Viewed 506 times

and here's the video, fwiw, from which i got the numbers:

i think cell in the top left pack is the runt, and it'll be interesting to check the IR of cell 4 from the other packs.

why are they low? do they coincidentally happen to be runts in their cell groups?

or have they been working extra hard to balance up the runt from the topleft pack, and are consequently overworked? what's the explanation? i sort of figured that when cells were paralleled, they'd balance themselves out?

i kinda expected the runt would be in the top right pack, which looks likes it's been getting poked by the locknut!

i think this dent is somewhat recent, the pack may have gotten mishapen recently. anyway, they may be tougher than we thought..

after 3.25hrs on the balance charger (set to charge up to 4.2v/cell):



after 4.5hrs on the balance charger:

[methods]

FYI: I recently found that my iCharger was off by 40mV on one channel. Not that I think this is what caused your runt situation, but I suggest carefully calibrating your iCharger channels. The calibration routine is posted in the maga RCGroups iCharger thread.

In my experience when a group of parallel cells all show low capacity (like your runt cell) it is because at some point a single cell failed and after that the parallel group of 4 was driven down deep past 3.0V when the pack was not being monitored for cell level LVC. This happened to two packs we recently built here (that were not running cell level protection)

-methods

[GCinDC]

thanks, methods. i balance charge other packs with the icharger and haven't noticed a difference, but will pay closer attention to that.

isn't another sign of a runt that when hooked up to a charge, the runt cell's voltage will rise quickly, comparatively quicker than healthy cells? why is that, just out of curiosity?

it should be noted that under load, it dives far lower as well, so just doesn't seem as stable anymore.

i'm afraid these cells have seen the mid to high 2V's once or twice, or three times, from lack of protection and lazy monitoring...

[methods]

Low capacity or high internal resistance.

Higher internal resistance
Drive a current into it and it will show a much higher dynamic voltage (I * R = V)
Pull a current from it and it will show a much higher dynamic voltage drop as well

Same would happen for a lower capacity...
Cells would climb faster and drop sooner

Oh well... anyone who is serious about ebikes has piles of lipo around that has been abused. All of my lipo has seen 2V at one time or another Dont you hate that 45min push home just *knowing* your cells are sitting at 2V? Arg... I dont miss those days.

For real bro... test your iCharger channels with a Fluke. You may be surprised.... mine were WAY off and from what I understand that is somewhat normal for older units. Check it.

-methods

[GCinDC]

thanks, that helps my understanding. i always think chemistry and forget math.

so what fluke would i need? most cost more than the icharger ..

and while we're on the topic of IR, is there any reason i would not be able to measure the IR of my whole pack, reconfigured to 5s8p? i tried this and blew my last icharger, but i probably screwed up, since i seem to recall that several cells displayed 0 mohm and one had an impossibly high number... perhaps i connected the leads in 20s... ?

ps. did i also read somewhere that there's a little deviant method in the oven? if so congrats. i always buy a bunch of stuff for my own projects to compensate, so 5 cromotors seems like a good start.

[Skippic]

I say, if you have a couple of bad packs, just throw them out or replace them. I read lipo fire is nasty stuff!

[GCinDC]

how bout you come over and we do some lfp tests to smoke 'em in the alley?

i just got some brake cleaner which shoots pretty far and i think is a tiny bit flammable and could add to the entertainment.

[Skippic]

We would need to charge them to at least 4.5V...

[GCinDC]

no prob... you know, i originally wondered if it would be a good test for your bms! what do you think? voltage differences too big??

[grindz145]

That's so weird how all the 4th cells are low.