Gary Fisher conversion

[Infinityminus1]

I have a late 90s Gary Fisher utopia which I spent a lot of money and time on over the years. I would like to convert it and need to climb hills on the road. It has 700c tires on it and i have a plethora of questions.
I was thinking geared hub rear but am now thinking mid drive. I have about 1000 to 1200 for now so heres what is whirling through my brain right now.
Should i even bother with this bike?
Hub or mid drive?
Sell the bike and start with something else?
Will 700c be ok?
Which kit?
I have to climb hills and when i look at my great running bike it appears to be a great base for electric but then wheel size, brake type, and so many other things come into question. Someone please help me with where to start.

 

[MadRhino]

We need more info to answer your questions.
How steep, how fast, how long you want it to go
Things like that, you know... :wink:

 

[Infinityminus1]

Don't need any kind of extreme speed or distance just good torque for pretty steep hills. Its a last mile kind of ride for a train commute but a huge hill when i get there thats pretty steep.

 

[MadRhino]

Then, if you build with a mid drive, you can keep your wheel as is. It will climb steep and efficiently, but slow.

The bike itself is a good one, you don't need to worry. Perfect to fit a BBS mid drive kit. Other ES members who are familiar with them will recommend better than I what you need for this kind of build.

Building with a hub motor would make it necessary to replace the wheels to a smaller size, that is a must to climb steep reliably. This would likely make your crank too low... You would need to replace many things, maybe even the whole bike to make it easier to build. A hub build can be much faster, and you could ride it like a motorcycle. I don't believe it is your goal right now.

 

[Infinityminus1]

Thanks. That was the conclusion i was coming to as well. Now... how do i know what you order with no measuring tools? Bottom bracket size? Thread? Need new shifters too, push buttons dont catch and click all the time.. any suggestions? What about a new chain? Are they all the same? Should i just wait till it snaps? Also what special tools will i need?
Thanks again to any and all advice. Finally, opinions on where to get the bbs02? or should i go with the hd? or generic? Or other? I think 48v shpuld siffice no? Batt and charger recommendations?

 

[MadRhino]

Tuning your derailer, changing the chain, any adjustments and upgrade to your bike should wait until you fitted the kit on it. That is when you will have a clear picture. Reading the build thread of those who are using those kits will give you ideas, and feel free to ask them about tips and tricks. I believe those Bafang mid drives are pretty straight forward to mount, on a hard tail especially.

I am not familiar with the BBS kits. I believe most are buying them from Em3ev.com and they offer 3 different Mid motor kits.

 

[Infinityminus1]

OK so the BBS02 it is! I will be ordering this week from luna, em3ev, or californiaebikes. if anyone has an opinion on that choice I'm all ears. now the question is about the most important issue...the batt and charger. I am willing to pay a bit more for the charger as long as I know why. any suggestions on charger and batt? even if it is from somewhere else?

 

[flat tire]

Get a member on here to build you a battery out of high quality 18650s. You don't want to mess with premade batteries from China cuz they use crappy cells. You can also use RC lipo batteries. If the motor is made for 48 volts, an easily solution with most chemistries except LiFePo4, would be a 12s or 14s configuration in 2p or 3p depending on the range you need and power you intend to consume. You can also use RC lipo batteries if you're careful as they can catch fire under rare circumstances or if you crash and mess up the pack or charge them improperly.

Since you have an efficient design and don't need high speed travel or long distance capability, you can get away with a smaller battery. Without knowing the exact distance you intend to ride between charges, robably as low as 300 Wh will do the trick if you're OK pedaling, and that size will leave the bike light weight.

 

[WoodlandHills]

The only charger I can suggest without reservation is the programmable Grin Satiator, it's more expensive than any of the others, especially when you add a basic charger to a battery order, but it is far more versatile and informative. If you get hooked on ebiking you will find that a high quality balancing charger is a must and that a charger that will grow as your needs grow is cheaper in the long run than a basic single voltage one. Having said that, the Chinese chargers in the extruded alloy cases are great at charging up to 90% for a storage charge or a daily charge, but you still need to balance charge once in a while and the two I have shut off before reaching balance voltage according to my Flukemeter. My packs are supposed to balance at 58.8 and both of the "bulk" chargers shut down at about .5v short of that, but the Satiator will balance them all to 58.8v.

 

[2old]

I've had good luck with a BBS02 and Luna 52V, 10 a/h battery. Installation is pretty simple, but you'll need tools to remove the bottom bracket (or have a bike shop do it. Probably your bike has a 68mm wide bottom bracket and that is perfect (although a 73 is OK too). Luna had a deal for BBS02 and battery for $750 that seems like a steal. You may want to order their 30 tooth front sprocket for better hill climbing (and lower top speed) or wait until you've tried the stock system

 

[flat tire]

You can remove a bottom bracket using a pipe wrench and a rag / paper tower just make to check which way it comes off.

 

[chas58]

I have worked with em3ev and Luna. Both are great, and use high quality cells. they are not the "cheap" chinese companies. Paul custom makes batteries for me (based on his core offering of cells, which is currently being upgraded to the latest technology). He has some of the best stuff out there.

I did buy a cheap setup from china years ago - the battery lasted me about 2 years.

General rule of thumb with a hub motor is that you want to keep it above 50% of its top speed on the flats. If you can't do that, you need a mid drive.

Looks like a good bike to work with. I would put as fat a tire as you can on there. Know how big you can go?

 

[chas58]

keep in mind EM3ev is currently upgrading their cells:

New cells include:
30Q Samsung (3ah)
LG MJ1 3.5Ah cell
Samsung 33G 3.2 Ah

 

[Infinityminus1]

Thank you sincerely for all the help. I am at the point of learning the wonderful and expansive universe of batteries. Im really not looking to travel more than 7 to 10 miles at a pop and it seems even the crappiest Chinese fire hazzards can get me that far. I need a batt. That can be removed quickly as i will be "hiding" it in a backpack regularly. Im also ok with the dangers of crappy batteries as long as i do get a good year or so out of it or until i learn more about what i really want need and actually use. That being said, any recommendations? Should i go as cheap as possible to learn for myself why i shouldnt have. Or can someone recommend a reasonably priced battery that is removable 48v that will last, and not cost an arm and a leg in shipping costs?

 

[Infinityminus1]

Btw it looks like em3ev is the way im leaning. Based on the last question should i just bite the shipping bullet and add a batt to my kit? If so which one? I get that they are lithium and i probably wont find someone who will "legally" ship me one for cheap so....?

 

[MadRhino]

Paul will ship a battery. He does it for years. His batteries are not the cheapest, but they last long. Ask him about what you need with the kit that you want.

 

[Infinityminus1]

ok final question everything seems to come out the same except batteries from luna and em3ev. it seems luna batteries are listed as 48v11.5ah and em3ev batteries are listed as 47v9.8ah and both are similar price?? luna however doesnt charge 130bucks for shipping. I am at a loss as to who to order from. any other opinions out there?

 

[chas58]

That is a big question (see my post above)

EM3ev tends to under rate their batteries a little. A 9ah battery from them may be as good or better than a 10ah battery from others. Mine are.

With batteries, you pay more for name brand, for high power density (Ah in a cell) and for high power output (C rate). Both those guys tend to make good stuff – but to answer your question you need to know the brand and the specific cell model they are using. And you need to know the power requirements of your controller.

Luna seems to like using 52v batteries, which will give you 8% more speed vs a 48v. Are you looking at 7-10 miles between charges? With your short range, I might just get the mighty mini – the 3.3lb battery. (I kinda like that size, and was trying to get them to make one when they first opened – but I was a little ahead of my time. Paul (emv) made me a custom one though, and that has worked out great).

 

[USAEBIKECO]

That is a great bike to convert.