one chain cog gearing

[mountain biker]

how can you change the chain cog for different gear ratio? what would you recommend for example a mid drive...it allows for only chain cog....the ratio is 20 to 1 i believe its a gng 24 volt double reduction....

i have found no cassetes with a big gear on it...only megashimano with a 34 i believe. the standard chain it comes with is a 48 t i believe....

i want a mega low gear for first for sure...and is it possible to still use the derailler?

what different gear options are possible and speeds....lets say 150 is stamped on crank from mid drive or if that is even necessary....to know..just
for academic purposes...how can i change up the gears with a wide gear range....i am looking for low gears...i need to get above 3 mph i guesse for stability...
or can i go lower or will the bike fall over? top speed is not a very crucial thing for me...maybe 20 or so..is cool.

i always heared that 24 volt can get past 15 or so...but i don't know...

i always appreciate you guys with your help...i thank you in advance.....
lets say i have 7 gears to play with on the standard cassete......what can i do...????? and where do i go and get these parts?????

 

[mountain biker]

love spamming my own posts...well after reading that a lot of mid drives are one chainring ...well stock...so

so lets go with a megarange shimano...

Picture Information







Image is loading NEW-Shimano-Altus-CS-HG31-MTB-Bicycle-Cassette-11-34t-8-Speed-Mega-Range







NEW-Shimano-Altus-CS-HG31-MTB-Bicycle-Cassette-11-34t-8-Speed-Mega-Range



Details about NEW Shimano Altus CS-HG31 MTB Bicycle Cassette 11-34t 8 Speed Mega Range
then add
http://www.ebay.com/itm/MTB-Tools-38-Tooth-Cog-for-Mountain-Bike-Cassette-38t-Sprocket-/251518157620?hash=item3a8fa68334

this is a 38t cog that says it can bolt on to an 8 speed 9 speed cassettes...anybody ever try this?

 

[Chalo]

I have some old 14-38 5-speed freewheels and I've accumulated years of riding experience with them.

In my observation, no modern derailleurs except the absurdly expensive SRAM 1x10 and 1x11 units are designed to shift to such à large sprocket. But some of them will do it, at least when mounted on certain derailleur hangers. I'd start with a derailleur designed for a 34 or 36t large sprocket and see if it doesn't do the trick.

An index shifter may not have any way to accommodate the extra sprocket, and you may have lock out the smallest sprocket in order to be able to shift to the big one.

 

[LewTwo]

Another alternative is an Internally Geared rear Hub (IGH):
This page is a list of internal hub gears for bicycles: https://en.wikipedia.org/wiki/Comparison_of_hub_gears

From that you can reduce the prospects to:
1) NuVinci CVT, 360%, https://en.wikipedia.org/wiki/NuVinci_Continuously_Variable_Transmission
2) Rohloff Speedhub, 526%, https://en.wikipedia.org/wiki/Rohloff_Speedhub
3) Shimano AlFine 11, 409%, https://en.wikipedia.org/wiki/Shimano_Alfine

There have been several reviews of the Bafang mid-drive paired to the Nuvinci.
I believe that there was at least one review of the Rohloff paired to the Bafang.

I have not seen anything regarding a AlFine 11 used with a Mid-drive but I think it might be something to consider.
There would be a question as to the power handling capability.

One advantage of the IGH is that you only need to change one small gear on the rear hub to adjust/tune the drive train to the motor.
Of course the problem of the large rear derailleur goes away as well.

check this out: http://electricbikereport.com/the-future-of-e-bikes-nicolaigatesnuvinci-concept-electric-bike/

 

[dogman dan]

If you are like the gieco dude, made of money, I think some of the 2016 mid drives will be geared a lot lower than the typical Bafang or other mid drive kit. This year, the Haibike and a few others are available.

Some trails, you really do need to have 3mph gearing to safely get up them, riding like trials. So a mid drive tuned to run 10 mph at the slowest is not ideal for that.

Some of these European models are geared that way I think, because they have 250w limits. So they aren't built for 30 mph, but they get up the badass trails in the alps with a fit rider on em.

 

[mountain biker]

i appreciate the input. so maybe the megarange...or probably the megarange may be more suited to bolt on a 38 or 41 than others gear set up because its 34 stock....so how would I bolt on the 38t extra cassete cog....I have seen wolfgang video on you tube and the dude takes out a middle ring like a 17t or something. more three quarters down the gear range.

in regards to the nuvinci hell yeah...that looks bad ass and they have been several reports on here about using them and getting good results with 36 volt and 48 volt bafangs. (but at those power levels you could have a bmx style set up and still be king of the mountain...at 35 mph.) I noticed the nuvinci has an automatic version out now. I believe its on the evelo bikes. if I had the funds that would be a top choice. its the only igh I seen out there that's rated for 250 watts of power. I don't think the others are putting that stamp on their products. the rodhulf would be number one and is used on some light electric vehicles the tag is a little steep for me but it seems to make sense. the alfines would be a nice fit because of gear range and price...maybe like 500 bucks fitted in a wheel for you with nice tires.
the issue I have with igh it seems is that they don't allow for a reduction. they all seem like a 2 to 1 ratio from the crankset..
at best maybe a one to one ratio at the wheel. however though for 125 bucks you can get a wheel and 3 speed turney archer that would be cool for price....and if you strip the gears its not that bad of a hit. but its still not a reduction. and the pedal cab igh seems like searching for a needle in a haystack and even with 24 volt 350 power levels there doesn't seem to be anybody supporting that kind of stuff...I was looking to put in 350 watts in a 24 volt type set up....the bewo at 36 bolts put outs maybe like 60 nm and 90 rpm...I assume the 24 volt one would be 1/3 nm but probably same rpm. this is kinda of where I was thinking it would be nice to have a little reduction in first and then we could work our way up....I have been playing around with I believes crossbreaks mid drive calculator on here....its a lot of fun. thank you by the way if y ou are reading. and with the lower power levels I need reduction.

the haibike....omg.....yes yes yes.....I would love it...but budget doesn't allow. I am sure many others on this site have just salivated just looking at its pics.

I was kind of going in the more traditional older bike gearing system route I guese but wanted to use modern parts. it sounds like from the post in here we need bikes from the 70's for your modern day mid drives. you know one chainring gear.... 5 6 7 8 cassetes. with a big gear 34 or perhaps 41 44 t as big gear and go down to 15 14 13 12 11 etc.....big jumps...kind of eyeing that bewo and getting a mega range shimano bike from Walmart.

I appreciate the input. I wanted to say thank you all for your help. i think i am going to call that 38 t 41t manufacture now and see what's up with it.

 

[mountain biker]

apparently the wolfgang 44 41 t will not work per amazon for the shimano megarange because No, this is an old school freewheel. You would need a compatible freehub on the rear wheel, and derailer. If u need lower gears consider a smaller chainring or crank

this is for the Shimano MF-TZ31 Tourney Freewheel (14-34T Mega


im waiting for the reply on the other 38t...

 

[LewTwo]

however though for 125 bucks you can get a wheel and 3 speed sturmey archer that would be cool for price....and if you strip the gears its not that bad of a hit.

Note: This is pretty much a futile exercise because I have no idea what the Bafang Crank RPM range is --- but I was curious.

Generally speaking the middle gear in a three speed IGH is a 1:1 (i.e. one turn of the rear cog is one turn of the rear wheel). The axle of is locked to the hub (i.e. no power is transmitted via the internal gears). However the gear range is very limited: 0.66:1, 1:1, 1.25:1. This works out to a 2:1 range between low and high speeds. So if you select cogs to allow for lowest practical speed of 3 mph then your low speed in high would be 6 mph.

The range of rear cogs is 16 to 22 teeth. Thus a 16 tooth rear cog and a 48 tooth front cog would yield 3 crank revolutions to 2 rear wheel revolutions at the lowest gear.View attachment 1View attachment RPMS.xls

 

[mountain biker]

Yeah that range is limited with archer.....especially if you want a reduction...
I.e. 1.3 crank to rear cog. And add. 66 reduction for first.... 0.858. So 100 cranks at peddle 85 rpm...third gear is. 1.625. ....... crazy...rpm at crank and limited range....
Shimano six speed mega range...14 to 34..gives 2.42 times range...... I'm looking into 7 speed conversion....eBay free wheel hub cassette. 11 to 34.....that's a little over 300 percent range......
Shimano had a 11 to 34 six speed but discontinued it......and hurried it...just Luke Lucas hurried his 3 million copies of. E T atarai 2600 game under a cactus in Nevada. ...

 

[mountain biker]

Sorry for typo on cell.... thanks for heads up on range of 3 speed hub.