meniosgko

Hello to all. I have a specialized sirrus men’s disc 2020. It has a rear derailleur 8 speed Altus shimano 11-32T . I just bought a 42T Lekkie for the front crankset ( if I am saying it right) for my BBSHD bafang motor. I want to buy

LITEONE 8 Speed Cassette 11-42T MTB Cassette 8 Speed Fit for Mountain Bike, Road Bicycle, MTB, BMX, SRAM, Shimano

because here where I live is very hilly. What rear derailleur I must buy for that cassette? Will I have to change my shifter also? Any ideas for cassete and rear derailleur combination for hilly areas? Please help...! Thank you!

andychrist

You do not need new rear derailleur, just a derailleur hanger extender to accommodate the wider cassette range. Notice there are a variety of styles including those that screw onto a fixed hanger and others that replace a removable hanger.

It can be a little tricky getting the derailleur to shift properly with the extender, you’ll probably have to play around with the B-screw.

andychrist

Also you might need to lengthen the RD cable+housing a little and add one or two more pairs of links to your chain. But recommend you replace the entire existing chain with this KMC designed for e-bikes, especially since you chose a mid drive which puts more stress on the drivetrain.

gsa103

When you say very hilly, what do you mean (what % grades)? 42:32 is pretty normal by ebike standards, for urban riding. For example, a Specialized Turbo Vado is 40:36, so lower, but it only has a 250W motor.
I would think you only need lower gears if you're very heavy (cargo bike, for example) or wanting to ride at very low assist levels.
How steep are the hills you're talking about? If it's San Francisco, then it's understandable.

Also, some people have reported that the bigger rear gears can't cope with high torque at a side-angle, and the largest rear cog bends. The Lekkie ring should help with the chain line though.
My advice, try the BBSHD on your stock gearing, then decide what you need to change. Just pay attention and don't lug the motor, so if the pedal rpms start dropping, up the assist level. Pick short routes so battery life isn't an issue.
Once you seen how the stock gearing works, then you can decide how to upgrade. I would seriously consider upgrading the cassette, shifter and derailleur to Deore, versus buying an off-brand cassette and extender hangar. You'll get more gears, better shifting, and likely better reliability.

2old

The questions and product description on Amazon (where the cassette is listed for < $30) state it can be used with "normal" Shimano derailleurs, although one individual used a "goat link" with his Tourney. I'd be surprised if it works, but you can try. The 442 gram weight listed for the cassette would have me suggesting they purchase a new scale.

meniosgko

Yes it’s like San Fransisco. Big uphills but also straights. When you say deore versus off-brand cassette and extended hangar you mean or the one thing or the other? Deore which model? Is it 8 speed?I also seen a video on you tube where a guy bought some cheap cassete 9 speed and kept only six gears( he had a chain issue problem on the lower gears. Chain wasn’t straight enough, and the trick he used I found it pretty smart he kept only six gears for his ebike and chain was straight on the lowest gears). If I could do that I would be happy. I don’t know what he did with shifter. He doesn’t mention on the video. Can I have a 8 speed shifter and only use 6 gears? Maybe I must go to a mechanic DONT know what to do

2old

I ran three gears in the rear with 8-speed spacing initially with my BBS02, 11-17-28. You can run as many as you want. Just make sure the thickness of the spacers is correct. See Sheldon Brown.

andychrist

You might be able either to adjust the derailleur’s L limit screw so that it can only reach the third largest cassette cog. Also you could loosen tension on the cable so that the derailleur cannot get passed the outer six. Not really so necessary to do either though, because you probably won’t ever feel the need to shift into the two largest cogs anyway. I live in very hilly terrain too, and even with an 11-28T 9-speed cassette and a 50-39-30T crankset, never have to use any gear combo lower than 39/21 with assist level on 4 (out of 9 on a 500W hub drive). So my chain stays off the two innermost cogs simply because I don’t ever have to shift any lower.

BTW SunRace makes good affordable 8-speed cassettes if you want something with more range than your current 11-32T.

gsa103

Deore is a tier of Shimano components, designed for mountain bikes. Currently, Deore is available in 10, 11 or 12 speed. It will take cassettes up to 51t, and the Deore rear derailleur is designed for the larger cassettes. So you would need to get a new shift lever, but those are the cheapest part of the system.
There's no particularly good reason to stick with 8-speed. Your wheels can accommodate 9/10/11 speeds, as long as you get a matching shifter and derailleur.
Your current derailleur won't work with a 42t cassette, so you need an new derailleur or extension piece to work with the larger cassette.

andychrist

OP will be fine with the bike’s original setup and maybe wider range cassette. 8-speed e-bike chains are the strongest and least expensive. Derailleur extender not absolutely necessary with an 11-42T cassette because largest cogs need never be used. We’re talking e-bike here, quite the opposite of mtb. Very little gearing required as the motor can sustain much higher continual power output than the rider.

meniosgko

28 gear for climbing big hills is that too small?

2old

It was adequate initially, then I changed to a 30t Luna front ring and now a 11-32 cassette. You just need to decide what gear ratios are best for your application.I don't ride on the road with the BBS02 bike (except short distances to get to a trail) so top speed isn't important. Also, you need to space the cassette gears so shifting isn't a problem. My system shifted from the "17" to the "28" easily. Also, I don't know which individual gears are available.

meniosgko

sunrace cassettes will they be compatible with my wheel? If I buy one, should I have to change me shifter also? 44-21 or 44-26 will it be ok for climbing big inclines? My motor is gonna be bafang 1000w mid drive

andychrist

Any 8, 9 or10-sped mtb cassette will be compatible, but to keep your current shifters choose an 8-speed like this. I use SunRace on all my cargo bikes, never had any problems with them.

Good advice from gsa103. Try out the motor on your current setup to see what is the lowest gear combo you need to get up the steepest hill, then choose a cassette with a couple larger cogs so that you don’t need to use the two innermost ones. Even if your current cassette works fine I’d still recommend replacing it with a new one as well as upgrading the chain to that KMC 8-speed for e-bike so you won’t have to worry about the drivetrain skipping.

Again, you will use a lot less of a total gear range on an e-bike because the motor does so much of the work. But with only a single 44T chainring, you might sometimes need to shift into a 32T cog. On an 11-42T, 8-speed cassette, that will be near enough the middle not to throw off the chain line. Then you’ll still have the 42T & 36T cogs available for emergency use if your battery ever runs out of juice before you get to your destination (but of course you’d need to install that derailleur hanger extender.)

Incidentally, the TSDZ2 mid drive is available with up to three chainrings, but it is kind of pricey an the vendor is currently sold out.

BTW, have you considered a hub drive? Even a 500W 48V Bafang would probably be enough for your needs, and allow you to keep your current drivetrain completely unaltered. Plus, if you choose one of their newer Intelligent displays, the motor/controller can be set to run on a 52V battery pack for greater power.

gsa103

Hub drives tend to struggle more with hills, because they can't use the bicycles gearing. Looking at the Grin motor simulator, a 500W Bafang will overheat very quickly >10% grades. A BBS02 and 42/32 gearing has no trouble getting up a grade 10% at 18 kph.

andychrist

??

Grin’s Simulator does not allow for varying assist levels.

Hub drives retain ALL of a bicycle’s original gearing, unlike mid drives which generally forfeit multiple chainrings. Plus they make shifting more easy and reduce stress and wear on the drivetrain; the opposite is true of mid drives. That’s why Justin only deals in hub motors: Grin does not offer mid drives at all.

Fully loaded my cargo bike and I tip the scales over 400lbs and with its dual 500W 48V Bafang hub drive we sail up hills at over 10mph on assist level 4, with the chain on the 39T middle ring and 23T cog. Intelligent displays show wattage hovering around 220 each motor. And as Justin noted, most hills are over and done with in a matter of minutes, not hours. Unassisted, it used to take me over five minutes to crawl up the worst hills on my route, and anywhere between 10 and 20 minutes all the times I had to walk it. Under assist it’s down to around a minute and a half. Retained the default speed limit of 25k/16mph and motors never struggle.





OP’s setup with his own weight included will likely come in around half of mine. Plus, there are 1000+W hub drives available from theebike and others that offer as much power as my dual drive, or even more.

Pop N Wood

I don't think you will need or even be able to use a 42 tooth low gear.

I have a BBSHD, 8 speed with an 11-28 rear cog and Lekkie 42 tooth front chain ring. I weigh 240# and the bike another 50-60. The bike climbs hills quite well. If fact, it flat flies.

Do what the others said and try it with what you have.

By the way 8 speed sets ups have advantages over set ups with higher number of gears. 8 speed chains are cheaper and reportedly stronger. Mid drives do go through chains. 8 speed cassettes are also all of $20. A strong reason to stay away from the 42 tooth versions.

Pop N Wood

The throttle setting varies the assist level.

Uncheck the auto throttle box than move the slider to simulate different assist levels.

KPREN

Grin's Simulator does allow for varying assist levels in two ways. First you can slide the throttle bar to adjust power and the second way is to put the throttle bar in automatic and adjust the speed line by clicking and dragging on the graph.
The OP would do fine with either a hub motor or a mid drive. His bike is more road/hybrid and he is looking at pavement. Most places do not have hills that exceed 10% on pavement. Where I live is an exception at up to 17%.
I did one Sirrus BBSO2 conversion and the owner is using the stock cassette just fine. He is thinking of going to a wide range cassette so he can do more of the work climbing hills. He needs the option of going faster and easier. He is 83 years old and concerned about maintaining fitness but also concerned about bonking or getting to slow to balance on any ride over a few miles.

Justin is a proponent of hub motors over mid drives but for reasons of advantages of hub motors at higher speeds and less stop and go work and throttle response. His opinions are modifying as the e bike technology sorts itself out.

My own experience with a mid drive is 2-3k miles on a chain, 10k miles on a cassette and 10k+ on a narrow wide chainring. Everything I have built has a very good chainline. I have very smooth shifting.

With the Bafang mid drives, the stock programing sucks for a road/hybrid bike on a multi purpose bike path. The jumps in power are too high and quick. I reprogram the first 6 steps out of nine with small jumps and the smallest power jumps are right around the speeds most people ride on the bike path . The programing reaches about 20-30% of power in 6 assist levels. The last three assist levels, 7-9, jump a lot.. This programming works very well for a cadence sensed bike.

I have mostly built e bike for those whom benefit the most from an e bike. Cadence sensed power works much better than torque sensing for elderly and handicap riders since they need the power to kick in higher when they are giving out and start dropping is speed. For them, putting more power in to get more power out is flat out scary for fear of falling if speeds get to low. When they bonk, they bonk. They do better with the lactic acid buildup if they can still spin at near zero power input from themselves. Some of them even start out the ride just tracing through the pedal stroke until they limber up. Once they limber up, they reduce the power to get exercise. Much the same as a therapy stationary bike. I do not put throttles on elderly bikes. The elderly are social, gabby and inattentive at stop lights. They can accidently hit the throttle standing there gabbing away and end up putting themselves and others out into moving traffic. I figure they can put a throttle on if they want one and my conscious is clear. Most do not.

KPREN

I set my fat e bike up to ride quite well without power. I have 11 speeds with an 11 X 46 cassette and use all the gears.

On shorter rides I often climb substantial hills without the use of power. It's much easier to climb with a power off e bike off than on an analog bike. Stickley a placebo effect on the psyche. I know the buttons and power are right there and I can activate them if I so choose.

andychrist

Hub Motor Advantages

fooferdoggie 

mid drive's boogymen. snapped chain. Maintain your chain carry a spare quick link. something may break in the drive train. Humm How have we functioned so long wit drive trains? more power causes problems with mid drive drive trains. man the obsession with more and more power. I am not even strong and my bosch mid drive will get me up 20% grades no problem. hell mt=y wife and I can do light mountain biking on our bosch powered e tandem. Part of this is if yo ride your bike like a e bike or like a regular bike. I want to spin to get h=my heart rate top and go long distances. I don't want to ride a scooter.

2old

Grin had a mid-drive, StokeMonkey mid-drive, but abandoned it. Their love of hubs is kind of like Luna's for mid, just the length of skirt they feel like wearing. Both have their applications.

OP, apparently that cassette will work with your system. Try it out; Amazon will take back anything that doesn't function as described.

Pop N Wood

Sounds like a nice set up for an offroad fat bike. Big difference than a street bike being used as a commuter.

Bet you aren't paying $20 for a replacement cassette and under $10 for a chain.

KPREN

Ahhh no, I am paying much more than that. My bike pedals quite well power off. I can pedal it 10-12 mph power off not loaded. Loaded 8-10 mph