What gearing/sprockets are you using on your MTB?

[ebike11]

Hi guys!
After trying to install my magic pie motor on my MTB, I started to wonder what gearing and sized sprocket that some of you are running on your MTB?? I did find out first hand after experienced members mentioned to me, that 6 sprocket cassette on the magic motor is pretty much the largest I could install without widening the frame which I dont want to do.
My MTB is a standard 9 speed, nothing special, so what are you guys running?

Thanks and sorry to make a new thread!

 

[DAND214]

I have 7 and 8 speed freewheels on my MTB's.
I had to add shims and spred the swingarm. 2 of them are steel one WAS aluminum, lasted quite a while before snaping off the lt dropout. Now it's hromoly. Lot's of work but well worth it. Now I can spread it if needed.

Most important on the gearing is the smallest gear, which is a 11 tooth on a freewheel. 6 thru 9 makes no differance on the performance, just how it shifts.

Dan

 

[Sunder]

I use a 6 speed also.

I spend 80% of my time in 38 x 13 (high 30s km/h), about 10% of my time in 38 x 11 (low 40s), and a handful of hills in 38 x 20(low 20s) or so.

I wouldn't worry about getting much more granular than 6 speed. When you pedal alone, sure, you don't want a big jump in gearing to throw off your cadence, but with an electric bike, the motor helps you over that sudden change in torque, and you don't notice it. Imagine playing tug of war with an elephant behind you. No sudden jerk is really going to pull you off your feet, is it? Same deal here: Motor will buffer you, and you just add what you can.

 

[ebike11]

So sunder, do you use a 6 sprocket assembky and 6 speed shifters?
What kind of shifters do you have?

 

[NeilP]

7 speed rear...11-32 DNT..cheap shimano copy. front is 48 -42 - 38

 

[Sunder]

So sunder, do you use a 6 sprocket assembky and 6 speed shifters?
What kind of shifters do you have?

Sorry eBike11. Brain Fart. I use a 7 speed, not a 6 speed. Original build was a 6 speed very old Shimano setup. I don't even think there was a model number to it. Just K-Mart bike level equipment.

Current gear is all Shimano Alivio except the rear freewheel. Like Neil P, pretty sure mine is just a copy, and it's 11-32 as well.

Front is an Alivio M410 triple; 28/38/48 which gives me a very good range of usable gearing. I rode it without power for a few weeks while waiting for a replacement motor. Even with the extra weight, I could ride it up hill in the lowest gears.

The shifters are Shimano V-brake integrated shifters as well, that I picked up for $40 for the set. Doesn't have Alivio printed on them, but the bike store said they were the same spec level and they would work, and they do work fine. Good, precise shift, and I can easily get a double shift downwards with a single easy push.

I'm vaguely thinking that one day, for the next build, I'm going to dump the rear freewheel and rear derailleur, and use a single speed 13 tooth. Then see if I can get a lightweight 34/50 for the front. That should give me the ability to pedal on the flat with no motor, or assist the motor above 40km/h. Something like that would probably save me 1.5kg from the bike, which is not much, but might help rebalance the weight of the bike more towards the centre. For my next build I'd probably be dropping to 5-6Ah, and using something like a Lyen Mini-monster instead of my current overweight controller, which would shed another 2 - 2.5kg from the back. That's when things start getting serious.

Anyway, the point is, I use the gears so little, that I wouldn't worry about 6 speed limitations. I've got more gears, and I'm thinking of going far less.

 

[dogman dan]

You have some problems, since you have 9 speed now. The chain is narrow, and the spacing between gears shorter. So your gear shifter index, the clicks, are going to be spaced wrong for a 7 speed derailur.

8 speeds can be fudged and still work tolerable good, but not a 9. You will need to replace the chain, and the shifters, and if the 7 speed chain can't fit, your derailleurs might not work either.

Got a deal on a cheaper 21 speed mtb handy? It could be said that ruining your nice bike with a motor is a bad idea, if you still like to pedal sometimes. I have a shitload of ebikes in my garage, but still have 4 nice pedalers in there too.

Front gear needs to be as big as you can fit now that you have a motor. 48 tooth is good. 44 too small for going fast.

 

[ebike11]

Hi guys

My rear sprocket is a 6 sprocket cassestte and the smallest is 14 and largest is 48T

Fronts are : 44/32/22T

Best option if I keep the rear 6sprocket?? Thx

 

[Obiwan007]

I am sure glad that this topic came up right now. It seems the perfect place to list a few things, as a noob, that I have learned and to ask some questions on issues that I am just now dealing with on my new Giant DH Team build.

When doing my first build I took some good advice from GCinDC and put a freewheel on that bike (the Electric Jeepster) that had an 11 tooth as the smallest cog on the stack. The largest of the front rings is a 44T. This has allowed me to pedal meaningfully up to 30 mph with my little crystalyte 408 motor.

Because this motor is small and narrow I was able to get a seven sprocket freewheel on it and the bike I started with had a three ring front arrangement. In practice though, I never use either of the smaller chain rings in the front I do shift through the rear stack regularly though and like having these options since the 408 is pretty wimpy on hills.

On my new project however, (18s2p 16ah, Cromotor, Giant DH Team) there are some new challenges. The added width of the new motor will allow a maximum of three cogs on the back and the Giant was designed for a single front chainring (4 bolt style). Now the only 3-speed freewheels I can find look to be real cheapos. I bought one of these and will try it.
http://www.amazon.com/Como-Scooter-...=1384962656&sr=8-2&keywords=3-speed+freewheel
But I don't hold out much hope for any kind of longevity. I considered using one of these
http://www.amazon.com/White-Industries-Dos-ENO-Freewheel/dp/B003NML7K4
But that then limits me to just two speeds.
I have ordered a 52T Rennen chainring for the front since they seem to be the only place that sells larger sizes in the 4-bolt pattern. Here is my big problem though; my current bike is 44X11 in its highest gear and this yeild good performance at 30 mph. But my new build will only be able to fit, at max, a 3-speed cog. Since this does not get the freewheel much past the freewheel threads on the side cover, there is no possibility for the freewheel to go smaller than 16T. Using this calculator for ratios and speeds:
http://www.bikecalc.com/gear_speed

I find that 52 X 16 is considerably worse than my current bike as far as being able to pedal at higher speeds. I have considered using a Shlumph drive on the front but will only take that expensive step if I think i need it after the main build. So if I am using a 3-speed cog on the back I will use a 5-speed deraileur and adjust the stops down to three speeds. Here is my question can I use a three speed front shifter to control a rear deraileur that is limited to three speeds? Does each click on a front shifter equal the same amount of cable travel as a rear deraileur if they are the same brand? Has anyone found a method of getting higher speed pedaling from fewer rear gears other than the schlumpf drive for a hub motor? Obiwan

 

[dogman dan]

Ignoring the 9 speed convert to 6 problem, you need to gear it high as you can if you want to pedal at 25 mph or more.

I find the typical mtb setup pedals good only to about 20 mph. Sure, you can flap your legs faster, but you won't push much past 20 mph on 48-14 gearing. 14 tooth is the smallest sprocket on typical 7 speed screw on freewheels. Sourcing one with 11t is good advice. 48-11 is not bad, can pedal to about 24mph ok. Again, you can be still pedaling at 30 mph, but clown pedaling does not push the bike, you just burn 100w flapping legs. Still good exercise, but not lowering your wattage on the CA unless you are sprint pedaling.

My own faster bike has a typical cruise speed of about 30-32 mph on the flat. I cannot pedal along at that speed, unless I stand on the pedals and go bezerk.
Sitting on the saddle, I can pedal to about 25 mph. I have a 56t front and 14 t back gear. So I tend to cruise 20-25 mph if I want to pedal too. Or I pedal to 30 mph and then stop, with the last 5 mph in a sprint till I fade.

Believe me, it was not easy to find a 56t sprocket that fits an MTB crank bolt hole pattern. It was an ebay find of pure luck. Most big rings fit only road cranks, and they will rub the frame if you put one on an mtb. So again, get the 11t rear freewheel, in 7 speed most likely.

There are a few motors on the market now, that take a 9 speed cassette. I believe bafang and crystalyte each make one.