getting a regular bike after my battery fails?

fooferdoggie said:
What I need is a calculator that tells me that at 240 pounds with gear and my bike weights say 35 pounds, what gearing do I need to get up a 18% grade, putting out say 200 watts and 400 watts. That will really help with the gearing. A triple on front would take care of it too.
Click to expand...

Bike Calculator

Useful calculators for estimating your speed on a bicycle velocity from various parameters.
bikecalculator.com

Bike Gear Calculator For Cyclists | BikeCalc

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You need to run both of them in sequence.

1768376600704.png

With the input of 200 W, you can only achieve 1.88 mph, which is impossible to maintain.
If it is 400 W, then the speed would be 3.75 mph, and probably you could barely maintain that speed. (18% grade is a killer).

Let us assume you could maintain the stability at 3.75 mph. So now we get to the other calculator, this part:

Bicycle Gear Speed Cadence Table | BikeCalc

Calculate cycling speeds at a specified cadence given chainring, sprocket, tire and wheel sizes.
bikecalc.com bikecalc.com

Assume your 2x chainring is of a gravel type, 30/46T. Again, if that's a 2x gravel cassette, the granny gear would be 36T. Let us eventually assume a typical wheel size for a gravel bike:
1768377586719.png

You can do it with a 30T front chainring and the 36T granny gear of the 2x system when you are out of saddle and pedalling at 55 rpm.

Next attempt. 1x, 32T chainring and 51T granny cassette gear. Let us assume you pedal at 70 rpm:
1768377005008.png

You need to pedal at around 70 rpm while inputting 400 W. The gearing can be achieved with a 32T chainring and a 51T granny gear, for example with an 11-speed Shimano CS-M5100 cassette or one of SRAM 12-speed MTB cassettes such as the 1275.

Note: The speed is independent of the gearing. To climb a specific grade at a specific speed, you need to input a specific power (calculator 1). When you know the speed, you can find a gearing that allows riding at that speed and at given cadence (calculator 2).

P.S. It is the technique @mschwett once taught me. I used those calculations before a race where 14% grade climbs were expected. It made me understand I needed my full power e-bike for that race. And an MTB gearing, too.
 
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fooferdoggie said:
SO I am going to need a pretty small granny gear. I don't need a really large outer ring, 34 or 36 would be plenty.
Click to expand...
Perhaps we misunderstand each other. You would need a small chainring. The granny gear is the largest sprocket in the cassette. If you go for the 1x drivetrain, you have the choice of 11-speed 11-51T (or 52T), or 12-speed, which might be even 10-52T (SRAM) but 12-s cassettes require a special driver for the freehub body to hold the 10-teeth smallest cassette sprocket (MicroSpline for Shimano or xD for SRAM).
 
well a small chainring then. I would like to stick to a 11-42 if I can I like the spacing better. but if I went with 11-52 I could go with the new linkglide. its so durable with the steel cassette and longer lasting chain.
 
If you have decided on the left side crank power meter, you will need to get a crankset compatible with that. You are looking for what's called a compact double crankset. I have a nice from IRD (Defiant?) on my Disc Trucker, but it uses a square taper bottom bracket.
 
Just bear in mind the small chainring would limit your pedalling speed on the flat (no way even to pedal downhill!)
I checked some gearing ratios. If you go 1x 34T(front) to 46T (rear) the gearing ratio will be 0.74. This is almost the same gearing like in a 3x drivetrain with the smallest chainring of 26T and the biggest cassette sprocket of 36T, which is 0.72.
 
so if I had a 32 or 36 chainring and 11-52 how much effort to get up that hill? I can get our tandem up to 28 with a 38, but I won't be going that fast, but downhill. my hills are way to steep to pedal down and too short. So I don't need a larger chainring.
 
It is all down to how much power you could input into your cranks (and only that matters). There is no gearing that could lift you uphill if you could not produce enough power with your legs.

You said the weight, grade, and the leg power of 400 W. The calculation shows you should be able to maintain the balance at 3.75 mph because 400 W won't take you any faster up the steep incline.

Now, the gearing is just for maintaining a good cadence at 3.75 mph. With a 52T big cassette sprocket, your cadence at 3.75 mph shall be:
1768432276364.png

Precisely speaking, you should input 400 W at the cadence of 73 rpm (32T chainring) or 65 rpm (36T chainring).

It is not a big difference in the cadence. Again, it is the power delivered to the drivetrain that determines the bike speed.
 
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Just to illustrate only the pedal power makes the bike speed (if we neglect the resistances such as air drag, etc.):
I was on a ride together with my friend, a strong traditional cyclist. We rode two abreast on a smooth gravel road on the flat. Marek suggested we speeded up and maintained a pretty high speed together. I rode my powerful Vado and he was on a carbon gravel bike. We both had power meters on our bikes (mine was in the e-bike motor and his was in the crankarm). As we rode at the same speed, he asked me to estimate my leg + motor power at the moment. I could do the math in my mind, so I told him I estimated the combined power on the Vado drivetrain to some 230 W. Excited, he replied: 'Same on my own power meter!'

You cannot cheat the laws of physics.
 
fooferdoggie said:
As my trek e bike with a bosch motors battery is over 500 cycles its getting close to its lifespan. the bike has 20,000 miles on it. The motor may give me another 20 or fewer before the bearings start to go. for most of my life, I had serious energy issues and without a ebike I could not really ride. but now I can average 120 to 155 watts on my commutes so I think I can ride an analog bike. I have two 1 block 18# grade hills I need to get up that I will need lower gearing for. I know I want flat bars and I have a lot of parts to upgrade a used bike. I have two sets of dt swiss wheels shimano deore


4 pistion brake parts shfters and such. though I think I would need a 11-52 cluster and maybe a 36t chainring. I don't need to go ver 20mph, so maybe that should work well for me? I could buy a bike and work on it and do what I can. I can't run new brake housing and i dotn want to buy the tools to do it so a local bike shop. not sure how narrow of tires I want to use. my first bike had 1.5” tires and my trek has 2” I don't want that large of a tire it makes the bike too sluggish.


I can climb my short hills putting out 450 watts


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Yeah, I’d say it’s totally doable to go back to analog with your numbers. 120–155W cruising and a 450W punch for short hills is solid — the only thing that’ll make or break those 18% blocks is gearing.

If you go 1x, I’d lean 30T/32T up front + 11–51/52 in the back. A 36T might be fine on normal stuff but can get grindy on steep ramps. For tires, if 2.0" feels sluggish, I’d try something like 38–45mm — fast enough but still comfy.

Also, 500 cycles doesn’t always mean the Bosch pack is done… sometimes a new battery is the cheapest “new bike” you can buy. What Trek model is it and what gearing are you running now?
 
JL0256 said:
Yeah, I’d say it’s totally doable to go back to analog with your numbers. 120–155W cruising and a 450W punch for short hills is solid — the only thing that’ll make or break those 18% blocks is gearing.

If you go 1x, I’d lean 30T/32T up front + 11–51/52 in the back. A 36T might be fine on normal stuff but can get grindy on steep ramps. For tires, if 2.0" feels sluggish, I’d try something like 38–45mm — fast enough but still comfy.

Also, 500 cycles doesn’t always mean the Bosch pack is done… sometimes a new battery is the cheapest “new bike” you can buy. What Trek model is it and what gearing are you running now?
Click to expand...
all the hills are short one block. portland isn ot flat anywhere. I can have a 3% grade on one block and two blocks over its flat. I have a allant 8 with a Gen 4 motor. The bike has 20k on it. Yes its hard to know how long the battery will go. my first 500 battery died after about 520 cycles. it was letting us go 15 to 20 miles on our tandem when it died in the middle of the ride with 48% left so you never know. the bike is a dog with 42t chainring and 11-34 cassette. the 2" tires or soemthing makes it so sluggish compared to my first bosch powered bike. with all the rain and my miles, I am worried a new battery may outlast the motor.
 
Stefan Mikes said:
It is all down to how much power you could input into your cranks (and only that matters). There is no gearing that could lift you uphill if you could not produce enough power with your legs.

You said the weight, grade, and the leg power of 400 W. The calculation shows you should be able to maintain the balance at 3.75 mph because 400 W won't take you any faster up the steep incline.

Now, the gearing is just for maintaining a good cadence at 3.75 mph. With a 52T big cassette sprocket, your cadence at 3.75 mph shall be:
View attachment 204612
Precisely speaking, you should input 400 W at the cadence of 73 rpm (32T chainring) or 65 rpm (36T chainring).

It is not a big difference in the cadence. Again, it is the power delivered to the drivetrain that determines the bike speed.
Click to expand...
you nailed it Stef!
 
well if you are as strong as you where when a teenager,just go to Wally world and get a good cruiser(single speed-3 speed if you are feeling froggy no maintenance to speak of,durable cheap,when I was teen ager I went everywhere on a cruiser and the hills around here were only limited by determination( last time I tried that hyper ventilated for 5 minutes,semi paralysis and bulk took care of the old 40 years ago aspirations-seriously get a decent cassette without many tricks)
 
fo far that surly trucker frame is the best bet. Everything I have but my suspension seatposts fits. Everything used even a frame, there are always things that won't. The rear spacing is the big one I need 142, and I have two great rear wheels that will fit that. So getting a normal bike spacing means a new rear wheel so no real money saved. or the polder side-mounted brakes not the post-mounted. it always seems it would cost mroe to change out those components then by aframe that has everything I want.
 
got thew frame and now I am hunting around to see if I can find the parts I dont have used or cheap. I am not in a hurry so I can hunt around. The biggest suck is my suspension seat post I am going ot have ot see if I need it
 
RunForTheHills said:
I think you'll like the Trucker. I like them enough to own two of them. Steel is real!
Click to expand...
Plus I can use any size tire. Trying to find something used is tricky unless your getting all your parts after. found a double crank in the right size I was not sure if I could most dont go down that low.
I dont need a triple. 20.00 less than normal. https://www.ebay.com/itm/306575703942 now I need to find the front shifter for this setup. https://www.ebay.com/itm/164445556176?var=464058594819
 
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