Does a mid drive really need a freewheel?

[Retrorockit]

I guess it's time to bust an E bike myth I've seen going around. "You can't shift more than 1 gear at a time".
Box will sell you a special E bike shifter that only does 1 at once. Most trigger shifters will do 1 up/3down. Still not good enough for serious street riding. Only a twist shifter gives you real control of your gears. That and an IGH hub or Rapid Rise derailer. Twiddling your thumbs with a trigger shifter is a very bad idea in urban traffic. Save that for calling 911.
This mod with a twistshifter on a 1500W BBSHD gives full gear control on a derailer setup. When you stop pedaling the drivetrain is under no load, but is still moving. Perfect conditions for a shift. Or even a bunch of them.
I've always run Gripshifters. Triggers were the first thing to go on my bike. I still have a Rapid Rise derailer which can downshift at a stop. But since doing this mod that hasn't been needed. The bike is always fully engaged in the gear I want before I stop.
So, this mod is cheap and easy to do. But if you still let your trigger shifters limit your choice of gears, you might be missing the whole point of it.

I'm sure AZguy won't give up his MC style twist throttle. So I guess we'll just disagree on this as usual.

[AZguy]

...So, this mod is cheap and easy to do. But if you still let your trigger shifters limit your choice of gears, you might be missing the whole point of it.

I'm sure AZguy won't give up his MC style twist throttle. So I guess we'll just disagree on this as usual.

Yup lol

We generally have different use cases and backgrounds so no wonder - I see it as a good thing

Well my M8000 does 2up and 4down... two very quick easy strokes dumps 8 gears, seldom need to go up so fast but two small pushes will get 4 gears which is ample

The up shift is nice that pulling will assure one gear and pushing can do one or two

Another nice thing is that I was able to mount it on the left side above the bars and I find it better ergonomically on the top and being on the left matches my long history of motos better (shifting on motos is left foot) and frees up the right side for the half-twist throttle

For me this is the way to go! ;-}

[Retrorockit]

I think our differences are good too. Usually one of us will have a solution for someone, or at least offer some options.
For me this mod has finished what I was trying to do with my Rapid Rise / Gripshift setup. Total real time gear selection.
Also it seems that having 2 one way clutches made it impossible to know what would happen with any given shift.It's very consistent now.

[73Eldo]

I was thinking of trying it but have not had much time to ride lately plus the street bike has the dork disc in the way of doing this easily. I would rather try it on that bike than the offroad one just because I don't know if the chain bouncing around would be a problem.

[Retrorockit]

Now we know what the dork disc is for. To keep you from doing this mod!
Someone who rides offroad will have to tackle that question at some point. My old Rapid Rise stuff doesn't have clutches on the derailer. So it remians to be seen whether it's an issue on modern bikes. I could probably add one of those since RR isn't required any more.

[Retrorockit]

The answer is NO. Mid drives don't need a rear freewheel.

I've got about a week in on this mod and I really like it.
1- This does require the habit of stop pedaling to shift. there is a slight decay to power if you just stop, but the slightest backpedal seems to eliminate that. No idea what the difference is electrically.
2- Multiple shifts up or down are no problem. When I use the throttle to accelerate it always takes 2 gears up for cadence to catch up with the BBSHD.
3- Not pedaling when braking is normal now, and I can dump all the gears I want. I've always preferred grip shifters. Better than Rapid Rise because no need to pedal it into gear after a stop. It's already done. Rapid Rise does let me downshift shift when stopped. Probably a rare situation now, but I already have it, so that's still there. Have to feather a brake lever until it's in gear or a big crunch when the motor kicks in ( that's only for stopped shift with RR derailer).

So for me all the theorizing is over. Cheap quick and easy mod. Works great. Local bike racers, MTB guys and LBS techs all like it. I'm surprised no one else here has tried it.
I put the bike on the center stand, spin up the rear wheel. They can see the chain ring going around with pedals stopped, and I run it up and down the gears. People who actually ride bikes think it's pretty cool.

[AZguy]

You using a shift sensor?

Prolly already said somewhere but I'm too lazy

[Retrorockit]

Moron this. Since this started as a freewheel project I looked into what Shimano did for a freewheel on these bikes.

https://www.youtube.com/watch?v=J39t1IxAPcg

That doesn't kill this mod, but it does need to be considered. I definitely wont be welding a freewheel solid.
The hub to cassette mod doesn't drive the bike forward through the zip ties. They just carry the chain around when coasting. The drive is still through the one way clutch in the hub. So less is more here. I will go back and put 2 real small zip ties in so if the chain jams they will breakaway leaving the bike with 2 freewheels again. If they're too weak I'll add another. Fail safe is the word for this.
You could test this with a rope like the guy did in the video if you want to.

[Retrorockit]

No shift sensor. I tried one and took it off. The delay in acceleration was too much for me in traffic. I like this much better. haven't had a blown shift with this at all.I can still power shift if I don't stop pedaling, but I haven't felt any need for that Throttle only just blip the throttle to shift, no pedaling to make the gear change This means I can change gears while standing on the crank

[73Eldo]

My thought too was to try it with a small nylon tie with the idea that if anything got stuck it would break fairly easily. And if it breaks? So what you are back to the way it was, not a real big deal.

I was looking at my dork disc and its pretty open in the center so I can likely try this without having to take things apart.

[Retrorockit]

Just keep the zip tie towards the inside so it doesn't move up between the cogs where it can hit the chain.
I used 3 regular zip ties to try it out, and it worked great. But no reason to think a chain won't come off at some point, so less is more. I'll go to 2 small ones.

[Retrorockit]

I was thinking that rolling the bike backwards would maybe break the zip ties, but now I realize that it already drives through the freehub when that happens. So they don't need to be beefed up for that reason.

[Retrorockit]

I made the change discussed above. Went from 3x 40# straps to 2x 14# straps about 1/4 of the strength before. I put one of the small ones around my finger and pulled it apart with a pair of pliers. It took a pretty good pull but nothing extreme. Didn't have to pull the wheel to do this.
If this works maybe I'll snip one out and try that.

[Retrorockit]

I had mild chain drop with this setup. Nothing unusual happened. The derailer went full travel, no tension on the chain so it just skipped over the rear cog. The failsafe wasn't activated. Probably lack of chain lube due to fooling around with the cassette mod, putting on new silicone foam grips, and dumping some Stan's in the rear Tannus.. I found an LBS with a small bottle of Squirt wax lube, that's now in my tire repair kit for roadside tochups.

[73Eldo]

4 oz bottle or the really tiny one? I have thought about getting the tiny one and carrying it but I have the space and carry enough other crap that the 4oz would not really be taking up that much space or adding that much weight in the grand scheme of things.

What size do you normally buy? The big like 32is one? I have been using the 4's. Worried that the big one would go bad over time because I'm only going through like 4 oz per year per bike.

[Retrorockit]

I normally buy the 4oz., small enough to squirt right on the chain. I got the tiny one for on the bike. I had one at home but never stuck it in the bike kit.Now that I hide my CO2 inside the rack tube there's more room in there.

[Circuitsmith]

Most trigger shifters will do 1 up/3down. Still not good enough for serious street riding. Only a twist shifter gives you real control of your gears. That and an IGH hub or Rapid Rise derailer. Twiddling your thumbs with a trigger shifter is a very bad idea in urban traffic.

I once had a twist shifter.
If I got caught in the rain without gloves (pretty frequently when I rode to work) the shifter became unusable.
Perhaps my city street riding style is laid back. Downshifting 3 gears (7 to 4) is all I ever seem to need.

https://www.amazon.com/gp/product/B08P5NCBDK

[Retrorockit]

Some of the SRAM gripshifters for offroad have very lumpy shift sections.

https://imgs.search.brave.com/w6a3CKJnd3hvhtPgmO4rCIDQV-vPBKFG-Ii4WbpDYm4/rs:fit:1024:570:1/g:ce/aHR0cHM6Ly9jZG4u/aGliaWtlLmNvbS9p/bWFnZS9wcm9kdWN0/L0VTVy9FU1dfU3Ja/R0UtaWwuanBn

But I've had the problem with Rapid Rise where the spring preload is the wrong way.Right now my Shimano Revoshfiers are useable when wet but not ideal.
2 up ans 5 down are common for me. 8-3 downshift when doing 30-0 mph, and 2 up to get cadence back after throttling the BBSHD in traffic.
I mostly run gripshift because there are no Rapid Rise trigger shifetrs that I know of.. TBH with this mod I could probably live without it.

[Retrorockit]

I've been running Rapid Rise Gripshift for so long I actually don't own any trigger shiftrs any more.

[Retrorockit]

AZ asked about the shift sensors instead of this mod. Here's my experience with them.
1- They have a fixed delay.
a- For acceleration in traffic the power seems to be off 1/2 the time when running up through the gears. This confuses drivers close behind me.
b- The power can cut back in unexpectedly when downshifting multiple gears at once. This can apply power when between gears. Not ideal when stopping from 30+mph.
So my take on them is they're like an old slushbox automatic transmission. They work within a restricted range of situations.
With the front freewheel mod I determine with my pedals the length of the delay needed for any situation. I also know which freewheel is active so I know how it will react to any inputs.

[Retrorockit]

I've got a couple more rides in and everything is working great. I'm going to cut out the 2nd 14# zip tie and run just one. That should satisfy the breakaway requirement. I'll stick a couple spare ones in my tire kit, and some tweezers in case I need to put 2 of them back in. I think one will be enough. if that works I can't think of anything that would be cheaper or easier than this mod

[Retrorockit]

I'd never even heard of it. All I "know" is what's in those links. But it looks like SIS, and Hyperglide came out of that, and maybe Rapid Rise too.
I think it's kind of funny that everyone calls it "entry level" or "low end". Is that because it actually is easier to use and works better than the older tech?
I actually can't think of anything an IGH can do that my bike can't. If I shift when stopped I do have to roll it into gear before applying power, but that's about it.

[73Eldo]

I think because it was easier was why it was on those lower end bikes. The 'pros' didn't need crap like that.

[Retrorockit]

Schwinns production exceeded the total output of all the bikes built by the outfits that catered to the "pros".
Put a BBSHD on one of those Pro bikes and you'll see what's crap and what isn't.

[Bob Anson]

Was wondering how to do this to help the shifting clang! Any pictures of the ty wrap locations? Just can't figure it out. Seems as if your limiting the back pedaling all together.

Thanks

[AZguy]

If the shifting "clanging" is occurring due to the motor applying power while shifting then this alone doesn't change that

The back-pedaling will stop the motor from applying power - this change described here (tying the cassette to the wheel) allows for shifting without pedaling since the rear wheel will be turning the cassette and moving the chain through the shifter and so the pedals can remain stationary

To stop shifter "clanging" is occurring due to the motor applying power while shifting something will need to cut the motor power while the shifting takes place. FWIW a gearsensor has always done this job exceptionally well for me and I pedal just like I was riding simply backing off the pressure while shifting. Others have used brake sensors to cut the power, just engaging the brake enough to trip the sensor and this can be "natural" for moto riders that are use to feathering the clutch lever while shifting (personally I've grown to dislike brakes sensors and they don't make much sense to me). And others will back pedal just prior to shifting to get the motor to cutout for the shift.

Personally I just pedal the bike like a normal bike, which is what comes most natural for me, and let the gear sensor do it's job

There's no right or wrong here, just different strokes as they say

But *if* (big if) your shifter "clanging" is occurring due to the motor applying power while shifting then you should consider doing one of these things (whatever works for _you_) to prevent it, it's very hard on the driveline...

[Retrorockit]

This mod is so simple a picture shouldn't be needed.
One very thin Zip Tie that holds the inner cog of the cassette to the hub or spokes. That is the whole mod.
Back pedaling will happen at the front freewheel. But only the pedals will move backwards. The wheel, chain , cassette,and front gear will all still move with the wheel.
But the back pedal will turn off the power and release the front freewheel (clutch). This will allow a smooth quiet shift just like a car. When the shift is done apply power either with the pedals or throttle. The video above on the Shimano FFS bike shows this. the wheel is turning, the pedals are stopped, and he runs the bike up and down through the gears. You can try this on a bike stand to see it work.
My own bike has XT hubs with holes in the flanges I used one of those, But the spokes will work just as well. Put it near the hub so it doesn't touch the chain on the next cog.

[Retrorockit]

I suppose I should mention that this is only for mid drives that have a front freewheel. There are some coaster brake versions of the TSDZ2 that don't have one. Probably more common in Europe.

[Bob Anson]

Thanks for the info! Have a X-2 and i don't even know if it has a shift sensor. I'm having trouble downshifting several gears at a time. Need more time in the saddle to learn the torque curve of the motor. Need to downshift 3 gears at a time instead of one. It's like missing a shift in a fully loaded semi up a steep hill [The Grapevine ], JUST STOPS! Used to riding dirt bikes,where downshifting is done one gear at a time as necessary . But these need to be kept "spun up",or they fall on their face like the semi's. I guess this mod will help to move the chain on the gears as soon as you shift, with motor off.

[Retrorockit]

If it has a shift sensor you would feel a power cut every time you moved the shifter. This mod makes it like a standard MC. Motor-clutch-transmission layout.
A quick baclpedal is the same as working the clutch and throttle for a shift.It stays off until you pedal again. You can also moto around on the throttle and shift with the pedals level if you want.
How many gears does that have? A powerful e bike 8 or so is usually enough.

[Bob Anson]

Has 12 spd in rear, is a one month old Luna X-2, shift sensor? Just placed (2) small ty wraps from spokes to rear cluster so it still spins when i stop pedeling and gears shift fine.
Should allow me to downshift as needed before adding pedaling or throttle. Before I needed to downshift once ,pedal,downshift pedal, ect.....
Not good when trying to get in the correct lower gear FAST. We'll see. Thanks Again

[AZguy]

Shimano Deore XT: https://bike.shimano.com/en-EU/produ...ext-m8000.html

The "RapidFire" shifters downshift up to four gears in one push, for upshifts a pull gets you one gear and a push one or two

I've got the long cage derailleur and while designed for up to 46t rear I've got it working well with a 51t sunrace albeit a little slower on the up shifts in the highest gears

The downshifts are great though, literally will do four shifts in about 3/4 revolution and easily does eight gears in just about one revolution (just took a look at it), very quick, snappy and predictable...

[Retrorockit]

I just stacked up new cassette that will require an 8-2 downshift for every full stop from speed. It's a modded Sunrace 11-40t 8 speed.
11-13-15-18-22-28-34-40
I added a 12t in between the 2 top gears and swapped the 34-40 pair for a single 36t to get
11-12-13-15-18-22-28-36
The 36t is for unpowered riding around pedestrians and won't get used much. So it can move on to the next cassette. This should fit most older MTB without a derailer hanger mod. I'll still be using the 28t for taking off in traffic. It will be a little more crosschained so IDK what will actually happen. Maybe the FFS mod will save it? At the top end I can adjust my cadence better, and spread the wear across 3 gears instead of just 2.

[Retrorockit]

I looked up the RD M8000. It looks nice. I wonder if I put 8 speed idler cogs in it if it would work for me. It says normal mount. I hope that means the same as my older bike, and not some new normal that I'm not aware of. It's not low normal )Rapid Rise)which can shift when stopped, so I may skip it,