Do you *have* to use a MTB for fitting a TSDZ2?

I read that only a mountain bike is strong enough for an ebike conversion because of the stronger forces from the motor vs muscle power.

However, a moutain bike doesn't fit my requirements: I want full fenders for commuting in the rain, and I want to fit a rear rack with paniers for errands. I still want to go on forest trails on the weekend, but the main use for that bike would be commuting and errands.

Instead, I am considering something like a Trek FX 2 Disc (https://www.trekbikes.com/gb/en_GB/bikes/hybrid-bikes/fitness-bikes/fx/fx-2-disc/p/27991/?colorCode=grey) or a Marin Muirwood (https://www.marinbikes.com/bikes/2019-pavement-fitness-transit-urban-muirwoods)

The Trek has 700x35c tires which might be a bit too thin (I think?) and the Marin has 700x40 (not much wider). The Trek has an aluminum frame vs Cromoly for the Marin.

Anyway, would these bikes make fine bases for adding a TSDZ2 or is it absolutely necessary to use a mountain bike as the base?

Ofcourse not, that bike will do just fine. Just make sure the bottom bracket is suitable for a TSDZ2 (68/73mm width, pressfit ones might not be compatible)

Right, I need 68/73mm square tapered, correct?

How do IGH like the Shimano Nexus fare with the TSDZ2?

Gonna hit ya with a couple cosmic concepts, here.

Most of the things that make a regular bicycle, "good", are things to reduce weight. Once you add a motor, and 3 to 5 times sustainable human leg power, most of that goes right out the window.

Max speed, and especially AVERAGE speed, goes up significantly. Strength and durability become primary considerations, weight concerns are largely insignificant. My fairly light motor and battery kit alone weigh about as much as my best road bike did, and make my older, cheaper, steel cruiser a much better system.

Steel becomes a superior frame material, it is stronger, more durable, and can be easily modified with a bit of welding to add things like disk brake mounts, better dropouts, frame extensions, permanent torque arms, etc. The only real drawbacks are higher weight, and secondarily, steel is usually found on the "less expensive" bikes, with other, somewhat less desirable features.

The "downhill racer" is often suggested as they are basically the toughest standard bicycles widely available, and older models are often significantly discounted by those upgrading to the latest and greatest. Another option is to get a cheap box store bike with a steel frame, strip it down to the frame, weld on disk brake mounts and torque plates, add quality accessories, and for similar money, end up with a much better, designed for the purpose, steel-frame e-bike.

The number of people reporting long-term success with an IGH and any mid-drive does not seem to be anywhere near as high as those reporting short-term failure with similar equipment. Get something that you can easily and inexpensively replace on a fairly regular basis, roughly in the 1,000 to 3,000 mile range. Chains, gear clusters, etc. It is not a question of "If", rather, "How often?".

There are a couple Sturmey-Archer units which were thought to be a bit more robust, possibly, mainly they do not target the weight-weenie crowd, but I have not seen any long-term user reports. RXK5, or something similar for model name.

I understand that downhill bikes are a lot more robust. But they don't suit my usage because they don't easily fit full fenders and a rack/paniers.

I would be happy enough doing 20-30 km/h on flat ground, I'm not interested into pushing the motor and frame to their limits (not for my first ebike anyway)

I get what you're saying about modifying the frame but I have no access to an arc welder and I am not competent to solder anything or alter the frame in any way.

I live in Switzerland, and local used bikes cost more than the same one new in Germany so I'd rather get a new bike for the money.

That lives me in a spot where I can't consider a downhill or MTB because they all come with suspension forks and fenders won't fit.

What I can't gauge is whether a hybrid bike would instantly explode with an electric motor or if it'll be fine provided I don't put a 1000W motor on it and go full throttle all the time. I understand "consumable" parts such as the cassette or the chain will be replaced more often than without an electric motor but as long as they don't wear out every 1k or 2k km, I can live with it.

Looks like either bike would work and are similarly equipped. Considerations might be battery location, both of which are ample; range of the rear cassette, since you'll be mating it to a single chain ring; seatpost diameter, nice to have a standard 27.2 in case you want to add a suspension post later; brakes, both look good; and tire clearance, in case you want to go up a size or two if you shift to riding on trails more.

E-HP said:

Looks like either bike would work and are similarly equipped. Considerations might be battery location, both of which are ample; range of the rear cassette, since you'll be mating it to a single chain ring; seatpost diameter, nice to have a standard 27.2 in case you want to add a suspension post later; brakes, both look good; and tire clearance, in case you want to go up a size or two if you shift to riding on trails more.

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I'm leaning towards the Muirwoods because I love the color and although it's more expensive, it's a Cromoly frame vs Alu for the Trek. But I think frame material only really matters for hub drives?

Frame material doesn't matter for hub drives either. Just use properly designed and mounted torque arms or plates.

skestans said:

That lives me in a spot where I can't consider a downhill or MTB because they all come with suspension forks and fenders won't fit.

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No reason you can't put a fender on a suspension fork:

amberwolf said:

Frame material doesn't matter for hub drives either. Just use properly designed and mounted torque arms or plates.

skestans said:

That lives me in a spot where I can't consider a downhill or MTB because they all come with suspension forks and fenders won't fit.

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No reason you can't put a fender on a suspension fork:

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It seems like MTB that comes with a suspension have very little clearance between the tire and the bent part that connects the two sides of the fork. I'm worried most fenders wouldn't fit there. They also have narrower triangles to fit a battery.

I can't decide if I need to go for a Cromoly frame imperatively, or if an aluminum frame will be just as good? There aren't many Cromoly frames made anymore, it's all aluminum.

skestans said:

It seems like MTB that comes with a suspension have very little clearance between the tire and the bent part that connects the two sides of the fork. I'm worried most fenders wouldn't fit there.

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There are several fender options for suspension forks, both above and below the arch, so that's not an issue. Mine is below, and still has clearance for a 2.5" tire.

Sometimes it's even easier to mount a fender on a suspension fork. Some of the rigid forks with canti brakes require drilling, and drilling a hole in tubular steel can be tricky if you don't have a press.

I settled on a Marin Muirwoods in Tequila Sunrise paint. It has all the required holes for fenders + racks, no suspension, and a cromoly frame. Thanks for your input everyone.