The SL bike is dead. Long live the SL bike!

[surlyrides]

Just came here to say that true SL bikes and true FF bikes are always going to be different. The whole intent of the bike industry is to make as many different variations as possible so people can purchase exactly what they want and it gets more people into the sport. I don't think it's too much different than an XC bike vs an Enduro bike - people are always going to want one or the other or both, they can't substitute for each other in most situations....

I'm fortunate to have several full fat bikes and SL bikes (some would say I have a problem ) and I will take different bikes out for different trails or days. Some days I just want to turbo up the climbs and some days I want the lighter bike for a trail that is steeper or jumpier. I like the way full fat bikes ride and I like the way SL bikes ride but they are different. If I had to choose, I would rather have a lighter bike so I think there will always be a market for lighter bikes and that's always going to mean smaller batteries and lower powered motors, that's just physics.

I just can't wait till the industry standardizes so I don't have to buy a new bike every year when the technology make a big jump

 

[jeanmarc]

As more and more trail centers (aka ski centers) are developing mtb trails for year-round business, I find myself thinking I’ll need a DH analog bike added to my “one bike for everyghint” Santa Cruz Vala…

 

[DanDeride]

Regulator SX seems like the sweet spot currently.

The Regulator is so fun!

 

[DanDeride]

I'm in the same boat Nick. Started out with a Turbo Levo Gen3 for 3 years, but after trying a few SLs realized I really loved that peppy poppy feel of a lighter bike, and the challenge of having to pedal harder to go higher & farther. I found a good deal on a Levo SL this Summer and have been absolutely loving it! When I need more range I throw on a booster battery & I'm off to the races.

 

[squeegee]

As a full fat rider I was skeptical that lighter SL bikes would ride that much better. I must admit I was wrong.

...more power at the expense of lighter weight. Is this trend driven by genuine customer demand or by the brand marketing departments who fear being left behind?

Marketing+YouTube influencers have everything to do with the current "more power=better"-Kool-Aid being served up to consumers, demand created in large part by media consumption rather than genuine demand from real use cases. More torque, more watts, more support, more battery, more weight, you just didn't know you needed it.

 

[sethimus]

The issue will soon become that the Maxon Is only .1kg heavier than the TQ60.
So then the weight is just determined by the battery size that you choose. No need to miss the power when you want it.
Imagine this: A Maxon bike with a 500w battery and a 300w RE. It's an SL, and a full power in one!

so far, the maxon is only available with a so called 400wh (usable 336wh*) battery, aka a dud. we will see how much of the way heavier 600wh is usable in reality, then you maybe get your 500wh…

*see the new motor comparison from ebike-mtb.com (which will look into the real efficiency in the upcoming releases and drag and all the other specs you always seem an expert to be about, and which you will get confronted by me ALL THE TIME in 2026 )

 

[Suns_PSD]

For sure the Maxon Is not available in the real world in a wide selection of bikes with an appropriate battery pack.
Just pointing out what the future holds. Very little of the weight is in the motor itself. It's mostly in the battery pack.
I would think people with reading comprehension skills and a little bit of common sense would recognize that, but I guess not

 

[G-Sport]

I came from a push bike to a Levo SL gen 1. The power seemed ridiculous at first and I mostly used Eco with just a bit of trail. Lots of range and not much weight penalty over my push-bike. I was reasonably fit and was still setting out to do a ride I would have done on the push bike.
3 years later and I spend a lot of time in trail and use turbo extensively and find myself wanting more assistance at times. This is because I have less patience for climbs and want to squeeze more descents in. The range has dropped (with battery age and more assistance preference) and the walk mode drives me insane.
But adding even the range extender annoys me. My bike is at 18kgs with a robust build and going to 19.5kgs with the range extender ruins the bike but is still a kg or so lighter than these supposed light-weight-full-power bikes.
I'd love for more brands to focus on weight saving and weight distribution. A 4-500Wh battery with a 300Wh range extender with the lightest possible 50-60Nm or so motor would be lovely. The Bosch SX seems close to this but the weight saving over full power doesn't reflect the power sacrifice adequately.
I can't see myself buying a bike over 19kgs (with pedals and reasonable parts) and the idea of a 23+kg bike seems horrific.

 

[Deleted member 19064]

I’ve been saying for a few years now. The SL and full power bikes will merge into one eventually. Once the full power bike weights come down the SL market is essentially dead. I think it is very close but probably two more new bike releases away. I have an SL and have ridden several full power. I can say a SL 43 lb bike rides way better than a full power 50+ pound bike.

Dead? Doesn't this validate the SL market? BTW: The Specialized Kenevo SL, "SL" stands for "Super Light," indicating that the bike is designed to be lightweight while still providing efficient performance. I want the SL's to come down to around 35lbs. I don't need/want 800W of power.

 

[Deleted member 19064]

I came from a push bike to a Levo SL gen 1. The power seemed ridiculous at first and I mostly used Eco with just a bit of trail. Lots of range and not much weight penalty over my push-bike. I was reasonably fit and was still setting out to do a ride I would have done on the push bike.
3 years later and I spend a lot of time in trail and use turbo extensively and find myself wanting more assistance at times. This is because I have less patience for climbs and want to squeeze more descents in. The range has dropped (with battery age and more assistance preference) and the walk mode drives me insane.
But adding even the range extender annoys me. My bike is at 18kgs with a robust build and going to 19.5kgs with the range extender ruins the bike but is still a kg or so lighter than these supposed light-weight-full-power bikes.
I'd love for more brands to focus on weight saving and weight distribution. A 4-500Wh battery with a 300Wh range extender with the lightest possible 50-60Nm or so motor would be lovely. The Bosch SX seems close to this but the weight saving over full power doesn't reflect the power sacrifice adequately.
I can't see myself buying a bike over 19kgs (with pedals and reasonable parts) and the idea of a 23+kg bike seems horrific.

I avoid turbo until the grades get really steep. I don't need turbo level cheat. In fact, on most rides I don't hit turbo at all.

 

[Deleted member 19064]

Marketing+YouTube influencers have everything to do with the current "more power=better"-Kool-Aid being served up to consumers, demand created in large part by media consumption rather than genuine demand from real use cases. More torque, more watts, more support, more battery, more weight, you just didn't know you needed it.

I agree with your sentiment.

 

[nickf]

I avoid turbo until the grades get really steep. I don't need turbo level cheat. In fact, on most rides I don't hit turbo at all.

Been out again this afternoon for another great ride on my new Fuel+. I was putting in some effort on a decent gradient climb in Med mode, so I switched it up to Hi mode. Immediately the bike started to fly up the track like my full fat Rail (which I love) but it spoilt the feeling. So I switched back down to Med again and loved it!

I'm sure when I get back on my Rail again I will also love the sensation of flying up the track and crushing the technical sections. But the purity of the ride on my new Fuel+ is like rediscovering the roots of mountain bicycling .

 

[Hob Nob]

I have been sceptical of the whole SL space since I had a KSL, which really didn’t have a lot of point in my world. It didn’t really add anything than I couldnt do riding a normal bike in terms of range or elevation & by the time it was spec’d suitably for the travel it had, it was over 21kg.

I haven’t ridden one since but now have been on a TQ HPR60 bike with the big battery & it’s about 18.5kg - it’s a significantly better bike than the KSL was & does actually offer more than a tiny battery & weedy motor.

I also still have a full power Gen5 Bosch bike which is my shuttle machine - it’s a very different experience to the TQ, which is i would describe very much like assisted normal riding - they big power bikes are great in their own way - when I’m tight on time or recovering from something else, or just fancy smashing as many laps as I can, both of which are great & have their place, as much as pedalling a normal bike does if that’s still your thing.

 

[Emailsucks98]

The reality is, the more power the motor puts out, the less cardio & leg exercise the rider gets, and over time fitness declines*. Heavier full-power bikes can be a work out, but it is not the same kind of workout.

So any advancements in motor power might come at some cost to fitness.
In a way, that "full-power eBike at SL weight" would actually be the worst case scenario. It does sound super fun though! And I am all for fun. I like the TQ specifically because it works best at low assist levels where I still do most of the work.

I tend to agree with Mike Kazimers take, the more work the bike does for me, the less satisfying the ride is.

But that's just my personal preference, I totally appreciate others have different priorities.

*I know this from spending '22 mostly riding full powers, '23-24 riding mostly riding SLs, and '25 50/50 between meat bikes and eBikes.

The issue will soon become that the Maxon Is only .1kg heavier than the TQ60.

For me, the biggest benefits of the TQ system are never mentioned in reviews. Of the (4) motor brands we've owned, it's by far the easiest to live with. Ease of charging while traveling is a massive benefit, as are the multiple battery options. And it's quiet. It's not perfect- durability could improve, walk mode kinda sucks- but overall I'm happy with it.

 

[Pauliemon]

I had both for a while, a full fat and a sl. I started with a Levo SL. I was the first in my riding group to move to the dark side. Watching me ace all the climbs laughing and smiling while my buddies puked a lung, a change was inevitable. So they all bought full fats, now I'm puking. I ended up getting a Turbo Levo so I could keep up.

I ended up selling the sl and I regret it. Don't get me wrong, I love both bikes. I'd ride the Levo on group rides. I'd ride the Levo SL on solo rides or rides with acoustic bikes. Somebody came around and begged the sl off me. "Heavy sigh".

Besides the difference in weight, full 29 vs mullet, 38 vs 36 Fox. The two bike were very different.

In the future, who knows?

 

[Emailsucks98]

Marketing+YouTube influencers have everything to do with the current "more power=better"-Kool-Aid being served up to consumers

Agreed and it's hilarious when they poke fun at the forums.

I mean yeah, forums are an echo chamber - but we're also the consumers and our opinions aren't paid for!

 

[irie]

Dead? Doesn't this validate the SL market? BTW: The Specialized Kenevo SL, "SL" stands for "Super Light," indicating that the bike is designed to be lightweight while still providing efficient performance. I want the SL's to come down to around 35lbs. I don't need/want 800W of power.

What exactly is "efficient performance"?

 

[sethimus]

What exactly is "efficient performance"?

ask @Suns_PSD, he is an expert on motor efficiency

 

[Suns_PSD]

What exactly is "efficient performance"?

There is some variance in efficiency in the motors. It matters because motors are starting to all weigh from 1.9-2.6 kgs, regardless of power level. But the battery is still the anchor in the equation. If you can make that battery go further, you can reduce it's size and save real weight in a significant spot.

I read an interview from (I believe) a Shimano engineer once that said the equation is simple, you can either allow the gears in the motor to rattle but turn freely, or you can tighten the gears up to reduce rattle but then efficiency is lost. Bosch Gen5 actually just made it where the gears disengage so that gets rid of the rattle and still turns freely. Which is how the Bosch both pedals freely with the motor turned off and is rattle free.

Here is a video of that if you care:

- YouTube

Auf YouTube findest du die angesagtesten Videos und Tracks. Außerdem kannst du eigene Inhalte hochladen und mit Freunden oder gleich der ganzen Welt teilen.

youtube.com

Francis mentioned here starting at 3:47, that the Avinox uses a tighter shaft seal to cover up the rattle noise and then he shows how it increases spindle/ motor drag. This highlights that more than just the gear lash can effect efficiency. He also mentions that it's a known issue and should be remedied soon. Just because you can't feel this shaft seal drag when the motor is turned on, doesn't mean that the motor isn't burning battery to overcome it.


If you go to a somewhat aged PB e-bike motor test they did efficiency tests, they are not perfect, none are, but you can see some patterns.

https://www.pinkbike.com/news/5-emtb-motors-review-bosch-dji-shimano-sram-specialized-2025.html#efficiency

If you just scan the review, you will conclude that the DJI vs the others isn't fair to the DJI, as the DJI is in turbo mode vs. the older power rating Gen4 Bosch (for example) and the DJI is a lot faster. But if you read the article you will see that they also tested the DJI in Trail mode, and it still had an efficiency in Trail mode of 23% LESS than the Bosch gen4 in Race mode. These numbers are shown in the text.

There are many more examples I could give, but you get the idea.

 

[Mteam]

I've got an orbea wild fs with the bosch CX motor, and also a trek fuel exe, but fitted with the new tq hpr60.

I much prefer the Trek, I only use the orbea when the Trek is broken (which is far too often!)

 

[irie]

There is some variance in efficiency in the motors.

In percentage terms how much is "some"? Verifiable numbers please for different motors.

 

[Rob Rides EMTB]

If you go to a somewhat aged PB e-bike motor test they did efficiency tests, they are not perfect, none are, but you can see some patterns.

https://www.pinkbike.com/news/5-emt...shimano-sram-specialized-2025.html#efficiency
If you just scan the review, you will conclude that the DJI vs the others isn't fair to the DJI, as the DJI is in turbo mode vs. the older power rating Gen4 Bosch (for example) and the DJI is a lot faster. But if you read the article you will see that they also tested the DJI in Trail mode, and it still had an efficiency in Trail mode of 23% LESS than the Bosch gen4 in Race mode. These numbers are shown in the text.

DJI Trail mode still provides 850w peak power. The Bosch (at the time of that Pinkbike test) gave 600w peak. The default amplification levels of the DJI motor are also set really high, even on Trail mode. It wouldn't take rider effort in watts to be given the full 850w even in trail mode. From their article "Remember, every bike was set to their stock motor parameters for this test."

Additionally, Its not easy to compare the efficiency of Bosch and Avinox just by setting the watts and Nm to the same levels. The amplification of rider input, overrun settings etc all make wild differences to how much energy the motors consume.

If I set the Bosch and Avinox both to 750w peak and 100Nm torque, the Avinox still feels more powerful, until I reduce the assitance setting of Avinox down much lower than its default setting. I really dont think there's that much in these differences of efficiencies. I'd take a punt that both motors are 80-85% efficient once losses to heat, friction etc are taken into account.

 

[nickf]

In percentage terms how much is "some"? Verifiable numbers please for different motors.

Can we please not digress from the original subject of this thread . If people want to talk about motor efficiency (again) please either start your own thread or comment in one of the existing conversations on the topic. Thx.

 

[nickf]

The default amplification levels of the DJI motor are also set really high

If I set the Bosch and Avinox both to 750w peak and 100Nm torque, the Avinox still feels more powerful, until I reduce the assitance setting of Avinox down much lower than its default setting.

This is a key point. If two motors both have (say) 1000W peak power, but one has a max support of (say) 200% and the other a max support of 500%, then for a rider who can only put out 200W of leg power the first motor will only deliver 400W while the second will give the full 1000W. So when it comes to the ride feel, one motor will seem much less powerful than the other despite both having the same power capability.

And when assistance ratios become excessive, the pedal input from the rider becomes less relevant and is now effectively serving only as a switch or throttle to regulate the motor output.

 

[nickf]

I've got an orbea wild fs with the bosch CX motor, and also a trek fuel exe, but fitted with the new tq hpr60.

I much prefer the Trek, I only use the orbea when the Trek is broken (which is far too often!)

Oh dear, that doesn't sound good . Is that problems with the TQ60 or the bike?

 

[Mteam]

Oh dear, that doesn't sound good . Is that problems with the TQ60 or the bike?

The hpr50 and the hpr60, they seem to suffer from premature failure of the torque sensor. I went through 4 hpr 50 motors and am now on my second hpr60.

The first hpr50 failure was the sprag clutch, but every other failure(of hpr 50 and 60) has been a torque sensor failure.

 

[Dax]

our opinions aren't paid for!

Mine is for sale at a very reasonable rate

 

[nickf]

The hpr50 and the hpr60, they seem to suffer from premature failure of the torque sensor. I went through 3 hpr 50 motors and am now on my second hpr60.

The first hpr50 failure was the sprag clutch, but every other failure(of hpr 50 and 60) has been a torque sensor failure.

Bummer! If there was an issue with the original torque sensor we might have hoped they'd have fixed that with the TQ60.

 

[Suns_PSD]

DJI Trail mode still provides 850w peak power. The Bosch (at the time of that Pinkbike test) gave 600w peak. The default amplification levels of the DJI motor are also set really high, even on Trail mode. It wouldn't take rider effort in watts to be given the full 850w even in trail mode. From their article "Remember, every bike was set to their stock motor parameters for this test."

Additionally, Its not easy to compare the efficiency of Bosch and Avinox just by setting the watts and Nm to the same levels. The amplification of rider input, overrun settings etc all make wild differences to how much energy the motors consume.

If I set the Bosch and Avinox both to 750w peak and 100Nm torque, the Avinox still feels more powerful, until I reduce the assitance setting of Avinox down much lower than its default setting. I really dont think there's that much in these differences of efficiencies. I'd take a punt that both motors are 80-85% efficient once losses to heat, friction etc are taken into account.

All relevant and spoken from experience.
There is also a review on that German online mag where they normalized for input power against the 750w Gen 5 Bosch and the Bosch was also more efficient at the same overall (or similar) speed as the Avinox.
Anecdotally speaking, many ex-Bosch owners say that the Avinox is a battery hungry motor. Like it's a common complaint actually. I get that the Avinox might be providing more assistance, but they are doing the same rides, in the same times, with the same group of friends.

 

[MichaelT]

Obviously no one on here travels on planes with their bikes. Airlines only let you travel with 2 x 160 wh batteries in carry on so full fat s are out.

For me I fly with my kenevo SL and my wife levo SL about 4 or 5 times a year. I dont want to fork out and be limited by times or availability of approp size, spec and good tyres for bike rental. I ride on eco and can get 2hrs out of a 160wh extender battery. I also take the extender battery out when riding park and so reduce my KSL from 17.5 to 16.8kg.

I can switch back to my analogue and becuase I have been putting in on the ebike, I dont suffer. I understand that uphill I will be riding slightly slower than a full fat ( 400m elevation single track 35 min on trail versus 30 on full fat).

Most of the people I know feel their ideal ride is 2 to 2.5hrs ( other than park days) and come back with 3/4 battery remaining. I actually leave my kenevo SL battery out even at home and just use extender. I hope bike companies continue SL bikes. It already seems that they are starting to reduce battery size on full fats.
I dont want bigger motors unless the extender alone can get me 2hrs.

By the way, despite differences on paper, my friend and I matched gears and cadence up fireroad on 50 NmKSL and 60Nm slash + and then switched. Bikes were the same speed.