Specialized Como 3.0 more torque

[macp]

Dear all

Just trying to figure out how to help my wife. We purchased a new como 3.0 with a 50Nm motor. It’s a great bike but my wife is finding it tough on the bigger hills. She tried my Tero X with 70Nm and found it far better, not surprisingly. But unfortunately changing her bike for something with more grunt is not really an option at the moment. Now my tero will have different gearing to her como so I wondered if changing the gearing would help ?

 

[Base]

Hi, Which como is it exaclty? One with IGH with Gates belt or a version with derrailleur? That would help to do some suggestions.

 

[macp]

Hi, Which como is it exaclty? One with IGH with Gates belt or a version with derrailleur? That would help to do some suggestions.

Fair point it’s the derailleur version with chain. And not the Gates belt

 

[Jeremy McCreary]

But unfortunately changing her bike for something with more grunt is not really an option at the moment. Now my tero will have different gearing to her como so I wondered if changing the gearing would help ?

I live in pretty hilly place and lowered the gearing on my Vado SL for exactly that reason. Reducing the chainring from 44 to 40 teeth was all it took in my case, and it only cost me $80.

But it all depends on your wife's preferred cadence. Motor performance in Specialized mid-drives depends strongly on cadence. To get all that the motor has to give, you need to keep cadence above 70 rpm and preferably in the 80-90 rpm range.

And that could well be all she needs with the bike she has. One The goal of a gearing change would then be to keep her cadence above 70 rpm on the hills that give her trouble. There are many online gearing calculators to help you dial it in. Your bike shop could also help.

EDIT: Conversely, if she can't or won't pedal above 70 rpm, a gearing change might not help much ON THE MOTOR EFFICIENCY FRONT. But she could probably learn to pedal faster if she really put her mind to it.

Read this recent post for more on cadence and motor efficiency in Specialized mid-drives. I was writing about the Vado SL and Creo at the time, but I believe the basic concepts apply to the Como as well.

 

[macp]

Much obliged Jeremy. I just had a good chat with the boss who tells me that she does spin for as long as she is able. So I’m guessing as you have suggested that a change of gearing will not help sadly. I also found this thread. But it’s looking like a change of bike with greater torque is needed

Gear replacement

 

[Jeremy McCreary]

So I’m guessing as you have suggested that a change of gearing will not help sadly.

I should clarify. Sounds like she's already spinning fast enough to get max help from the motor at highest assist. So lower gearing won't help on the motor efficiency front. But if she's willing to go slow enough, it might still help on tough hills — as it would on any bike.

She tried my Tero X with 70Nm and found it far better, not surprisingly.

I see from the specs that the low gears on her Como are substantially higher than your Tero's. Could that be part of this result?

If she doesn't mind spinning out a somewhat lower ground speed in top gear, a smaller chainring might still be worth a try.

 

[Base]

or a mega-range cassette

 

[Jeremy McCreary]

or a mega-range cassette

The OP says a new bike for his wife isn't feasible right now. A new cassette±chainring is certainly the ultimate interim measure, but slapping on just a smaller chainring might help her climbing enough at much lower cost.

Ground speed in top gear at spinout becomes an important figure here. If she spins out at, say, 35 mph now but could live with 28 mph (a 20% reduction), the chainring-only approach would buy her a 20% lower bottom gear for climbing.

That would be like going from 30 to 24 gear-inches — a big difference.

 

[Base]

Correct.

With a mega range casette you would keep the max ratio for on flats and a much lower geraing with the biggest rear sprocket which could be the crawl up a hill bailout gear.

Thats what most roadies do here, use a caasette with close steps for the flatter parts and when they go to the hills they swap chain and cassette for a "mountain)-cassette with a mucht wider spreading in the bigger sprockets.

Thats also what I do for our loaded traveling bikes, build our own cassettes with a part of a mountain bike cassette and the smaller sprockets of a roadbike cassette. Smaller steps at the smaller sprockets and the bigger ones for the bail-out when riding up a big hill fully loaded. I crawl up at a speed where I just bearely can keep the bike up so slow I am riding at that moment. And for flatter parts we use the smaller sprockets with smalt steps for the best cadance.

 

[Stefan Mikes]

Como has a 48T chainring while Tero X is 38T. This difference is fundamental.
The 48T chainring is for a high speed on the flat (and for a powerful 90 Nm motor) but absolutely not for climbing.
A change to a 38T chainring (and shortening the chain by 4 links) will make the Como a climber.
The motor power only affects the achievable ground speed, so the Como would be slightly slower on the inclines than Tero X. However, the max motor power difference between Como 3.0 and Tero X 5.0 is only 40 W! (430 vs 470 W).

 

[Jeremy McCreary]

Correct.

With a mega range casette you would keep the max ratio for on flats and a much lower geraing with the biggest rear sprocket which could be the crawl up a hill bailout gear.

Thats what most roadies do here, use a caasette with close steps for the flatter parts and when they go to the hills they swap chain and cassette for a "mountain)-cassette with a mucht wider spreading in the bigger sprockets.

Thats also what I do for our loaded traveling bikes, build our own cassettes with a part of a mountain bike cassette and the smaller sprockets of a roadbike cassette. Smaller steps at the smaller sprockets and the bigger ones for the bail-out when riding up a big hill fully loaded. I crawl up at a speed where I just bearely can keep the bike up so slow I am riding at that moment. And for flatter parts we use the smaller sprockets with smalt steps for the best cadance.

Interesting approaches to building custom cassettes for particular purposes.

Many cassettes come with an exponential cog spacing, wherein in each larger cog has, say, 15% more teeth before rounding. To many riders, this will feel like a fairly even spacing all the way through the cassette.

Exponential spacing also results in smaller tooth-count jumps in higher gears, but probably not to the extent you're describing.

 

[Stefan Mikes]

The Como 3.0 drivetrain is one of cheaper (not the cheapest) on the market. The cassette is 11-36T, which cannot be even compared to the 11-50T on Tero X 5.0. It fully explains why the Como feels so weak against the hills.

However, I would not advise an expensive revolution in the start. The chainring swap alone should make the Como alive uphill. If that's not enough, I can recommend going for the Shimano M5100 drivetrain (11-speed, 11-51T), which would involve a new shifter, derailleur, and the cassette. Still, the inexpensive chainring swap should solve the main issue.

 

[macp]

Thanks guys no it’s not about top speed. The ability to climb more easily is paramount.

 

[Stefan Mikes]

Thanks guys no it’s not about top speed. The ability to climb more easily is paramount.

@macp the Specialized specification for the Como is based on the U.S. Class 3, where the speed is the objective. The 48T chainring makes no slightest sense with the British 25 km/h 15.5 mph restriction... While Tero X as a mountain bike is a climber right from the design.

 

[macp]

@macp the Specialized specification for the Como is based on the U.S. Class 3, where the speed is the objective. The 48T chainring makes no slightest sense with the British 25 km/h 15.5 mph restriction... While Tero X as a mountain bike is a climber right from the design.

Thanks @Stefan Mikes but don’t get me started on the ridiculous European restriction. But you make a good point re US class 3 spec.

 

[Stefan Mikes]

My original Vado 5.0 was a Euro 45 km/h S-Pedelec. It had an 85 Nm motor and a 48T chainring. That chainring was too big even for that speed e-bike! The optimum size for speed was 44T but I was swapping the chainring for a 38T one for high mountain rides... with a 11-46T cassette.

 

[Saratoga Dave]

Going from a 46 to a 40 on my Creo completely changed its climbing personality. It’s a low cost, simple change that should be a big win for your wife. 38, 40, 42 would all be viable choices, I’d think.

 

[macp]

Going from a 46 to a 40 on my Creo completely changed its climbing personality. It’s a low cost, simple change that should be a big win for your wife. 38, 40, 42 would all be viable choices, I’d think.

Many thanks Dave. And I guess dropping the front cog will mean the chain guard can remain.

 

[Stefan Mikes]

And I guess dropping the front cog will mean the chain guard can remain.

The chain guard will remain but it could be different with the chainring guard.

Let me explain.

Specialized e-bikes of the series/generation to which the Como 3.0 belongs use a Praxis chainring that is easily mounted on the e-bike spider with four threaded bolts (no nut). Additionally, the plastic chainring guard is mounted on the top of the chainring with four small screws. Unfortunately, it is a rare OEM solution.

Your Tero X comes with a 38T SRAM chainring but has no chainring guard.

The chainring mounting system both on the Como and Tero X is called "104 BCD round". The 38T, 104 BCD round chainring is mounted with four 8x8 mm MTB chainring bolts with nuts (this set includes a chainring bolt wrench). The installation process is fairly simple (I can help with more information).

If you are not a mechanically gifted person, I would give the labour to a Specialized shop.

 

[macp]

Ah yes Thankyou I forgot about the chainring. It doesn’t look too difficult. But then a day in Chester whilst the bike is in the specialized shop is tempting.