Smallest chainring / largest cassette installed on RipCurrent S?

tyyoda

New Member
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USA
Question for the group. I'm planning on reducing my front chain ring to something smaller than the stock 51T 130BCD ring to improve single track blue and black trail riding. Note: I also plan to swap the cassette to a 11-36T (would love to go to a 11x40T or 11x42T but not sure the LTWOO A5 derailleur can handle the 40/42T size (anyone know the max size as configured on the RCS?)

Tell me about your going to a smaller chainring swap experience?

Tell me about your going to a larger cassette (11x36T or larger)?


Some background data. With the current gearing (51 x 11) I have no trouble hitting 29 mph on flat ground and I don't feel like I'm "free wheeling" (per bikecalc my cadence is 70 rpm) In fact, I can go 40-41 down a big hill and still not feel like I'm freewheeling - cadence is almost 100 rpm. Per bikecalc, it feels like I could go to a 40T chainring (40 x 11) and still hit 29 mph with a 90 rpm cadence. I wouldn't be able to go 40 mph down the hill but 33-35 mph is still plenty fast

Gear calc tables
Gearing RPM mph
40x11 89.2 29
42x11 85 29
44x11 81.2 29
45x11 78.4 29
51x11 70 29
 
While not a Ripcurrent S , I have found a 42t front chainring for all my ebikes capable of 28mph speeds (including Juiced CCX), coupled with a 11-36t 9-speed Shimano HG-400 cassette to be a good compromise of speed and hill climbing ability. I used bikecalc and a cadence of 90rpm at 28mph(roughly) as my max speed. I have routinely reached 36mph on this setup and up to 40mph spinning like a hamster (Juiced CCX with GMAC 10T at 52V 1500w).

Sounds like a 40t chainring would work great for you
 
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Great topic, I was wondering similar things since I recently got a CCS and I too found the top gearing speed bizarrely high, and wanted more granular gearing after using a road bike (but I'm getting used to the bigger jumps between gears now.) If I needed to replace things, I'd prob go for a 42/44t.
While not a Ripcurrent S , I have found a 42t front chainring for all my ebikes capable of 28mph speeds (including Juiced CCX), coupled with a 11-36t 9-speed Shimano HG-400 cassette to be a good compromise of speed and hill climbing ability. I used bikecalc and a cadence of 90rpm at 28mph(roughly) as my max speed. I have routinely reached 36mph on this setup and up to 40mph spinning like a hamster (Juiced CCX with GMAC 10T at 52V 1500w).

Sounds like a 40t chainring would work great for you
Why do they spec such a big chainring to begin with, given what you've said? A 46t gives 28mph at 80 rpm on a stock 700 x 45 tire. My default assumption is Juiced hasn't really revisited any of their design/spec choices on the CC since it came out in 2017, besides in response to part failures and shortages, or motor/battery upgrades. So things that dont make sense just stay on in perpetuity. The whole big wheel skinny tire setup on the CCX has been abandoned by big brand commuter models for 27.5x2.35"s
 
A throttled, 76 lb, 1000w rear hub propelled RipCurrent S with beyond Class 3 speed cap on "blue and black" MTB singletrack trails? Assuming you're referring to Trailforks color-coded "trail difficulty" ratings, this seems extremely dangerous and highly illegal.

It's also one of the reasons a lot of land managers still won't allow ANY ebikes on trails they're responsible for - they don't want to constantly check bikes for Class 1 compliance, nor do they want to haul riders with broken bones or worse out of the woods.

Please keep your "Class 4" ebike on ATV and other motorized trails. And wear a full-face helmet when doing so, even if you change the OE gearing.
 
You going to do 20mph on your class one on technical singletrack just because your bike allows it or do you ride within your ability to keep safe? What makes you think he's any different - his equipment? He never mentioned using a throttle, if request is for hub bike then sounds like he's pedalling.
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A throttled, 76 lb, 1000w rear hub propelled RipCurrent S with beyond Class 3 speed cap on "blue and black" MTB singletrack trails? Assuming you're referring to Trailforks color-coded "trail difficulty" ratings, this seems extremely dangerous and highly illegal.

It's also one of the reasons a lot of land managers still won't allow ANY ebikes on trails they're responsible for - they don't want to constantly check bikes for Class 1 compliance, nor do they want to haul riders with broken bones or worse out of the woods.

Please keep your "Class 4" ebike on ATV and other motorized trails. And wear a full-face helmet when doing so, even if you change the OE gearing.
Hmm...not helpful, off topic and didn't answer my questions how to make my bike a better trail bike to be able to ride it slower. Where I ride, I'm legal and I ride within my limits.
 
I replaced the 52T chainring with a 38T narrow wide ring and reduce the chain length appropriately. Easy job and wow what a difference. Bike is still plenty fast (able to reach 28 mph without spinning out) and to honest the wife and I mostly ride between 10-15 mph when we ride together anyway. The hill climbing performance is way better. Can't wait to take it out on the hilly single tracks to see the real difference.
 

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Swapped the stock 42t chainring for a 38t on my 65-pound commuter/light trail ebike, and I'm very happy with the result.

With the stock 27.5" wheels and 9-speed 11-34t cassette, that took my gear-inches from 34.0 - 105.0 to 30.7 - 95.0. The lower gearing works well on the short, steep hills here in coastal San Diego County. At the top end, I can still hit 28 mph at a cadence of 100 RPM -- fast enough for my taste.

A spreadsheet's a good way to explore gearing changes. My spreadsheet shows an interesting result: To a very good approximation, this change just took stock gears 1-8 to positions 2-9 and reduced 1st gear by 10%. Have yet to miss the old 9th gear.
 
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One more thought: I see that our bikes use the same rear drop-out torque+cadence sensor. This sensor assumes a smallest cassette cog of 11t -- presumably for cadence-sensing purposes.

Something to keep in mind when you change your cassette.
 
Jeremy and tyyoda, I've got a question - the hub motor only adds linearly to the mechanical speed right? Eg with 11x52 and 1.75" wide 622 tires, I get 35 mph at 90 rpm, so a hub motor would make that even faster, right?

The same setup with a 38t front tooth gets 26 mph, and the hub motor could get you to 28+ mph (provided it has enough watts for incline, wind etc), right?

I think I'm too cheap to replace a perfectly good cassette for now, and I may find I need even lower gears, but an 11-25t with a 38t upfront would give me much smaller gaps between gears, slightly lower lowest gear, and still retain 28 mph speed. Very enticing!
 

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Jeremy and tyyoda, I've got a question - the hub motor only adds linearly to the mechanical speed right? Eg with 11x52 and 1.75" wide 622 tires, I get 35 mph at 90 rpm, so a hub motor would make that even faster, right?

The same setup with a 38t front tooth gets 26 mph, and the hub motor could get you to 28+ mph (provided it has enough watts for incline, wind etc), right?

I think I'm too cheap to replace a perfectly good cassette for now, but an 11-25t with a 38t upfront would give me much smaller gaps between gears, slightly lower lowest gear, and still retain 28 mph speed.
Your ebike has a (possibly adjustable) max assisted speed -- typically 20 or 28 mph in the US. You're welcome go faster (e.g., downhill or with a tailwind), but the motor's not going to help you do it. At 35 mph on such an ebike, you'll be entirely on your own.

Since the hub motor adds power at the rear axle, after the chain and gears, it can only provide so much help against high resistances (steep grades, stiff headwinds, surfaces with a lot of tire sinkage). How fast you go will then depend a lot on the power your body can chip in. And that power will fall off significantly at cadences well off your optimum (mine's ~70 RPM). To keep your cadence close to optimum against high resistance, you may well need a gear lower than 25x38, which at my wheel size (27.5") comes out to 41.8 gear-inches.

No way a 41.8" 1st gear would work for me where I live. But if you have much stronger legs and more tolerant knees, face lower max resistances, and place a very high value on tighter gear spacing -- or if you have a lot more motor power than my 500W -- an 11-25t cassette could be a reasonable trade-off.
 
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Jeremy and tyyoda, I've got a question - the hub motor only adds linearly to the mechanical speed right? Eg with 11x52 and 1.75" wide 622 tires, I get 35 mph at 90 rpm, so a hub motor would make that even faster, right?

The same setup with a 38t front tooth gets 26 mph, and the hub motor could get you to 28+ mph (provided it has enough watts for incline, wind etc), right?

I think I'm too cheap to replace a perfectly good cassette for now, and I may find I need even lower gears, but an 11-25t with a 38t upfront would give me much smaller gaps between gears, slightly lower lowest gear, and still retain 28 mph speed. Very enticing!
I don't think the hub motor will make it faster in the way you are describing. The speed will only go up to a point where wind and rolling resistance cannot be overcome.

What is your current top speed (along with the gearing) on a level surface with your bike?

On my bike, the hub motor will only go to 20 mph with throttle only. My Class III bike can only go faster than 20 mph if I add pedal power. Certainly my fat tire bike (RipCurrent S) didn't add enough electric power to go faster than 28-29 mph on level surfaces with the stock gearing (52T x 11T 69 rpm - at least with my available pedal power). I get the same top end speed with the 38x11 gearing only with a faster cadence of 92 rpm. The only thing I lost with the smaller chain ring is the ability to go faster down big hills. 40 mph was easy on a 14-16% grade with the 52x11 ratio (95 rpm). With the 38x11, I will be lucky to get 30-31 mph down that same hill with a 100 rpm cadence.
Currently, a 90 rpm cadence gives me 27.7 mph on my 26" 4" wide fat tire bike. Plenty fast for me.
 
Your ebike has a (possibly adjustable) max assisted speed -- typically 20 or 28 mph in the US. You're welcome go faster (e.g., downhill or with a tailwind), but the motor's not going to help you do it. At 35 mph on such an ebike, you'll be entirely on your own.

Since the hub motor adds power at the rear axle, after the chain and gears, it can only provide so much help against high resistances (steep grades, stiff headwinds, surfaces with a lot of tire sinkage). How fast you go will then depend a lot on the power your body can chip in. And that power will fall off significantly at cadences well off your optimum (mine's ~70 RPM). To keep your cadence close to optimum against high resistance, you may well need a gear lower than 25x38, which at my wheel size (27.5") comes out to 41.8 gear-inches.

No way a 41.8" 1st gear would work for me where I live. But if you have much stronger legs and more tolerant knees, face lower max resistances, and place a very high value on tighter gear spacing, an 11-25t cassette could be a reasonable trade-off.
I wouldn't change your cassette unless you want a lower first gear like a 11x36. With a 11x25, climbing hills will not that much easier than you have now with the easy. In my case, I wanted to maintain the legal max speed with a reasonable cadence and dramatically improve hill climbing ability for steeper single track trails.

Change your chain ring to match the top speed you want at the cadence you want. In my case, I wanted to preserve the legal top speed of 28 mph with a 90-95 rpm cadence while dramatically improving the low end performance

To be honest, running in PAS 3 or more burns battery pretty fast. I can easly burn 27-30 watt hours per mile to ride in PAS 2-4 to maintain a 22-23 mph pace, or I can run as low as 7 wh/mile riding with the wife in a mix of PAS 0 to 1.
 
Thanks for the remarks, very illuminating, though also baffling as to why Juiced would put such big front chainrings, besides I guess allowing you to pedal downhill and hit 40 mph. I don't pedal much downhill on a nice road bike, and certainly not with a heavier dodgier ebike. I checked Ride1Up and they indeed have smaller chainrings, 45-46t vs Juiced's 52.

Yeah changing the front chainrings would give me nearly all of what I want anyway (more granular gearing), good points all around.

I mostly use eco 1 on juiced (level 1 for faster roads), and average about 11 wh/mi. Mostly flat but some hilly terrain.
 
I wouldn't change your cassette unless you want a lower first gear like a 11x36. With a 11x25, climbing hills will not that much easier than you have now with the easy. In my case, I wanted to maintain the legal max speed with a reasonable cadence and dramatically improve hill climbing ability for steeper single track trails.

Change your chain ring to match the top speed you want at the cadence you want. In my case, I wanted to preserve the legal top speed of 28 mph with a 90-95 rpm cadence while dramatically improving the low end performance

To be honest, running in PAS 3 or more burns battery pretty fast. I can easly burn 27-30 watt hours per mile to ride in PAS 2-4 to maintain a 22-23 mph pace, or I can run as low as 7 wh/mile riding with the wife in a mix of PAS 0 to 1.
Just to be clear, I'm fine with my own cassette. I was just responding to the 11-25t cassette @Asher has in mind.

Our goals in going to smaller chain rings are pretty much the same. Like you, I prefer to ride at the lowest PAS my old muscles and knees will allow. The added range is icing on the cake.

As for riding with a slow-poke, definitely something to be said for slowing down to smell the roses. So many interesting things to see/hear/smell anywhere outdoors. But even at 15 mph, much of it goes by in a blur.

Everything in the world is strange and marvelous to well-open eyes. -- Jose Ortega y Gasset
No way around it, my eyes and ears and nose are a lot more "open" in this sense at 10 mph than at 20.
 
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Thanks for the remarks, very illuminating, though also baffling as to why Juiced would put such big front chainrings, besides I guess allowing you to pedal downhill and hit 40 mph. I don't pedal much downhill on a nice road bike, and certainly not with a heavier dodgier ebike. I checked Ride1Up and they indeed have smaller chainrings, 45-46t vs Juiced's 52.

Yeah changing the front chainrings would give me nearly all of what I want anyway (more granular gearing), good points all around.

I mostly use eco 1 on juiced (level 1 for faster roads), and average about 11 wh/mi. Mostly flat but some hilly terrain.
IMO- there are a few reasons Juiced used 52T chain rings. #1) they use the same size on all their bikes - mostly a cost savings measure. #2) the average buyer of their bikes doesn't want or feel the need to pedal faster cadences because it feels like more work (even though it isn't) and they can climb any highway/bike path hill that they need to with the pedal assist, #3) they sell a lot of moped style ebikes - I can't imagine pedaling those bikes at faster cadences. #4) San Diego is flat
 
IMO- there are a few reasons Juiced used 52T chain rings. #1) they use the same size on all their bikes - mostly a cost savings measure. #2) the average buyer of their bikes doesn't want or feel the need to pedal faster cadences because it feels like more work (even though it isn't) and they can climb any highway/bike path hill that they need to with the pedal assist, #3) they sell a lot of moped style ebikes - I can't imagine pedaling those bikes at faster cadences. #4) San Diego is flat
Good points - plus the founder is an Olympic athlete and is very involved in setting vehicle specs, so he may have set is Using his own max effort.

Their 52t chainrings long precede the moped style bikes (just checked the 2017 CCS review on EBR).

When you poke around, you find a lot of their specs/standards are outdated, obsolete. Almost no one but Juiced is still using 700c (vs wider 27.5s) wheels on commuter ebikes; cheap QRs for front wheel; straight forks that are extinct in the mainstream bike brand ecosystem, etc
 
I found this article from a leading bike design firm, and they make a good case for a small chainring for gravel - and given that we are neither top shelf athletes nor racing, I think much the same applies for hub motor ebikes.

 
#4) San Diego is flat
Agree that the parts most visited by tourists are pretty flat -- westernmost downtown, Coronado Island, Mission Bay, and Ocean, Mission, and Pacific Beaches. But the city limits extend ~30 km up the coast, ~40 km to the NE, and ~20 km east from downtown. And most of that is hilly to ruggedly mountainous. Flattish loops can be had atop some of the coastal mesas, but the grades between mesas are often quite steep.
 
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I found this article from a leading bike design firm, and they make a good case for a small chainring for gravel - and given that we are neither top shelf athletes nor racing, I think much the same applies for hub motor ebikes.

Thanks for that link -- very informative and nicely written. Gravel gearing seems like a good starting point for a 60-pound ebike that you might have to ride home on a dead battery -- especially if you live in a hilly place, run hybrid to fat/knobby tires, and prefer lower PAS levels when you still have juice.

Just one small niggle: Judging from some of the jaw-dropping ocean-view mansions and $500,000+ cars I see around San Diego -- especially in La Jolla and Del Mar -- I think some of these folks could afford to have roads repaved before their rides.
 
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