A-DamW
1 kW
Just an fyi, there is a button to reverse motor direction in the PC/phone app, no need to completely re-run motor detection etc.
Mini Hiryuu - Mid power ebike
- Thread starter neptronix
- Start date
Sweet, thanks for the tip!
Grin v7 torque arms are here.
They're relatively heavy units that look super strong. All the machining is ultra tight and the axle snugness with the adjusters is awesome. It's the ultimate torque arm.
This is necessary for the RH212 because it has what seems like a 8mm wide axle instead of 10mm. This causes an insane level of slop in grin's older torque arms, and in the bike's dropouts. It's the loosest hub motor axle i've ever seen... by a lot.
I read in the manual that they recommend no more than 50nm of torque per torque arm. That means that despite this extra strength, i still need two of these heavy torque arms, especially considering the weak axle.
If i could go back and do it again, i'd get a leafbike 30mm wide stator motor that had a proper thickness axle and didn't require these special clamping torque arms. The motor is already heavy as it is.
I think this wimpy axle limits the power i can extract out of this motor too without snapping the axles. I'm going to limit the power to 40A batt, 100A phase, aka 2kw.
They're relatively heavy units that look super strong. All the machining is ultra tight and the axle snugness with the adjusters is awesome. It's the ultimate torque arm.
This is necessary for the RH212 because it has what seems like a 8mm wide axle instead of 10mm. This causes an insane level of slop in grin's older torque arms, and in the bike's dropouts. It's the loosest hub motor axle i've ever seen... by a lot.
I read in the manual that they recommend no more than 50nm of torque per torque arm. That means that despite this extra strength, i still need two of these heavy torque arms, especially considering the weak axle.
If i could go back and do it again, i'd get a leafbike 30mm wide stator motor that had a proper thickness axle and didn't require these special clamping torque arms. The motor is already heavy as it is.
I think this wimpy axle limits the power i can extract out of this motor too without snapping the axles. I'm going to limit the power to 40A batt, 100A phase, aka 2kw.
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Not necessarily...
I've got one clamping torque arm on one side and for the other side I just fully clock it's 'legacy' torque arm before tightening up.
This has worked fine for over 10000km so far.
Cheers
Are we talking about the RH212? I have the same motor...pushing 3.3KW in a 20" rim with this setup....works fine.
..thanks for prompting me to second guess myself.
I think i was crabby yesterday because so much of my ebike shit has been giving me grief like non stop.. both new and old.
I remeasured things.
The axles measure 10mm +/- 0.1mm.
..except for this point where the side with the cable ( disc brake side ) is right next to the frame.. this is where i get that extreme slop in the torque arm... and you also have a huge hole within the mounting interface.. it's not confidence inspiring..
The other axle that's solid is just average width, but.. not a tight fit with the ol' grin v5/v3 torque plate... whereas the leaf was a nice tight fit and i believe i had to hammer the Grin TAs on.
Okay, this axle interface is less wimpy than i was thinking and i turn out to be bad at eyeballing millimeters.
I also weighed the pair of TAs and it came out to about 520g, or 1 pound. I think their weight is deceptive in the hand.
The resulting fit is one notch away from "that's not going anywhere" status and the tightness is a massive improvement over regular TAs. I think i feel confident with this setup.
CD, if you have 10000km on this setup then i might be under-estimating the holding power and everything is probably oK!
I think i was crabby yesterday because so much of my ebike shit has been giving me grief like non stop.. both new and old.
I remeasured things.
The axles measure 10mm +/- 0.1mm.
..except for this point where the side with the cable ( disc brake side ) is right next to the frame.. this is where i get that extreme slop in the torque arm... and you also have a huge hole within the mounting interface.. it's not confidence inspiring..
The other axle that's solid is just average width, but.. not a tight fit with the ol' grin v5/v3 torque plate... whereas the leaf was a nice tight fit and i believe i had to hammer the Grin TAs on.
Okay, this axle interface is less wimpy than i was thinking and i turn out to be bad at eyeballing millimeters.
I also weighed the pair of TAs and it came out to about 520g, or 1 pound. I think their weight is deceptive in the hand.
The resulting fit is one notch away from "that's not going anywhere" status and the tightness is a massive improvement over regular TAs. I think i feel confident with this setup.
CD, if you have 10000km on this setup then i might be under-estimating the holding power and everything is probably oK!
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Yeah, it should be fine. I'm not using the V7 torque arms, but just have the one side clamped.
As a point of comparison, I ran (and needed) dual clamping torque arms with my old Stealth Fighter pushing 8KW. Prior to that I ran simple torque blocks at 5-6KW and it was a nightmare keeping everything tight.
Cheers
Just another data point, have had a cycle somewhat similar to yours (10.2rpm/V RH212 in a 26" wheel, ~90lbs total, 110A peak phase currents in both directions) with a v7 torque arm on the brake side, homemade one on the cassette side, and it has clocked approx. 37000kms to date without any issues related to the motor and TAs.
I've decided to get rid of the RH212. I just don't like the weight & how this weight makes the bike counter-steer when turning. I don't like the fact that replacing the tubes in the instance of a flat is a huge ordeal, especially since it's goathead season.
I've let my lady borrow my car for the last couple months. There's been numerous occasions where my bike had to be loaded into my tiny car, and the ability to quickly disconnect has been invaluable.
Since going back to fulltime keto 8 months ago, i've also gone from 283lbs to 239lbs. The improvement in my power to weight ratio has made this motor acceptably fast in a 24" wheel. I plan to keep losing weight and think that by next year, i will enjoy this motor a lot.
One recent addition is a cheapo Bolany cassette that gives me the kind of gear range a modern 11 speed cassette would have. For acoustic bicycling purposes, this cassette sucks due to to the massive jumps in gearing. For ebiking, it's perfection when you have a gigantic chainring so that you can pedal at the top speed of the motor.
I've let my lady borrow my car for the last couple months. There's been numerous occasions where my bike had to be loaded into my tiny car, and the ability to quickly disconnect has been invaluable.
Since going back to fulltime keto 8 months ago, i've also gone from 283lbs to 239lbs. The improvement in my power to weight ratio has made this motor acceptably fast in a 24" wheel. I plan to keep losing weight and think that by next year, i will enjoy this motor a lot.
One recent addition is a cheapo Bolany cassette that gives me the kind of gear range a modern 11 speed cassette would have. For acoustic bicycling purposes, this cassette sucks due to to the massive jumps in gearing. For ebiking, it's perfection when you have a gigantic chainring so that you can pedal at the top speed of the motor.
I learned countersteering in my youth MC riding days. Where you initiate a turn by turning (trying to turn) the handlebars in the opposite direction. This shifts your weight force to the inside bar, causing the bike to lean in the direction you want to turn which is really what causes the bike to turn, rather than turning the handlebars (and front wheel) any appreciable degrees. (At least above 8 MPH?)
But that's not the counter-steer that you are describing?
I just got a Sondors OG fatbike with huge 4.9 inch wide tires. The gyroscopic effects are so immense it takes a set course and puts up a fight to effect any change. Is that what you are describing?
It's more like a wagging or tugging on the rear end as i carry the bike or make sharp turns at low speeds.
It's like the weight of the motor is causing the frame to flex slightly.
I don't like how tire changes work either and i have a lot of experimenting to do with flat prevention.
Lots of negatives to a heavy hub tbh!
Another factor - i have a 1kw 4lbs mid drive and an All Axle, so i'm very spoiled!
It's like the weight of the motor is causing the frame to flex slightly.
I don't like how tire changes work either and i have a lot of experimenting to do with flat prevention.
Lots of negatives to a heavy hub tbh!
Another factor - i have a 1kw 4lbs mid drive and an All Axle, so i'm very spoiled!
So i found a cheapo 8 speed 'Bolany' Cassette that has insane stepped gear ratios. I was curious if this would allow for uphill riding with the motor off, given the 52T front chainring.
I made it up this protracted 5% grade in 6th gear against the drag of the motor, unpowered. I'm really impressed. This means i can bump to from a 52T front chainring to 56T and still be able to ride it as a pedal bike.
The downside is that the motor drag increases with speed. Really limits you when going downhill. That part sours the unpowered experience.
I have an acoustic bike i ride for exercise that has 32c x 700c tires which is significantly faster.
I find myself riding acoustic bike for exercise a lot lately. Only get on the ebike when i have a long distance to go.
I kinda hate having a total of 3 bikes. I want to consolidate.
Since my recent minor crash, i feel uneasy about going fast on an upright. Building a good safety system for an upright bike is quite hard. Building a very good safety system for a recumbent is easy. Therefore, the bike that goes fast should be the recumbent, not this bike.
The All Axle needs to be sent to Grin for repair, probably involving a new stator. I could get a fast winding put into it and have it spoked into a 20" wheel and it'd be a better motor than the lightest mid drive for the recumbent. With ferrofluid it's climbing 10% grades
I think a geared motor would be where it's at for this bike, in a 26" wheel.
I can output 250-300w to the pedals for at least 5 minutes, and i've lost a bunch of weight recently. So i re-ran the numbers on the Shengyi SX2 with a 26 x 1.75" wheel.
In this worse case scenario for my around-town jaunts, the motor is making 213 watts of heat. The hills in my local area are short, so this motor is just barely up to par for that duty.
Top speed on the flat, efficiency, and range are all awesome.
Interestingly, 57.5v produces 0.1% better efficiency on the flat. 30mph and the motor is producing 99w of heat, which it can probably sustain indefinitely. 60V is where efficiency starts to drop again. Incredible performance for such a small motor.
I think this motor would be happy with a little flux weakening. I'm only looking for a 9% speed increase to hit 30mph. I'll use the VESC controller's feature that allows flux weakening over a certain throttle percentage to limit my use of it.
Per this thread:
Compact Field Oriented Controller, ASI + Grin, limited run
A 30% speed boost produced a 8% efficiency loss. Napkin math tells me my efficiency loss will be 2.5%, and this loss should be at the controller. Not bad.
Boo, i feel dumb for letting someone talk me out of a SX2!
I made it up this protracted 5% grade in 6th gear against the drag of the motor, unpowered. I'm really impressed. This means i can bump to from a 52T front chainring to 56T and still be able to ride it as a pedal bike.
The downside is that the motor drag increases with speed. Really limits you when going downhill. That part sours the unpowered experience.
I have an acoustic bike i ride for exercise that has 32c x 700c tires which is significantly faster.
I find myself riding acoustic bike for exercise a lot lately. Only get on the ebike when i have a long distance to go.
I kinda hate having a total of 3 bikes. I want to consolidate.
Since my recent minor crash, i feel uneasy about going fast on an upright. Building a good safety system for an upright bike is quite hard. Building a very good safety system for a recumbent is easy. Therefore, the bike that goes fast should be the recumbent, not this bike.
The All Axle needs to be sent to Grin for repair, probably involving a new stator. I could get a fast winding put into it and have it spoked into a 20" wheel and it'd be a better motor than the lightest mid drive for the recumbent. With ferrofluid it's climbing 10% grades
I think a geared motor would be where it's at for this bike, in a 26" wheel.
I can output 250-300w to the pedals for at least 5 minutes, and i've lost a bunch of weight recently. So i re-ran the numbers on the Shengyi SX2 with a 26 x 1.75" wheel.
In this worse case scenario for my around-town jaunts, the motor is making 213 watts of heat. The hills in my local area are short, so this motor is just barely up to par for that duty.
Top speed on the flat, efficiency, and range are all awesome.
Interestingly, 57.5v produces 0.1% better efficiency on the flat. 30mph and the motor is producing 99w of heat, which it can probably sustain indefinitely. 60V is where efficiency starts to drop again. Incredible performance for such a small motor.
I think this motor would be happy with a little flux weakening. I'm only looking for a 9% speed increase to hit 30mph. I'll use the VESC controller's feature that allows flux weakening over a certain throttle percentage to limit my use of it.
Per this thread:
Compact Field Oriented Controller, ASI + Grin, limited run
A 30% speed boost produced a 8% efficiency loss. Napkin math tells me my efficiency loss will be 2.5%, and this loss should be at the controller. Not bad.
Boo, i feel dumb for letting someone talk me out of a SX2!
Well if my experience is anything to go by, my fast wind did struggle a little on 10-15% grades, but switching to the std wind now and it can tackle lengthy 15-20% grades with ease. It still does eventually get too hot, but that typically takes climbing an actual mountain.I could get a fast winding put into it and have it spoked into a 20" wheel and it'd be a better motor than the lightest mid drive for the recumbent. With ferrofluid it's climbing 10% grades
Cheers
Need to resend the all axle back to ebikes.ca for respoking and re-statoring, so i put the lightest mid drive on Mini Hiryuu so i can enjoy what looks like the last 2 days of rideable weather.
Bike comes out to 55lbs, not bad considering that 10lbs of that is due to comfymaxxing. I think a 29er version of this would require less comfymaxxing and therefore be a bit lighter.
I love the nice weight distribution of this thing now.
I'm thinking v2 i build next year will have 29" wheels and put some of this weight savings towards a 50% larger battery and still fall under 60lbs.. which is the point where an ebike starts to feel like a bull in a china shop when maneuvering it in tight corners in an apartment.
Same idea for this bike as before.. to basically be a sidearm to my other experimental bike while i work on revision 7,8,9..
v2 is up next!
Bike comes out to 55lbs, not bad considering that 10lbs of that is due to comfymaxxing. I think a 29er version of this would require less comfymaxxing and therefore be a bit lighter.
I love the nice weight distribution of this thing now.
I'm thinking v2 i build next year will have 29" wheels and put some of this weight savings towards a 50% larger battery and still fall under 60lbs.. which is the point where an ebike starts to feel like a bull in a china shop when maneuvering it in tight corners in an apartment.
Same idea for this bike as before.. to basically be a sidearm to my other experimental bike while i work on revision 7,8,9..
v2 is up next!
Some notes from riding with the lightest mid drive.
Not a fan of these 165mm cranks. My long legs hate them and my human power output sucks. I can get 170mm cranks aftermarket, but my legs really like 175. Kind of a sour point.
Crank wobble is unnerving to look at, but not causing problems currently. An aftermarket crank should solve it.
Rear 26" versus rear 24" hub increases standover, which is pretty annoying even on a 1.75" tire.
Hard to get used to the crank area of the bike twisting when hitting the throttle. Some of this is because i have a cheap 21" frame. But this is on only 900w power. i wonder if this is harmful to the frame long term. This wasn't a problem on the recumbent, which is stiff as hell. This isn't specific to the lightest mid drive.
Don't like the feeling of the chain tensioner vibrating on power level 5 at high RPM, it's just unnerving. The effect is worse in single chainring mode.
Recently, I made it up my 5 mile hill test climb. Top speed with the 3lbs rear tire that's known to have almost the drag of a motorcycle tire is 25mph instead of the 28mph i was achieving on a regular tire, which is OK.
Overall this mid drive was a lot nicer in my semi recumbent whose top speed on the flat was 34mph.. 18% faster.
My running idea for Mini Hiryuu v2 has been a 29er with a 27.5" rear wheel and 29" front to get back to low standover height.
For comfymaxxing purposes, there exist fat 29ers ( 3.0" tires ) but they are quite expensive. 29 x 2.0" comes out to 2430mm diameter, and 32 x 2.0" is 2471mm, which is a small difference.
This has me thinking about instead going with a Kent Big league 32" bike. This gets me the wheel diameter of a 29 x 3.0", but the bike costs $500.
I called Kent and found out it has a 68mm bottom bracket and takes a 1-1/8 in fork.
We could run 32" rear, 29" front with a suspension fork to boost the comfy.
A big advantage of this 32" wheel is that i'd be able to run the lightest mid drive with a single chainring and hit the high speeds i'm after. Looking at the frame, we probably don't have a standover height issue, so the rear wheel doesn't need to go down a size to achieve that.
Also looks like a 44T chainring would be sufficient for hitting a max speed of 32mph or so in single chainring mode.
The fact that there are only 2-3 makes of 32" tire, and probably just one supplier of tubes, makes the option a potential pain in the ass. It's likely that i'd have to use a sealant on the rear tire because puncture proof tires aren't available in this size.
Still on the fence about this one!
Not a fan of these 165mm cranks. My long legs hate them and my human power output sucks. I can get 170mm cranks aftermarket, but my legs really like 175. Kind of a sour point.
Crank wobble is unnerving to look at, but not causing problems currently. An aftermarket crank should solve it.
Rear 26" versus rear 24" hub increases standover, which is pretty annoying even on a 1.75" tire.
Hard to get used to the crank area of the bike twisting when hitting the throttle. Some of this is because i have a cheap 21" frame. But this is on only 900w power. i wonder if this is harmful to the frame long term. This wasn't a problem on the recumbent, which is stiff as hell. This isn't specific to the lightest mid drive.
Don't like the feeling of the chain tensioner vibrating on power level 5 at high RPM, it's just unnerving. The effect is worse in single chainring mode.
Recently, I made it up my 5 mile hill test climb. Top speed with the 3lbs rear tire that's known to have almost the drag of a motorcycle tire is 25mph instead of the 28mph i was achieving on a regular tire, which is OK.
Overall this mid drive was a lot nicer in my semi recumbent whose top speed on the flat was 34mph.. 18% faster.
My running idea for Mini Hiryuu v2 has been a 29er with a 27.5" rear wheel and 29" front to get back to low standover height.
For comfymaxxing purposes, there exist fat 29ers ( 3.0" tires ) but they are quite expensive. 29 x 2.0" comes out to 2430mm diameter, and 32 x 2.0" is 2471mm, which is a small difference.
This has me thinking about instead going with a Kent Big league 32" bike. This gets me the wheel diameter of a 29 x 3.0", but the bike costs $500.
I called Kent and found out it has a 68mm bottom bracket and takes a 1-1/8 in fork.
We could run 32" rear, 29" front with a suspension fork to boost the comfy.
A big advantage of this 32" wheel is that i'd be able to run the lightest mid drive with a single chainring and hit the high speeds i'm after. Looking at the frame, we probably don't have a standover height issue, so the rear wheel doesn't need to go down a size to achieve that.
Also looks like a 44T chainring would be sufficient for hitting a max speed of 32mph or so in single chainring mode.
The fact that there are only 2-3 makes of 32" tire, and probably just one supplier of tubes, makes the option a potential pain in the ass. It's likely that i'd have to use a sealant on the rear tire because puncture proof tires aren't available in this size.
Still on the fence about this one!
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Good that you are taking this into consideration. I used to ride a Moulton in the '80s. By far the worst aspect was the sole-source supplier of tires (an oddball size). The were expensive, difficult to obtain, and QC was hit-or-miss. Frustrating paying high price for tires that often failed prematurely, or wobbled, or rode "lumpy." Dunlop. No other options at the time.
Yeah there is at least one solid looking manufacturer for these tires that also sells quality stuff for unicycles:
Nimbus Nightrider 32" Lite Tire
These recent 32/36er MTBs tend to use the above tires which look halfway decent.
Another option to utilize a 29er frame is to use these expensive pedals that drop the foot position by 12mm. This way i can retain the rear 29" tire and have okayish standover height.
Looks like 30mph is still achievable with a 29 x ~2.25" rear tire and a bit faster pedaling cadence
This does make the 32" option look a bit silly because a 29 x 2.5" in the rear is gonna be close to an inch difference diameter vs a 32 x 2.15".
In theory the 29er bike would be good for geared motor duty with a 27.5" rear wheel, but the 32er bike, since it only has vbrake posts, can't really go down wheel sizes in the back to get acceptable acceleration/efficiency out of certain hub motors. It would be a 1 trick pony that only works with a mid drive or dual geared hub motors.
Just today i'm seeing a crowdfunded bike with 32 x 2.4" tires from vee rubber... kind of indicates the tire support may be there in the future.
DirtySixer's New 32er Gravel Bike Rolls on 32 x 2.4" Tires, Preorder Ends Soon
Man, i am not sure which path to go!
Nimbus Nightrider 32" Lite Tire
These recent 32/36er MTBs tend to use the above tires which look halfway decent.
Another option to utilize a 29er frame is to use these expensive pedals that drop the foot position by 12mm. This way i can retain the rear 29" tire and have okayish standover height.
Looks like 30mph is still achievable with a 29 x ~2.25" rear tire and a bit faster pedaling cadence
This does make the 32" option look a bit silly because a 29 x 2.5" in the rear is gonna be close to an inch difference diameter vs a 32 x 2.15".
In theory the 29er bike would be good for geared motor duty with a 27.5" rear wheel, but the 32er bike, since it only has vbrake posts, can't really go down wheel sizes in the back to get acceptable acceleration/efficiency out of certain hub motors. It would be a 1 trick pony that only works with a mid drive or dual geared hub motors.
Just today i'm seeing a crowdfunded bike with 32 x 2.4" tires from vee rubber... kind of indicates the tire support may be there in the future.
DirtySixer's New 32er Gravel Bike Rolls on 32 x 2.4" Tires, Preorder Ends Soon
Man, i am not sure which path to go!
On the other end of the insanity:genius spectrum:
I'm VERY impressed by how it takes going down stairs.
In other videos, people say steel 36ers are said to ride like full suspension bikes, are harder to steer due to the wheel weight, maintain momentum like crazy, are hard to get up to speed, and with effort can be quite fast.
I think my original idea of using a suspension fork and 29" wheel on the front of the big Kent would help negate some of the 32" wheeled bike's oafiness.
Honestly? tough call
I'm VERY impressed by how it takes going down stairs.
In other videos, people say steel 36ers are said to ride like full suspension bikes, are harder to steer due to the wheel weight, maintain momentum like crazy, are hard to get up to speed, and with effort can be quite fast.
I think my original idea of using a suspension fork and 29" wheel on the front of the big Kent would help negate some of the 32" wheeled bike's oafiness.
Honestly? tough call
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Some math to see if 32" is really 32"
32" ISO dimension: 686 mm
29" aka 700c ISO dimension: 622mm
Difference in rim size is 64mm or 2.5 inches
Existing bike
24 x 2.2" = diameter 25.63 inches <-- where i started
26 x 1.75" = diameter 25.477 inches <-- current tire
26 x 2.5" = diameter 26.97 inches <-- could step up to this size with the pedal hack
Bikesdirect 29er - $379 free shipping
27.5 x 2.0" = diameter 26.956 inches <-- what i planned to have on the rear wheel before the pedal hack
27.5 x 2.25" = diameter 27.46 inches <-- actually 27.5 inches
29 x 2.1" = diameter 28.65 inches <-- stock size
29 x 2.5" = diameter 29.45 inches <-- optimistic max with pedal hack
29 x 3.0" = diameter 30.45 inches <-- won't fit, but curious
Kent 32er - $449 plus shipping
32 x 2.125" = diameter 31.22 inches <-- stock tire
32 x 2.25" = diameter 31.47 inches <-- Nimbus tire, would work with the Kent
32 x 2.4" = diameter 31.743 inches <-- theoretical vee rubber tire, interestingly still not 32 inches
Theoretical land
36 x 2.25" = diameter 35.44 inches <-- not 36 inches
Okay, 32" is 31.5" in reality which is still a sizeable upgrade. The difference between an almost fat 29er is 2 inches, notable but not world changing.
Tires with a fair amount of puncture proofing max out at 29 x 2.4" ( Kenda Kwick Nine ); i think that's the tie breaker factor that makes the 29er a more practical win, once we've added the pedal hack.
32" ISO dimension: 686 mm
29" aka 700c ISO dimension: 622mm
Difference in rim size is 64mm or 2.5 inches
Existing bike
24 x 2.2" = diameter 25.63 inches <-- where i started
26 x 1.75" = diameter 25.477 inches <-- current tire
26 x 2.5" = diameter 26.97 inches <-- could step up to this size with the pedal hack
Bikesdirect 29er - $379 free shipping
27.5 x 2.0" = diameter 26.956 inches <-- what i planned to have on the rear wheel before the pedal hack
27.5 x 2.25" = diameter 27.46 inches <-- actually 27.5 inches
29 x 2.1" = diameter 28.65 inches <-- stock size
29 x 2.5" = diameter 29.45 inches <-- optimistic max with pedal hack
29 x 3.0" = diameter 30.45 inches <-- won't fit, but curious
Kent 32er - $449 plus shipping
32 x 2.125" = diameter 31.22 inches <-- stock tire
32 x 2.25" = diameter 31.47 inches <-- Nimbus tire, would work with the Kent
32 x 2.4" = diameter 31.743 inches <-- theoretical vee rubber tire, interestingly still not 32 inches
Theoretical land
36 x 2.25" = diameter 35.44 inches <-- not 36 inches
Okay, 32" is 31.5" in reality which is still a sizeable upgrade. The difference between an almost fat 29er is 2 inches, notable but not world changing.
Tires with a fair amount of puncture proofing max out at 29 x 2.4" ( Kenda Kwick Nine ); i think that's the tie breaker factor that makes the 29er a more practical win, once we've added the pedal hack.
If you go 32 you would be almost a trailblazer (looks like Portland Trailblazer Jusuf Nurkic already has one).
Too bad there aren't more 32ers around to test fit one, see how it suits you. Might have to make a run out to Boulder CO.
Look at the comparison to 700c: (!)
from https://zinncycles.com/32_inch_wheel/
Too bad there aren't more 32ers around to test fit one, see how it suits you. Might have to make a run out to Boulder CO.
Look at the comparison to 700c: (!)
from https://zinncycles.com/32_inch_wheel/
Okay there's a large variable i didn't think about.
These fancy pedals are on a kickstarter and going through their first production run.
I can't depend on the pedal hack working to lower step through and get good rear diameter.
If i'm stuck with the 29er, to reduce stepthrough, i need a 27.5 x 2.25" on the rear, which has a diameter of 27.46 inches.
In this case, the 32er offers an extra 4 inches of tire diameter and it's the undeniable right choice.
Return policy check for the Kent 32er:
Not good, this would delay the project until feb because it's gonna be way too cold to ride during dec-jan.
Googling, i find:
Ultra thin pedals with 2 bearings ( good! ):
Crampon Ultimate Pedals - BOGO 1/2 OFF
Maybe another method would be one of these 'magic stepper' devices. They may screw up the pedal stroke, but damn, that's a decent amount of offset.
Order of operation should be, then:
These fancy pedals are on a kickstarter and going through their first production run.
I can't depend on the pedal hack working to lower step through and get good rear diameter.
If i'm stuck with the 29er, to reduce stepthrough, i need a 27.5 x 2.25" on the rear, which has a diameter of 27.46 inches.
In this case, the 32er offers an extra 4 inches of tire diameter and it's the undeniable right choice.
Return policy check for the Kent 32er:
Not good, this would delay the project until feb because it's gonna be way too cold to ride during dec-jan.
Googling, i find:
Ultra thin pedals with 2 bearings ( good! ):
Crampon Ultimate Pedals - BOGO 1/2 OFF
Maybe another method would be one of these 'magic stepper' devices. They may screw up the pedal stroke, but damn, that's a decent amount of offset.
Order of operation should be, then:
- Buy 170mm cranks
- Buy magic stepper
- Buy super thin pedals
- Are we able to cure the stepover on existing bike with these methods?
Yes: get the 29er this Dec. because 29.5 inch wheel diameter is allright
No: get the 32er in Feb.
Yeah, i'm naturally attracted to trailblazing, but my pioneer spirit got muted this year when i spent more time tinkering on my ebike than riding it due to the fact that most of the parts are first generation.
Definitely trying to dial it back, lol.
Goodness!
Definitely trying to dial it back, lol.
Look at the comparison to 700c: (!)
Goodness!
Doing more research, apparently we have another 32er build on this forum.
(2nd Build) GNG Gen2 - Genesis 32" (Ultra 32 inch - 7 speed)
It's an older version of the Kent Big League sold as a Genesis.
Owner reports a 52 inch wheelbase
. Mini Hiryuu v1 ( 21.5" xlarge frame ) has a 44 inch wheel base. The 29er i'm looking at has a 44.5 inches wheelbase.
I think this extra 7.5 inches of wheelbase is a huge plus. Some of these additional inches are in the rear.. and the seat position can be pushed forward somewhat to put proportionally a little more rider weight on the front suspension fork versus the 29er.. that's going to boost comfort a bit.
The fork has what looks like an above average offset, replacing it with a suspension fork should forward bias me a hair more..
I imagine the thing rides like a motorcycle & may be suited for 35mph duty.
Huge pluses i didn't think about!
(2nd Build) GNG Gen2 - Genesis 32" (Ultra 32 inch - 7 speed)
It's an older version of the Kent Big League sold as a Genesis.
Owner reports a 52 inch wheelbase
. Mini Hiryuu v1 ( 21.5" xlarge frame ) has a 44 inch wheel base. The 29er i'm looking at has a 44.5 inches wheelbase.I think this extra 7.5 inches of wheelbase is a huge plus. Some of these additional inches are in the rear.. and the seat position can be pushed forward somewhat to put proportionally a little more rider weight on the front suspension fork versus the 29er.. that's going to boost comfort a bit.
The fork has what looks like an above average offset, replacing it with a suspension fork should forward bias me a hair more..
I imagine the thing rides like a motorcycle & may be suited for 35mph duty.
Huge pluses i didn't think about!
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Finally found a cheap(ish) 29er with ideal geometry..
Honestly? very tough choice here!
 Kent big league with 29er front wheel - $399 shipped ( photoshop visualization of how i'd set it up ) Pros: Insane size triangle Extreme crank forwardness; have to push seat forward +7 inches bigger wheelbase vs existing bike Comfymaxxing achieved 29 x 3.0" rear tire conversion can improve aesthetic and be -1 inch of the OE size Great top speeds w/mid drive, can oversize gears for durability Tall rear tire should be fast The combination of crank forwardness + MTB handlebars might improve aerodynamics Cons: Limited to <= 60mm suspension fork No matter what, the bike will look weird.
33lbs stock Not a good choice for hub motors Wild cards: Bike construction quality might be crap May not fit a suspension seatpost but might not need one Reach might be excessive, may need zero reach stem Insane size triangle may = lateral flex, might require support bars |  Motobecane fantom 29 SS12 - $688 shipped Pros: Nice aesthetic -1 degree seat tube vs usual = more crank forwardness 13mm longer than usual chainstay +3.3 inches bigger wheelbase vs existing bike 3-5lbs lighter than existing bike Takes disc brakes on both sides Most hub motors still usable at this wheel size Cons: 73mm BB instead of 68mm BB Rear tire must change to 29 x ~1.9" to increase crank forward Drilled holes in the chainstay aren't confidence inspiring considering we want to use a mid drive Wild cards: Fancy expensive -7mm drop pedals might actually work and allow me to use the stock 29 x 2.4" Swiss cheese chainstays might be fine May not like 73mm BB |
Honestly? very tough choice here!
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