Bionx PL 350 speed results

[Canadian Cadence]

I have the Bionx 350 on a 2006 Marin mountain bike. The crankset is a 42/ 34/ 24 with the rear 8 speed cassette 11- 32. Riding the bike last year I was impressed by the power and hill climbing ability but knew there was more top end possible. With this set up I found that my cadence was uncomfortable when driving in the top gear at 34 kph (20 mph) so I knew the bike needed higher gears. ( I have found that most pedelectrics need to be used at lower cadence than my road bike......ie. road bike cadence is 88 but pedelec is around 65 for me.....anyone else notice this??)

Anyway I took the top speed limit off the bike over the winter and I am now sure that I will need higher gears. Here are the results.....In Kph (mult. by .6 to get mph )
Lifting back end off the ground using throttle (with speed restriction on ) the motor cuts out between 33 and 34 kph (speed goes higher before slowing down and motor cuts in again at 33 )
Unrestricted throttle takes wheel up to 56 kph and holds at that speed with throttle activated. ( no load speed)
Results using pedelec on flat was 42 kph but my cadence was crazy ( I am sure it was over 100)
The way the bike is geared now the cadence feels good at 31 kph in top gear.

There is a crankset made by the same company (48 / 38 / 28 ) that will fit on this bike. So top gear would be 48 and 11 compared with the 42 and 11 used now. Any ideas about this upgrade?

I know from the few speed runs I did today that overcoming the air resistance is the key. The amount of energy needed to get 10kph more was astounding ( very exponential !!! )

So this is my progress so far in search of the elusive 50 kph ( 30 mph) !!!!
I am thinking maybe 45 kph with the addition of a new crankset......and probably lots of spandex for the air resistance.....oh my , not a good visual, I am on the large size!!!

 

[flecc]

That 42 kph was very good on the flat for any e-bike with a large frame rider, but the extra power required for the additional 8 kph is much higher again, it's one heck of a target to get to, and I wish you luck.
.

 

[allotmenteer]

There is a crankset made by the same company (48 / 38 / 28 ) that will fit on this bike. So top gear would be 48 and 11 compared with the 42 and 11 used now. Any ideas about this upgrade?

I know from the few speed runs I did today that overcoming the air resistance is the key. The amount of energy needed to get 10kph more was astounding ( very exponential !!! )

So this is my progress so far in search of the elusive 50 kph ( 30 mph) !!!!
I am thinking maybe 45 kph with the addition of a new crankset......and probably lots of spandex for the air resistance.....oh my , not a good visual, I am on the large size!!!

I have a Marin with a 48-36-26 Shimano Hollowtech II crankset which replaced my original 42-32-22 setup. I found that it helped quite a bit and now I can do 21mph on the flat with a reasonable cadence (about 18mph on the old setup). The fact that the new drivetrain is brand new as opposed to the 5 year old knackered one it replaced helped enormously with avoiding losses due to mechanical inefficiencies.

I think to get 30mph you will need:

1) slick tires, the slickest you can find, well inflated.
2) a drivetrain in tip-top condition, well lubricated and no worn bits.
3) stronger legs
4) a tailwind

From my limited knowledge it seems that above 20mph air resistance is the biggest factor in the power needed to achieve higher speeds. Have you considered a recumbent bike? With a fairing?

Regards

Paul

 

[coops]

I thought my cadence would be lower on an electric, and I am still adapting my ride style to my new ezee Torq, but I noticed only yesterday that my cadence often increases from a leisurely 72rpm on my MTB to around 85 or more on the Torq!

It may be the nature of the bike & motor combo, but that's my findings!

As for gearing, I've also been considering a front chainwheel change, though downward from current 8-speed 52T 12-25T to more like 40-44T or even 38T, so long as the cadence increase I've noticed is constant that would give sufficient gear range for me. Multiple front chainwheels is a bit tricky on the Torq due to the chainline, but on the whole I don't feel that's too big a deal.

My advice re gearing would be to be aware of your cadence & how much it may vary in different circumstances, and your motor-assist speed range, then select your gear range accordingly, ensuring spacing is sufficient especially where the motor assist tapers off & pedal-assist is harder, and at the range of maximum motor-only speeds your terrain allows i.e. will be at a lower speed in hills.

One thing to add: I'm not sure if it applies to the Bionx and I'm sure you've checked this, but on the Torq for instance, when the speed is delimited, the range decreases too... I'd be interested to hear how your delimiting the Bionx affects your range.

Hope that's helpful and good luck with your Bionx

Stuart.

 

[Canadian Cadence]

Flecc.

I am finding the air resistance is very hard to overcome and every mph above 20 needs more and more energy from the motor and my legs.
I really doubt I will reach the 30 mph ....but it will be fun to try!!!

.......

I think to get 30mph you will need:

1) slick tires, the slickest you can find, well inflated.
2) a drivetrain in tip-top condition, well lubricated and no worn bits.
3) stronger legs
4) a tailwind

From my limited knowledge it seems that above 20mph air resistance is the biggest factor in the power needed to achieve higher speeds. Have you considered a recumbent bike? With a fairing?

Regards

Paul

Thanks for the info about the crankset.....that is what I was hoping for ....about 3mph.

I believe I will need #3 in your above list. Any idea where I can pick up a pair ???

I have a friend with a recumbent and I have almost got him convinced to get a bionx kit for it!!

I thought my cadence would be lower on an electric, and I am still adapting my ride style to my new ezee Torq, .....

My advice re gearing would be to be aware of your cadence & how much it may vary in different circumstances, and your motor-assist speed range, then select your gear range accordingly, ensuring spacing is sufficient especially where the motor assist tapers off & pedal-assist is harder, and at the range of maximum motor-only speeds your terrain allows i.e. will be at a lower speed in hills.........

Stuart.

I know what you mean by adjusting your riding style. I used to be a long distance cyclist and it is so important to keep your cadence up to prevent lactic acid build up in your muscles. The pedelectrics can be driven at any cadence but the few I have tried Panasonic, Giant and the Bionx seem to give their maximum motor effort with the lower cadence.....just my observation.
I am not to worried about the change to the crankset as there should be enough overlap with the 24 speeds. I am only using a very few now and most of the lower gears are not used at all.
With the Torq are you adding an additional front chain wheel to the 52T ?

Thanks for the info guys.
I am really enjoying the forums!

 

[flecc]

The pedelectrics can be driven at any cadence but the few I have tried Panasonic, Giant and the Bionx seem to give their maximum motor effort with the lower cadence.....just my observation.

That is correct on all those using the Panasonic system, it's set to interpret low cadence as the rider needing assistance, and high cadence as the rider getting on fine and not needing help.
.

 

[coops]

With the Torq are you adding an additional front chain wheel to the 52T ?

Sorry I was unclear: I'm thinking of replacing the front chainwheel for a smaller one, around 38-44T region. The chainline of the Torq & the position of the battery case preclude a 2 or 3 front chainwheel setup I've heard, so I won't try that, but one is sufficient I think.

On the cadence issue, I think its something about the Torq that I find a higher cadence most comfortable: I think the Bionx aswell as the panasonic give motor assist proportional to the force on the pedal, or inversely proportional to the cadence, is that right? So to get more motor assist either you push harder or slower, or both!?

I'd actually considered such a "torque-sensor" type setup for an electric, but now I find a simple throttle control very flexible & seems to allow a more natural pedalling style & cadence for me, but can be a bit tiring on the wrist for long trips! (see throttle mods for Torq for solutions! - I just loosened the spring in mine, which was a bit fierce, & now its quite comfortable )

Hope you get your gears sorted, but don't burn yourself up hitting the 30!!

Best wishes & safe cycling,

Stuart.

 

[Canadian Cadence]

Hi Stuart

I think you might find a 38 tooth front chain ring a little small . I think you would be spinning like mad if you wanted to assist the motor at the higher speeds.
After reading some of Fleccs advice in another thread I fully charged my battery....pumped up the tires and tried to find a clean patch of road ( the roads are a mess covered with sand from our tough winter this year)
New results Fully charged battery unrestricted and no load (wheel in the air) --58.3 km/h
When battery is almost depleted no load speed is 50.2 km/h (this is using the throttle and is a constant speed)
Fully charged battery right off the charger and using throttle only---42.3 km/h
I tried to assist it with pedalling and saw 46.5 for a brief moment. But this was spinning way to fast.
So I am looking forward to getting the new crankset....maybe I can reach the goal....but will i be able to sustain it for any length of time...probably not!
To answer your earlier question about eating up battery power....it sure does. Yesterdays distances travelled used up the battery about twice as fast. But I was really making it work.
The Bionx 350 has the pedal assist and the thumb throttle which I call the Boost and it really has a strong power band around 12- 22 kph. If you use the throttle at these speeds you really feel it kick in.
Good luck with your search for the perfect set up for you. There are some gear charts out there that would help with picking the right chain ring.

 

[coops]

Thanks CC, I think you're right about the 38T - it wouldn't be enough with 12-25T rear for downhills or "bursts" of speed on the flat, though the two closely spaced top gears on the 12-13T coupled with a high cadence 85ish rpm would work well & give some flexibility of gears for cruising speed on the flat on my Torq, which averages around 19-20mph.

Its either that, or higher gears for speed bursts but less flexible cruising top gears... some compromise is required! (I could go for a more wholesale change of front & rear gearing, but I'm not sure its worth it for the limited extra benefits...)

There was a time I'd have been going all-out for speed, but not now I think . I certainly think that having the gears set up for the bike's speed is fairly necessary though, to get the best use of it, so good luck with choosing your chainset too & continued safe progress on your Bionx, however briefly you hit top speed! .

Stuart.

 

[Mike Robinson]

I didn't understand a word that anybody was talking about on this thread! So I looked up cadence on google and came up with this site which seemed to give some good advice on setting up gearing for bicycles.

Cycling Cadence and Bicycle Gearing

it was interesting to me but may help out.

Mike

 

[coops]

Sorry Mike, didn't mean to bamboozle thank goodness for google eh?

Thanks for the link - I think I came across that page while researching leccies. So according to that page I'm a nerd then? well, I suppose you could say that, but I'll try to behave

I think you'll find that bike gearing, on Torqs especially, has come up here on the forum before & been discussed & explained quite a bit, though its not the easiest subject to search for threads on & maybe there should be an item to demystify it, but that's not essential as I think most people wouldn't want info on it!

"Gearing on Torqs" & "Torq owners: What range are you getting from your battery" are two threads come to mind, but also mentioned in the introduce yourself thread.

Hope that helps,

Stuart.

 

[ITSPETEINIT]

Cadence

I didn't understand a word that anybody was talking about on this thread! So I looked up cadence on google and came up with this site which seemed to give some good advice on setting up gearing for bicycles.

Cycling Cadence and Bicycle Gearing

it was interesting to me but may help out.

Mike

There a very good site for calculation speed from any gearing set-up x cadence: you just enter the parameters and up pops the answers.
Bicycle Analyzer

Peter