Which bike for off-road?

[Straylight]

I may be talking nonsense (no change there ), but if the rider is not working hard enough on a loose surface, could this not cause the front wheel to slip because of the increased drag of the rear wheel. What I mean is, does the 2-wheel drive model not fail if the wheels become out of sync? If so, perhaps a system could be developed to match the torque of the front hub to that of the rear wheel.

 

[flecc]

I may be talking nonsense (no change there ), but if the rider is not working hard enough on a loose surface, could this not cause the front wheel to slip because of the increased drag of the rear wheel. What I mean is, does the 2-wheel drive model not fail if the wheels become out of sync? If so, perhaps a system could be developed to match the torque of the front hub to that of the rear wheel.

I think in reality that even the slightest rider effort would enable the rear to keep pace with the front.

However, if the rider didn't pedal fast enough, the loss of two wheel drive is true. In fact this is a common occurrence of small wheel bikes like folders due to them sometimes having 15 mph motor capability but rider gearing too low for the rider to keep up on the flat without spinning the pedals like mad.
.

 

[Andrew harvey]

I've done some off roading on both front and rear wheel hubs.
They both work, with front hub motors you just have to balance the weight to keep the traction on both wheels, but remember there are times you want to lean back to help the wheels over humps. This is not a problem after a bit of practice, the two wheel dribve comes into it's own on slippy, rutted surfaces were the rear wheel tends to spin and skip sidewards. The Tongzin if properly geared for the low speed does produce very respectable amounts of torque. If you could get a 140 rpm version it would prove ideal upto about 12mph off road.
when the back wheel does begin to slip a front hub can still grip pulling the bike through, I had great fun in the snow recently doing just that.

The idea of a varible transmission on a hub motor is not new or so impossible, it just needs a little lateral thinking.

 

[Straylight]

Perhaps a nuvinci style CVT insted of orbial gears with teeth? This way a rider can adjust the torque to suit the speed and keep the motor's actual rpm in the most efficient range? To help this you could even have mph markings as guide on the CVT twist control.

 

[Fecn]

I have a Nuvinci CVT on my Agattu and it's extremely capable for climbing hills up hills. I have long been of the opinion that it will effortlessly climb up any gradient that I point it at (albeit at 3.5mph when it gets really steep). I do most of my riding on tracks and trails as a lot of the roads near me are pretty unsavoury. I've never yet found a hill where I've needed to get off and push.

However... the Nuvinci is quite heavy, and I tend to get nervous about going downhill fast on rough ground and hit the brakes at about 15mph.

 

[Straylight]

I think it could be quite fun though, as you'd get a kick down effect when the motor was beginning to struggle on steep hills - how pleasing would that be?

Thinking about it, you might need some kind of indexing (three positions maybe?), or automatic shift, as dealing with that as well as your own gears for pedalling might over complicate the bike controls, and as you say, weight would start to be a factor.

But then if it were a CVT with three notches it'd be no more complicated than a standard bike with dual dérailleurs.

 

[NRG]

I hadn't realised something like the Nuvinci was available, very neat!

Fallbrook Technologies

 

[Fecn]

Thinking about it, you might need some kind of indexing (three positions maybe?), or automatic shift, as dealing with that as well as your own gears for pedalling might over complicate the bike controls, and as you say, weight would start to be a factor.

There's a computer-controlled servo-operated gear changer available for the Nuvinci too... I've been thinking about getting one for myself this summer for a bit of fun. I'd have bought it already if they'd sell the electronics seperately from the hub. I'd have to find a buyer for my old hub to make it all worthwhile, or I'll end up with a collection of spare hubs in the garage.

Nuvinci Automatic Developer Kit

 

[eTim]

Well I gone and done it ! I hauled myself down to Bridgewater to test out the Thorn cycles (these are non-powered bicycles). I tried the Raven Tour, looked at the Sterling and bought the Nomad Mk2 after a test ride

enlarged picture

What can I say, sorry folks it hasn't got a motor, but I'm sure it can take one, it does have a Rolhoff though. It was just one of those moments where the heart says yes and my head said yes and my budget allows, so I did it, it should arrive within 3 weeks!

Now which electric kit to consider ??? Can't be a Bionx, it has a Rolhoff. Plenty of carrying capacity for a large battery. It's got massive Marathon Extreme's, they are lovely and smell so new. It's going to have a Honey Brooks (my arse had better thank me for it). I've ordered a black one with the S&S, so its a practical folder also !

So an expedition grade, folding mountain bike that can be electrified, did I mention it has a Rolhoff ?

 

[Caph]

Thanks Caph, interesting bike at only £999. Are you able to list any of the components as the website shows nothing, e.g. shock, forks, gearset, brakes, rims and tyres? How has it all held up over time? 40 miles out of a 240wh battery is going some, are you a fit rider ?

My experience when trying a bionx off-road is the same as yours, only a low level of assistance is needed otherwise you can get out of shape pretty quickly, but the assistance is great when ploughing through mud and on those long uphills with 26" wheels.

Looks like I'm too late again! I'll reply anyway though.

Front shocks are basic Zoom but I believe this is changing this year to RST forks with lockout option. The rear shock is KindShock. Gears are Shimano Acera (rear cassette Shimano HG30). Rear hub is Quando. Rims are Chinese Huafeng, but seem pretty good to me. Brake levers are Shimano EZ Fire. Brakes don't seem to have a brand but I've swapped mine for Avid BB7s - that's not to say the stock brakes are bad, to be fair I can't tell much difference between them and the Avids. Tyres are Cheng Shin - very hard wearing 2.25" knobblies, but I'm running Ice Spiker Pros at the minute.

I wouldn't say I'm particularly fit. More slow and steady!

I'm glad you made your choice. You'll have to post pics after the conversion.

 

[Tex]

hey. if you are offroading and have silly amounts of $$$$ (sorry no "pounds" on my computer) and so legality less of an issue try:

Stealth Fighter, Stealth Electric Bikes | Environmentally Friendly Motorised Bikes |

these are made down under - i inspected one at the MTB World Championships in Canberra and they are N I C E ! !

 

[Tex]

that said. i know this isn't the forum for such things: leave that to those right High-Power nutters on Endless-Sphere and V is For Voltage, etc.

 

[AndyOfTheSouth]

Bump!

A very good thread and one worth revisiting, but the specific question is, what happened to eTim's Thorn/Rohloff? Apologies if this has been covered on another thread.

 

[eTim]

Bump!

A very good thread and one worth revisiting, but the specific question is, what happened to eTim's Thorn/Rohloff? Apologies if this has been covered on another thread.

Hi Andy,

Still waiting for a suitable kit, just recently started looking at the feasability of getting No-hills to fit a Cytronex and I see that Wisper are about to release the Dahub, so it's a project in the waiting. The bike is great, I love it!

Tim.

 

[schoe]

Cytronex are due to launch their own kit this year but they are keeping the details close to their chest at present !

 

[eTim]

Cytronex are due to launch their own kit this year but they are keeping the details close to their chest at present !

They were supposed to be launching the kit last summer!?!

 

[flecc]

They were supposed to be launching the kit last summer!?!

Yes, it's been a bit like electric car launches, always next year but of course it can never be next year.
.

 

[AndyOfTheSouth]

Hi Andy,

Still waiting for a suitable kit, just recently started looking at the feasability of getting No-hills to fit a Cytronex and I see that Wisper are about to release the Dahub, so it's a project in the waiting. The bike is great, I love it!

Tim.

Thanks, Tim. Intrigued that you are thinking of fitting a Cytronex. Does this mean that they now have a Tongxin that is tough enough for off-road use... Now, that would be tempting!

 

[EdBike]

Have Cytronex announced when they're launching their kit?

 

[HarryB]

Thanks, Tim. Intrigued that you are thinking of fitting a Cytronex. Does this mean that they now have a Tongxin that is tough enough for off-road use... Now, that would be tempting!

Agreed - Tongxin and off-road are completely incompatible.