[Sandro]

Just saw this on autoblog, and it looks... "interesting":

Small-bore motorcycle maker Derbi, a company who's name is literally "DERived from BIcycle," has launched a new concept bike known as the DH 2.0. Derbi refers to its concept as "a machine taken to the minimum to achieve the maximum," a phrase which we can really get behind. Using an air-cooled single cylinder 4-stroke engine displacing 100cc's and an automatic transmission, Derbi believes that the machine would have very low emissions and very high fuel mileage. That engine can be removed from the frame, leaving a downhill mountainbike chassis for when the motor is not needed. Most of the components appear to have been taken from the mountainbike shelf, meaning that the DH 2.0 weights just eighty-eight pounds. The frame is made from aluminum and holds the gasoline. This is an interesting concept, and one which we think could really go somewhere.


Are they serious? I'm sure that nobody would use this for downhilling sans the engine, and while i'm no engineer i highly doubt that bikeparts are suited for this application.
Discuss

Edit: here's the link: http://www.autobloggreen.com/2008/05/13/derbi-dh-2-0-looking-to-mountainbikes-for-inspiration/

 

[caputo1989]

I saw one like it at a shop near me. It weighd 55lbs dry, Speced with Fox and hope.

 

[howloftheyeti]

i dont really know what to think? but it would probably be fun to ride.

 

[buildyourown]

Awesome.
I'm not sure where the market is though. It would be great for DH training. No more need to shuttle. You could rally up the fire roads and then ride DH down the trails.

I'm sure heavy DH bike parts can handle the weight.

 

[Prettym1k3]

55 pounds without gas? I call BS. Most DH rigs are still in the 40-45 mark, which means that this whole thing only weighs 10 pounds more? I don't know...

Either way, the Avid Codes with that 9" or 10" rotor look mean, but I'd still question it's stopping ability for repeated stops on a heavy "motorcycle" with a fully geared rider on top.

 

[MobileChernobyl]

lol, people always trying to reinvent the wheel.

Look up any moto trials bike and its much more suited for the application. Granted you can't take the engine out "leaving a downhill mountainbike chassis for when the motor is not needed" But I wouldnt be in a big hurry to do that with the Derbi either.

If you don't think the moto trials bikes are "capable" of being a moto DH rig, look up Julien Dupont on youtube. Not only is that 100cc 4stroke engine most likely not even close to the high output of a moto trials engine, but its prolly overweight for it's own power output. it looks very similar to most "convert your bike" mass produced chinese box engines. Another thing is the automatic tranny - wtf - there aren't any pedals (ok so there are, but they should be pegs if they use countless years of experimenting on the moto scene with fully pivoting pegs as an example) on there, use a clutch.

They are trying to appeal to two different markets with their design. like always said, jack of all trades - master of none. The small 100cc 4stroke engine may get decent mpg ratings, but a proper frame and wheelset would help that even more. And while the frame and wheelset may look extreme, the engine is lame compared to what the frame can do, essentially becoming more of a boat anchor after faster DH speeds have been reached.

Moto Trials - proven. Good attempt in all fairness however, I don't like to shun sweet fabrication, but these guys are unfortunately just reinventing the wheel.

 

[tsamps]

There have been a few of these in the past, like this one that was featured on sicklines: http://www.projectm85.com/ . Or this one based out of australia: http://www.fxbikes.com/ . Heres a video of John Kirkcaldie riding it: http://www.fxbikes.com/movie/kirkcaldie_fxbikes.wmv

He almost directly quotes buildyourown

 

[ire]

I like the pedal pegs

 

[demo 9]

glorified moped?

 

[Huck Banzai]

D00ds - wth - thats the 09 Sunday!!

 

[go-ride.com]

Now that would be cool if it was electric http://www.zeromotorcycles.com/

Oh, and I hate to say it, but I actually mean it... that Derbi swingarm looks flexy for even a 40 lb DH bike.

 

[sperkins]

i love that bike! it looks like it would be alot of fun to ride.

 

[DirtyMike]

It looks like Moto trials bike, I would have to revamp that motor a bit to rip alot more power out of it

 

[MobileChernobyl]

It looks like Moto trials bike, I would have to revamp that motor a bit to rip alot more power out of it

Wouldn't be worth it - its a 2 valve air cooled 100cc 4stroke. moto trials are liquid cooled beasts compared to that haha.

 

[DirtyMike]

Wouldn't be worth it - its a 2 valve air cooled 100cc 4stroke. moto trials are liquid cooled beasts compared to that haha.

Exactly my point!!! I would mount up something worthwile!!!!!

 

[sriracha]

looks pretty fun to me. i'd rather ride that instead of a 250lb motorcycle.

 

[kuksul08]

They should have put a 2-stroke engine in it. Less weight, more power. Then again, it kinda defeats the whole efficiency and environmentally friendly aspect

 

[EVILTWIN]

I'd break the hell outta that.

 

[jonKranked]

2001 called, they want their saddle back.

 

[FOXROX]

2001 called, they want their saddle back.

bender called, he said he wants to order three

 

[Huck Banzai]

Is that an air shock on the back?

Swingarm does look a bit siss'

hmm....


the fatter I get, the more appealing this is.

 

[dh415]

that thing looks savage

 

[Steve M]

haha that thing looks like it'd be sick fun actually. Sure it's not a proper DH bike, but who likes pedalling anyway? Just hope it has a freewheel, engine braking on a DH bike would sh*t me to tears.

 

[kuksul08]

haha that thing looks like it'd be sick fun actually. Sure it's not a proper DH bike, but who likes pedalling anyway? Just hope it has a freewheel, engine braking on a DH bike would sh*t me to tears.

probably centrifugal clutch

 

[motomike]

 

[Steve M]

probably centrifugal clutch

The problem with a centrifugal clutch is that you need to let the engine speed slow down to a certain point before it disengages. If you use the engine to get up to a certain speed then try to coast, the wheel will keep the clutch spinning fast enough that it'll stay engaged. It still really needs a freewheel.

 

[MrPlow]

Pfft, The BB is way too high.

Seriously, looks like it may be fun though.

 

[William42]

does it come with a 13in bb? 62˚ HA?

 

[kuksul08]

The problem with a centrifugal clutch is that you need to let the engine speed slow down to a certain point before it disengages. If you use the engine to get up to a certain speed then try to coast, the wheel will keep the clutch spinning fast enough that it'll stay engaged. It still really needs a freewheel.

Yea you're right. Also there would be a lot of extra drag without a freewheel from turning the sprockets and such.

 

[norbar]

Wasn't tere allready some MX bike with DH parts? Monster and stuff? Or is this the same that was the previous fuss about?

 

[DH Diva]

looks pretty fun to me. i'd rather ride that instead of a 250lb motorcycle.

I guess you've never ridden a 250lb motorcycle. The weight isn't an issue if you know how to ride, even for someone of my size. And besides, wtf are you going to do with a whopping 100cc of power and air cooled to boot? 100cc is a kiddy bike, no power=no point.

 

[beaverbiker]

DH Diva got it right on. There's no way I'd give up riding my moto for that thing. If I want a sissy bike, I'll just ride my mountain bike.

 

[norbar]

I guess you've never ridden a 250lb motorcycle. The weight isn't an issue if you know how to ride, even for someone of my size. And besides, wtf are you going to do with a whopping 100cc of power and air cooled to boot? 100cc is a kiddy bike, no power=no point.

You don't feel the weight but try to do some techy small jump or go on a dh track and you will fill it. The idea is not to make a light bike for MX trails but to make sth for completely other riding conditions.

 

[MobileChernobyl]

^Good point, but moto's arent meant to be jumped on little DH bike sized jumps. Where 60 foot tables and 40 foot doubles would be a tow in size jump almost on a DH bike, they're cakewalk 3-4th gear jumps on a 220lb (thats a 450f - 250lbs is overweight lol) beast. Not to mention all the added gyro and intertial stability a moto has. And i've ridden some stupid sick enduro trails, with a clutch and 20+ hp on the rear wheel, getting the bike around a technical turn is usually not hard. Technical trails on a dirtbike are impossible trails to a bike. There more like army battle grounds with holes and trenches, deep rutted stream crossings, log crossings almost 2feet high, and your bike needs to be overbuilt to say the least. that little 8hp whatever you want to call it Derbi bike wouldn't make it a quartermile through some enduro trails before the wheels fold, unless ridden by a champion natural trials rider (who's extremely patient and has a long fuse lol).

But this little motor powered DH bike would be bad for our sport if used as a "replacement" dh bike. Half the time just riding trails with our quiet .5hp pedal powered beasts is enough to spark local controversy and get trails shut down. Throw a 8hp gas powered noisy motor on there and you start ripping up the trails more than people on horseback do. That equals local trails getting shut down and thats lame, just for feeling badass and riding the comparison of an XR100 haha.

 

[DH Diva]

You don't feel the weight but try to do some techy small jump or go on a dh track and you will fill it. The idea is not to make a light bike for MX trails but to make sth for completely other riding conditions.

Have you ever ridden a moto on the soverign singletrack in Moab? I have. Techy, narrow, rocky, ledgy, sidehill cliffs. A 100 will not cut it. No torque and no power to "trials" ride over the majority of the obstacles the way you have to ride that stuff on a moto.

Do you have much technical, trail riding moto experience?

 

[norbar]

No I don't but I don't think you see my point.

It would be the same as if you said that 11kg dj bike makes no sense as you don't feel the weight of a 16kg DH bike. Different application.
I know that you can do really much on a full bike but are you implicating that it has no limitations and you can do everything with it? I know I can't Dj my Dh rig so you should feel it with the MX bike... sorry.

MobileChernobyl - I would never use that kind of bike on a dh/fr trail as it would destroy it. I'd rather try to find with it it's own niche of trails. I have a couple ideas.
Plus the idea is great as with a DH like MX bike you can build tracks similar to DH on flat. You won't learn all on it but for sure more than on a MX trail.

 

[DH Diva]

I know that you can do really much on a full bike but are you implicating that it has no limitations and you can do everything with it? I know I can't Dj my Dh rig so you should feel it with the MX bike... sorry.

I believe there is a lot less limitation than you are assuming, especially since you yourself admit to not having much experience with dirt bikes.

I have a lot of experience with both DH and Moto. I ride my moto on a lot of the same trails we DH.

 

[MobileChernobyl]

MobileChernobyl - I would never use that kind of bike on a dh/fr trail as it would destroy it. I'd rather try to find with it it's own niche of trails. I have a couple ideas.
Plus the idea is great as with a DH like MX bike you can build tracks similar to DH on flat. You won't learn all on it but for sure more than on a MX trail.

I see where your going, but the derbi is almost like an answer to a problem that doesnt exist. If you wanted to ride "flat DH trails" you would participate in observed moto trials. There isn't a big "gap" in the market like your imagining, look up julien dupont on youtube, and just do a nice search on moto trials videos, you'll be surprised what theyre capable of.

 

[Huck Banzai]

Why the 'hate'?

Enough with the extremeness of MX. DH trails and MX trails are different, the idea that an MX could even approach the same trails universally is ludicrous. (and vice versa) People are always trying to compare the two, they're neither the same, nor is MX a progression.

Don't like it (these motorized DH bikes)? Maybe ignore it, because all the MX smack talk is hollow posturing.

 

[MobileChernobyl]

Not hatin' Brah, I just don't like the idea of calling it a "motorized DH bike". For one, You won't be able to hear "Hey man wheres the engine" anymore when your seen toting your DH rig around.
And it's just another reason for the cops to arrest people riding on semi-legal trails, and consequently shut them down, aka bad image for our sport.

I like DH cause it's like a quiet, pure form of moto/enduro.

But the fact remains, these "motorized dh bikes" have been thought of before, (see Yamaha trixter, FXbikes.com, etc.) and they never catch on so i guess theres no worth arguing lol - ride on brutha