bballe336 said:It's inside the frame so it should not be experiencing any of the harm a hub normally would.
im wondering about that too, guess we'll just have to wait and see.revmonkey said:shimano lists nexus as a commuter system... can the system handle the abuse a DH/FR bike is put through?
sorry, no pics right now. I'll get some when the bike is nice and dirty for ya.revmonkey said:you have any more pretty picutres of your bike other than those previously posted?
Brilliant. Just brilliant.mack said:If its a commuter hub then why wouldnt it handle the stress? A commuter bike gets pedaled the whole time, and it has to be built to withstand all the strain that commuter bikes are put through, no maitnence, shifting while putting the hammer down, and not to mention all the miles. I would think that a hub like that would last longer in a down hill bike than on a commuter bike as long as the dirt is kept out.
I'd have to disagree with that, most DH riders are bigger and stronger than most XC guys, who sprint and full power alot of the time, and shift under full power sometimes, all of which are harder on a hub than XC riding.trialsmasta said:There also isn't nearly as much torque seen on a DH bike as you would XC, but a DH bike ratio spread is wide enought that if used for the wrong application it could do some damage to the internals.
Double disagree. I think that xc riders are harder on hubs, torsionally at least. It is rare that you pedal as hard as you can on a DH bike, but the wheel just shoots up and under your bike. Happens all the time on shorter-chainstayed xc bikes, especially on techy climbs.Zutroy said:I'd have to disagree with that, most DH riders are bigger and stronger than most XC guys, who sprint and full power alot of the time, and shift under full power sometimes, all of which are harder on a hub than XC riding.
regardless of who is stronger (because in light of the following engineering aspect those differences would be negligable), there is one gaping reason why XC use would put alot more stress and thats because of gearing. If you used a baseline max force input of the riders mass (ie. not wearing clips, he can only exert his own body weight down on the pedals), between two equal guys it'll be the gearing that determines the torque. So that guy hammering up the hill with a 32/32 will be dishing twice the torque as the guy spinning across the flats with a 42/21 combo. Now add in the fact the guy climbing is clipped in and pulling more than his body weights worth in force (on longer cranks and smaller rubber most likely for an even lower overall gearing), he's putting gobs more torque in.Zutroy said:I'd have to disagree with that, most DH riders are bigger and stronger than most XC guys, who sprint and full power alot of the time, and shift under full power sometimes, all of which are harder on a hub than XC riding.
if you did, you wouldnt come to that conclusion (if you dont understand torque, how can you say which creates more???). The weight of the bike has little to do with it, that only means you will have lower acceleration for the same given force.bikenweed said:Who puts more force on a hub, XC or DH? Easy, a DH rider. ............. (but) I do not understand the subject of torque very well,
That´s what I wanted to get at. A DH bike with a 38t chainring and a 32t or 26t rear cog will need more torque to climb than an XC bike with a 22t chainring and a 34t rear cog. XC guys can put it in a higher gear and push, but with them narrow bars and small tires, standing and pushing on the super steep stuff sucks. Therefore, DH bikes should be prepared to handle plenty of torque. That would be hilarious if a GT couldn´t be ridden up a hill. I´m pretty confident that the Nexus will do alright, but we´ll just have to wait and see. Don´t all kinds of pedi-cabs and several person bicycles, tandems, etc, use the Nexus all the time?zedro said:But if the climber is using half the gearing, he is contributing twice the torque. It's not hard to see the harder/steeper the climb, the more torque will be required.
no, you still dont understand, and you are confusing 'needing' more torque with 'providing' more torque. In that situation (gearing), the XC guy will be (and be capable of) producing more torque at the wheel. You seem to be assuming that the XC guy is taking a leisurely time up the hill in his granny gear when really he may be pounding as hard as the under-geared DH guy. The DH guy is struggling because he needs more torque, because he is not actually producing as much as the properly geared XC guy.bikenweed said:That´s what I wanted to get at. A DH bike with a 38t chainring and a 32t or 26t rear cog will need more torque to climb than an XC bike with a 22t chainring and a 34t rear cog.
zedro said:no, you still dont understand, and you are confusing 'needing' more torque with 'providing' more torque. In that situation (gearing), the XC guy will be (and be capable of) producing more torque at the wheel. You seem to be assuming that the XC guy is taking a leisurely time up the hill in his granny gear when really he may be pounding as hard as the under-geared DH guy. The DH guy is struggling because he needs more torque, because he is not actually producing as much as the properly geared XC guy.
Dont confuse the ease of pedalling; just because it feels harder to pedal with a 42t doesnt mean you are producing more torque. The reality is the opposite: you arent producing enough torque at the wheel therefore the effort seems higher. Also if you are heavier you will accelerate slower, the net force is the same if you were lighter and accelerating faster (Force = mass x acceleration)
Another example: a car in 1st gear can easily start from a stop, another in 4th will stall the engine. The 1st gear (xc setup) is producing more torque at the wheel (ie our hub) than the other guy in 4th (DH setup) struggling to get going. The fact that he's struggling means he needs more torque at the wheel (the engine is producing the same amount of torque in both cases) which is the whole basis of gearing.
To see how mass doesnt matter, if car A weighs 1 ton and car B weighs 2 tons, and both have the same engine (torque), car A will accelerate twice as fast as car B, yet both are producing the same amount of torque. So the DH rider could have an elephant on his back and it would only make him slower, it wont allow him to produce more torque through his legs, he'll just be slower.
Anyways you can pick up a 101 physics book if you like, it's all there.
well the elephant was really metaphorical so any present life-burden will do, like say...really expensive diningroom furniture bills for instance.....MMike said:Where the HECK am I supposed to find an elephant this time of year??
zedro said:well the elephant was really metaphorical so any present life-burden will do, like say...really expensive diningroom furniture bills for instance.....
vitox said:zed
just to tease ya
ever though of the "peak torque" theory at work here....