What on earth is this component?
TheKrikkitWars
Posts: 178
From SR Suntour's website. It looks like a combination of a BB, Hub gear and dynamo/motor for an electric bike, but there's no info to confim what it is any ideas?
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errr No! its clearly a time machine! :P0
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flux capacitor from a gull wing delorean.
didn't look really.
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Whats the advantage of that? At 4.5kg its one hefty component! I understand that hub gears suffer less wear due to them being enclosed and its likely that this is the same, but for that weight i see no advantage.0
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It keeps all the weight at the centre of the bike, and most noticeably reduces unsprung weight on the rear wheel. An un-dished rear wheel can be stronger. Also, looking at that, it looks like some of gearbox is structural to the bike, which should mean the frame would lose a bit of weight...Rock Lobster 853, Trek 1200 and a very old, tired and loved Apollo Javelin.0
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Apparently shifting's more reliable, and can be done staionary or cranking backwards; they're the future...apparentlybennett_346 wrote:Whats the advantage of that? At 4.5kg its one hefty component! I understand that hub gears suffer less wear due to them being enclosed and its likely that this is the same, but for that weight i see no advantage. What We Achieve In Life, Echoes In Eternity0 -
Poor mans Hammerschmidt 0
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chedabob wrote:Poor mans Hammerschmidt hammerschmidt is such an amazing idea. too expensive atm though 0
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I used to wonder how derailleurs had been around so long when most non-cycling engineers look at it & shake their heads! They comment that chains are meant to go round 2 sprockets and NOT jump off. So a derailleur system seems illogical.
However, and it's a big one, a singlespeed or derailleur chain drive is something like 98 or 99% efficient, meaning that almost all your energy goes into moving the bike forward.
Gearbox systems, hub gears or stuff like the Hammerschmidt are not so efficient, as you waste energy making the gears move. I don't know how much less efficient they are & I guess the different systems would have varying degrees of efficiency, but none are as good as a standard set-up. So they have advantages, but the big one for me is that I don't want to waste energy if I don't have to! I guess for DH set-ups the efficiency loss won't be such a big deal, as the pressure on the system isn't as great as when you're pedalling uphill.
I'm sure there'll be some engineers on here that can give some more accurate figures and or physics, or tell me I'm talking rubbish! But I think I'm basically correct.0 -
Yeah, dérailleur systems are efficient because in any gear you have on chainring driving one sprocket and a couple of jockeys. The chain itself is extremely mechanically efficient, so it's all good. Hub gears run through a variety of the different internal thingamajiggers to create the different gears, so there is more drag. The chain gets all the ration shifting done while moving, before you really use it for drive, then settles down- the hub has to do it all the time you're pedalling.Rock Lobster 853, Trek 1200 and a very old, tired and loved Apollo Javelin.0
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Didn't GT make a bike with this sort of thing on/in it a few years ago. That was supposed to be the future according to MBUK.GT Avalanche 1.0
Orange Five0 -
Don't forget the Honda DH bike that Minnaar rode in the WC a few years back. That had a gearbox system fitted too.0
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The Honda "gearbox" was literally just a derailleur in a box. There's only a couple of half decent "proper" gearbox's out there. The one specced on the DB on the link above is made by Universal Transmissions. The prototype was 13spd but the production model is 7spd (more than enough for DH!). The internal gubbins basically look a bit like a cassette, there is a clutch mechanism that contiuously spins when the rear wheel is in movement - this allows the gears to be changed when the pedals arent moving (handy through rock gardens, big jumps, etc preparing tp pedal). The gear change is also rediculously smooth so theres no jolt that you sometimes get when the chain jumps from one cog to another on a derailleur drivetrain.
The weight is still a bit of an issue, but all the weight is low and central so the bike handles like a much lighter DH bike and, the DB Sabbath is within a pound or 2 of most world cup DH rigs.
Other advantages include:
No rear mech to catch
No need for a chain device
No chain slap (as it runs as tight as a single speed)
Lighter rear end creating more active suspension
Low, central weight
Very low maintenence, everything is hidden away, not on show to cling onto mud
Once you open the gear box up (if you feel the urge) they are actually quite simple - there's no little pixies in there pedalling a chain!)
Also, as for it creating more resistance because you've got to put more effort into move the gears - thats not true. It creates the same resistance as pushing a cassette around...
Its really impressive technology and they're even trying to develop a gearbox to include a drive belt for even less maintenence, but thats yet to be seen. Also, i think it'll be a while before the derailleur gets replaced so it could be some time before these become more mainstream.0
