Opinions on Alchemy ELF front hub?

neeb

Any disadvantages with this hub? Seems too good to be true, extremely light but supposedly builds a very stiff wheel because the flanges are very widely spaced (although they have a relatively small diameter).

Would I be right in thinking that this would make a wheel which is laterally stiff because of the increased spoke angle, but radially not-so-stiff because of the smaller flange? For a front wheel, presumably the only disadvantage of any decreased radial stiffness would be in braking? (if this was even detectable).

ugo.santalucia

There are a lot of cigar type hubs at 60-70 grams. The bearings are 20 x9 which is a very very small size. They don't last very long. I would not spend that money... Get a novatec 291, it is pretty much the same thing, but much cheaper. As for wheel stiffness, it is a front wheel, how much stiffness you think you need? Besides, they are thought to go with deep carbon rims, so no problems of stiffness

neeb

Apparently the ELFs are 22 x6 - is that going to be significantly better than 20 x9? Here's the blurb:

http://www.alchemybicycleworks.com/Alch ... 062810.pdf

it is a front wheel, how much stiffness you think you need? Besides, they are thought to go with deep carbon rims, so no problems of stiffness

Good question, I hadn't thought it through. I was assuming that at least some of the lateral stiffness you feel when climbing hard out of the saddle was down to the front wheel as well as the rear. Obviously the rear is nearer the crank where the force is being applied, but both wheels are on the ground so presumably both will flex laterally a bit? Not so bothered about radial stiffness in the front of course.

neeb

Ok, scrub that, I guess 22 x 6 is 22 balls of 6mm diameter? So they are even smaller?

ugo.santalucia

neeb wrote:

Apparently the ELFs are 22 x6 - is that going to be significantly better than 20 x9? Here's the blurb:

http://www.alchemybicycleworks.com/Alch ... 062810.pdf

it is a front wheel, how much stiffness you think you need? Besides, they are thought to go with deep carbon rims, so no problems of stiffness

Good question, I hadn't thought it through. I was assuming that at least some of the lateral stiffness you feel when climbing hard out of the saddle was down to the front wheel as well as the rear. Obviously the rear is nearer the crank where the force is being applied, but both wheels are on the ground so presumably both will flex laterally a bit? Not so bothered about radial stiffness in the front of course.

They are 10 x 22 internal and external diameter... Balls probably 3 mm, slightly better... Still, seems a lot of money for a front hub. Get a Hope one, good quality, large enough flange... Weight in a hub is pretty much irrelevant

neeb

Thanks, all useful information.

huuregeil

To disagree with ugo, I think this looks a really nice hub, but it depends on what you're using it for. Radial stiffness is a complete non issue, disregard this completely! Lateral stiffness matters only if you're dropping the spoke count - if you're after a light racing wheel, these hubs would make sense. The bearings are chunky for the weight - yes, they're not up to Hope standards but they're a damn sight bigger than most ultra-light front hubs. The mechanical design is interesting and well thought out. If you've got the cash, and the application suits, go for it! Depending on what you pay, they're similarly priced to other similarly specc'ed front hubs (e.g. Tune) and lighter than other hubs with similar bearings/design (e.g. PMP, Goldtec).

huuregeil

PS Braking loads are not transmitted through the hub!

neeb

Yes, I must admit that while I completely accept the wisdom of what ugo is saying (I'm sure the hope would last longer), I do suffer from chronic low-level weenyitis which my more rational side can never quite keep at bay, and 50 grams is 50 grams, dammit, even if it's not peripherally revolving..

huuregeil wrote:

PS Braking loads are not transmitted through the hub!

Oops, no they're not are they? I had this idea in my head from thinking about disk brakes at some point in the past...

Well, at least I've learned a lot in this thread!

Eyorerox

Should answer most of your questions:-
http://fairwheelbikes.com/cycling-blog/ ... pdate.html
http://fairwheelbikes.com/cycling-blog/ ... rload.html

ugo.santalucia

huuregeil wrote:

To disagree with ugo, I think this looks a really nice hub, but it depends on what you're using it for. Radial stiffness is a complete non issue, disregard this completely! Lateral stiffness matters only if you're dropping the spoke count - if you're after a light racing wheel, these hubs would make sense. The bearings are chunky for the weight - yes, they're not up to Hope standards but they're a damn sight bigger than most ultra-light front hubs. The mechanical design is interesting and well thought out. If you've got the cash, and the application suits, go for it! Depending on what you pay, they're similarly priced to other similarly specc'ed front hubs (e.g. Tune) and lighter than other hubs with similar bearings/design (e.g. PMP, Goldtec).

The reason not to buy these hubs is that they need to be imported... then you build them up and after a few miles you realise there is something not quite right... so you take the wheel into parts and send them back to the USA, where they replace it with another one which has exactly the same issues...
It is incredibly time consuming and a great pain in the axxe for the sake of a 50 grams saving. I have had a few problems with 60 grams hubs and I have decided I will not use them any more, as the hassle involved is just too much.

Bear in mind the problem often is not the actual bearings, but the shell, which is so thin that it deforms and the bearing does not sit happily any longer. At theta point there is nothing one can do but replace.

This is my experience

huuregeil

No, that's the reason why you don't but 60g cheap far-eastern knock-off hubs!!! It's easy to go weight-weenie in the design of a hub, but quality may suffer - this is where good design pays off, and where it pays to pay for good design. If you want a 60-70g front hub, you need to buy a decent one - everything about the Alchemy hubs suggests that extremely close attention has been paid to the design of these things, and I'd be very surprised if they have major quality issues like this. So, if you're in the market for a hub of this ilk, it's high up on the list of contenders (Tune being the other) - the geometry suggests it's ideal for e.g. something like a 20 spoke, 25mm carbon rim, where stiffness is at a premium and low weight is desirable.