25 rims are the new aero

[dana_e]

Apologies on this, but here we go:

https://speed25.fulcrumwheels.com/en/

[robt57]

Go to your room...


:cool:

[DRietz]

It's funny, because the front wheel should have an asymmetric rim, too...

[Davist]

"the spokes don't touch" meaning they're not laced I guess? Doesn't this make the wheels less strong? (I know Schwinn never laced their wheels on the varsitys and sting-rays, and their steel rims were hookless, but...)

[oldpotatoe]

"the spokes don't touch" meaning they're not laced I guess? Doesn't this make the wheels less strong? (I know Schwinn never laced their wheels on the varsitys and sting-rays, and their steel rims were hookless, but...)

They are 'laced' in that they cross but for straight pull, not uncommon for the spokes to not actually touch at the crossings.

And for above, yes, for disc, asymmetric rims on the front are an advantage.

In the 'wheelsouttaboxes' world these days, Campagnolo/Fulcrum are kicking butt....to bad the 'big boy, shimano, can't see fit to make anything but a shimano compatible rear hub..that are 'sometimes' not even compatible nor convertible with their own groups(micro spline)...

[saab2000]

Odd that the front is symmetrical but Campagnolo/Fulcrum have my trust. I rode Nucleons for years and loved them and I'd ride these if I had a bike for them. I don't care much for aero rims and these low-profile rims with a 21mm internal width are something I believe I would like!

[mcteague]

26mm deep, 27.6mm external and 21mm internal but they are called 25s?

Actually I like them. My BTLOS wheels are 40mm deep and I still get some front end instability in strong cross winds or when a big truck passes. Never felt that with my old BORA 33mm deep wheels. Of course the BTLOS set were a LOT less money.

Tim

[Davist]

They are 'laced' in that they cross but for straight pull, not uncommon for the spokes to not actually touch at the crossings.

And for above, yes, for disc, asymmetric rims on the front are an advantage.

In the 'wheelsouttaboxes' world these days, Campagnolo/Fulcrum are kicking butt....to bad the 'big boy, shimano, can't see fit to make anything but a shimano compatible rear hub..that are 'sometimes' not even compatible nor convertible with their own groups(micro spline)...

I meant laced being the final cross of the outer spoke goes under the inner spoke. And fully agree cool stuff lately from Fulcrum/Campy inc.

EDIT: Never mind, didn't realize they were triplet

[charliedid]

I like.

[redir]

Wait... Why would the front need to be asymmetrical?

[prototoast]

Wait... Why would the front need to be asymmetrical?

Disc brakes.

[openwheelracing]

losing the protective coating to save weight. Doesn't that allow faster damage to the rims?

[tomato coupe]

Wait... Why would the front need to be asymmetrical?

The front wheel is dished for disc brakes, but the rim doesn’t have to be asymmetrical.

[prototoast]

The front wheel is dished for disc brakes, but the rim doesn’t have to be asymmetrical.

A rear rim doesn't have to be asymmetrical either, but it can help and they clearly chose to do that with these wheels. The front hub spacing, spoke count, and spoke pattern are all asymmetrical. Not sure why they wouldn't make the rim asymmetrical too, as long as it was clearly already on their mind since they did it in the rear.

[Mark McM]

A rear rim doesn't have to be asymmetrical either, but it can help and they clearly chose to do that with these wheels. The front hub spacing, spoke count, and spoke pattern are all asymmetrical. Not sure why they wouldn't make the rim asymmetrical too, as long as it was clearly already on their mind since they did it in the rear.

In this case, an asymmetric front rim would actually be worse. Another design feature of the front wheel not yet mentioned is that the front wheel is laced with a triplet pattern (16 left spokes and 8 right spokes). If there were no dishing, the right spokes would have twice the tension of the left spokes. Dishing allows the right tension to decrease and the left tension to increase. In fact, the spoke tension would be even better balanced if the rim were asymmetric in the opposite direction, but they'd have a hard time selling that.

[dana_e]

For some, reason the tire nub things bug me

[Mark McM]

"the spokes don't touch" meaning they're not laced I guess? Doesn't this make the wheels less strong? (I know Schwinn never laced their wheels on the varsitys and sting-rays, and their steel rims were hookless, but...)

"Lacing" simply means that the spokes are run from hub to the rim. When the spokes cross-over inside to outside it is referred to as "interlacing"

Interlacing is not absolutely necessary, and doesn't by itself contribute to the strength or stiffness of the wheel. However, it can have certain advantageous side affects, including: Interlacing can pull the line of the outer spokes inward, leaving a bigger gap between spokes and derailleur cage (hub designers can take advantage of this extra spacing to move the right flange outboard, to improve lateral stiffness); and in case a spoke breaks, the spoke is less likely to flop around and hit the fork or frame.

[Clean39T]

I like.

Same.

[soulspinner]

Same.

Like everything but the price probably

[Alistair]

26mm deep, 27.6mm external and 21mm internal but they are called 25s?


Head-scratcher for sure.

My Trek came with actual 25mm rims. Pretty common for gravel bikes. Really confusing name for these.

[Nomadmax]

So we're back to what Matrix was basically making decades ago in aluminum?? This is why I ride old stuff, if you keep it long enough it all circles back. I may not live long enough for my leisure suits to come back though :banana:

[Mark McM]

EDIT: Never mind, didn't realize they were triplet

Wheels with triplet spokes can still be interlaced - at least on the "drive" side. If there are an even number of spokes on the "non-drive" side they can be crossed, and depending on the number of crossings they can also be interlaced.
I've built several interlaced triplet wheels.

[Mark McM]

So we're back to what Matrix was basically making decades ago in aluminum?? This is why I ride old stuff, if you keep it long enough it all circles back. I may not live long enough for my leisure suits to come back though :banana:

I think the point of these new wheels is that they are lightweight. Based on the components, I'm guessing that the rims on these wheels weigh about 300 grams each. There have been aluminum tubular rims about this weight, but they tend not to hold up well with only 24 spokes and/or high amounts of dishing. The only clincher rims I'm aware of that have been around this weight were American Classic Mag300 rims (which were really closer to 340 grams) but these were notoriously for their short life spans, and they weren't anywhere near 27.6mm external or 21mm internal. Modern aluminum clincher rims this shape typically weigh closer to 460+ grams.

So yeah, there have been aluminum clincher rims/wheels with a similar shape (and probably similar aerodynamics), but they were probably about 400 grams (or more) heavier than these new wheels.

[redir]

Ah! I did not realize that the front wheel was dished for disk brakes.

I'm still kickin' it oldskool.

[Mark McM]

Ah! I did not realize that the front wheel was dished for disk brakes.

Yes, and this is probably the main reason that disc brake front wheels have more spokes than rim brake front wheels. The dishing reduces the wheel's lateral stiffness (which is very important for a front wheel), and the extra spokes are there to get it back.

[oldpotatoe]

Head-scratcher for sure.

My Trek came with actual 25mm rims. Pretty common for gravel bikes. Really confusing name for these.

Well, 700c tubulars are still called '28inch' so who knows? :)

[Applesauce]

losing the protective coating to save weight. Doesn't that allow faster damage to the rims?

WR1 rims get no treatment after removing them from the mould save cutting off the flashing. Thermoplastic resins are absurdly durable.