Am I going to die?

[PaMtbRider]

Originally Posted by ripvanrando

Pressure gauges are notoriously inaccurate.

One boys rock hard 38psi might be a limp noodle for another because gauge accuracy can easily be off +/-5 psi

This! 180 pound me pumps up my 38c gravelkings to 40 psi on the dial of my pump. I then check / adjust it with my digital pressure gauge that will read 32psi.

[Dave]

Ideally, a heavier rider should use a 25mm IW rim and 30-32mm tires to keep the pressure down, but there's nothing wrong with using 73. I'd be sure that my pressure gauge is accurate. My old Silca read 8 psi high, so 80 was really 72. I installed a new, larger gauge. I just recently added a 7 inch round base, so it doesn't tip over easily.

[ripvanrando]

Originally Posted by oldpotatoe

Like I said, not what the marketeers say..

Like I said.

I linked that simply to educate you. Are you still in the 80's thinking 32H 3x box rims with tubies are as fast. If so, why bother asking your question?

Let's take them one by one

Lower rolling resistance: Internal width of 25 and external width of 29 mm vs typical 21 mm and 25 mm for hooked, why would you think the narrower contact patch would have lower rolling resistance? It doesn't.

Lower CdA: We'd need Hambini to explain. The tire and rim transition is critical for airflow. Swisside even has taken out a patent for the tire that is most efficient for its rims. A narrow rim with a sharp tire transition is slow. I've tested this myself. There are countless wind tunnel tests for you to confirm. Everyone likes wider tires, they work best with wide rims and hookless rims naturally support wider tires vs inherently narrower hooked.

Lower weight: Firecrest 303 hookless are way lighter than the hooked version, is there a dispute?

Lower cost: Is there any dispute? Retail prices are lower and mfg costs are lower (mostly due to lower scrap rates)

Higher stall: I have no independent data but tell me how a cleaner transition from rim to tire would not have an effect on the airflow. And if so, what would be that effect. In my seat of the pants testing, the transition is at a lower speed. That is good, if my seat of pants is correct

Further, our work in the wind tunnel and using CFD software has indicated to us that a hookless bead may achieve a slightly more aerodynamic shape because of the way the tire interacts with the rim

https://us.huntbikewheels.com/blogs/...d-an-explainer

In 2016 we launched the SES 4.5 AR which consequently was our first road wheelset featuring the tubeless specific hookless-bead design. The design priority for this wheelset was to achieve overall performance with a 28mm-30mm tire that was on par with leading wheel tire combos where the rim was optimized around 25mm tires. In short, the hookless design won out in testing as its straight sidewalls further refine the airflow transition zone between the tire and rim, creating a more stable and efficient interface

https://www.enve.com/journal/behind-...ho-theyre-for/

[EB]

Woah we're talking wind tunnels now?

I assure you I strive for the least aero setup possible with my death tires.

[redir]

Originally Posted by mstateglfr

Its a rim that has sides which look like old steel hookless rims from 40 years ago.
The rim cant handle high pressures because the tire will blow off it and lead to faces slamming into pavement.
- This is OK for MTB where tubeless gets down into the teens for PSI due to wide enough tires.
- This is OK for Gravel where tubeless is in the 35-50psi range depending on tire width and total system weight.
- This gets a bit dicey for road where tubeless has to be higher pressure due to narrower tires. If 73psi is the max for a hookless rim, that gets really close to unsafe for some(many?) cyclists. A 28mm tire on a hookless 20mm internal width rim is at 80-82psi for me, according to Silca. According to Zipp, its 74psi. Regardless, basically I would risk blowing off tires every time I pump up for a ride or actually ride my bike and make a turn.

Thanks.

OP I would stick to what the tire manufacturer says else...

Why risk it?

[EB]

Originally Posted by redir

Thanks.

OP I would stick to what the tire manufacturer says else...

Why risk it?

So I should stick to a minimum pressure of 45 psi, then?

I'm fairly sure the molds are just out of date. Tire molds are surprisingly expensive - a Maxxis product manager on the pinkbike podcast awhile back mentioned they range up in the hundreds of thousands of dollars. My guess is that they just didn't bother to re-do the molds for existing sizes. The new sizes they've released of the exact same tire design lack the warnings.

[redir]

Originally Posted by Eli Bingham

So I should stick to a minimum pressure of 45 psi, then?

I'm fairly sure the molds are just out of date. Tire molds are surprisingly expensive - a Maxxis product manager on the pinkbike podcast awhile back mentioned they range up in the hundreds of thousands of dollars. My guess is that they just didn't bother to re-do the molds for existing sizes. The new sizes they've released of the exact same tire design lack the warnings.

Ok but now it's all about the jinx, ya know what I mean?

[mstateglfr]

Originally Posted by ripvanrando

Lower cost: Is there any dispute? Retail prices are lower and mfg costs are lower (mostly due to lower scrap rates)

I am not disputing this as I wont pretend to be up on the cost difference at the retail level of hooked vs identical hookless wheels.
I can say, with confidence, that when I look at carbon wheels I really dont see a trend in lower costs over the last 4-6 years even though hookless has become more accepted.
There are certainly more lower cost(under $1k) carbon rim wheelsets now compared to 2017-2019, but I think that is more tied to Chinese direct brands gaining traction in the marketplace.




You mention Firecrest wheels and I understand the hookless version is lighter than the old hooked version. Is that what you are basing your weight comment on? They switched from brass to aluminum nipples, which as 24spokes front and back, is about 40g lighter. Plus the layup changed...which I would think impacts weight.
Not sure how much of the weight difference is based on the lack of a couple small carbon hooks? I cant say Ive looked into that.

[Mark McM]

Originally Posted by ripvanrando

Lower rolling resistance: Internal width of 25 and external width of 29 mm vs typical 21 mm and 25 mm for hooked, why would you think the narrower contact patch would have lower rolling resistance? It doesn't.

Lower CdA: We'd need Hambini to explain. The tire and rim transition is critical for airflow. Swisside even has taken out a patent for the tire that is most efficient for its rims. A narrow rim with a sharp tire transition is slow. I've tested this myself. There are countless wind tunnel tests for you to confirm. Everyone likes wider tires, they work best with wide rims and hookless rims naturally support wider tires vs inherently narrower hooked.

Hooked rims are not inherently narrower than hookless rims. Heck, the addition of a hook to the inner face of the sidewall would tend to make the hooked rim have a wider outer width for a given inner width, compared to the same rim without a hook. There are plenty of hooked rims with internal widths wider than 25mm.

Lower weight: Firecrest 303 hookless are way lighter than the hooked version, is there a dispute?

How do you know that the weight reduction was entirely due to being hookless? Vintage hookless aluminum rims are lighter than modern hooked aluminum rims, is that solely due to presence or absense of hooks?

Higher stall: I have no independent data but tell me how a cleaner transition from rim to tire would not have an effect on the airflow. And if so, what would be that effect. In my seat of the pants testing, the transition is at a lower speed. That is good, if my seat of pants is correct




https://us.huntbikewheels.com/blogs/...d-an-explainer



https://www.enve.com/journal/behind-...ho-theyre-for/

Why would a hookless rim have a cleaner transition? The Hunt and Enve web pages claim this, but they have misleading images.

Here's the image from Hunt web page:



Notice how they distort the hooked tire into an oval shape to make it look wider than the hookless tire. In reality, the hooked tire would be just as round as the hookless, with just as clean a transition.

Here's the image from the Envy web page:



Notice how they put the hooked tire onto a narrower rim than the hooked, to make it look like the hookless tire has cleaner transitions. If they swapped tires and rims (the hooked tire on the wider rim), the hooked tire would have the cleaner transition.


Just like many other marketing claims, most of the technical claims for hookless rims don't hold water.

[EB]

Rode em. Didn’t die. Great combo too!

[oldpotatoe]

Originally Posted by ripvanrando

Like I said.

I linked that simply to educate you. Are you still in the 80's thinking 32H 3x box rims with tubies are as fast. If so, why bother asking your question?

Let's take them one by one

Lower rolling resistance: Internal width of 25 and external width of 29 mm vs typical 21 mm and 25 mm for hooked, why would you think the narrower contact patch would have lower rolling resistance? It doesn't.

Lower CdA: We'd need Hambini to explain. The tire and rim transition is critical for airflow. Swisside even has taken out a patent for the tire that is most efficient for its rims. A narrow rim with a sharp tire transition is slow. I've tested this myself. There are countless wind tunnel tests for you to confirm. Everyone likes wider tires, they work best with wide rims and hookless rims naturally support wider tires vs inherently narrower hooked.

Lower weight: Firecrest 303 hookless are way lighter than the hooked version, is there a dispute?

Lower cost: Is there any dispute? Retail prices are lower and mfg costs are lower (mostly due to lower scrap rates)

Higher stall: I have no independent data but tell me how a cleaner transition from rim to tire would not have an effect on the airflow. And if so, what would be that effect. In my seat of the pants testing, the transition is at a lower speed. That is good, if my seat of pants is correct




https://us.huntbikewheels.com/blogs/...d-an-explainer



https://www.enve.com/journal/behind-...ho-theyre-for/

No reason to get snarky there. Eh?
Let's just say I'd like to see an objective evaluation of hookless VS hooked, bicycle, tubeless bicycle rims. Not the TSE or whatever sram came up with. I kinda think sram/Zipp isn't the most objective source for info..if the past is any indication.

-Lower rilling resistance-how about rims that are the same ID and OD?
-Lower cda-'are slow? I'll bet similar sized tires and rims, the difference is lost in the noise and bambini-yikes, that speaks volumes. Wind tunnel..w/o a rider..check.
-Lighter-'Way' lighter. For BTLOS, the hooked rims and hookless rims are not only the same weight, but the same prices. Maybe the zip 303 is 'way lighter, but not all are.
-Lower Cost-see above
-Higher 'stall'..yikes..

Ya love them hookless, sram wheels..groovy but like I said, something more 'objective'...

Say hookless is way cheaper, way lighter, way more 'aero', implies that hooked rims of the same dimensions are expensive, heavy and not aero. I think the differences are small, if there at all(BTLOS)...

If so, why bother asking your question?

I guess it bothers YOU that I asked the question...it's a part of a toy, no reason to get personal-eh?

[oldpotatoe]

Are you still in the 80's thinking 32H 3x box rims with tubies are as fast

Discussion group, discuss or not. For this .72 of a century guy, they ARE just as fast because, ya know, I'm never gonna have anything tubeless, wheelwise. Perfectly happy with my 32 and 36h tubular, box section wheels. I haven't been into 'chasing' performance via equipment for about 36 years..not gonna start now.

So, a LOT of tubeless, hookless 'performance' advantages is the stuff of coffee shop points at that Sunday 25 mile ride. And those guys with $, eat that stuff up..fine and dandy...whether they can 'feel' it or 'see' it or not.

But, discuss....or not....this 'trend' in today's toys is interesting to me, not a bother at all.

[NHAero]

Originally Posted by oldpotatoe

Discussion group, discuss or not. For this .72 of a century guy, they ARE just as fast because, ya know, I'm never gonna have anything tubeless, wheelwise. Perfectly happy with my 32 and 36h tubular, box section wheels. I haven't been into 'chasing' performance via equipment for about 36 years..not gonna start now.

So, a LOT of tubeless, hookless 'performance' advantages is the stuff of coffee shop points at that Sunday 25 mile ride. And those guys with $, eat that stuff up..fine and dandy...whether they can 'feel' it or 'see' it or not.

But, discuss....or not....this 'trend' in today's toys is interesting to me, not a bother at all.

Peter, I have two sets of BTLOS wheels for 650B tires and they are hookless. I might have chosen hooked if they offered hooked in 650B, but for my use running 42 and 38mm GK slicks, the hookless rims are rated for the pressures I use. I'm sure someone makes a hooked 650B carbon rim with similar specs but most likely more money (or a lot more money) and the BTLOS wheels as you know are very reasonably priced and my sets have been great for my use. I have over 5,000 miles on the first one (but 140 pound rider).

I run these at just over 40 psi because most of my riding is pavement and I don't like how the tires feel cornering at lower pressures. At an event like D2R2, or the 4 day dirt road trip I did last June in VT, I run more like 35 psi. Tubeless with Stans sealant.