New hub generation?

[La Bourde]

Hi,

 

 

recently two new hubs were released (for mods at least), both with integrated freewheel and a high number of engagement points:

• the comas rear disc freewheel

• the clean rear disc freewheel

()

 

Pictures from https://trial-world.com

And Hope released its PRO V SS/Trials some months ago.

Does a new generation of trials hub arrived on the market or is this just a reaction to the Industry Nine Hydra hub?
What changed recently, that allows more engagement points in a hub?

 

To be honest, I am really skeptical about the reliability of most of these hubs (even more on the Clean, it looks like a bad design to me - by placing the outer one piece steel ring now on the inside, all the engagement forces operate on several small aluminum parts. In addition, the spokes already pull out the aluminum shell, which can lead to a misalignment of the pawl axle).

I know that Industry Nine uses a specific machining process called EDM (Electrical Discharge Machining), that allows to machine really hard materials with amazing tolerances. I doubt this is the case on the other hubs, as this machining process is quite slow and thus expensive.

 

What are the real benefits of these freewheel hubs?

• One advantage I can think of is that the chain is no longer moving. This means less wear and less noise.
• Due to the ratio of the gear, with the same number of engagement points, you get a smaller angle at your pedals to engage (for mods, 18/12 -> ratio 1,5 and for stock 18/15, ratio 1,2)

It seems also that the drag is reduced, weaker springs being used.

But it the drag so relevant?
This video compares a PRO IV to a PRO V and the reduced drag seems to have no relevant influence.

 

According to my experience, this was not the case with trials freewheels at least. I bought a freewheel with 9 pawls and 108 engagement points to test of my old street trial bike. It has really strong spring and the bike was less rolling that with a freewheel with 72 engagement points.

That is why I switched back to 72 engagement points.

 

Other relevant points:

• past a certain number of engagement points, there is no significant advantage, cause the chain has to get tension first (even with a tensioner). Maybe this can be counteracted by the rider if he always has pressure under his feet.
• having two times more engagement points divides the angle of engagement by two. But the more engagement points you have, the smaller is the perceived improvement in engagement. E.g: when you switch from 72 to 120 engagement points, you loose 2° of engagement (from 360/72 = 5° to 360/120 = 3°) without doubling the number of engagement points, but from 120 to 690, you loose 2,48° (360/120 - 360/690 ~= 2,48°) by multiplying by 5,75 (120*5,75 0 = 690) the number of engagement points. With 240 engagement points, you will loose 1,5° compared to 120.
• the form of the pawls and ring can make a difference in feeling and how fast or firm the engagement feels.

 

So what do you think? Do you ride with such hubs (or alternative like Halo Supadrive, Spank Hex Hub)? How do they feel? Are they reliable?

Edited November 5, 2023 by La Bourde

[SergeL]

46 minutes ago, La Bourde said:

One advantage I can think of is that the chain is no longer moving. This means less wear and less noise.

But isn't there more stress due to same chain segment is loaded from kick to kick?

I know this is an extreme example, but imagine you have multiple rail-gaps in a row. While front freewheel setup is naturally rotating from every pedalkick, chain on a freehub is "frozen" during jumps without crank rotation.

From street rider perspective I can confirm that freewheels have more drag, especially if you have double sprocket tensioner or dirty chain. Also with freehubs, tricks like tailwhips are less prone to backward crank spins due to chain tension.

Edited November 5, 2023 by SergeL

[craigjames]

I did read that the Clean hub has had a few failures already, there are a few questionable design features, the Comas hub seems like a more solid design. High engagement point hubs have been readily available in the MTB world for a while now, like everything it just takes a bit of time for the technology to filter down to the trials world.

I'd be interested to see if the new Hope Pro5 hub could be converted to mod sizing.

[La Bourde]

5 minutes ago, SergeL said:

But isn't there more stress due to same chain segment is loaded from kick to kick?

I know this is an extreme example, but imagine you have multiple rail-gaps in a row. While front freewheel setup is naturally rotating from every pedalkick, chain on a freehub is "frozen" during jumps without actual rolling.

From street rider perspective I can confirm that freewheels have more drag, especially if you have double sprocket tensioner or dirty chain. Also with freehubs, tricks like tailwhips are less prone to backward crank spins due to chain tension.

Good questions!

Regarding the load, I guess you are right in your extreme case. But over a session of riding I guess the wear due to the load will span over all the links.

The freewheels have more drag and one can perceive it. But does it mean, we roll less? For a comp rider, does it mean he losses a lot of energy and could go higher with a freehub then? As described in the video, I guess the tire pressure might have even a bigger influence.

For tailwhips, I can imagine it makes a huge difference.

 

[La Bourde]

9 minutes ago, craigjames said:

I did read that the Clean hub has had a few failures already, there are a few questionable design features, the Comas hub seems like a more solid design. High engagement point hubs have been readily available in the MTB world for a while now, like everything it just takes a bit of time for the technology to filter down to the trials world.

I'd be interested to see if the new Hope Pro5 hub could be converted to mod sizing.

Yeah, they exist in the MTB world for a while now.

There are also some with freewheel roller/sprag clutch (e.g. Onyx, True precision hubs, old Shimano Silent Clutch) ... people say it has an immediate engagement and it is absolutely quiet. But most of them are heavy/not so reliable saddly: http://pardo.net/bike/pic/mobi/d.winners-hub/index.html

[SergeL]

1 hour ago, La Bourde said:

There are also some with freewheel roller/sprag clutch

Do you know something about crewkerz (or atomz?) idea of a clutch freewheel. Were there any ridable test samples?

[Canardweb]

20 inch riders love the freehub because of the reduced drag, they say it's a game changer. The Clean one is highly unreliable. Some 26 inch comp riders like Hermance or Carthy have tried that sort of hub and say it doesn't change anything for them. Don't know what they mean by that though...

You can get Hope hubs to fit trials frame but you need to modify them for mods.

Also Crewkerz still believes in "standard" freewheels so far.

[Swoofty]

I've owned I9 Hydra SS, Profile Elite SS, several Hope SS models (not 5 yet), TMS SS and I've just ordered a new Aluadark SS hub. Anything over 72 click is ok by me for street trials, but it's really easy to get comfortable with the instant engagement of the I9 or the Profile. The new 120mm freehubs do look a bit questionable, but we'll be the first to hear about it. Only advantage I can see is less weight, less drag and faster engagement. Reliability has been on par across the board from my experience. Don't forget that the higher engagement hubs also experience less load on the pawls/ring due to less acceleration before engagement, ie less force slamming the pawl into the ring.

[La Bourde]

36 minutes ago, Canardweb said:

20 inch riders love the freehub because of the reduced drag, they say it's a game changer. The Clean one is highly unreliable. Some 26 inch comp riders like Hermance or Carthy have tried that sort of hub and say it doesn't change anything for them. Don't know what they mean by that though...

You can get Hope hubs to fit trials frame but you need to modify them for mods.

Also Crewkerz still believes in "standard" freewheels so far.

 I just put a Maxxis Holyroller 2,4" and a KHE 26"Mac 2 on a Crewkerz cleep, with an used standard trial freewheel (I think it is a 108.9) on Waw cranks. It rolls quite well, much better than with the trials tires. It seems to be more drag than with the Hope Pro IV of my street trial though. I have to try really long manuals to see if there is a difference (without touching the brake). But first, I have to adjust the brakepads correctly. 😁

I think a well built "standard" freewheel (using EDM and many teeth on the pawls, ball bearings) could work as good as a freewheel hub.

29 minutes ago, Swoofty said:

I've owned I9 Hydra SS, Profile Elite SS, several Hope SS models (not 5 yet), TMS SS and I've just ordered a new Aluadark SS hub. Anything over 72 click is ok by me for street trials, but it's really easy to get comfortable with the instant engagement of the I9 or the Profile. The new 120mm freehubs do look a bit questionable, but we'll be the first to hear about it. Only advantage I can see is less weight, less drag and faster engagement. Reliability has been on par across the board from my experience. Don't forget that the higher engagement hubs also experience less load on the pawls/ring due to less acceleration before engagement, ie less force slamming the pawl into the ring.

A friend rode an i9 Hydra SS on his dirt bike. He wanted to switch with the Hope Pro IV of his fresh street/trials, but he eventually bought another I9 ... He said, he is so used to the instant engagement. It feels amazing though.
From my own experience, I know that between 108 and 120 engagement points, I really feel the difference on a comp bike.

I agree with you regarding the lower load with more engagement points, due to less acceleration. But the maximal load when the system is engaged stays the same and I guess this can also be a problem.

[craigjames]

On 11/5/2023 at 11:14 AM, craigjames said:

I did read that the Clean hub has had a few failures already, there are a few questionable design features, the Comas hub seems like a more solid design. High engagement point hubs have been readily available in the MTB world for a while now, like everything it just takes a bit of time for the technology to filter down to the trials world.

I'd be interested to see if the new Hope Pro5 hub could be converted to mod sizing.

Looks like Clean have made an official announcement that there was a manufacturing fault in the heat treatment of the ratchet ring leading to failures.

[La Bourde]

Found some valuable information about the I9 hubs:

So I posted it here.

[Daan]

Whilst having had issues with my Hydra skipping, and axle length tolerance being off causing too much preload on the freehub bearings, I've never had an axle break, and I break a lot of stuff.

I believe their 12 mm axle may just not be up to the task. I use a 10 mm bolt on axle.

Also, flex happens in any axle, i9 just chooses to use it to their benefit.

[La Bourde]

I agree with you.

It wouldn't be the first hub having issue with its 12mm version (remember the hope pro II evo?)

I think one major point in this video is about the stiffness of the rear end.

Trials frames are hardtails, most of them being really stiff. This reduces how much the axle can bend, reducing fatigue a lot due to smaller load peaks.

In the comments, you can also read an answer from Peak torque, that thinks that high antisquat value of certain full sus frame will increase the maximal load a lot.

This sounds sensible to me.

So I guess trials use is less of a concern.

 

I think for trial riders making a regular maintenance and consider replacing the axle as soon as the hub creaks are the take outs of this video.

[Canardweb]

There is one famous pro trials rider who breaks his rear axle on his Crewkerz Jealousy approximately every 3 weeks. He is the only one who does 

Edited November 13, 2023 by Canardweb

[Daan]

Watched the entire video this time (was on the train previously), and it's funny they mention a stiffer axle causing more wear on the pawl pockets of the freehub body. This is exactly what I saw on mine, with the 10 mm bolt on axle, which is stiffer and doesn't break. I even posted a video about the pawl pockets deformation here on the forum, after just a very short time of use. Recall Adam saying that it was more wear than he'd like to see in such a short time, so it must be true

[AdamR28]

Weirdly, one of their 10mm bolt on axles is the only bicycle component I remember breaking (rather than wearing out, getting bored of, etc) in the last few years!

Lots of pseudo-engineering chat and garbage in that video 🙄

[La Bourde]

2 hours ago, AdamR28 said:

Lots of pseudo-engineering chat and garbage in that video 

Oh... Can you point out what exactly?

I don't like to share inaccurate information.

 

[La Bourde]

OK at least I noticed something about aluminum stiffness (it is actually less stiff than steel at the same dimension) and also fatigue, as one can say that aluminum shall not fatigue if the parts are dimensioned properly.

 

[AdamR28]

I skipped through the video briefly and almost everything I heard was... sketchy. But the alu vs steel thing stood out.

[craigjames]

Sounds like I9 or someone should develop a titanium axle kit. Would allow the flex without fatiguing as quickly as the aluminium axle.

Does seem like an inherently flawed design though, especially so for trials. Not something i'd go for personally, but i do imagine the 690 POE feels great. Think i'd rather go for a Hope or for a mod, a Comas freehub.

[La Bourde]

This is ridiculously well thought:

 

[AdamR28]

Agreed. The guy in the video is as great as the hub, too!

[aener]

I'm onboard with improving things, but my hackles instantly rose when the first thing I saw was a proprietary rotor bolt system   (Unless it matches the Rohloff type which has some existing rotors available? I'm at work so skipped through bits.)

Hopefully I can put that aside as the rest of it looks like a fairly solid improvement. It depends on a few things implementation-wise - if they make those bearings custom sizes, which I can imagine they might, it's either going to be a huge pain in the arse to replace them, or just very, very expensive.

Conceptually though, big thumbs up.

[craigjames]

Some really good ideas there, be interesting to see how they hold up. Would ideal if they made a singlespeed version, looks like it could be adapted to fit a 116/120mm mod rear end too.

£550 is a small stumbling block though.

[Canardweb]

On 1/12/2024 at 12:28 AM, La Bourde said:

This is ridiculously well thought:

 

Saw that on Youtube but didn't bother watching it. Because you posted it, I did and that is amazing!

Top bloke explaining reallly really well too!