MTB Hubs

[bustthesickness]

 

er' date=' you don't think the "email hope" thing was a little tongue-in-cheek?[/quote']

 

 

 

 

 

Errr..no. I read the entire comment and interpreted it as: "do you really think you can tell real engineers from credible companies what's what?"

 

 

 

 

couldn't you have just read it for what it is? as it was? interpretation, like the proverbial "a little knowledge", is a dangerous thing.

 

No I can't and I won't. This South African inferiority complex is pathetic and the comment in question is a manifestation thereof. It is always presented as "who are you/we, mere South Africans, to criticise a huge big international company. What do you (the local) know about design they don't know in New York/London/Paris/Tokyo."

 

As soon as it is revealed that the local understands his topic, then he is fingered as arrogant or worse, opinionated. If he doesn't work for a big company or presents his credentials, he is also not allowed to criticise. I wonder how many people ask Barry Ronge if he's ever made a film?

 

Therefore, when I present a concept and someone who cannot understand what I'm saying because he's not prepared to think or ask, disses the concept with a "who are you to dare criticise a big corporation who can afford lots of clever people", then I get hostile.  

 

It doesn't make me popular at dinner parties, but then again, dinner parties suck.

 

I sat down with one of the guys on The Hub one afternoon and discovered that he is a world authority on weapon sighting systems. He told me how an American engineer dissmissed his views on one or other design. Although he didn't express it as such because the conversation demanded otherwise, it was one of those clear cases of the little guy cannot possibly come up with anything intelligent.

 

Go send the dammned e-mail, lets have an intelligent discussion around O-rings as seals on moving parts.

 

 

 

 

 

 

 

 

 

Johan, perhaps you mean YOUR inferiority complex? It seems you're the one with the issues here. Why blame South Africans? I know many many South Africans who have excelled in the world arena, from musicians to doctors to designers. In our sport even, we have a World champion XC racer and a downhill champion.

 

"As soon as it is revealed that the local understands his topic, then he

is fingered as arrogant or worse, opinionated. If he doesn't work for a

big company or presents his credentials, he is also not allowed to

criticise. I wonder how many people ask Barry Ronge if he's ever made a

film?"

 

But do you Johan? I would assume that companies like CK and Hope, who have many products on the market, who have become massive because of this, would have top engineers and consultants on their design teams. They will have done extensive market research and product development before setting up a production line and tooling which would cost a fortune. They would not still be selling  these products if they didnt. Besides this, as a user of their products, I'm entitled to like it over something else, based on how it works for me.

 

Out of interest Johan, besides your background in wheelbuilding, what are your engineering qualifications? My remark wasnt aimed at Saffas, it was aimed at you. You have lots to say about these products, and so I was aiming at what qualifies you to say these are bogus, inferior and overrated designs.

 

...and Barry Ronge!!!! I wet myself after reading this! The difference between an engineer/designer and a film critic is that a film critic's purpose is to provide an OPINION. I very much doubt that if he dissed a film the director would give a sh*t though. Film making is big money and you can bet that most film houses would do the very same type of R&D and market research before dropping 100 bar on a production.

 

"It doesn't make me popular at dinner parties, but then again, dinner parties suck."

 

WOW! Lighten up man. Lifes not so bad.

Anyways, this is going around in circles now, and I'm done. Dont expect any business from me and my friends, or invites to our dinner parties, which are HEAPS of fun (think girls jumping out of swiss choc cakes, djs, mechanical bulls, baths of cream...)

 

Xenomorph, your comment about the 'throw away culture' we have these days is so true. It's what has ultimately led to our planet being in the state that it is in.

 

[Xenomorph]

 

or invites to our dinner parties' date=' which are HEAPS of fun (think girls jumping out of swiss choc cakes, djs, mechanical bulls, baths of cream...)[/quote']

 

Don't forget my invite

 

 

[MintSauce]

 

 

I know you're just dying to dig up the old post again, so why don't you?[/quote']

 

I'm not dying to dig it up. What kind

of pleasure is that supposed to give me? I was merely mentioning it to provide

some context to our fellow readers, seeing as I was being slated as malicious

and, by implication, an idiot.

 

 

Yes, I called the ring drive's splines (for want of the

proper word for that type of ridge) a pawl. I meant the engagement

mechanism. It didn't detract from the meaning though. Ring Drive is a

proprietary term of CK's and I just don't know what they call their

helical engagement splines.

 

 

Please get over that.[/quote']

I fail to see how someone as

well-versed in engineering terms as yourself can describe what is clearly a

spline as a pawl.

 That,

combined with the fact that you have on occasion ripped people to shreds for

using the incorrect terminology, raises my suspicion. I'm tempted

to 

call bullsh*t on your

explanation here since I suspect the truth to be that you didn't bother looking

at the diagram I posted the first time because you were just too convinced of

your own opinion. In this very thread you recently called it 'pawl-equivelants'.

That's rather vague and you know better. And it does in fact detract from the

meaning since it implies something completely different.

 

Nonetheless, I'll give you the

benefit of the doubt and leave it at that.

 

 

I'll

try one final time.

[/quote']

 

Now really Johan, that statement is

just a little bit on the rich side, because this is the first time you're

actually providing any remotely, descriptive explanation for your

statements.

 

 

In a pawl mechanism where the torque is supplied by

a shaft (perfect scenario), you'll find that one single pawl transmits

most of the torque. Like I said, it is because of engineering

differences. No matter how good your tolerances, one pawl (a different

one in different positions possibly) carries the can. Because it is

elastic, it compresses and the others also start to make contact. But

one carries the burden. It is a fact of engineering that your denial

won't alter.

[/quote']

 

I am not in denial. Not in any way. What I am however, is uninformed and uneducated about things related to engineering and

manufacturing. I do however have a fairly good understanding of mechanical

components, partly helped by the fact that I work in a light-engineering and

manufacturing environment.

 

One also can't use the term 'ignorant' or 'all-knowing' to describe me. I'm interested to learn about these

things and I respond to correction and criticism very well. Besides that I also

have a fairly, healthy dose of common sense.

 

So perhaps if you'd had the

wherewithal to write this kind of detailed description a few months ago, we

wouldn't be here now.

 

 

Further,

when that torque is supplied by a chain, you can envisage that the hub

flexes from the chain's pull. The hub is unsupported over most of its

135mm width and chain tension is massive. The axle flexes and because

the force is not delivered in a nice and round form like with a shaft,

the housing also flexes and deforms.

[/quote']

That makes sense. I assume the flex

generated is a result of the drive not being generated along the same axis as

the axle but is in stead generated a few centimeter off centre(especially in the

larger cogs where higher torque is generated)?

 

It's just that I struggle to see that

so much flex can be created when taking into account the confines of the drive

system, the size of the axle and the size of the 'engine'.

 

Please have a look at the diagram I

posted earlier as it relates to my next question. The drive ring is not fixed to

the hub or the driveshell. It rests freely on the driveshell, held in place by a

spring. The nature of the spline, being helical, results in the drivering

being forced onto the driven ring harder the more force is applied by the

driveshell.

 

Is it possible that the drive ring

might be allowed to have some sort of movement or 'twist' (don't know the correct term) on the splines

thereby allowing the teeth on the flat side of the drive ring to make proper

contact with the driven ring even if the axle were to flex? In this instance, is

it possible that both the set of teeth and the splines would make proper contact, assuming that the

flex in the axle would be compensated for by the movement in the spline? I

realise this might be purely speculation. I have never pulled the drive ring out

of my hub so cannot comment on how precisely it interfaces with the driveshell

spline.

 

 

This

worsens any engineering aberations and disengages pawls in front of the

hub. As the hub rotates, those again engages and another one disengages.

 

Now

CK hubs are subject to the same reality. I don't want to pretend it is

a problem, it is not, it is just a phenomena. The fact that it has a

ring drive does not alter what happens from chain tension or machining.

 

Remember,

even ball bearings with aberations as small as 20 microns have the same

issue. The balls with the biggest aberations carry most of the load,

albeit that the bearings are at least preloaded and therefore already

squashed to full contact.

 

Thefore,

you have one pawl/tooth/spline/ring thing engaging first and as

pressure is applied, others may or may not make contact.

 

In systems like these the pawls/teeth/splines/ring things are always designed to take the entire load one at a time.

[/quote']

 

Understood. Nonetheless, my

thoughts are as follows. Considering the size of the ringdrive's

splines, I would be hardpressed to believe one of these splines can take all the

load on it's own. They really are very small and being made from aluminium(a

stainless steel driveshell is optional), I highly doubt one such spline would

take all that force.

 

I can understand your argument might

apply to a pawl system where there are maybe 3 or 4 pawls. In such a case it

makes sense. If you are correct and the flex in the axle causes such a

distortion though, I would imagine that on the ringdrive system it would perhaps

lose contact on the front side of the hub but still be engaging several splines

on the rear.

 

 

CNC machines that work to tolerances of 100th of a mm? Not in

hubs. That's finer than the bearing's tolerance. It is like displaying

a 5 meg photo on a VGA screen. There is no need for such tolerances on

the CNC parts.

[/quote']

 

To what tolerances CK works I don't

exactly know. They manufacture their headset cups to within 0.0005 inches which

is roughly 100th of a mm. It is entirely possible that they do the same with the hub internals. I asked them. Will see what they say. This might explain why they

charge so much for these things as costs rise as manufacturing tolerances decrease.

 

 

I

have never dissed the ringdrive or CK hubs. Lets get this straight. I'm

just not in awe of everything that comes with an aura and a price tag.

I dont get emotional about inanimate objects and put them all under the

same magnifying glass. Every new gadget presented to me gets the same

question: "What problem does that solve?"

[/quote']

 

The ratchet and pawl system does not

have inherent problems. It works well. I do however believe it can be improved

upon. And yes, I believe the ringdrive is a system that does improve upon it. As a friend of mine says, the fact that it works

does not mean it's the best solution.

 

 

I

believe there is a manufacturing fault or perhaps a design fault there.

It is not the norm for pawls and pawls shouldn't be written off because

of one bum design.

 

Obviously the ratches chip and pawls break, but the norm is for them to just stop engaging and offer permanent freewheel.

[/quote']

 

I am not writing off the concept because of

one dodgy execution of it. As I said, it's an example of pawls breaking. Further, I don't

see a pawl sticking due to dirt ingress as necessarily being a failure. I would

venture a guess that in most such cases the 'failure' is perhaps on the part of

the owner in not doing maintenance.

 

 

I am also of the opinion that the quick engage is

moot. Lets differ on that, who cares?

 

Exaggerated metaphor. I don't know if you said that

or sketched some other scenario where you had to ratchet your way out

of an obstacle. The "you" was a spray all retort at the argument. I

usually encounter that type of answer from the ratchet clan. They

always want to ratchet out of some technical situation that I seldom

seem to encounter. Perhaps I just don't ride enough gnarly stuff. If

you want quicker engagement, it's fine by me too. I just don't see

it being an issue with 99% of riders.

[/quote']

 

 

I don't recall exactly what I said in this

regard, but cetainly 'ratcheting' is required in technical situations. I can only

assume that you don't ride a lot of technical trail. That is not meant in a

derogatory way. I simply say that because it's something I do often while riding

technical trails, especially rocky ones. As stated before, to each his

own.

 

 

 

 

 

MintSauce2008-11-18 05:31:19

[dirtrider]

Call me lucky but I have never had a hub fail on me . Most of my bikes got bottom of the range stuff .

[NotSoBigBen]

Call me lucky but I have never had a hub fail on me . Most of my bikes got bottom of the range stuff .

 

Ja but I guess our 'enyins' are a bit to weak to break anything?

[supertorro]

I have the Hope XC hubs built onto Mavic XC717 rims with DT Swiss spokes....they've performed flawlessly, and I am a fat boy.

 

don't know if that helps, but they work me.  oh, and they went through the cedarberg escape without any problems...

[Johan Bornman]

<?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

 

I fail to see how someone as well-versed in engineering terms as yourself can describe what is clearly a spline as a pawl. That' date=' combined with the fact that you have on occasion ripped people to shreds for using the incorrect terminology, raises my suspicion. I'm tempted to call bullsh*t on your explanation here since I suspect the truth to be that you didn't bother looking at the diagram I posted the first time because you were just too convinced of your own opinion. In this very thread you recently called it 'pawl-equivelants'. That's rather vague and you know better. And it does in fact detract from the meaning since it implies something completely different.

 

Nonetheless, I'll give you the benefit of the doubt and leave it at that.

[/quote']

 

How come so surprised that I make mistakes?

Don?t you think it is a bit harsh to say I ?rip people to shreds? for using incorrect terminology. Sure I advocate correct terminology but either I use humour or no emotion. My favourites are right and left for the pomous drive-side and non-drive side. Crank for the superflous crankarm and elongate for the incorrect stretch. I don?t think there are any terminology sinners out there with gashes and teeth marks from me.

[quote name='<?: prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Johan BornmanonName>]I'll try one final time.

Now really Johan' date=' that statement is just a little bit on the rich side, because this is the first time you're actually providing any remotely, descriptive explanation for your statements.

[/quote']

 and....

 

So perhaps if you'd had the wherewithal to write this kind of detailed description a few months ago' date=' we wouldn't be here now.

[/quote']

 

 

If you want to be fair on me you'll do an advanced search on my name and "pawl" and engage" in the phrase and you'll that I've said on one or more occasions that only one pawl engages at a time. If people don?t believe me, I sometimes leave it, sometimes go into an explanation. For flow of argument I don?t want to explain everything from first principles. However, when someone asks me nicely I am more than generous with my answers and don't skimp on explanation.

 

[quote name='Johan BornmanonName>]

 

In a pawl mechanism where the torque is supplied by a shaft (perfect scenario)' date=' you'll find that one single pawl transmits most of the torque. Like I said, it is because of engineering differences. No matter how good your tolerances, one pawl (a different one in different positions possibly) carries the can. Because it is elastic, it compresses and the others also start to make contact. But one carries the burden. It is a fact of engineering that your denial won't alter.[/quote']

 

 

I assume the flex generated is a result of the drive not being generated along the same axis as the axle but is in stead generated a few centimeter off centre(especially in the larger cogs where higher torque is generated)?

 

It's just that I struggle to see that so much flex can be created when taking into account the confines of the drive system' date=' the size of the axle and the size of the 'engine'.

 

[/quote']

 

A bit of what you describe and a bit of the hub getting squashed in on the one side by the lobsided force on it.

 

Either way, the force is huge. It was the last nail in the coffin for the freewheel (screw on cassette) system. When that went to 8-speed, the unsupported length of the axle was large and the axles continually broke.

 

We still see this today but not so much. Most people just think the axle is bent. But if you put it in water and blow air through it you?ll see that it is actually cracked. That?s from this force that bends the axle forwards and distorts the hub.

 

 

People underestimate the tension in the chain and compression in the right chainstay. It is the most highly stressed component in a bicycle. The pulling force on the sprockets is massive.

 

When the chain is on the largest sprocket, the force on the axle is at its highest, bending it a few (don't know exactly how many) millimeters forward. That also distorts the hub shell which in turn distorts the bearing alignment and pawl ring.

 

 

Please have a look at the diagram I posted earlier as it relates to my next question. The drive ring is not fixed to the hub or the driveshell. It rests freely on the driveshell' date=' held in place by a spring. The nature of the spline, being helical, results in the drivering being forced onto the driven ring harder the more force is applied by the driveshell.

 

Is it possible that the drive ring might be allowed to have some sort of movement or 'twist' (don't know the correct term) on the splines thereby allowing the teeth on the flat side of the drive ring to make proper contact with the driven ring even if the axle were to flex? In this instance, is it possible that both the set of teeth and the splines would make proper contact, assuming that the flex in the axle would be compensated for by the movement in the spline? I realise this might be purely speculation. I have never pulled the drive ring out of my hub so cannot comment on how precisely it interfaces with the driveshell spline.

 

[/quote']

 

If I understand you correctly, I?ll say that in order to engineer for the scenario you describe you'll have to know exactly how much torque will be applied to the hub and from which gear. I don't think that's the scenario. I think the engagement under no load is pretty sketchy and patchy and as load is applied, your scenario of all splines engaging comes more and more into play until there is full contact.

 

This contact is dynamic and as the hub rotates, some points will relieve their pressure and other increase it.

 

 

Considering the size of the ringdrive's splines' date=' I would be hardpressed to believe one of these splines can take all the load on it's own. They really are very small and being made from aluminium(a stainless steel driveshell is optional), I highly doubt one such spline would take all that force.

 

[/quote'] The surface area is quite big due to the spline's length - 90mm or so?? But as we agree, the elasticity of the alu eventually sees to it that they all eventually engage.

 

[quote=Johan BornmanonName>]

CNC machines that work to tolerances of 100th of a mm? Not in hubs. That's finer than the bearing's tolerance. It is like displaying a 5 meg photo on a VGA screen. There is no need for such tolerances on the CNC parts.

To what tolerances CK works I don't exactly know. They manufacture their headset cups to within 0.0005 inches which is roughly 100th of a mm. It is entirely possible that they do the same with the hub internals. I asked them. Will see what they say. This might explain why they charge so much for these things as costs rise as manufacturing tolerances decrease.

I think that is mostly marketing hype. There is no need for such tolerances. They also don?t say where they machine it so fine. If it is forged, the tolerences will be even less on the shell. The bearings are another story. Maybe they?re extending the hype from the balls to the shell?

 

[supertorro]

Can I interrupt this faskinating topic with some imperical (or is emperical) evidence:

 

my hope hubs just feel cool!

[rock]

after having hope pro disc hubs for a few years, I now have hope pro 2's, great hubs, very noisy, but great quality imho.

 

Plus you can't upgade a XT front hub to 20mm/15mm/Maverick etc like you can with Hopes.

[GoLefty!!]

Nope but you convert a XT20mm bolt through to QR15.

 

Once you leave Quick Release you never go back

[rock]

am pretty sure my next fork will have a QR15 hub, just kinda makes sense once you go over 100mm travel.

[GoLefty!!]

thru20, thru12 and QR15 just makes more sense than simple QR for MTB anyway.

The interface is ignificantly stiffer than a QR to the point where you can feel the difference in the steering.

[bustthesickness]

 

thru20' date=' thru12 and QR15 just makes more sense than simple QR for MTB anyway.

The interface is ignificantly stiffer than a QR to the point where you can feel the difference in the steering.

[/quote']

 

+1

I felt that too when I went from Shimano hub & QR to a 20mm Hope Pro 2. A much stiffer front fork, and the steering improved drastically.

 

[bustthesickness]

 

thru20' date=' thru12 and QR15 just makes more sense than simple QR for MTB anyway.

The interface is ignificantly stiffer than a QR to the point where you can feel the difference in the steering.

[/quote']

 

+1

I felt that too when I went from Shimano hub & QR to a 20mm Hope Pro 2. A much stiffer front fork, and the steering improved drastically.

 

[Dirtbreath]

How do all these hubs compare pricewise. What would the range be going from XT, Hope, XTR, I9, CK? 

[bustthesickness]

Well, because we keep getting ripped off at the bike shops here, all of these items are VERY overpriced.

 

As an example, a bike shop quoted me R2 200 for a rear Hope Pro2 the other day, with an additional R700 odd Rand to build the wheel up for me. The same hub will cost you R1 500 from Chain reaction.

 

In the end I decided to to buy a FULL Hope Pro2 wheelset with DT 5.1 rims for a mere R3 200, only R300 more than it would have cost me for only a rear hub and the wheelbuild onto my existing rim.

 

I'm ending up doing this more and more these days, buying online from overseas. I've done it for years with the studio gear, and now started with my bike kit too. Shops need to stop ripping people off. It's bad for cycling. What they don't realise is that more people might get into the sport, and they'd sell way more in the end. It's a short sigted, greedy mentality. And let's not hear the good old one "...but we have to pay tax, and duties and bla bla bla...". I have to do the same buying from CRC, they have already marked the item up from the suppliers and it STILL comes to my door cheaper.