Author Topic: The technicality you can't see: handlebar ergonomics & RSI  (Read 3110 times)

Andre Jute

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The technicality you can't see: handlebar ergonomics & RSI
« on: September 09, 2023, 01:07:32 am »
Thorn and its bicycle owners spend a lot of time on bike fit, and rightly too. But proportionately very little of that time is spent on considering the ergonomics of handlebars. I think this is an oversight.

Like many here, I too use a short grip on the side with the Rohloff rotary control, so that my hand rests half on the grip and half on the pad of the original triangular Rohloff gear control.

While I find it convenient and pain-free, I'm hardly ever on the bike for more than an hour before I stop to sketch something, or take in the view, or wait for pedal pals. I cycle in leather dress gloves of a thickness and with thin linings appropriate to the season (silk, cotton, wool), no gel or padding, but even if there were gel in my gloves, I would reconsider this arrangement if I ever took to being hour after hour in the saddle, hands on the grips.

Repetitive stress injury from definitely anti-ergonomic, anti-kinesthetic, variable-pressure arrangements like these is a pretty serious consideration. Pins and needles, callouses on the cushion of your hand where it falls on the rotary grip, these are warning signs of more serious injury to come.

Yes, I know, drop bar users have several grip variations they can and do avail of. Positional variation is good, but I hardly consider any of the possible handholds on a drop handlebar to be anywhere near an ergonomic optimum; they merely temporarily transfer the pressure somewhere else. It's one of those bodges cyclists have come to accept because we've been doing it so long, not because we've put our brains in gear about it. Ameliorating the problem with foam or cork wrapping is not a solution, merely a postponement of the undesirable effects.

Danneaux

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #1 on: September 09, 2023, 02:10:17 am »
Excellent points, Andre.

For the last 39 years (since 1984) I have ridden my favorite randonneur bike equipped with Morgan Grips, made by Morgan Concepts in Coer d'Alene, Idaho. Morgan Concepts first patented the idea  in 1983 for the lower portion of drop handlebars and by they marketed it, sections were available for the upper portion of the handlebars also, making a complete set. See...
https://patents.google.com/patent/US4522083A/en

I love them for my longer 300-400km day rides, especially for chip-sealed or gravel surfaces as they really do help absorb vibration and even on smooth roads, the ergonomic shape beats round handlebars.

Sadly, the company went out of business some time ago and no one picked up the ball to keep producing the grips once Morgan Concepts went under. What made the grips so fantastic was a) their ergonomic shape coupled with b) a clever system of shock-absorbing columns that soaked up vibrations. They were made of extremely durable urethane (mine have gone well over 56,000km on this bike) but had one fatal flaw for the roadie set -- they weighed 300g a set and were not so easy to install. The bottom sections slid on with a toluene-based glue to hold them in place, while the upper portion used the same glue coupled with some plastic jute or vinyl craft lacing. The grips were available in black, yellow, blue, and brown, perhaps other colors I don't now recall. My late father had a set in black and another in blue for his two bikes and loved them for his arthritic hands. I guess you could call them Ergon grips intended for drop handlebars. If only the "gravel bike" market had evolved sooner, they might still be available. Redshift Sports has picked up the basic idea in their Cruise Control Drop Bar Grips. See...
https://redshiftsports.com/products/cruise-control-drop-bar-grips

Lacking anything like Morgan Grips for many years, I installed thick, dense neoprene foam tubes, then compression-wrapped them with grippy handlebar tape. The foam and larger diameter help but not so much as the even hand supported by true ergonomic shapes.

Best, Dan

Andre Jute

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #2 on: September 10, 2023, 12:09:09 am »
That Morgan patent application makes a super read, Dan. But it is quite clearly not a DIY project to copy their grip. Still, it is enough information to grasp in outline how it works and why your dad loved it. And you too. 300-400km per day! Never mind the wear and tear on the rest of you, you really need varied, ergonomically padded handgrips if you don't want to cripple your hands into claws.

My guess is the Morgan grips would be alive under your hands as they work to spread the pressure dynamically. Do you feel it or is it micro-movement?

***
I'm afraid that your dream of a manufacturer picking up the idea is not really practical after Morgan went out of business. My bet is that besides the outline drawings in the patent, you will need a real live human who remembers what was poured in what order -- that's the first essential, and the original molds would be very handy too.

Many products which are revived after the originators went out of business are blatant badge-engineering, at best workalikes, at worst nothing but the name on an entirely reinvented product because the blueprints are gone, the manufacturing knowhow of the line foreman and plant manager and mould-makers and hand-fettlers is gone, and because it is just plain cheaper to start from scratch.

I don't think something even modestly difficult to fit will make anyone's fortune by selling directly to today's cyclists. Something like the Morgan grips should be aimed at the OEM market where the component maker can piggyback on the bicycle manufacturer's advertising and credibility. Think of how Franklin Niedrich marketed the n'lock: he basically sold it to OEMs for upmarket bikes in a well-defined niche. His ventures into licensing people who wanted to sell it to DIYers were dangerous failures because the salesmen didn't understand what Diedrich, an engineer, did, that the most important thing about the n'lock was close supervision of the manufacture of a product with extremely close tolerances because otherwise there could be swingeing liability suits. It may interest you to know that I looked at an earlier version of the n'lock that Niedrich licensed to a French firm, and decided I was most definitely not giving those clowns my money to organise a face-plant for me by cheapening the manufacture of a good idea. I came back later when Niedrich designed a new version which, like a Chevrolet mouse-motor, resists even incompetence; in short, I waited to buy and, important, recommend the component, until I could be certain that the production was appropriately supervised, in the later case by the inventor himself.

The key takeaway is "marketed via OEMs with mechanics capable of fitting a product with such close tolerances".

Danneaux

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #3 on: September 10, 2023, 01:14:31 am »
Quote
My guess is the Morgan grips would be alive under your hands as they work to spread the pressure dynamically. Do you feel it or is it micro-movement?
This is difficult to answer, Andre, given different road surfaces produce different levels of vibration. I think I can best answer by saying under the weight of hand pressure, the columns/walls deform into a gentle S-shape and these are then in a better configuration to absorb bigger hits. So...dynamic deformation and micro-to macro movement depending on the road surface. These deformable walls have always recovered and the grips feel firm under hand. Apart from their shock-absorbing capability, they do have a "different" feel because their ergonomic shape spreads pressure over a greater surface area.

I live in dread of mine "wearing out" though all I have done over these many years and miles is to wear off the pebble grain where my hands rest most often. I did lose one pair in a crash that was enough to shred them as the bike slid along the pavement. The lowers of another pair did not survive removal and transfer to another bike...though it was possible with a different set.

Yes, long day rides are much less fatiguing if the rider is isolated from vibration; that's why my randonneur bikes are equipped with Thudbuster ST suspension seatposts (Short Travel models, due to limited clearance between horizontal tip tube and saddle clamp). It takes the edge off chip-sealed pavement and such and I find I finish feeling fresher than I do with rigid seatposts over the same distance. Alex Moulton also felt suspension was of great help in reducing rider fatigue, especially with the small-diameter wheels used on his separables.

Best, Dan.

JohnR

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #4 on: September 10, 2023, 09:41:25 am »
It's a shame that the Thudbuster has zero setback or I could get interested as I'd like more comfort on roads with patched tarmac. The other alternative is a sprung saddle such as the Brooks Flyer. I've got one on the garage but it won't coexist happily with my preferred saddle packs (and adds significant weight). It's time that someone invented a lump of rubber to fit between saddle and seatpost. 5mm travel would be sufficient to improve comfort.

I've been using Ergotec AHS handlebars with Ergon GP1L grips for several years and can cycle as far as I want to go in a day without discomfort as they provide two main hand positions. They don't however, have a very high load rating.

A bike's primary suspension is the tyres. I can feel a noticeable improvement when on 50mm tyres compared to 40mm while 30mm gives a noticeably harsher ride. I put some on the bike out of curiousity expecting I would see a speed benefit but that didn't materialise, perhaps because I subconsciously went slower on the rough surfaces due to the reduced comfort. The tyres in these unscientific tests are all Schwalbe G-Ones running tubeless.

Danneaux

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #5 on: September 10, 2023, 03:43:59 pm »
Quote
It's a shame that the Thudbuster has zero setback or I could get interested as I'd like more comfort on roads with patched tarmac.
This initially put me off as well, John, until I realized the elastomers squish under the rider's weight, causing the clamp mounted atop the parallelogram to decline rearward as well as downward. In my case and with my weight and preferred amount of squish, that rearward declination or the saddle at rest under me (one might equate it to "preload") is about 5-8mm, though could be more or less depending on the durometer of the elastomer puck(s) selected and of course is somewhat more under bump-loading. I know I much prefer a softer setup than recommended for my weight, the result of using drop handlebars and a preferred 45 back angle, which places less weight on the saddle than a more upright position would. It may be by happy accident and my dimensions that the clamp fixes just past the center point of my B.17 rails, so the saddle is not cantilevered off either end of the rails. With the elastomers removed for a full service of the pivots (rare), or to change elastomers, the difference between actual and theoretical travel becomes clear.

The good news is, after the popularity of the Thudbusters was established, other makers have come up with parallelogram designs that use setback rail clamps and even tunable springs. I might well have chosen one of these had I not already purchased four Thudbusters (two LT, two ST) that have worked well for me. (Cane Creek) Thudbuster have since revised their LT to use a single insertable puck like the ST, abandoning their finely tunable ealstomer stack. I'm not sure it would be as good for me as what I have but fortunately there has been no need to buy and try, as my older models are still working well after more than a decade of use. One word of caution: It really is a good idea to buy some sort of neoprene cover for the pivots, as they are lubed bronze bushings and tend to attract dirt and dust without some sort of protection and I would assume exposure could eventually affect bearing service life.

Regardless of design, I found the Thudbusters in really do not practically provide anywhere near the theoretical amount of vertical travel you would expect . They decline downward and rearward, keeping saddle to bottom bracket distance pretty constant, but the effective travel under most conditions in my use is likely about 8 vertically for my LT posts, maybe 5mm for the STs, almost impossible to measure while riding, so I tried to simulate by leaning full body weight on the saddle and measuring travel. The combined down-and-back travel (about 10-16mm total combined rearward-and-downward travel with my LT) has been "enough" for my needs, taking the edge of bumps small or large, depending on the travel of the post and elastomers fitted. For anything large, I post (stand) on the pedals. Standing on the pedals when "honking" uphill also takes the suspension out of the mix. FWIW, despite some warnings by others, I have found my Brooks saddles work nicely when combined with these sus-posts. Some others, notably one produced by SR, can conflict with Brooks B.17 saddle rails, causing a clamp-rail collision under compression. A Forum search for "suspension seatpost" (no quotes) will pull up a wealth of impressions.

Early in my tandeming, I made a telescopic elastomer-damped seatpost for my stoker when I could not afford to buy one. It was a fairly easy project, based on cutting the head off a forged 'post, threading the bottom of the shaft to take an adjustable stop made from a hex-socketed crankset dust cover, then drilling a hole in the top I filed into a hex to accept a short length of hex shaft repurposed from a very large allen key. The top I milled into a saddle-shaped cradle that would accept a radius of sectioned seatpost to make a clamp, the lot tensioned and secured via long allenhead bolts and a threaded cross-seat. It has worked reasonably well except for some lateral play which my stoker has come to prefer over the last 32 years of service. The vertical travel with a fairly high durometer elastomer "stick" amounts to abut 5mm, which she finds helpful when we hit bumps she hasn't prepared for. She seems to be okay with the true zero-offset design, but I would not find it good.

Best, Dan.
« Last Edit: September 10, 2023, 03:45:38 pm by Danneaux »

Andre Jute

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #6 on: September 11, 2023, 02:24:22 am »
A bike's primary suspension is the tyres. I can feel a noticeable improvement when on 50mm tyres compared to 40mm while 30mm gives a noticeably harsher ride.

Short of giving test rides to convey how amazingly different these tyres truly are, we need to calculate the volume of the air column being compressed at each diameter. The results of factoring will surprise you. You should also in the torus calculations note that while all these tyres fit on the same bead radius of your rims, their circumferences are different and thus their air columns have different lengths as well as different diameters.
https://www.omnicalculator.com/math/torus-volume


martinf

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #7 on: September 11, 2023, 09:04:30 am »
Short of giving test rides to convey how amazingly different these tyres truly are, we need to calculate the volume of the air column being compressed at each diameter. The results of factoring will surprise you. You should also in the torus calculations note that while all these tyres fit on the same bead radius of your rims, their circumferences are different and thus their air columns have different lengths as well as different diameters.
https://www.omnicalculator.com/math/torus-volume

To calculate the effects of different tyre sizes on volume in the same rim diameter, if I already have the tyres I just multiply the outside height by the width.

When I put the outside tyre diameter into the torus calculation, it gives very similar results, the  difference is about 2-3%.

Of course, neither method is correct, because it is tube diameter that matters, which depends on the casing and tread thickness. And tyre sections aren't round, the shapes vary quite a bit between models. Additionally, at least as far as comfort is concerned, tyre volume isn't the only thing that counts, the tread and sidewall construction and the type of inner tube (if not using tubeless) also play their part.

To get a rough and ready comparison of volume between the various tyre possibilities for the rims I have, before actually buying the tyres, simply calculating the square of the nominal tyre size comes close enough for me.

For example, using the "rough and ready" method, going from 50 mm to 55 mm theoretically makes a difference of 20% more tyre volume, which means that the bigger tyre can be run at a correspondingly lower pressure for better comfort and better performance on soft surfaces.



PH

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #8 on: September 11, 2023, 11:12:34 am »
Thorn and its bicycle owners spend a lot of time on bike fit, and rightly too. But proportionately very little of that time is spent on considering the ergonomics of handlebars. I think this is an oversight.
Thorn have, for a number of years, fitted Ergon grips as part of the standard spec.  Ergon have considered the ergonomics, the clue is in the name!
https://www.ergonbike.com/en/ergonomics.html
Prior to that, Thorn had their own "Comfort Bars" designed and manufactured, again the name reflects the consideration given (Even if, like for me, they weren't ideal)

I have my own set of anecdotes.  I can't imagine riding any distance further than the shops without variable hand positions. That isn't just about comfort, I'll vary position on the bike depending on how I'm riding in that moment. The long grips of the Ergon GP5 suit me well, the composite (Plastic) material acts as a damper, so much so that approaching a rough section of road I'll move my hands to take advantage of it.  I was very happy Rohloff replaced the triangular shifter, I can't imagine anything less ergonomic, I look at that shifter, then my hand and struggle to see how anyone designed one to fit the other. It's a mystery to me how some could prefer it, but I know they do.

One thing that goes beyond my anecdotes and seems to be agreed upon by all who specialise in bike fit, is that hand position is set after saddle position.  If you're not sat comfortably on the saddle, it's easy to attribute the issues that causes to the hand position and sometimes the answers are counterintuitive.

Tyre sizes are even more complicated, the deflection that provides comfort is a consequence of volume, pressure, load and rebound, there isn't much point discussing those in isolation. It isn't easy to test that, it can be even harder to distinguish comfort from the other differences which might lead you to prefer one size over another.  For decades road cyclists have believed narrower higher pressure tyres were faster, it's easy to see why, they undoubtedly feel faster.  You could try using an accelerometer app on a phone, with different size tyres, of the same construction, at the same pressure, on the same road, at the same pace, but the differences might be too subtle for anything less than specialised equipment. 

In the end it doesn't really matter, if you're comfortable and happy on your bike, then it's all good. There's no harm in looking at how others achieve that and giving it a go if it appeals. Just don't assume that however well it works for them it'll work for you. 
« Last Edit: September 11, 2023, 11:14:16 am by PH »

Andre Jute

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #9 on: September 12, 2023, 06:03:33 am »
I agree with Martin, no way we'll get a precise and exact volume of air in a tube inside a tyre and in the rim of the well. I thought of doing finite element analysis and got an instant ice-cream migraine. The space is just too irregular, definitely not an idealised torus as the calculations assume. You can't work with a bare tube either, because even a quality tube bulges irregularly without a tyre to constrain it; I tried it and won nothing but frustration.

However, we're not looking for an exact calculation, we're looking for a ratio between two tyres containing correctly scaled tubes, and that is likely to be relatively constant for the same tyres and rims as in John's example to which I was replying.

Taking a 622mm rim and tyres of 30, 40, 50 and 60mm width, and assuming that the tyres in combination with the rim well are as high as they're wide (another questionable item of lore), and also that a line through the beads coincides with the centre of the tube (ditto) we garner the following information from calculating the (idealised) toroid air volume:

Data in the order:
tyre size mm, cubic air volume cm^3, step up over previous as percentage
622x30, 1381, 0 (first datapoint)
622x40, 2456, 78
622x50, 3837, 56
622x60, 5525, 44

I'm not surprised John's 30mm tyres felt harsh after he rode on 50mm tyres! That's a step of 78% in volume of air and consequent lower pressure and more comfortable ride. From 30mm tyres to 60mm is 400%. You can see why I love my Big Apple Liteskins to which I changed from rock-hard Marathon Plus 37mm (2101cm^3 or a step up in comfort of 167%). In this perspective, 60mm tyres are a cheap upgrade.

I'm an economist, so I expect the marginal cost to be proportionately higher than the marginal benefit at each step, but it seems that balloon tyres are one of the few exceptions.

***
I have a letter in my mailbox from someone who lurks here, who writes, "Can't you guys stick to the subject even once. Hands are important." But we are sticking to the subject. Your body touches the bicycle at five points. Three of them get priority in fitting (feet on pedals, bum on saddle). The truth is that whatever isn't fixed in the fitting to these three points and especially the saddle position, will be felt in your hands. So in a discussion of hands and grips, we are crucially interested in first eliminating as much as possible of the vibrations, including micro vibrations, delivered to the handgrips, and in this regard the tyres, their width and pressure of inflation, are tools or at least considerations in the choice of handlebars and grips. A bicycle is an extreme example of everything being connected to everything else.


PH

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #10 on: September 12, 2023, 01:28:26 pm »
Someone had a good play with tyre pressures and an accelerometer.  I'm not sure the methods would stand up to peer review in a scientific journal, but it makes interesting reading and 10/10 for the effort.
https://www.cyclingabout.com/lab-test-lowering-tyre-pressure-improve-bike-comfort/
If you don't want to read it, the main takeaway is
Quote
Simply put, larger volume tyres allow for lower tyres pressures and lower tyre pressures allow for more vibration attenuation

Andre makes the comparison between Big Apple Liteskins and Marathon Plus.  I'm not a fan of Plus tyres, I may have mentioned that before. I'm not surprised the Big Apples are more comfortable, though it would be incorrect to attribute all of that to the volume.  I've swapped Plus to Pasela in the same size, at the same pressure and the comfort difference was instantly noticeable. 
We haven't yet considered tubeless either, the advantage being the ability to run the same size at a lower pressure.  I have no experience to comment, though those that have wax lyrical, mostly. 

Andre Jute

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #11 on: September 12, 2023, 10:55:06 pm »
Andre makes the comparison between Big Apple Liteskins and Marathon Plus.  I'm not a fan of Plus tyres, I may have mentioned that before. I'm not surprised the Big Apples are more comfortable, though it would be incorrect to attribute all of that to the volume.  I've swapped Plus to Pasela in the same size, at the same pressure and the comfort difference was instantly noticeable.


I'm generally suspicious of single cause explanations, especially in tyres, on the illinearities of which I spent a huge amount of time as a young motorcar racer. But in this instance Paul and I both went from the all-round stiff and unyielding Marathon Plus to tyres with softer sidewalls. I think it is fair to conclude that some very large part, definitely a majority of the improved comfort, results from the combination of greater air volume and soft sidewalls with more elasticity (more give in them).*

* I'm assuming that the Pasela in the same size as the Marathon Plus offers a greater volume of air simply because the Marathon has thick walls whereas the Pasela is more lightly built, leaving more space for the tube.

PH

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #12 on: September 13, 2023, 10:53:21 am »
I think it is fair to conclude that some very large part, definitely a majority of the improved comfort, results from the combination of greater air volume and soft sidewalls with more elasticity (more give in them).*

* I'm assuming that the Pasela in the same size as the Marathon Plus offers a greater volume of air simply because the Marathon has thick walls whereas the Pasela is more lightly built, leaving more space for the tube.
I don't think we're in disagreement about that.  I was raising the point that volume alone isn't the only factor. Of course, I know you knew that, it just wasn't clear from your previous post.

* It was some years ago, when I still had a Raven and all Panaracers had a reputation for being undersized, something I believe they've corrected.  It's quite likely the same size Paselas were smaller than the Plus and still more comfortable.

Andre Jute

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #13 on: September 15, 2023, 12:02:24 pm »
Personally, I believe that a competently designed bike on (very) wide tyres operating at a (very) low pressure, and preferably fitted with a Brooks (or workalike) hammock saddle plus ergonomically sound handle-bars and -grips, doesn't need an additional old-fashioned suspension fork until you ride it in challenging offload situations, which I don't do, though some of my lanes are plenty rough.

In any case, suspension forks in the normal course of their operation change the bike's steering geometry adversely every time they compress or rebound, which is unacceptable. The only correctly designed suspension fork of which I'm aware, long unobtanium, was designed and sold for some years by a French motor racer; it basically used the head tube as the fixed strut and offset the suspended part of the assembly by two unequal length and non-parallel A-frames working around the head tube, arranged so that the moving forks at all times operated only perpendicular to the ground, so preserving the designer's intended steering (and, important, roadholding and handling) geometry without possibility of exception. I was outbid for the last NOS version of it. I can't remember the name (Cobra?) and can't find a photo of it. Instead I show you a Honda Goldwing front suspension design, which isn't anywhere near as clear. You'll have to take my word for it that the French bicycle version was a lot smaller, lighter, neater. For a decade or two it was the ne plus ultra for every Continental downhill bomber, a genuinely grown-up suspension system. Here's the stand-in Honda Goldwing independent front suspension.


Honda Goldwing independent front suspension with a high degree of isolation from the road.
Image courtesy Honda.

Note that the steering tube is isolated from the suspension mechanism. You can clearly see the top A-frame surrounding the steering tube and fixed to the moving struts of the suspension. The spring and damper sit on the lower A-frame, so it is not immediately obvious.

***
The suspension fork on my Gazelle Toulouse failed under 5000km. Unacceptable.

The suspension fork on my Trek L700 Di2 "Smover" (the full auto Di2, not the cut down cyclist-assisted electronics sold for a premium to roadies) is made of sterner stuff. However, the way it operates is to lock out the suspension when the bike starts up or when it is accelerating hard, but at a high sustained speed to offer Colin Chapman's dream of long travel soft springs firmly damped. (This is the opposite of, for instance, the way the air suspension on some Range Rover models operate: it's soft at low speed and firms up with speed or sporting driving.) On the Trek Smover, the way I ride, on undulating (that's putting it kindly) terrain where I'm always either slogging up a hill or speeding down it, the suspension is mainly locked out until I hit a pothole or other obstacle when, in a fraction of a second, it soaks up the two impacts and damps them without dipping so far I suffer a header. That's a great advantage. But the biggest advantage is that the Shimano electronic adaptive fork in the Smover gruppo reacts to micro-vibrations all the time, regardless of what else is going on. A little more about the electronic adaptive fork and its computer control here:
http://coolmainpress.com/BICYCLINGsmover.html

Basically, my Kranich, the bike with which I replaced the Smover, uses low pressure 622x60 Big Apples to do the same job considerably less expensively.

All of this is intended to keep micro vibrations out of my hands, as I wrote in a post above.

***
This isn't a digression. As teenage and adult hotrodder, I knew for a fact that Ford doughnuts were the best. When my wife's Volvo Estate irritated me with a vibration in the exhaust line after I fitted a 5.7 litre Chevrolet V8 in the place of the agricultural tractor motor this supposedly "luxury car" came with, I asked the best local motor factor to line up the Ford doughnuts for various sizes of Ford cars on the counter, and soon found the right sizes by comparing the Volvo's doughnuts, which I had brought with me. Killed the vibration stone dead, or, more precisely, absorbed it so that I could no longer feel or hear it.

The same idea is basically used on the Thudbuster saddle suspension Dan likes, though with boutique elastomers, necessitated by the limited space and the need for a high profit margin.

Now a reputable and innovative bicycle component maker has taken up the same idea to quiten micro-vibrations (which they call "fluttering" for one of their peculiar niche markets) coming up the fork and into the cyclist's hands.


The elastomers are coloured red. Image credit: SRAM.

The article is here for the technically curious:
https://bikerumor.com/utterly-butterly-sram-patents-shock-fluttering-end-mounts/

As I said above, I don't really need a suspension fork. But these elastomers on a fixed fork surrounding the axle and at the crown (without the hydraulic bits in between, but instead a normal tube fork) would be tuneable to mop up the very last micro-vibrations that are let through by the Big Apples. (Hey, even paranoids have enemies!) Or imagine a bike on which for some reason you cannot fit a fork wide enough to accommodate true balloons, such elastomers top and bottom of the fork would be a welcome additions, with the substantial advantage over a moving suspension fork that the movement in the elastomers would be so small that the steering geometry is hardly altered, thus obviating the need for a fork with moving parts.

In time the elastomers might even be adapted to the other joints in this micro-vibration transmission line, at the juncture of steering tube and stem, and the juncture of stem and handlebars, and why not at where the steering tube is fixed in the head tube to make the line completely isolated.

Elastomers are cheaper than hydraulic or air suspension and far more tuneable.


flocsy

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Re: The technicality you can't see: handlebar ergonomics & RSI
« Reply #14 on: September 16, 2023, 10:11:09 am »
There are already stems with elastometers.
https://redshiftsports.com/products/shockstop-system