Cycling UK Forum

Brucey wrote: ↑25 May 2024, 3:04pm 70mm SA drum brakes

SA= Sturmey Archer

Can you suggest me some (other) brand/model, so I will evaluate it for purchase?
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Found this discussion, and this one, here on this forum.

Brucey wrote: ↑25 May 2024, 3:04pm largely theoretical consideration

No doubt about.

Keep in mind that all the considerations I make do not come from road tests with different bicycles, but from experience with only the same two road bicycles - even if have been ridden for over 6000 Km, each - combined with computer FEM simulations which can potentially overestimate a possible problem.

In addition to the fact that I am not a mechanical engineer but an electronic engineer, and therefore I add a worsening factor due to my ignorance.

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I just saw the new Van Rysel (France-based company) bicycles commissioned by Decathlon, for the two top of the range carbon ones (namely "ProX", it's a ~ 8.000 euro bicycle) they estimated "no more than 100Kg of cyclist" otherwise probable structural failure of the fibres, yet they did a test one of their frames on a loong piece of ground covered with nothing but with little stones (they call this kind of white-road as pave'), asking a dude who weighs 110 kg to ride the bicycle at his max speed.

Surpriselly nothing broke nor, according to the sonar test in the laboratory, was any part of the structural resin damaged.

That is, engineering safety factor applied.
(say the customer "no more than 100Kg", test the bicycle on a "110Kg" rider)

Shops that actually uses Ghisallo rims. They may know better about the above discussed issues.

• Woodys Cyclery (USA), see here
• CycleTrading Co (New Zeland), see here

As expected, they both seem to suggest rims with a carbon insert (e.g. Ghisallo Ultimate/Sprinter rims).

Drum brakes have advantages and disadvantages, but from point of view the have the same disc-brake defect: the torque from heavy use of a front hub brake results in "brake steer" unless the front fork is especially stiff, and can bend a fork blade unless it is especially strong.

Cyclothesist wrote: ↑24 May 2024, 9:47pm Actually I wonder if they make a disc braked version?

For a disc brake I would have to replace the fork and the front hub.
The disc brake generates enormous torque during operation.
The smaller the radius of the disk, the greater the stress.

The fork must be designed specifically to manage these things.

At this point... you might think about mounting the front wheel with a wooden rim and a light hub motor (200Watt) that acts as an electric brake, installing a small battery in a fake bottle cage.

It all adds up to at least 1Kg, and if anything happens to the battery, you're totally out of control.
Therefore - fail safe - it would be better to implement both, perhaps on two different levels.

• left level -> front elettro-brake
• right level -> front rim-brake (to be used only if the electro-brake fails)

The electro-brake is an "hub-brake" like the mechanical counter-pedal brake(2). However, when activate the counter-pedal brake suddenly blocks the wheel, whereas with an electronic control the electro-brake can dose braking. This is good! Even if .. here we need to build a brake knob that works digitally, therefore choosing to use a linear or logarithmic braking map, at the most imitating the ABS technique to avoid blocking the wheel, which, especially on the front wheel of a bicycle, is useless and dangerous.

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It should also be understood whether it is possible to impregnate the braking surface of the wooden rim with a fireproof compound. It would be very useful for security.

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I need to understand if it is not possible to glue on each side of the wooden circle a 1mm thick stainless steel ring with a very powerful two-component resin with high resistance and high temperatures.

If Ghisallo made an ad-hoc profile for this ring it would be even better.

In this case the pads would work on the steel rim, which however is only able to dissipate on the surface, which is sub-optimal(1), but we are still talking about a large surface.

Not sure, it's just a couple of idea ...

(1) In aluminum rims the entire rim absorbs and dissipates the temperature generated in contact with the pads.
(2) Sturmey Archer has several rear hubs. From model to model, the counter-pedal brake is an optional that you can have.
When I ordered my 3-speed internal gear hub I specifically chose not to have the counter pedal brake because I couldn't have the hub with OLN=130mm. And this is another big problem: fixed gear hubs with both counter-pedal brake and OLN=130mm are more easily found. Everything else seems to be going towards 135mm... and I certainly can't widen a titanium frame.

Found on Amazon, immediately bought for my Kindle Paperwhite (11 euro)

• Tim Moore's 'Gironimo! Riding The Very Terrible 1914 Tour of Italy'

A 3,162 km race. A 48-year-old man. A 100-year-old bike. Made mostly of wood. That he built himself.

Tim Moore sets off to recreate the most appalling bike race of all time. The notorious 1914 Giro d'Italia was an ordeal of 400-kilometre stages, cataclysmic night storms and relentless sabotage - all on a diet of raw eggs and red wine. Of the 81 who rolled out of Milan, only eight made it back.

Committed to total authenticity, Tim acquires the ruined husk of a gearless, wooden-wheeled 1914 road bike with wine corks for brakes, some maps and an alarming period outfit topped off with a pair of blue-lensed welding goggles.

From the Alps to the Adriatic the pair relive the bike race in all its misery and glory, on an adventure that is by turns bold, beautiful and recklessly incompetent.

Thanks for suggesting this great book!!!

Found this article online.

Brucey wrote: ↑24 May 2024, 2:13pm one of the traditional problems for wooden rims was that there are seasonal changes in relative humidity

umm, I wonder ... shouldn't waterproofing (e.g. Flatin) also solve or mitigate this problem?
It is not bare wood, it is treated wood, covered with flatin, which should be done regularly, especially in autumn and winter

Brucey wrote: ↑24 May 2024, 2:13pm one of the traditional problems for wooden rims was that there are seasonal changes in relative humidity and they can greatly change the tension in a built wheel. I was successfully put off wooden rims by folk who had used everything in the past; they told me that not only were they only really suitable for summer use, but also they could be expected to go out of true during winter storage. Al rims are a lot less bother by comparison.

Doesn't the thin carbon ring that Ghisallo introduced in the Ultimate/Sprint line solve or mitigate this problem a bit?

Brucey wrote: ↑24 May 2024, 2:13pm If you are looking for improved vibration absorption I would suggest that you choose your tyres and fork carefully.

We should understand *how much* the fork and type of tires dampen vibrations, compared to how much wooden rims do!
I seriously wish someone had published some scientific data, or installed accelerometers on both the fork and the handlebars, repeating the test, for at least 50km, on the same bike, same rider, only changing the wheels.

Fork
Anyway, in my case: don't touch my fork!
It's handmade, made in NivaCrMo, it cost 300 euros for a total weight of only 650g, which is not bad for a steel fork.
Cheaper (industrial Unicrow) ones cost 50-60 euro, and have a weight of 900-1000g.

Aside from the weight, it has compensation and a curvature that dampens quite a bit. I feel the difference e.g. with the original steel fork mounted by Moser on my Forma-1996 (mid-range steel bicycle). It's even better, not in terms of weight, but in terms of comfort, than the carbon fork (just 350g) mounted by Litespeed on my Classic Titanium frame.

Plus, that fork has great dynamic response, and I wouldn't change it for any reason.

Tires
The type of tires, and the width... there isn't much choice on a frame that accepts 25mm at most.
I am currently using 24mm, and there isn't much difference in changing the type of tire compound. Yes, there is a difference, but it's very small.

In any case, I would seriously like to try the wooden rims. I'm doing some research to understand what problems they have, how to solve them, to be able to choose the best solutions, and to fully enjoy them for the best possible experience, and if possible, on a 400km journey.

jimlews wrote: ↑24 May 2024, 1:41pm heat generation; remember how those old stone age guys used to make fire ?

I have a big 0.9l Campagnolo water bottle, with a long straw, attached to the frame with thin velcro straps, which reaches up to the handlebars. The reason is that I find it very difficult to unhook the water bottle without having to slow down and waste a lot of time.

So, I'm thinking - I'm joking - of also carrying a small tube on the fork, attached to a spray bottle like the one used for windshield wipers, so if the rims catch fire... you can "spray fresh water on the wooden rim!!!".

Can we patent it as a “fire protection mechanism for wooden rims”?

jimlews wrote: ↑24 May 2024, 1:41pm Mine were un-braked being on the rear wheels of an old trike. Perhaps significantly, the front (braked) rim was alloy.

I would do the opposite, as people like Ganna did on their early 1900s bike made of iron (pre steel technology: only front brake (Campagnolo caliper), no rear brake installed.

In their day leather-pads were used, but I will try cork-pads, and I will treat the braking surfaces of the front rim with hardener.
it was much heavier, we're talking about over 16kg, mine is made of grade 9 titanium, with a NivaCrMo steel fork, we're halfway to its weight, and this definitely helps the brakes.

However, for security reasons, I will never make pronounced descents (which take you to exceed 40km/h), I will maintain a maximum speed of 50km/h on level ground only on extra-urban roads (where there is no need to use the brake for a complete stop), max 28km/ h in the city center (1), and I will pinch the brake lever instead of holding it down.

(1) traffic lights need complete a stop. I have to carefully calculate and then verify experimentally, the meters I need to stop the bicycle, in relation to the weight of the bike, and to the type of "pinched" braking; 28km/h is a provisional indication based on rubber pad brakes on a safe complete stop distance

Thanks for your feedback.
There are few people who appreciate wooden rims and are willing to share feedback, impressions, etc

jimlews wrote: ↑24 May 2024, 1:27pm if I were considering wood rims today, I would want to be very sure that they had received an effective treatment against damp (Wood is hydroscopic; it draws in moisture - that is how sap is transported around the tree).

Ghisallo applies two or three layers of "flatin", which is a waterproofing agent.
It should fix this problem.

jimlews wrote: ↑24 May 2024, 1:27pm wood is subject to local compression/deformation when subject to localised stresses such as screws, nails and indeed spoke ferrules.
So I would want to place washers or some other insert into the spoke 'cups' (for want of a better word) to help spread the load of the spoke nipple as it is tensioned.

This is the reason why I said above that you have to use their special nipple kit: not only are they longer, but they are supplied with special washers to solve this problem.

One of their bag-kit contains 36 nipples+washers, and costs ~15-20 euros, you need two for two wheels, but it's worth it.

jimlews wrote: ↑24 May 2024, 1:27pm Other than that, I'd say if you want wooden rims and you have the money burning a hole in your pocket - go for it !

Yup. 800/900 euro are a lot of money, but It would be a great experience, decidedly "different".

How was the experience with your bike? Is it true that rolling on wheels of wooden rims gives you the sensation of having two softer wheels, which better absorb the vibrations caused by road roughness?

Based on the fact that until the early 40s all the roads had no asphalt and were practically what we now call "white roads" (aka "roads for gravel bikes"), that type of wheels, in use until 1936, should be was ideal.

There is also a problem with the brakes, which seems to be THE big problem with wooden rims: they require brake pads that do not melt given the high temperatures they reach when rubbing against the wood.

Disc brakes have brake pads that exceed 100C, and that's not a problem because they are built with materials that not only don't melt at those temperatures, but also dissipate the temperature quickly.

With rim-brakes it's a completely different story; at 100C traditional pads do melt, and and since wooden rims don't have a metal braking track ... one solution seems to be to use cork-brake pads.

Fortunately, Ghisallo also has cork-brake pads.

That's good, since another problem is that they wear out very quickly, you need to stock up on them.

hi
I am considering the purchase of a wooden rims set made by Ghisallo, Italian craftsmanship since 1946.

They say

Why choose Wooden Rims ?

The answer is not obvious, anyone may ask '

• Are they not subject to break?
• How do they behave in case of rain?

Well the answer is very simple, wood it is an extremely elastic material and thanks to the subsequent careful and accurate workings improved over the years lead to a product of craftsmanship excellence that resists bad weather and allows a safe and comfortable drive, greatly reducing vibrations and stresses.

So, the advantage here is that they are comfortable drive, greatly reducing vibrations and stresses!
(to be verified)

In particular I'm considering their "Ultimate" rims made for ISO TSS hookless tyres, specifically the Ultimate-Sprinter rims set:

• 28" wheel
• 36 spokes holes, to be coupled with a Campagnolo Record/8Speed hub set
• 24.5mm width, to be coupled with a good TSS-clincher-tire (I still have to choose the best one)
• inner tube optimized for TSS, inflated for no more than 5 bar (ISO TSS specification)
• special nipple kit for wooden rims, to be combined with Sapin Race spokes
• carbon fiber ring less than 1mm thick , applied with resin to inner tube seat at pneumatic/clincher rim surface

It's advertized as

Pneumatic – Clincher Rims with a carbon fiber ring less than 1mm thick , applied with resin to inner tube seat at pneumatic/clincher rim surface.

Ultimate allows an inner tube inflating pressure till 6/7 bar (87/101 psi) and also a spokes tension equal to same tension generally applied to aluminium rim.

I don't think that carbon ring is used to inflate the tires to more than 5 bar because the TSS specifications expressly say not to exceed 5 bar.

Rather, I think it is advantageous for three reasons

• Without a carbon ring, from what I understand, wooden rims, given their flexibility, loosen the nipples and you have to adjust the spoke tension much more often. With the carbon ring this problem is solved.
• Without a carbon ring, adjusting the spoke tension is not an operation that is done in the same way as with aluminum rims. That is, you need to proceed much more slowly with the adjustment, give less than a quarter of a turn, and wait for the wood fibers to adapt, then give less than another quarter of a turn. The whole operation took up to a few hours. With the carbon ring the problem is not solved, you simply adjust them less frequently (see previous point)
• With the carbon ring, the spokes tension is equal to same tension generally applied to aluminium rim

A set of wheels of this type costs, complete, assembled, around 800/900 euros.

I would like to know if anyone has ever ridden this type of wheel, and if so, impressions, defects, advice, opinions...

(I don't want to read comments about the fact that today carbon rims are used etc etc, I know it and I don't care)

Thanks

Brucey wrote: ↑21 May 2024, 4:43pm it will only make the bearing more susceptible to damage.

Do you write that for the smaller dimensions of balls?
In a NOS Victory headset, a Caged Balls is standard.