How To Repair A Rear Derailleur Hanger

When something terrible suddenly happens to a possession one dearly loves, it is quite natural to utter WHAT THE… and then top it off with a globally recognised expletive associated with horizontal entertainment.

To find out how my beloved celeste Bianchi Via Nirone 7 bike (Shimano 105 R7000), and the Shimano SH-RC7 cycling shoes got damaged during a recent accident, please read my previous two articles:

Getting Hit By A Motorcyclist

How To Repair Cycling Shoes

QUIZ: Can you spot any differences in the hangers shown above? Find your answer at the END of this article.

Now let us get on with repairing a rear derailleur hanger that looks like the hunchback of Notre Dame.

Drop(out)dead gorgeous

A hanger is a metal bracket that connects a bike’s frame to its rear derailleur. During the post-accident inspection, my rear derailleur emerged unscathed but the hanger got damaged. I sat cross-legged under a Banyan-tree, researched the subject, read articles and watched YouTube videos until a solution unveiled itself.

I took off the rear derailleur for the first time since buying the bike. With a wire I tied it to the chain so that the two would not hang lose and interfere with tinkering.

The derailleur and hanger specifications for Shimano WH-RS100 aluminium wheels are as follows:

1. Mounting Bolt Thread: M10 × 1.0 (10 mm diameter with a 1.0 mm fine thread pitch)
2. Required Tool: 5 mm hex (Allen) key
3. Recommended Tightening Torque: 8 to 10 Nm (using a torque wrench)

Hang ‘em high

I used three tools to get the two hex bolts out:

1. Hex (Allen) 5 mm bit
2. MXITA digital torque adapter
3. Stanley ½” drive ratchet (set 2-85-586)

Unscrewing them revealed a weakness: both were only torqued to 4 Nm (or only half of Shimano-recommended 8-10 Nm).

Bolts and nuts do tend to become lose due to road vibrations. Besides, the manufacturers are not very particular about correctly torqueing the hardware of lower and middle tier bikes. Whether you buy a new or a used bike, do correctly torque all your bolts and nuts before riding.

I recall how after a few rides on my new bike, I found a calliper brake-pad that was ready to fall like the Roman Empire. From that day on, I worked to create a master-list of all the hex bolts, their Metric sizes and torque (Nm) settings. The data was painstakingly collected from official Shimano catalogues.

It does not hurt to be a nutcase. I now maintain a precise inspection schedule based on the mileage and the number of riding hours.

Alignment, but why?

Not until I got into serious maintenance did I realise that bicycles, much like cars, required alignments of important parts. Looking at my deformed hanger I realised that a derailleur hanger alignment tool was needed to straighten it. Disappointingly, neither any repair shop owned one nor was it available locally for purchase.

To read about professional alignment tools, click HERE and then HERE, but rejoice, cheaper options are also available from other manufacturers. Currently I am working on making the tool myself—you guessed it—to save money and learn new things.

Standing at the rear and slightly to the right side of the rear wheel, I eyeballed the hanger. Vertically, its front edge was twisted inward and the bottom end bent inward towards the wheel.

Without removing the hanger from the frame, and using very small and careful corrections with an adjustable 10-inch wrench, I unbent and untwisted the hanger back into position. The chain could now be easily slipped over the cassette and the chain-ring.

Off to the mechanic

Finding and then importing a hanger from a foreign on-line shopping platform seemed like an uphill task. I called several cycling stores but none had the exact same hanger for sale.

I headed to a friendly bike mechanic. His verdict was, “Since we don’t have a new hanger of this shape, we’ll repair the old one”.

When he tried to remove the wheel from the vertical drop-out, it was stuck. Earlier, I had failed to notice that due to the accident’s impact, the claw-shaped opening of the hanger had narrowed down from 12 mm to 9 mm, which was insufficient for a 10 mm axle bolt to boldly go where no axle bolt had gone before.

Open your mouth and say ahhh…

I suggested using the edge of a chisel and hammer to gradually open the claw to an acceptable degree. This worked.

The mechanic noticed a wrinkle in the hanger’s aluminium. First he recommended heating and then beating the hanger at a welder’s workshop but I instantly rejected the idea.

With no option left except to have the bike-doctor hammer the hanger, I became an apprehensive patient experiencing his 'piece of cake' procedure.

Later research showed that my 8-metres long gut-feeling was spot-on about the dangers involved in both the repair methods.

A minor diversion here. Interestingly, it stands proven beyond a shadow of a doubt that the word is not ALUMI-NUM but rather alu-min-ium. In 1990 The International Union of Pure and Applied Chemistry (IUPAC) accepted aluminium as the international standard.

The dangers of hammering and heating

Hammering changes the microscopic internal crystal structure (microstructure) of aluminium, but it does not change its chemical composition, basic molecular or atomic identity.

Although bikes usually use fairly strong high quality 6061 aluminium alloy, hard hammering will make it brittle and prone to sudden cracking or component failure (metal fatigue) during a ride.

Heating the aluminium is even worse as it causes thermal expansion, phase changes and chemical reactions. Therefore, keep hammers and blow-torches away from aluminium. I shall not delve into how irreparable the expensive carbon ('plastic') bikes become after a crash.

The mechanic’s third suggestion was to ‘have a hanger fabricated out of steel’, I again shot down an idea that was based on his personal preference but not backed by science.

Research later revealed that an aluminium hanger is designed to fail (bend) and acts like a cheap protector of other expensive components. Like all mechanics here, my man had learnt his trade by the roadside and without formal mechanic's training.

After the hanger was carefully hammered back to about 95% correct shape, minor re-adjustment of the rear derailleur using the cable tension barrel adjuster, gave us smooth and noise-free gear shifting.

A problem remained

After what seemed like a job done, we got stuck again. The hanger’s top inside edge was shaped to fit the vertical drop-out at an angle of almost 110°.

Since it did not fit perfectly, I suggested, “Let’s hammer this in”.

Fearfully, the mechanic put his hands in the air, “Sir, you do it; I won’t touch the bike.”

I wrapped a piece of cloth over the vertical drop-out to avoid scratches and used a spring-loaded locking grip wrench to hold the hanger firmly in position.

A piece of wood was then placed over the hanger’s curved rear end for further protection and then gently hammered.

The L-shape aligned but not 100%. I left it at that and tightened the 5 mm hex mounting bolts using a digital torque adapter atop a ½” drive ratchet.

Wait, one more problem!

The top hole of the hanger had become somewhat oval due to hard hammering. Its 5 mm hex mounting bolt had a retaining notched-nut on the back with two small holes in it. To properly tighten the bolt, a pin-wrench was used to hold the nut in place. I would later make the tool myself. Stay tuned for an entire article on the subject. 

Once at home, I noticed that the torque setting of the top hex mounting bolt had dropped by 50% (to 4 Nm). Furthermore, the hex bolt’s head had become round, hence unusable.

Spare hex nut and bolt

Another visit to the mechanic. He found me a new set of hex bolt and retaining nut. This was successfully torqued to 8.5 Nm (Shimano-recommended range: 8 to 10 Nm).

He even found me a small M10 bolt with 1 mm thread-pitch which I needed for making my own rear derailleur alignment tool. Stay tuned for an entire article on the subject.

Since the hammered hanger’s claw was still not wide enough to fit over the vertical drop-out, I again used a chisel’s edge and a hammer, then twisted the slight bend with a wrench. The rear derailleur’s gear shifting was re-checked and the cable tension re-adjusted with the barrel adjuster.

As a final bit of DIY, I used a permanent marker to paint the scratched hanger black. I thought I heard the hanger cry, “Please leave me alone!”

A final note

Incidentally, a 150 mm digital Vernier calliper is an absolutely essential tool to have in the toolkit. I use a Chinese copy of Mitutoyo (originally an excellent Japanese brand) which runs on a cheap LR44 coin battery.

After long sessions of precision, methodical tinkering and dedication, do enjoy your rides.

💚

Now here is your ANSWER to the quiz: Yes both the hangers are different in shape. The one on the right is the original shape with the correct angles and curves.

Read more CYCLING articles HERE.

©Tahir Gul Hasan, 2026

How To Repair Cycling Shoes

In my previous article titled, Getting Hit By A Motorcyclist, I narrated the details of the accident and the mild injuries I suffered.

In this piece I shall show you how I repaired my cycling shoes whose carbon heels took a hit like those of the Greek hero Achilles.

She-man, oh!

When riders wear cycling shoes, they cannot magically click the heels thrice, wish for something and have it all come true. Real life is very different from the movies.

Cyclists always work hard but all this is changing due to the introduction of e-bikes that cost as much as motorcycles do. It is a money-spinning scam created for lazy cyclists who think they are helping the environment but are in reality guilty of creating huge landfills of toxic lithium-ion batteries in a technology-driven world.

That fateful July Morning, seated on my fully manual celeste-coloured Bianchi Via Nirone 7 (Shimano 105 R-7000 group-set), I wore white-coloured Shimano SH-RC7 shoes. As I took a hit from a motorcyclist, the stiff carbon soles and the locked cleats saved my feet. However, the heels which had been lightly repaired earlier, crumbled.

I considered ordering a new pair but found AliExpress suddenly very expensive due to the imposition of government taxes and Customs duties. A pair that cost $175 earlier was being sold for $375. Tired of counterfeit products, deceptive shop-owners and the hopeless refund policies of the Chinese on-line shopping platform, I decided to repair my shoes.

Then in July 2026, we heard: AliExpress hit with $629 million EU fine over sales of illegal, counterfeit products. Thank you European Union and goodbye AliBaba Group.

DIY all the way

After carefully scraping the carbon material off the heels, I thoroughly cleaned the curved surface underneath.

From a cobbler I bought a patch of 5.5 mm thick tyre, cut two small pieces and trimmed them to fit over the soles.

Since two different types of materials—tyre rubber and carbon—needed to be glued together, I lightly sanded the carbon part of the heels and the tyre pieces using 220 grit sandpaper.

These were then washed and dried to obtain good adherence. After applying Super Glue to the tyre rubber and the carbon heels, I secured them using book-binding tape. The shoes were left alone for an hour.

After seeing very small gaps appear around the edges of the tyre pieces, I applied a thin coat of clear epoxy and it let it cure for a few hours. Although the job did not appear photogenic, the aim was never to surpass the finish quality of Dorothy Gale’s red ruby shoes, in the movie 'The Wizard Of Oz'.

Look ma, no cleats!

The cycling accident only destroyed the right shoe’s cleat but that necessitated replacing the complete set.

In my spares’ kit I found a Chinese copy of Shimano SM-SH11 cleats. These yellow cleats offered 6° of float (±3° sideways movement of the shoes, comfortable even for advanced cyclists).

The Shimano-copy cleats came with poor quality metal hex bolts and brackets that self-destructed when tightened. I reused the Shimano hardware from the old set.

Then with straight knees and neutral heels, I adjusted the following important positions to:

Fore-Aft: Align the ball of the foot over the pedal axle.

Lateral: Centre the shoe inward or outward for correct knee and leg tracking.

Heel rotation angle: Twist the cleat so that the heel points naturally without stressing the ankles.

All the above required matching both cleats very precisely by using the markings printed on the soles. For professional level tuning, you may wish to look at other cleat adjustment tools.

Using a digital torque adapter over a ½” ratchet, the hex bolts of the cleats were tightened to a torque of 5 to 6 Nm (Shimano-recommended) to prevent them from drifting during rides.

For a final check, I hopped onto my bike, locked both the shoes into the Shimano 105 R7000 carbon pedals and checked for satisfactory engagement and disengagement.

Rewards

As a bonus, my tyre rubber heels gave me better grip even on hard floors, whereas the original carbon material felt very slippery. Are you reading this Shimano-san?

Not buying a new pair of shoes saved me $375. Elated at having spent only fifty cents on the repairs, I took to the road to click my heels together three times and say there’s no place like home.

The next article will show you how I repaired my bicycle’s rear derailleur. Do NOT miss reading it.

Stay tuned. Safe cycling until then.

💚

Read the first article in this series: Getting Hit By A Motorcyclist.

Read more CYCLING articles HERE.

©Tahir Gul Hasan, 2026

Getting Hit By A Motorcyclist

The road traffic in this land of the pure (al-Bakistan) is truly chaotic. Few use the roads in a sensible and predictable manner. Motorcyclists are the worst offenders. Almost nobody notices a lone cyclist pedalling away. Pedestrians risk getting run over by speed-monsters. This story is about yours truly getting hit by a motorcyclist.

He came, he never saw and hit me

It was 07:16 a.m. on Friday, the 3rd of July 2026—a day before the famous Tour de France bicycle race was scheduled to start. I was in good spirits, humming the lyrics of Uriah Heep’s 1972 classic rock song, July Morning:

There I was on a July morning,

I was looking for love
With the strength of a new day dawning,
And the beautiful sun.

There was almost no traffic and certainly no lost love on the roads. The stressed school-going children and their speed-demon chauffeurs seemed to be enjoying the summer vacations.

It was the tail-end of my fifty kilometres ride. A glance at my bike’s side-view mirror—mounted at the end of the handlebar—showed a motorcyclist approaching from the rear. It being a right hand drive country, I moved from the left side of the road while hand-signalling a right turn. The motorcyclist did not appear to be slowing down. To avoid confusing him, it made sense to maintain the course and make no abrupt moves.

The motorcyclist might have been confused since birth. On our pure roads, such motorcyclists shamelessly disregard traffic signs and dart about unpredictably while ogling at their hand-held cell phones.

Wham, bang, thank you Sam

At a moderately fast speed, this motorcyclist crashed into my rear right side. I heard no screeching brakes; it happened very fast. Miraculously, I remained mounted but the Food Panda delivery-boy fell hard. Luckily there was no regular vehicular traffic behind us.

I moved to the left side of the road and stopped to scold the boy. In accordance with the national trait, he blamed me while lying flat on the road. His bike showed damage, an elbow bled but he was quick to get into an argument.

I felt pain on my right toe. The bike’s chain had come off the chain-ring and the rear derailleur was bent out of shape. I went, oh my Bianchi, my baby! Luckily no bones felt fractured. I was unsure if God tested this Adam like a crash-test dummy or Satan engineered the accident.

Poor people versus rich folks

Several pedestrian males gathered around, listening with temporary neutrality to the arguments and counter-arguments that followed. They would soon begin to side with the motorcyclist.

Upset at being treated as an invisible cyclist on the road, I maintained an unforgiving stance. My Shimano cycling shoes showed damage on their carbon soles but their stiff material saved my feet. The damage to the bike and my apparel prompted me to demand compensation for repairs and parts replacement.

“I want to call the police. Will someone lend me a phone?” Unluckily, that day I was not carrying a cell phone.

Earlier, in June, my trusted Samsung Galaxy S7-Edge died in my arms after having been a loving companion for ten full years. The cause: the black screen of death. With its beloved motherboard completely gone, I lost all the data which felt worse than losing one’s soul in a digital world.

With six men around, none obliged but instead announced, “We don’t have a phone. Sir, let the poor boy go.”

I retorted, “Your poor boy hit this rich man from the rear. Why has he not admitted his mistake? And who engaged you all as defence lawyers?”

In this land of the pure, perhaps 1% people will ever readily admit their mistakes. By this time, emotions were running high. When the boy got loud, I got louder and it worked. He offered repairs at the nearest tyre-shop.

I refused, “This is an imported bike whose parts can’t be repaired by roadside tyre shops.”

To cut the story short, he finally coughed up a small compensation. The aim was to teach the boy a hard lesson so that he would cease being reckless and not harm others on the road.

There is a story behind my strong reaction and demand for compensation. A few years ago, another Food Panda delivery-boy crashed into my parked Mercedes E200, broke its taillight and caused damage worth PKR 28,000 (USD 100) which went out of my pocket.

Off the saddle

Serious repair work of the bike was postponed in favour of attending to the light injury to my right knee and foot. I walked with a limp and by the third day, the red bruises had turned purplish and swollen. Taking Neurobion pain-killer tablets, massaging the leg with muscle-relaxing Voltrel 2% gel and getting sufficient bed-rest was essential.

Even after two weeks when I could walk normally and all the swelling and redness had vanished, there was mild pain deep in the bones. I was not eighteen any more. Complete healing would take two additional weeks. I remained grounded for well over a month.

What now?

If one refuses to learn from an accident, more accidents sometimes take place to teach harder lessons. This is how God’s universe appears to operate.

I immediately adopted the following safety strategies:

1. When turning, be more vigilant. In the land of the blind, the one-eyed man is king.
   
2. Avoid taking silly chances with fools around or behind. Forget Muhammad Ali’s saying: "He who is not courageous enough to take risks will accomplish nothing in life."
3. Ensure carriage of a cell phone.
4. Call the police if things go out of control.

In upcoming articles, I shall talk about how I handled the bike repairs and how I repaired my cycling shoes.

Stay tuned and enjoy safe cycling.

💚

Read more CYCLING articles HERE.

©Tahir Gul Hasan, 2026