Category Archives: 2. Repairs & Tools

Overhauling bikes and parts is funny, isn´t it?

20 spoke disc wheel for cyclo-cross


24-hole is widely considered the minimun spoke count on disc hub wheels, front or back. This is due to the need to provide at least a 2-cross lacing pattern in the flange involved and enough spoke count to handle the braking forces as the torque is transferred from the hub to the rims thru the spokes unlike conventional rim brake systems where spokes don´t deal with torsional forces.

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The resulting wheel is one of my best creations. By the way, I started to build my wheels under the name ‘beespoke project’ just for fun

Now that a friend of mine is moving on to disc brakes in its cyclo-cross rig it is time to reuse their old tubular 50mm carbon rims.

Riding both 20/24 hole rims I was guessing if such a low drilling pattern was enough to switch to a safe cyclo-cross wheel. Seen the bracing angle of a 24H wheel laced 2x it seemed quite cheeky to try just 20 spokes crossing them over twice. After drawing the prototype in my computer I was delighted with the idea and wanted to try uncharted territory.

Rueda 20 radios a 2 cruces (II)

Spokes leave the hub in a extreme angle but still doable in my opinion

I’ve never ever seen a conventional 20 spoke front disc wheel laced with a regular hub and J-bend spokes. Indeed, there are no regular 20H front hubs in the market to choose from (Hope, Sun Ringlé, Chris King, and so on…). So far only top notch system builds with hubs that make easier the geometry of the spokes.

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2014 Rolf Prima 4CX carbon wheelset retail price is over 2000$ whilst our planned wheels are on a budget of 500$

The biggest concern then was to get some information about the rim, more specifically if the spoke bed was going to be able to carry out all the stress coming from twisting spokes.

No information was given with the original wheels. A further inspection ended up with a great finding: reinforcing eyelets inside each hole that fired the starting signal of the project. You might say I’m a believer… time will prove :).

At this stage, I was feeling like breaking new ground. My fears were:

  • 20 spokes and 2x, will they get on well?
  • Will the spoke bed stand the test of time?
  • How can I find a standard quality 20 hole disc hub?
  • Can I go with alloy nipples?
  • What’s the sort of spoke should I lace the rim with?

The first two questions have been already pondered over.

After some unsuccessful research looking for 20H hubs an amazing quality 40H White Industries MI6 tandem hub was placed first in our priority list. The idea was to use half the spoke count to build the wheel.

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Adjacent spokes leave the hub with too much of an angle with a 2-cross pattern, but still doable despite some wheelbuilders

I am a fanboy of aluminium nipples but this was not the ocassion to risk in a minor detail. A saving of 25 grams would never be taken into account in this build.

For choosing the spokes I was looking at middleweight but top quality extra beefed butted spokes. Something with 2.18 or 2.34 mm in the elbow end and swaged middle section which seemed to be the right choice to provide better lateral stiffness and stress relieving. Remember how convenient are butted spokes to release forces in the thinner part resulting in a more reliable and lighter wheel at the same time. Triple butted Sapim Force spokes and DT Swiss Alpine III were the only options I found. Because the spanish Sapim distributor is sourcing spokes at the speed of a turtle my friend finally ordered the spokes to an online german store. 44 Alpine III at a price of 0,65€ each plus shipping fees. It is certainly annoying that there are no interest in Spain to sell a wider variety and range of spokes.

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Spokes are rare DT Swiss Alpine III 2.35/1.8/2.0 mm

With all the ingredients on the table it was just a matter of patience to get all the spares and build the wheels.

There is just one issue I have left to discuss: the spoke length.

Because there are not available in the market 20H disc hubs (broadly speaking the industry doesn´t consider doable this alternative) an uncommon 40H option was the last resource unless you want to pay top dolar for a custom made hub by a CNC machinist.

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In good wheels I like to place the logo of the hubs on top of the valve stem so that you can see your lovely investment every time you are pumping your wheel

Using a 40H hub in a 20H rim means you only make use of half the hole count. OK, that’s easy to wonder. But have you noticed that once you choose any of the two constellations in the first flange for the lacing process, the spokes to be inserted in the other side don´t have the holes where you expect them to be? The opposite hub flange has offset its related constellation of ten holes by half the distance between holes in a forty drilling pattern hub. As a consequence, the spoke length is slightly modified.

The heads-out spokes of that side will be shorter if you twist the hub clockwise and longer if you do it counter clockwise. For the spokes with the heads facing inside the hub it happens the contrary. Eitherway, half of them are shorter and the other half longer than the theoretical measure required for a pure 20H hub. Some spreadsheets for wheelbuilders allow to calculate this discrepancy by changing the hole pattern by some degree. Something that occurs in paired-spoke wheels. Our deviation is 360º divided by 20/2, which is a total of 9º varying the length in a couple of millimiters.

I hope you like the wheelset at least. It’s going to be ridden by a good cyclist (not a pro though) and hopefully winning local and regional races in Andalusia.

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Experimental disc brake wheels with low spoke pattern as we started off reusing more common 20/24H road carbon rims. The rear hub is a 135mm Sun Ringlé Dirty Flea hub

Lucas Arcos Liroa, 6th December 2013, Parque Moret Huelva

Lucas Arcos Liroa, 6th December 2013, Parque Moret Huelva

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Park Tool pin spanners and three newsworthy repairs you can do with them


One of my favorite bicycle wrenches are Park Tool pin/peg spanners. It’s because they are handy, strong, cheap and simple tools but also because of the different coloured grips that break the monotony of any tool wall display.

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Spanners are made of hardened carbon steel to ensure long life while the handle is vinyl coated

My own experience tells me they are not on a daily basis tools anymore, but still esential for any all-round workshop that services freewheels or old fashioned bottom brackets for example.

The green handled SPA-1 fits the adjusting cup on many old three pieces cranksets. The pin ends are round with a diameter of 2.9mm.

The most popular repair you can tackle is a cup and cone type bottom bracket service.

Mural Park Tool SPA-1

Wherever there are two holes with the right size the Park Tool hanger cup pin spanner will allow you to do different repairs. Adjust the tension of the chain by turning the eccentric BB, removing a dustcup and so on

On the other hand, the SPA-2 red spanner has 2.3mm pin diameter. Due to its smaller size fits better a wider range of hole widths. It releases retaining rings on Shimano and Campagnolo crank bolts and the adjusting cone on most freewheel clusters.

A very interesting repair suitable with this tool is the removal of certain type of non-serviceable freewheels that don´t have an extraction tool option. A freewheel destructive removal method will require this spanner to get rid of the lockring.

The Park Tool cluster cone pin spanner is ideal for several repairs where a lockring needs to be removed, on self extracting or one-key release crank bolt systems or even if you need to fit/extract the guides of the BB facing tool inside the frame

The Park Tool cluster cone pin spanner is ideal for several repairs where a lockring needs to be removed, on self extracting or one-key release crank bolt systems or even if you need to fit/extract the guides of the BB facing tool inside the frame

The third and last peg spanner I own is the discontinued yellow SPA-4. It has a flat section designed to uncrew the adjusting cone of one-piece cranks. This is virtually the only repair you can do with this tool, the service of entry level cranksets on BMX’s and department store bikes.

The tool engages two notches of the adjustable left bearing cone. Rare cup and lockring cartridges BB's can also be serviced with the yellow spanner. The cup is run up to the bearings and then the lockring is secured. Note there is no bearing adjustment in this system

The tool engages two notches of the adjustable left bearing cone (2nd pic). Rare cup and lockring cartridges BB’s can also be serviced with the yellow spanner (3rd pic). The cup is run up to the bearings and then the lockring is secured. Note there is no bearing adjustment in this system. Nowadays the best use I found for it was while wrapping the handlebar of a road bike (4th pic)

At this point you might wonder what happens with the Park Tool reference SPA-3. Does it exist? Well, it does. But I haven´t seen one so far. It took me a lot of time to find a presentable picture of this tool and some information.

Blue and black peg spanners are top-rarity Park tools. SPA-3 has the ends facing one to each other. I don´t know the intended use for both tools. It seems the blue one can be used for adjusting old french bicycles headsets and the black for extracting crank bolts dust cups/retaining rings

Blue and black spanners are top-rarity Park tools. SPA-3 has the ends facing one to each other. I don´t know the intended use for both tools. It seems the blue one can be used for adjusting old french bicycles headsets and the black for extracting crank bolts dust cups/retaining rings

Meanwhile SPA-6 uses replaceable pins of approximately 2.2mm in diameter. The distance between the pins is adjustable, allowing use on virtually all hanger cups using pin holes. I have to say I do prefer fixed pegs as they are faster and more comfortable to use.

I have never faced a situation where you need to use the pin spanner wrench with such a distance between pins on a bicycle as in picture 2. Pin holes are likely to be close one to each other and thus more convenient a regular pin/peg spanner

I have never faced a situation where you need to use the pin spanner wrench with such a distance between pins on a bicycle as in picture 2. Pin holes are likely to be close one to each other and thus more convenient a regular pin/peg spanner

Swapping a Shimano Mavic Aksium freehub wheel to Campagnolo


The next repair will show how to upgrade a Mavic rear wheel that do NOT use QRM+/QRM SL technologies, just the standard QRM hub, to a different Shimano or Campagnolo freehub type. It’s also helpful if you just want to service the hub to clean&refresh with oil the pawls, replace bearings and so on.

Road wheels cassette-freehub interfaces are not universal. If a rider changes his mind and decide to switch from Shimano/SRAM to Campy and vice versa on his equipment, he will have to decide what to do with the wheels. Get a new whole wheel or replacing the freehub are the options.

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Mavic freehubs are a ripoff. An Aksium wheelset is around £150, £90 for just the rear and… £40 for the freehub! Campagnolo left, Shimano right

Mavic entry level wheels do not implement the famous QRM+ micro adjustment features, just the standard QRM design. As a result, the hub construction is totally different affecting how to precisely tweak the bearings or remove the freehub body, for example.

Mosaico tecnologias QRM estándar y QRM+

Top: QRM standard hub assembly with just a large hollow axle type. Bottom: QRM+ hub diagram that implements and axle end and a screw type axle

If you type on YouTube Mavic freehub removal or Mavic freehub service you will come across with some videos about how to dismantle it. But nobody has considered to do it with the cheapest version of the FTS-L hub, or at least I have not seen it.

In this year 2013, Mavic offers three road models (Aksium S, Cosmic Elite, Ksyrium Equipe) and one off road (Crossride models for 9mm axles) with the cheap hub and axle version.

Mosaico bujes sin tecnología QRM+

Aksium S, Ksyrium Equipe, Cosmic Elite and Crossride QRM standard wheel freehub

The procedure to take apart the freehub is similar in all of these wheels. Even if they belong to different seasons. Mine is the Aksium Race model sold during 2010-2012.

We can recognise a QRM standard hub wheel if there are not small holes to fit the Mavic specific hub tool in the left flange of it. Otherwise you can spot a 17mm hex nut on the right axle end. On QRM+ this nut is circular.

Mavic SL

Mavic R-Sys rear wheel

We need a stiff/long 5mm hex wrench and one 17mm hex combination wrench for the freehub body removal.

Park Tool 5mm P-handled hex wrench and 17mm socket type tool. It appears 15mm engraved but in the other side is also a 17mm one

Park Tool 5mm P-handled hex wrench and 17mm socket type tool. It appears 15mm engraved but in the other side is also a 17mm one

Fit the 5mm key inside the axle. Grab it with your left hand and keep stationary the axle. Turn only counterclockwise the red tool. Make sure you fit the wrench straight not to damage the nut. If you use an open end spanner it is likely to happen that the tool will slip under preassure. My advice is to get a combination wrench where you can hold the nut in all of their 6 sides with the box end of it.

Removal 1

Undo with your fingers the nut once is loose and keep it in a safe place. A magnetic parts tray is perfect for wheel repairs.

Shimano M10 freehub units need a specific spacer to fit 8/9/10 cogsets compatible with Shimano or SRAM systems. Remove it to have better grip while you are lifting with your fingers the base of the hub body. Do it slowly. If you are lucky none of the two pawls will pop out.

Removal 2

The last picture tells that one off them did not stay in place. Nothing mayor as you will have to double-check them after swapping over the bodies

By the way, the removal and installation process of the Campagnolo ED10/ED11 freehub is identical to the Shimano M10 version.

After taking off the freehub body clean the inside and the pawls. You can use light mineral oil. If you are desperate lube it with chain oil but remember to clean it regularly.

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. In my case everything was spotted on as the wheel has only spinned for 500km

Notice about the existence of the washer in the next mosaic. It is in between two bearings, the one inside the freehub in the axle end and the one in the hub shell that appears in the picture. I reckon it has the right dimensions to fit the width of the bearing units. We need it to remove any undesirable play.

Fit both pawls securely. At this point, choose the freehub wanted.

Installation 1

Never install the new freehub without the washer. It must be fitted like in pics 2 and 3

Compress both pawls with you left hand so that you can slide in the freehub body with the other one till the end. Then thread the nut back.

Installation 2

Use the same tools to secure the hex nut properly to10Nm by fixing the blue one in place and turning the red one clockwise

After all we have the wheel in working order. This repair should take around 5 minutes. The time necessary to grab the tools.

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Mavic Aksium Race 2012 with Campagnolo ED10 freewheel

The new wheels in the 2013 range feature a new axle size and thus a different freewheel bearing dimension. On these wheels, freewheel bearing has an inside diameter of 9 mm (instead of 8 mm on earlier models) and the freewheel bearing protection cap is silver (instead of black on earlier models).

The old freehubs M10 M40592 and ED10/ED11 M40591, with bearing diameter of 8 mm and a black bearing protection seal are not compatible with the 2013 range.

The new models HG11 30871101 and ED11 30871301 feature both Shimano and Campy 11 speed cassette systems. A shouldered washer is included in the freewheel kits to ensure the compatibility of these freehub bodies with wheels marketed prior to 2013.

2013 wheel range 9mm bearings

Discard the old washer and fit the new one provided in any type of hub (QRM, QRM+, QRM SL)

It must be used instead of the flat spacer M40066 to install these new freewheels on the old wheels, whose axle (QRM standard hub) or axle end screw (QRM+ or QRMSL hubs) have a diameter of 8 mm.

Sun Ringlé Dirty Flea front hub inspection


A friend of mine dropped few bits for me to build a new 29er wheelset.

Before the lacing process I had to keep an eye onto the front hub as one of the bearings had popped out from its original location and as a result the axle was moving back and forth. Time to take a look at a typical modern CNC hub that uses industrial bearings.

The tools you need are very basic. You will find these sort of hubs are even more simple than classic cup and cone units. The homemade bearing press consists on a threaded axle, washers and nuts. It is operated by adjustable spanners.

To service a rear hub you only need a couple of 5mm allen keys and wet lubricant on top to service the freewheel

To service a rear hub you need a couple of 5mm allen keys, a circlip plier and wet lubricant on top to service the freewheel

The first thing to do is pry out the end cups from the axle. I did with my nails :mrgreen:. Now the bearings are exposed, tap any side of the axle ends gently with a mallet or rubber hammer. Bearings are pressed inside the hub shell, that’s why we need to tap. A much more clever method like a bearing puller won´t help because there is no room. After tapping, the oposite bearing and axle will come out together. Take apart bearing and shaft. You are going to fit the axle inside the hub and bearing bore again to take this one off the same way.

Full front hub dissasembly

Full front hub disassembly. Notice this hub comes with a 9mm axle type

As you see, the axle supports the fork in their 9mm ends and is also perfect to remove bearings because it has a barb that protudes a little to push out the bearings. The 6001RS bore is 12mm, quite uncommon by the way if you are planning to look for them in a hardware shop.

You can upgrade the front hub with ceramic or hybrid rollers, but in my opinion it does not worth the price. It is possible as well for silly money to convert the hub to a 15mm Thru Axle. In that case, new size bearings and caps are mandatory.

sdf

15mm axles are easier to produce and at the same time noticeable stiffer

Checking that everyting was OK and after cleaning the shell I proceeded to put the parts back together.

Because bearing’s cage are made of steel and the hub from aluminium, I applied some anti-seize compound sparingly to the hub to avoid galvanic corrosion.

dfg

Finish Line copper based anti-seize paste

My cheap homemade press is essential not to screw up bearings when fitting them back.

I’ve got lots of washers to play with different bearing sizes

Once one of the bearings has been installed we can fit the axle. Thankfully the axle doesn´t go so tight inside the bearings as the outer race of them do against the hub. With just our fingers we will manage to insert the axle to the bearing that has been already pressed and then do the remaining one, this time without pressing.

IMG_4806

At this stage there is one bearing left to be put on

Without the possibility to use the homemade tool anymore, washers and surprisingly helpful spanners will  ease the task of fitting the last bearing.

sdfsf

The hole of both spanners are perfect to tap the end caps safetely by buffering the 9mm axle ends

With only two washers on hand I decided to use the spanners to conceal the axle as I did with the washers on the other side of the hub. Otherwise the bearing would not go in.

Remember the axle middle section barbed design is made so that it helps to pop out bearings and hold the inner roller exactly at the place the stepped wall machined shell stops the outer bearing race. We start off fitting with our hands the bearing carefully so that it goes straight, and finally we put on the end caps and washers. Tap on top of the pile (picture 4) until you notice the bearings reach their final position. Washers will push the end cap, and this one, will do the same with the bearing. If we use enough stack height to hide both axle entries we should end up after tapping with both bearings inserted till the end.

dfg

This is a good weight for a front disc hub. Not a extreme light part but perfect for a bombproof wheel

If you’ve ever wondered how is it the Sun Ringlé Dirty Flea rear hub I will show you:

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Yes you are right, the circlip is missing and the splines sheared off

We are done!

Bromtpon Eazy Wheels


Replacing the factory wheels was the first repair that came to my mind when I got the Brompty. Although I did it long ago, I have saved it for last within this saga of Brompton repairs because the result is not satisfactory. I would say work in progress 🙂

Factory rollers vs. Eazy Wheels

Factory rollers vs. Eazy Wheels

By installing the Eazy Wheels you have the added advantage of being able to pull the bicycle along on the ground. Stardard wheels are just simply a shame and won´t work.

I love the idea of the versatility of a Brompton

I love the idea of the versatility of a Brompton

Good, I have no more to carry mine everytime I go walking with it when commuting, I thought. But the reality is that your bike needs also a rear carrier, or Brompton mudguard at least, to support parked mode and wheel it along. Otherwise the Eazy wheels by themselves won´t make any difference. I can’t believe I didn’t figure it out until I put them on. Well, at work I never needed to pull/push the bike around :mrgreen: .

Eazy_wheels_4_close_up

Tyred rollers with industrial bearings can also be fitted to the rear rack

A rubber bung, fitted to the bottom of the seat post, can be used as a brake to prevent unwanted rolling.

Full kit

Eazy Wheels full kit with rubber thingy

My Brompton does not have a rear mudguard that will add the extra wheel for stability, or what it could be even better, a rear rack that comes equipped with two wheels improving the handling when it is half-folded.

IMG_4666

Bikes with no mudguards/rack but Eazy Wheels installed, are as stupid as mine looks in the picture

Not everybody need to enable this function. That is the reason it is offered as an option when placing your order. In that case you will have to pay on top 20 quid for the better quality wheels, and another 50 quid for the pricey mudguards or 100 quid for the Version R of the bike (mudguards & rack).

The installation of the wheels is so straightforward… nothing to say about it. What a drag!

Brompton Y trigger


Throughout Brompton three speed models history the bikes have been equipped with Sturmey Archer or SRAM internal gear hubs (IGH). The one to service has a SRAM 3 speed gear hub combined with a Sachs Torpedo shifter that operates the gears.

Sachs Torpedo and Sram Torpedo

Sram owned Sachs at the end of the 90’s. Components were relabelled (right picture)

After years of use there are no signs of shifting smoothness at all. The main reasons are rusty cables and a tatty Torpedo unit that needs replacement.

Fortunately the better functionality of the original Brompton trigger, and the fact that can be either used with Sturmey Archer or SRAM 3 speed hubs, will ease gear shifting for peanuts (£12.75 plus gear cables).

IMG_4589

Brand new in package. You can reuse the old clamp to fit the new trigger

Sachs Torpedo vs. Brompton Y trigger

IGH control components installed in the bars are very basic as a rule. In the Torpedo’s design the simplicity is carried to an extreme. It looks like an old downtube gear lever but clamped in the handlebar instead. It works in friction, due to the index mechanism is incorporated in the hub. With Sachs Torpedo thumbshifters you will only notice gear changes in your legs because this Sram internal hub gear is very silent unlike Rohloff hubs, for example, that emit a loud click each time you change between gears.

The Y trigger, besides winding the cable, incorporates a design that simulates the ratcheting system of a SIS shifter thanks to a pawl leant against a stepped inner wall. It is different however, as you can tell some play of the lever when you move it slightly back and forth. It reminds me of the Rohloff twister which must be setup with some slack. Now when you rotate the thumb levers you will listen to a reassuring snap noise that confirms the gear has been engaged.

IMG_4623

Brompton control trigger has two operating arms so that it can be reached when is in the farther position.

With regard to how conventional indexed shifters work vs. IGH shifters remember that all internal gear hubs require to fully ease pressure on the pedals when operating the shifters. Geared hubs allow users to change gears if the bicycle is stationary, just ease the pedals slightly backwards and the gear will be selected for when you start off pedaling again.

Sturmey Archer 3 spd. vs. SRAM 3 spd. hubs

Both gear hubs surprisingly look and performance the same.  Let’s see a SRAM unit:

Old fashioned IGH shells always bring to my mind the image of sweet corn cans, don't they?. :mrgreen:

Old fashioned IGH shells always bring to my mind the image of sweet corn cans, don’t they? :mrgreen:

As far as the cable attachment and cable tension are concerned these two hubs have similarities and can receive the same shifter. A new trigger installation will be a straightforward task in both cases. The differences start when the gear cable leaves the specific Brompton cable pulley assembly (CPULA):

Forom the point of view of the user, the pinch bolt and chain rods are the only difference

From the user’s point of view, the pinch bolt and chain rods are the only differences

Sturmey Archer system have a rod that goes screwed in to a barrel (B) with a lockening nut (N) that indicates the final point where rods are connected establishing cable tension. In Sram hubs the threaded rod shown below engages easily by pressing the tab (C) of the plastic adjustor A. SRAM has a more solid system (I’ve seen some snapped Sturmey Archer anchor bolts) but it is missing the tension reference provided by the nut.

The down chain must be completely screwed in before setting connecting the rod and pinching the gear cable to the plastic adjustor

Note that the gear indicator chain must be completely screwed in to the hub before connecting the rod and pinching the gear cable to the plastic adjustor A

Shifter installation

The manual for the Brompton Y trigger can be downloaded here.

I’m not going to explain the entire process. In that case follow the instructions. I want to focus and highlight those features that make Brompton parts universe so particular.

The first surprise (and thankfully the only one) was something as common like a gear cable. I knew 80% of Brompton parts are manufactured solely for its design, but I was not expecting a cable to be a problem. I should have inspected the Torpedo carrier first, the narrow groove hints that the head of the cable is smaller.

Hooked carrier conceals a very small cable end

The double hook conceals a very small cable end

My last hope was looking at the Brompton trigger, but a regular cable did not suit as well.

I stripped the whole trigger unit to show that the goes does not go fully home

I stripped the whole trigger unit to show that the cable does not go fully home

The solution was to grind away the excess of cable end so as to ensure hole fitting:

File the tip squarely or if you prefer finish the cable with just two flat sections.

File the tip squarely or if you prefer finish the cable with just two flat sections.

The original cable for these shifters look like this:

From left to right: conventional gear cable (Jagwire), Campagnolo and small headed Brompton shifter cable

From top to bottom: conventional stainless steel gear cable (Jagwire), Campagnolo and small headed Brompton cable (it’s red!)

You don´t need to disassemble the trigger to proceed with a cable or shifter change. If so it will give you an idea that 10-15 pounds items cannot be complex.

The parts are made of plastic. The splined clamp will allow any angle positioning

Inner parts are made of plastic. The splined clamp will allow any angle positioning

To insert the cable select middle gear and slightly push back the lever as I do with my fingers to make visible the hole.

IMG_4637

Remember that you do not need to remove the top cap of the shifter to pass the cable. And do it with the trigger installed on the bars if you wish.

Once the end of the cable seats in the resting position go back to top gear, where the cable is not pulled.

Trim the housing, introduce the inner cable inside and gently remove the slack from the rear frame pulley assembly.

Unfortunalety ferrules are also specific and none were used. I hope bare cables don´t slide inside the shifter.

Unfortunalety ferrules are also specific and none were used. I hope bare cables don´t slide inside the shifter.

Then attach the cable to the adjustor A in SRAM hubs or anchor bolt in SA mechanisms and cut the cable. Fit a cable crimp to prevent fraying.

To close the system connect the down chain until cable slack is almost removed.

IMG_4615

Feed the grooved end B of the gear indicator chain into the adjustor A until it is just not loose. Observe you are not pulling the indicator chain out of the axle at all.

Don´t go forcing too far when fitting the chain inside the plastic device. The secret in SRAM hubs is to take up the slack of the cable in top gear by pulling it softly leaving 5mm side-to-side movement at D-D (see black and white cable attachment diagrams). In Sturmey Archer hubs the axle nut has a hole to verify gear alignment. In middle trigger position, the chain end should be leveled with the axle. Adjustment is carried out by turning the barrel B to obtain correct setting. Relock the nut N to remember cable fitting. Next time, when you have to take off and reinstall the rear wheel, no tweaks need to be done in the cable tension.

In my bike the cable is just slack in top gear with the Brompton Y trigger. Otherwise the shifter pawl would find the cable taut and difficult to step back along the stepped trigger cage.

Before, when the Torpedo lever was installed, I adverted a tighter cable in third gear.

RIP :)

RIP 🙂

It is rewarding when every trigger click corresponds the hub gears. Job done.

Brompton brake levers and cables replacement


I’m on a roll :mrgreen:. Second repair this week for the old Brommy… and still planning more upgrades.

It’s now time to get sort out the dodgy brakes by replacing levers and set of cables. Don´t be surprised if I tell you old Brompton brake levers have very poor braking power and quality construction. They are made of cheap materials and lack of spring return. Very nasty indeed.

1999 Brompton lever

1999 Brompton lever

Because my budget is low I decided to install a pair of Tektro levers suitable for the actuation ratio of the side-pull calipers that came originally with the setup. They get on well with u-brakes and road type calipers, such us side-pulls, dual-pivots and so on… and not compatible with linear pull brakes.

Cast aluminum Tektro lever. It's not compatible with linear brakes

Cast aluminum Tektro lever. Clamp bore 7/8″ (22.2mm)

These particular levers are found on many reasonably priced BMXs, and because they are small, match perfectly with Brompton tiny bars. Sure not the best choice but they do the job. Better anyway than any brake lever made by Brompton until the new 2013 models were unveiled.

Left: former brake lever Right: 2013 design

Left: former brake lever. Right: 2013 design

There is nothing much to be said about the brake cables. Then again, I decided not to use Brompton spares and go for cheaper inner and outer cables. The original housings are known to be more flexible to accommodate sharp radii when the bike is folded and also more durable. With dry weather the difference should be negligible.

I’m not bothered about getting dual-pivots. Old side-pull brakes still work fine despite superior dual-pivot design. Original Brompton’s calipers are pricey, £65 the brakeset. An alternative would be the Shimano R450 57mm drop calipers. Even tough, I’m really tempted to get new ones. 2013 bikes must brake amazingly with new aluminium brake levers, machined double walled rims, dual pivots and better pad coumpoud.

IMG_4787

Final result

A quick wheel truing and brake pads adjusment brought the service to an end.