Posts tagged #Maintenance

Hydraulic Brakes. Make Them Like New Again.

Hydraulic Brakes are one of those components that everyone wants to have and then, when things go wrong, they bail and become anti fluid and pro cable actuated. I will admit that there are some good cable actuated discs out there that are very good, the Avid BB7 for instance, however, nothing comes close to the feel and operation of a good hydraulic system. That is why it is a shame when people ditch them. Even some bike shops are more than happy to sell the hydro's but don't want to mess with them afterwards for service. A hydraulic brake system can be ordered as a kit, hoses attached and filled with fluid. You can always tell a system that has come this way as it will have 3 feet of extra hose in a big loop off the bar, just waiting to be snagged by a passing Moose or even a tree limb. Now sometimes this is just laziness on the part of the mechanic but often it is fear of cracking the system open. So here is a little primer on the hydraulic disc brake system...

I have already mentioned Avid above, apart from making the BB7 they also make some great hydraulic units, the older Juicy and Code plus the newer series of Elixir and Trail. All of these models are easy to service and durable apart from working very well. Shimano also make a range that are popular and again easy'ish to service and repair. Other companies that we are fans of are Formula and Hope, both of these produce disc systems that also qualify as works of art, sadly they also  have price tags similar to a minor work from Rembrandt...

So, back to my point. What do you do when things start to go sideways? Well you service them.  Below I have taken some pictures of the complete internals of a set of Avid Juicy levers and calipers. These brakes recently came to us from a customer at the Lake of the Ozarks and they were in dire need of some TLC. These brakes are very common but basically all hydraulic brake units are following the same principles, so with a spec sheet of your particular make and model you will be in good shape.

These particular units had developed one of the common issues of older neglected sets. They had developed the sticky lever syndrome. Another common issue is a soft lever which means air is in the system either through the need of a good bleed or the hose has developed a hole or an o ring has failed on a bleed port. The sticky lever however means that the internal plunger in the lever is in need of replacing or that the caliper pistons are beginning to stick and corrode. My rule is; do both, if one end is gummed up and failing the other ain't far behind.

Wear gloves as DOT fluid is not something you want to be bathing in all afternoon and a pair of safety glasses, you would be amazed at how often I have shot myself in the face with a full syringe of this stuff.

I usually start with the lever first and, with a new bag of the correct internals, start cracking it apart. Below is what you end up with, again this is a Juicy so you will have a different looking pile of bits but they will be doing the same job.
Once the lever blade is removed it will reveal the circlip that needs to be removed to slide out the reach adjust mechanism and the plunger.

Reach adjust mech is next. If yours is a more basic model this will be missing.
In this case the parts were worn
All the parts laid out ready to clean. In this instance everything is being replaced except the body the blade and the reservoir cap.
The main culprit of the sluggish lever return is the plunger unit, in the above picture it is the thing with the spring attached to it. However when you are pulling it apart you may as well replace all the bits as they are all in the rebuild kit anyway.

Once the lever is rebuilt I attack the caliper. Again disconnect the hose first. The only way to get into the pistons is to split the caliper body in half. this is achieved by undoing the three bolts. Once you have the body in two the fun begins. The way to get the pistons out of their press fit home is with the use of compressed air. You cannot get them out any other way so don't be jamming screwdrivers in there or you will damage the body itself and you will get fluid leaking out and the whole unit will become a paperweight. The compressed air does a great job of popping them out. Warning; Make sure you don't have the thing aimed at anything soft and fleshy, it will hurt...
Waiting to be cracked open like a walnut...
The main culprits in here are the quad rings (the square edged rubber washers) and the round pistons.All of which will be replaced.
Once the caliper has been rebuilt all that is left is to run new hose, to the correct length as mentioned earlier to avoid lassoing stray Moose... Also never re-use banjo fittings or crush washers. Once they have been tightened up they have to be replaced. That's it, job done. Go ride.
Good as new.



Posted on April 13, 2014 .

Square Taper Crankset Woes.

The method of affixing crank arms to a bottom bracket spindle using a square taper system has been around for many, many years now and even though we have had lots of designs since it is a method we still see a lot especially on the comforts and hybrids and anything that comes from a box store.

Because we see a lot of these cranks on the cheaper bikes does not mean that it is a bad method, White Industries make a very high end crank set that uses a square taper fit and Phil Woods produce some of the most expensive bottom bracket cartridges ever in square taper format.

If the square taper crank to bottom bracket interface has ever had a problem it has been with installation and maintenance. The basic principle behind the method is that the crank arm gets tighter as it is drawn onto the square spindle because of the tapering. The most comon issue we see is the crank arm bolt coming loose or falling out completely and the bike is still ridden. Even though the crank arm is tightly fixed onto that spindle with the bolt gone the pedaling action will break the bond within a mile of riding. Now here is were it gets interesting. People just assume that a new bolt when they get home and a wrench to tighten it up will solve it. Wrong. When the arm gets loose and you continue to ride it the square hole in the crank arm just mushrooms out. The crank arms are made of soft aluminum and the spindle is steel. Once that crank arm hole becomes deformed it will never stay put, no matter how tight it feels when tightening it back up. The only cure is a new crank arm.
This is a typical example of a crank that became loose and was still ridden.
This is what they are supposed to look like
The above are pretty generic examples of the square taper cranks that you see on multiple bikes nowadays. Below is a picture of a White Industries VBC crankset and bottom bracket. This one was recently installed on a Ti Moots road frame and made a significant upgrade to the bike.
White Industries VBC crank set in anodized black.
The bottom bracket to match.
One slight issue that you have when using the white industries bottom brackets is the choice of spindle lengths or the lack of choices. In the event that a different length is needed then the Phil Woods bottom brackets are a great alternative.




Yearly Maintenance. (The Bottom Bracket)

 This is the time of the year when the workshop is full of bikes waiting for their annual check up. Mixed in with the bikes that we see every year are the bikes that have just been dragged out of the barn for the first time in 5 years and were put up wet in the first place. Those bikes are always interesting to pull apart and really highlight what can happen to bikes that have suffered some neglect.

However it is just not neglected bikes that have problems, any bike that is ridden regularly and hard throughout the year desperately needs that overhaul before the new season starts. Recently we had just such a bike in the workshop. This bike is one that has been overhauled by us before, not yearly I think we did a frame up rebuild on it 3 years ago, however the bike always is cleaned and lubed on the outside by the owner and kept inside.

Below is a picture of what we found inside the bottom bracket shell, once we had used a breaker bar and 2 of us to get the cartridge out!


 Keep in mind that this is an aluminum frame so that is not rust from the frame itself that you are seeing however aluminum does create a powder like substance under the right conditions. This is a mixture of sweat and moisture that finds its way down the seat tube and also the cartridge itself being steel bodied can supply some rust to the mix as well.

Moral of this story is. "If it looks good and clean on the outside, it doesn't necessarily mean everything is cool inside..."
 
This is a bottom bracket tap. The threads were so damaged after removal we had to re-cut them. Not an ideal scenario but the only option at this point.
This is the material that was removed in the re-tapping.       
Posted on April 2, 2014 .

How Not to Treat Carbon

             I have written many times on the subject of carbon fiber and rarely does a week go by without someone thrusting a scratched or damaged carbon doodad under my nose and asking is it OK.  Well last week we had a bike come in for a full overhaul and prep ready for the new race season with a couple of good examples of carbon fiber that is definitely NOT OK.

             The parts in question are a carbon drop bar and a full carbon seat post. These two components are the most common to suffer abuse and these examples are the most common way to kill them. Over tightening the clamping pressure. The handlebars have been squashed in the stem to the point of cracking through all the layers on both sides of the face plate. The seat post has suffered a similar fate by being  over torqued at the seat clamp. Both these components are dead and will fail in a spectacular fashion if used further.
             If you only buy one tool in your life let it be a torque wrench.
Again, probably twice the specified torque on the stem face plate to cause this.
Carbon has been squashed so hard it has made a peg in the carbon.
Posted on February 20, 2013 .

Raleigh Competition Renovation

Recently we had a renovation project come through the doors, a 1973 Raleigh "Competition". This bike had been owned since new by the present owner and he had decided that it was time for a makeover.

Before the new paint and decal job.
What started as a simple pull apart, service and rebuild turned into a pull apart and update everything to a modern Campagnolo group and a custom wheelset.

First the frame was treated to a blast and full repaint including a new original spec decal set and three coats of clear-coat. The frame then had the lugs highlighted with gold pin striping. A new custom wheel set hand-built by myself and sporting a set of Eldon rims and a matched set of high flange polished Velo-Orange hubs.
Back from paint.

The customer wanted the build rounded off with a 10 speed compact group from Campy.

The conversion was not without its headaches and a lot of small shims and add-ons had to be handmade to get the new technology to work. However the end result was definitely worth it.

Complete and ready to go.

High gloss and gold pinstripe, classic 70s...

Posted on February 17, 2013 .

Check the Pads



Tis the season to pay special attention to your brake pads, wet conditions are notorious for embedding grit and debris into your brake pads, I am sure you have all heard that long shoooshing noise the first time you apply your brakes after riding through a wet section or a puddle, that is the sound of grit being sandwiched between your pad and rim. What happens next is a lot of that debris gets pushed into the rubber of your pads and from then on gets applied to your rim every time you brake. Now, what also begins to happen is that little pieces of your rim get chiseled off and they end up in your pads as well. It becomes a vicious circle.
                You should keep an eye on the condition of your brake pads throughout the year but especially after wet or very dusty rides. Keeping the pads free from debris makes a big difference to your rims wellbeing.
                If you do see some grit and rim material in the pads the easiest way to remove it is by buffing the surface of the pads until you reach new rubber, free from the junk. Use 80 grit emery-cloth on a small block, if you just use the cloth on your finger you will place a concave profile on the pad. Do not use sand paper for wood, that stuff will put more grit in than it takes out.
               Also periodically check the rims for digs or rough spots caused by contaminated pads. Any rim trouble spots can be addressed by carefully using a 120 grit cloth. If in doubt come see your friendly bike mechanic.
Before; A road pad (top) and a mountain pad (below), both with rim material embedded
After; Same road pad after some buffing. Good as new.

Posted on October 28, 2012 .

To Powder or Not to Powder...

          

A recent post on inner tubes "Latex v Butyl" has created interest in another of those topics which can stir passionate debate, whether to use talcum powder on inner tubes. So I shall offer my views on the subject and you can make your own decision.
           I shall state from the outset that I do not usually use powder when installing tubes. That being said I have customers that do and I have a canister of 'Johnson's' in the cupboard so, if requested, I can powder up a tube to keep everyone happy.
           Firstly, what are the reasons behind some people’s choice of using powder? Well, powder can make the tube easier to glide around against the tire when you are trying to wedge everything together. I know many people have trouble when trying to poke a tube into the tire and pinching the tube under the bead of the tire is a common problem for some. Also, when removing a tube from a tire, it is easier when dealing with a tube that was powdered. I have also heard the argument that when a tube is powdered there is less friction between tube and tire and less likelihood of failure from abrasion. Finally people see that there is often some trace amounts of powder when you get a new tube out of the box so therefore powder must be good.
            Okay, I think that covers most of the arguments that commonly get mentioned for the use of powder, now for my rebuttal.
            Starting from the bottom of the list, the reason manufacturers use powder is actually during the manufacturing process itself, it is not as some suggest them pre-powdering the tube for you. When the tubes are made the rubber becomes very hot, even by the time the process is over there is still considerable heat left. The powder is actually used on the inside of the tube so that when the tube is folded flat and pressed into the packaging the two sides of the tube will not bond together. Next time you have an old tube at hand cut through it and you will see a fine white powder coating the inside.
            Friction. I have never quite got my mind around this one. If anything you are creating a scenario to create more friction by using powder. When a tube is correctly inflated inside of a tire there really is no room for any movement between touching surfaces. Also we have all seen how a tube bonds slightly to the tire, if there was a need for any movement it would be very slight and the tube would be much better flexing instead of sliding against the surface as the powder argument suggests. And before the cries of tubes completely bonded to tires rises to crescendo, this never happens to the extent of tossing a tire away because of a tube that cannot be removed. I have replaced more tubes in my life than I have eaten hot dinners and never have I had a tube that refused to “Part Company” with anything more than a sharp tug. In fact that slight bonding helps out in another way too. When a puncture does occur, due to an errant thorn or some such, having the tube attached to the tire means that the air only comes out through the hole at that spot around the thorn, if you powder the tube and there is no bonding the air will escape from the tube into the cavity and be gone much quicker.
             Lastly, the installation. Here at least I do see a benefit for those who struggle with tube replacements. However, if you follow a set of rules such as, inflating the tube enough to give it body, make sure to get it seated up into the tire before popping the final bead on and never sticking tire irons in there, you should be fine. Most issues come when popping the last 6 inches of bead on and no amount of talc is going to help you there.

Posted on October 20, 2012 .

Sturmey Archer 3 Speed Hubs



Have been working on a renovation project this week, a Raleigh 20 folding bike. The bike was complete and looked to be in pretty good condition, apart from renewing the usual tires, tubes and cables, everything else has cleaned up nicely and gone back together without replacement of any internal parts. Back in the day they built things to last.

The Beast Laid Bare
                 As is often the case with bikes like this, I am the first person to see the inside of them since they were put together, this bike was no different and when it came time to open up the 3 speed Sturmey hub I was not sure what to expect. The hub was still working, albeit a little clunky in the changes, nevertheless I took that as a good sign. As is usual with the big hubs all the grease that had been originally packed in there had long since turned to a wood like consistency but, once all that had been chipped out of there, the parts showed very little sign of wear. These hubs never fail to disappoint, I have lost count of how many of them that I have rebuilt over the years but I have never had to scrap one.
The Gear System. 2nd gear is direct drive, 1st gear is a decrease of 25% and 3rd gear is an increase of 33% over direct. Clever stuff.

Posted on October 19, 2012 .

Campagnolo Ergoshifter Rebuild. It Can Be Done...


           Modern road brake lever shifter units are not cheap; in fact they are downright spendy. Head towards the upper range of any given companies offerings and the prices start to look like zip codes. So when we have a bike come in for repair that has a broken shifter, there are going to be tears. If that shifter happens to say Campagnolo we may need a cardiac crash cart.
So it was recently when a beautiful Colnago, lugged frame and dripping with Campy, came in for a full overhaul. All was going well until l strung new cables and found a dead shifter. The call was made to the owner and, to his credit, EMT's did not have to be called.
Torn apart (note broken index spring at top of 3rd column from right)
The good thing about Campy, actually there are a lot of good things about Campy, is that the shifter units are completely re-buildable. Shimano and Sram units can have certain parts replaced with success but I have never been totally happy with delving in too deep with them and even ones that have been factory overhauled never feel the same as a new one. However with the Campy units the end result is sometimes better than new.
Pulling one of these bad boys apart though is not something for the faint of heart and I get beads of sweat forming on my brow when I release the first spring. But, so far anyway, with some patience and some good technical drawings that l have acquired over the years, I have had great success with them and a rebuild with some new springs is a lot cheaper than a new shifter.
Back In Business...
So, if you have a set of Italian gear changers that need a service just give me a call. Hell I will even give your Rolex a spring clean too...
Posted on August 31, 2012 .

Drive Train Woes.


                Never a week goes by without at least a half dozen bikes with shifting issues. Most of the time it is an easy fix, a slack cable or a tweak of the limit screws, (see a previous post). Sometimes a bent derailleur hanger is the culprit and, occasionally, it is a simple case of 'it is worn out’!
                If we have checked all the above and it still has not fixed the problem, then chain, cassette and chain-ring wear is likely' the problem. Checking chain wear is a relatively simple procedure, there are quite a few chain checkers on the market, none of which are necessary or even reliable, the best way to check a chain is to lay it lengthwise on a bench and measure it over 3ft using an ordinary yard stick that measures 3 feet in inches. Line the center of a chain pin on the 1 inch mark and pull it taught; now look at the 36 inch mark, a chain pin should be centered on it. A new chain has its pins exactly a half inch on center, if it is not, then, how far off is it. Here is my rule of thumb on chain wear.

⅟₁₆ inch past = Fine, absolute minimal wear. If you are one of those people who like to slap on new chains every five minutes, then now would be a good time. I, personally, am not a follower of that cult.
⅟₈ inch past = Still fine, lots of wear left, however you are probably past the point of just renewing a chain.
⅟₄ inch past = Time to renew the chain, cassette and chain rings.

As the chain wears and the rollers start to migrate away from each other they wear the teeth of your cassette cogs and rings to suit their new dimension. Once the chain has reached that ⅟₄ inch mark it has done a lot of reshaping and a new chain will have no chance of adapting to the new tooth profile and the old chain will be having a hard time hanging on to the teeth in your favorite gear combinations, the ones that are worn the most, under heavy pressure. So, end result, suck it up and open up the check book…
Just recently we had a Time Trial bike in for the very problem of slipping under pressure. This particular bike had lots of underlying issues as well and ended up taking a good deal of my Sunday afternoon, however, I will not bore you with them now. The bike did bring up an issue which surfaces from time to time though, especially among club riders and weekend racers who are prone to swapping wheels and cassettes from bike to bike. After I had addressed each of the underlying problems and adjusted the derailleurs the thing still gave me a fit shifting in certain gear combinations. The chain was showing minimal wear so I persevered with trying to fine tune it, to no avail. On closer inspection I found a Connex chain, which suggested a renewal at some point, a Sram cassette of a different vintage and chain rings of a Shimano system, which was probably original equipment After talking to the owner of the bike I learned that the cassette was recently borrowed from a friend, the chain was possibly renewed by the previous owner of the bike before it was sold and the crank and rings were, indeed, original.
The moral of this story is; keep track of your drive-train components. Swapping things around on bikes that wear at different rates causes mismatched parts. Modern, high end, gear systems are finicky, hell they barely get along with each other at the best of times and, they definitely prefer to stick to the components they know. Grab the chain off one bike and the cassette from another and there’s gonna be trouble, with a capital T…

Posted on August 16, 2012 .

Adjusting Front Derailleurs.


        Had an email from a guy yesterday telling of his recent success tuning his rear derailleur, following my recent post on the topic. However, his bike also has a front derailleur...
        So, with sincere apologies for neglecting the front end, here is how to whip those doubles and triples into shape.
        The procedures and adjustments are very similar to the rear but, we do have one rather important extra step. Unlike the rear, there is not just one single point of simple attachment. We have to set the height and angle using our own judgment.
        So, what we are looking for is clearance of the cage of the derailleur as it swings over the chain rings, while still keeping it low. A gap of about 1mm between the top of the big ring and the bottom of the outer cage plate is ideal; manually pivot the cage out to get a look at the gap.
        Next we need to set the angle. As you look down onto the chain rings the cage of the derailleur needs to run parallel with the rings.
       Now you have your derailleur mounted correctly we can set the limit screws. We start on the low limit screw first.
Change gear at the rear so the chain is on the lowest gear, biggest cog. Without a cable attached to the front derailleur, adjust the Low limit screw until there is clearance of about 1mm between the chain and the inner cage plate.
       Change gear at the rear to the high gear, small cog. Here is where it gets a little tricky. You now have to manually swing the front derailleur out while turning the crank to shift into the high gear, big ring. It might take you a couple of tries, the spring on the derailleur is pretty tough. Once you get it pushed out to its stop, adjust the High limit screw to get clearance between the chain and outer cage plate of 1mm, when you are happy, release hold of the derailleur and cycle the chain back to the small ring. Attach the cable making sure that the shifter is set on the low gear or number 1.
       Try it out. If you have a slack in the cable, just take it out using quarter turns on the barrel adjuster, until it works perfectly.     
Posted on August 9, 2012 .

Tip for the Day.


     There are lots of choices when it comes to picking new cables for your bike. Galvanized, stainless, slick, we mainly use the Stainless Steel slick from Jagwire. These guys are pre-stretched and perform very well. Some time ago it became popular to coat the cables with a 'Teflon Coating'. While on the face of it this sounds like a terrific idea, like many things it falls way short in reality. Here's why: 
    The Teflon is a coating, it is put on the finished cable, it is nice and slick and I'm sure that if you wanted to, you could fry a rasher of bacon on it, all be it a very skinny one, but that coating does not like to be pulled and rubbed through housing and it starts to peel off, now we have strips of coating clogging up inside the housing and binding up the cables. 
     If someone brings in a bike with shifting problems and it has coated cables we clip them and run slick stainless with new housing. Problem Solved.
Posted on August 8, 2012 .

Hello, I'd Like A Service Kit For...

      A good part of my, or I should say Pam's day is spent sourcing parts. I am not talking about the usual everyday stuff but rather the one off wotnots and thingamabobs that are peculiar to certain brands or models.
      The two chief problem areas are;
1. Bushing kits for full suspension mtb's
2. Seal kits for older suspension forks.
      Believe me when I say there are plenty more components, even new ones, that getting spare parts for is akin to replacing a thrust unit on a space shuttle, which is probably why NASA quit flying them.
      Let's take a simple task of bushing replacement in a frame. Now when a company builds a full suspension mountain bike there will be at least two joints on it that will be required to pivot. No matter the design, something, somewhere is going to have to move up and down. This is not a big deal but whilst we need to have the movement up and down we do not want any from side to side and also, we want the pivot to be smooth and not grinding. To achieve both these aims bushing are used, either little brass units or nylon or a mixture of both on a machined bolt or link pin. The thing with bushings though, they wear out. That is where I come in. Simple you say and yes, it should be.
       A conversation with a bike companies parts department usually goes something like this;

Me;                 Hello my good man, I would like a bushing replacement kit for a "DillyWotsit 6000" please

Parts Guy;       Oooh, I'm sorry sir we stopped making those 2 years ago.

Me;                 But the bike is only 3 years old.

Parts Guy;       Like I said we stopped making them 2 years ago. We make the "DillyWotsit 9000" now.

Me;                 Cool, will the bushings on that fit the 6000?

Parts Guy;       Not a chance, but we can sell you the whole frame...

Me;                 Thank you for your time.

      And believe me it can be much more painful than that. We recently had a K2 mountain bike in for bushings, it took us two days to figure out who now owned the company before we could work out who to call. Only to be told that when they bought the company the spare parts inventory was zero. Not a few or some but squat. We made our own.
        It is not just companies that have been sold or swallowed up by others that we encounter problems, it seems that the norm these days is to faze out re-stocking spares on models that are four or more years old. They just assume by then that you will be buying a new bike. I would love to sell you a new ride every year and, some folks with the budget and a weakness for the new and shiny, do just that. But, I have a feeling that if you were told that your 3 grand race rig is toast for the lack of a 30 dollar service kit, you are going to be pissed, probably enough to switch brands. It amazes me that manufacturers do not see that. Hell, maybe they do.
        Another big ticket item on the bike that suffers from the same problem is, suspension forks. I will add a caveat here and exclude RockShox and Fox. Both these companies have bent over backwards to help me out over the years and I have never had to scrap a fork from these guys for the want of replacement parts. If only some of the others were more accommodating.
        So, there you have it, a little rant from the workshop. If there is anything you could take from this post it would be; If you are in the market for a full squishy mtb, look carefully at the linkage. If it is a weird intricate design, maybe stock up on a couple of bushing kits at the time of purchase.
Posted on August 5, 2012 .

Rear Derailleur Capacity.

     Any derailleur will work back there, right? Wrong... I have lost count how many times someone has come into the store after swapping out or, upgrading a rear mech., only to find that it now does not work properly. When I ask if the derailleur capacity matches their setup, I usually am greeted with a vacant stare.
      So, before yanking off chains and clipping cables let us take a moment to work out what you need to put back there.
      Before we do the math, (yes, there is always math), it might be helpful to clarify exactly what a rear derailleur does. I imagine most people can see how it operates to change gear, you make a gear change at the shifter and the cable that connects to the derailleur pulls it side to side and derails the chain from one cog to another, simple. The other thing it does, that is equally important but possibly not as readily understood, is to take up the slack in the chain and keep it tensioned correctly.
       Why the hell is there any slack in the chain you ask? Because each gear combination requires a specific chain length to wrap around the selected cog and chain-ring. When you select the big ring at the front and the big cog at the rear, the chain wrap is at its longest. Conversely, when on the small ring and small cog it is at its shortest. The difference between these two extremes is the amount that the rear derailleur has to be able to handle. The Chain Wrap Capacity.
        
The math;

(No. of teeth on big cog - no. of teeth on small cog) + (No. of teeth on big ring - no. of teeth on small ring) =

For example;
cassette 12-25 and crank-set 53-39
25 - 12 = 13
53 - 39 = 14
add them together 13 + 14 = 27.
So 27 is your chain wrap requirement that the derailleur needs to be able to handle.

      The way that the derailleurs are made to handle larger capacities is primarily by increasing the distance between the jockey wheels. This is often referred to as cage length and you will see terms like, short cage and long cage used to describe different models. However do not just assume a mid cage will handle what you have, always refer to the actual chain wrap capacity figure that is published with every model and make out there to be sure

       Happy shifting..
Posted on July 31, 2012 .

Adjusting Rear Derailleurs.


It seems that the temptation is great to mess with those little screws on the back of your derailleur when the shifting has gone off the boil. While I'm not suggesting for a minute that you should not attempt this adjustment yourselves, trust me when I tell you that you will not get a satisfactory result by just screwing with the, err screws. You need to follow the steps which I shall outline for you below.

Before we get to messing with limit screw adjustment I will assume that you have checked to see if your problem lies with just a slack cable, which is easily taken care of with a 1/4 turn or two of the barrel adjuster.

The picture on the right shows you the three adjustment screws that reside on your rear mech. From the top we have the B limit screw then the High limit screw and on the bottom the Low limit screw.

The B limit screw adjusts the height of the derailleur another way to look at it is the clearance between the cogs of your cassette and the top jockey wheel. Often the clearance is good until you change into the large low gear cogs and then you start to get a rumble as the jockey and chain is bumping along the underside of the cassette cog. If this is happening on your setup just turn that screw in clockwise to increase clearance. ideally we are looking for a gap of about 4-6mm. Sram works best at around the 6mm mark. Anyone using a Campagnolo system may have to search for the B limit screw, they have a few models with the screw mounted on the pulley cage behind the body and hidden from view.

If you have clearance Clarence on the jockey wheel and your problem is more on the indexing, then you need to check the adjustment of the H and L limit screws.

Firstly loosen the pinch bolt on the cable to release it. Turn the pedal to bring the derailleur to its relaxed position which should position the jockey wheel under the small cog, the high gear on the cassette. If the derailleur shoots inward and comes to rest under the big cog, low gear, then you have a low normal derailleur. These are sometimes found on mountain bike setups. Whatever you have the principles are the same and  I will cover them both. If the derailleur has come to rest under the small cog place a screw driver on the H screw, if it rests under the big cog then the Low limit screw. Stand behind the bike and adjust the screw in and out to center the jockey wheel perfectly under the above cog. As you turn the screw you will see the mech. move from side to side, use that movement to center the jockey wheel perfectly.


Now it gets a bit tricky. You have to cycle the chain through while shifting the derailleur to its other stop. The picture to the right shows it centered under the big cog or Low gear. Again stand behind the bike and use the low limit screw, for a normal derailleur, to center the jockey wheel perfectly under the cog. All the while keeping the derailleur pushed to the stop by hand, as you turn the screw in and out you will feel the pressure in your hand and see the derailleur move from side to side. Once you are happy with the adjustment cycle the chain and let the derailleur come to rest.  Now turn your barrel adjusters in and make sure that you change gear on your shifters to let all the cable out. Pull the cable taught and attach with the pinch bolt. Now try it out. If you shift at the handlebars and nothing happens at the rear then take a\ little slack out with the barrel adjuster. Try again. Keep doing this until you get crisp shifts all the way up and down.

If you are sure of your adjustments and still the shifting is not as it should be then you may have some other problems. Most common is a bent derailleur hanger, which can be aligned, but takes a special tool to do so. Come see us and we can take care of that for you. Another possible cause is a bad cable or contamination in the housing. Easily rectified with a nice slick new cable and a couple of feet of Jagwire housing. Again we can hook you up.
Posted on July 29, 2012 .

Lube Responsibly.

I spend a good portion of my days in the workshop with a thin bladed screwdriver in hand chipping away at derailleur jockey wheels  and chain plates removing great clods of greasy muck.
      It seems that riders fall into two main categories when it comes to lubing the drive-train. The "I lube every March 8th in a leap year" crowd or the " I use a whole bottle of lube per ride" bunch. While both scenario's are sad sights to behold, the latter is the toughest to clean.
      So with the hopes of prolonging some chain and cassettes lets go over correct lube procedures. Firstly let's start with a good clean, if you are a serial luber this may take a while. I use a product called "Simple Green" to good effect, available at all the usual hardware stores, if all you have is dish soap then that will work as well. Remember whatever you use as a degreaser must also be washed off as well. Just flush everything with clean water and let dry.
       Now, lube choice. So many options to choose from but here is the rule. Dry conditions use a dry or wax lube and conditions are definitely dry at present, wet conditions use a wet lube. Really though the dry lubes are so good now that I recommend using them all the time. The only time you need consider a wet lube is if you plan riding your bike up the Amazon.
       Besides the wax lubes being good at lubricating they also, being dry, attract less dust and debris. Another plus point is the ability to re-apply a second, third and probably a fourth application of lube over the top of the existing coats before having to clean the chain to start fresh. Just wipe the chain down with a clean rag and apply the lube. When using a wet lube you must clean thoroughly before a fresh application. In these dusty conditions a freshly wet lubed chain will look like a ships anchor chain after a 20 minute ride on the trail and all that dusty mess will act like sandpaper on your expensive drive-train.
        Whatever your choice of lube and, regardless of make and type, show a little restraint when it comes to applying it. Go for the delicately dripping a drop on each roller approach rather than the squirting back and forth method. There really is no need to flood the whole thing to the point of drowning it. Also, no need to squirt the cassette either, all that does is pack down between the cogs and requires digging out with the trusty flat bladed screwdriver.
        So there we have it, follow these guidelines and you will be lubed to perfection.
Posted on July 26, 2012 .