Kona bike ute miniute brakes

Some cyclists feel unsafe with brakes at bit spongy the cause of a trend towards hydraulic brake bikes. Most of us never do like slack pulling up efficiency on any bike anyway. The cause is often by DIY ( do it yourself ) reassembly producers.

Fixing sloppy Kona ute and miniute brakes the manufacturer chose a mechanical disc brake brand Avid BB5 for their ute and mini ute cargo bike range. It is a mechanical system basically the same arrangement as any garden variety rim brake bike from the handle bar to the wheel calliper brake arm anchor points.

In dealing with the Kona ute and mini ute braking system we will be concentrating on the Avid BB5 brake system. When you squeeze the handle bar lever only one pad is pressed against the Rotor ( disc ). The opposing pad is fixed. The design means efficient breaking is ninety per cent is the adjustment of this fixed pad.

Slack braking is felt when this pad is adjusted to far away from the rotor. It doesn't press it properly the opposing pad pushes over the rotor potentially distorting the disc. Angled inner wire cables at the brake arm wheel end is also a cause. Angle and bends causes slack spring force to open the pads away from the rotor properly. The pads are half dragging on it.  A sign of this is a disc with a ridge cut round the circumference of the rotor. Comparing new disc brake bikes is a clear initiation of what rotors should be.

Examining the inner wire cable anchored on the brake arm of rim and mechanical brake bikes at bike shops the inner wire cables are always straight. They are not slopping at any angle a clear initiation of what the inner wire cable should be anchored like.

If the wire cable is at an angle the inner cable needs to be disassembled from the brake arm, relocated so it is as straight as new bikes are. Missing inner cable end caps on the tip of the inner wire cable help cause fray problems when you come to reassemble the cable. You will always observe theses on the ends of the cable with all new bikes. They stop the ends of the wire cable from becoming fayed. They are an important anti fray device. Clamping down the anchor bolt without them in the finally assembly only helps to fray the end of the cable more.

 It is often a reassembly mistake to apply wrapping a hook or eye round the stem of the bolt technique because the tightening distorts the cable crushing massive kinks it and breaks the individual strands leaving frays there rendering the cable beyond any safe use when you need to disassemble the cable again during regular routine maintenance  or repair at some other date.

Examining new rim and mechanical disc brake bikes is vindication standard lock jamb is quite sufficient.

If the fray is minor with a missing anti fray tag you will have your work cut out for you with a lot of time consuming fiddling trying to avoid making the fray worse when it comes time to reassemble the cable. It's always recommended to fit new end before tightening down on the cable.

You will need an anti fray cap, and a meathead to clamp it on hand before you're ready to assemble tighten the cable down. If the tag is still connected you should have no problem. However you should be able to get away with minor frays if at the tip. But the bigger the fray the bigger the problems you will have. Replacing the inner wire cable and trimming frayed tips, a decent pair of side cutters for a clean snip off  is important. Any other meathead frays the cable making things worse.

Adjustment

Adjustment is provided on the caliper bake arm and handle bars. If the handle bar adjusters are adjusted at maximum of close to it causes a fair bit of bending stress on the threads when squeezing the brake levers striping the adjuster threads. Squeezing takes it's tool. So too to a lesser extent the adjuster on the caliper.  To prevent and solve this problem problem screw the adjusters all the way back to nil. You need to readjust the bake arm anchor bolt position.

The bike can either be left up right on it's wheels or turned upside down resting on the seat and handle bars it's up to you. Professional workshops have bike stands everything chest height both wheels off the ground. In a backyard situation with the bike upside down the wheels at lest are free to rotate when adjusting the pads to the disc. ( Or the rotor ).

An Allan key unlocks the anchor bolt holding the inner cable to the caliper brake arm. The arm will spring back to maximum distance.

Make sure to locate the wire so it going straight into the adjuster. Depending whether left or right handed and looking at the bake arm the bike upside down or if chosen the right way up, pull the tail of the wire to maximum taking up the slack and with the other hand free to push the bake lever moving the pad close to the rotor.

Give a little extra to compensate for the taking up slack cables tend to do when retightening. You will have a bend in the cable again bringing you back to square with effecting brake performance again. Not only that but causes extreme maximum handle bar adjustment problems again. Don't allow run out of adjustment or every time you squeeze the handle bar levers or will stress the threads again. Leave the handle bar adjusters screwed right back to nil. So to the caliper brake arm adjuster.

As you finger tight to hold it letting it free you will observe the cable takes up the slack pulling the extra closeness of the pad away from the rotor. Turn the wheel round to check you haven't over compensated for cable slack movement the pad is too close to the rotor. If it is a bit close for your taste you can fine tune from here. Fine tuning is the key to efficient braking. Undo just enough you can slip the cable a bit a retighten enough and double check on the wheel is free to spin.

Spin the wheel gripping the handle bar levers so the wheel jambs instantly to a stop. Remember to bear in mind all bike manufactures can't afford to allow severer brakes specially the front wheel in fear of back lash law suites riders going over the handle bars because the form wheel because their models front wheel locks up. It is the reason for criticism for the B55 not very efficient. As you hold the lever the wheel should be jammed in position. If this does not happen follow the text step

Turn you attention on the spoke side of the caliper. In the center is Allen key bolt. This adjustment adjusts the fixed brake pad. An Allan key through the spokes turning inward adjusts the fixed pad towards the rotor and screwing outwards away from it. Screw inwards finger tight on the rotor squeezing the handle bar lever checking the wheel is jammed by the pads.

Next gently unscrew outwards a little so the wheel is free to turn and spin freely. To far out will cause the spongy braking problem all over again. When the handle bars are squeezed you can actually drag the wheel against the squeeze of the handle bars. Adjust gain retracting back inward a bit. When you squeeze the handle bar lever again the wheel should suddenly jamb stop and can't move while the brakes a squeezed. When you release the levers the wheel will be free to spin freely.

When satisfied don't wrench the maximum tight the anchor bolt or you will start the processes of striping threads. Just a light wrench tight is enough.

When adjustment like this is carried out the original adjustment is disturbed and the brakes have to be run in again. This is usually done in time during normal braking procedures while riding. A popular trick to help hurry up the processes is a bit of sanding on the pads. This is usually a bit of a discretion on your part if the pads look a bit to warn down a bit for that. It is a decision processes based on your own judgment how much they can take.

As you use your bike you will notice braking power is satisfactory even great. Never the less in time you will experience a slack growing. It is a normal sigh of time for the routine maintenance procedures of adjust the slack cause by the normal ware stretching of the inner wire cable and on the pads.

After a while when the pads get to be a bit thin noticeable adjustments of the brakes the caliper brake arm gets close to the adjuster as the brake pads get closer and closer to the rotor eventually there will be no more margin left left in the pad surfaces causing the inside brake arm lever mechanism from working properly to work the moving pad. Time to replace.

Replacing brakes

When you come to remove the cover small parts can easily fall out and get lost. Or at lets spending all your time looking for them that could fall anywhere. It pays to put a catcher tray in direct line the parts may fall caching them so you don't loose them.

You don't need to remove the inner cable from the caliper anchor bolt. This can be ignored. Instead concentrate in unscrewing the fixed pad adjuster bolt out as far as it can go. You will find when you remove the wheel the pads won't interfere catching on the rotor. The wheel will come off just like that. The same Allen key that fits the cable fixed adjuster will fit the two bolts on the wheel side of the caliper. Don't be shy to put some weight on them to undo. But don't be rough unscrewing because of the aluminum threads. They must be with drawn out dead straight.

Once the bolts are withdrawn the cover comes off, one or both pads, along with the spring may fall into your catcher. Remember you are handling the brake pads from now on so your hands should be pristine clean to insure you don't transfer oil and crease to the oil absorbing pads and rotor.

Examining the spring is a “V” shaped steel spring as seem in the left picture each tip crumpled each end a "u" shape hook that fits in a slot in each pad. The spring is effectively sandwiched between them.

Notice the hole in the center of the pad. This refits to the corresponding peg in the covers. Make sure you reassemble the pad hole in the corresponding pegs in the caliper covers properly.

Reassembly is tricky as it is a bit fiddly. Fit a pad color side into the corresponding recesses in the caliper cover fitting the spring in the corresponding pad slot as shown by the left picture. Make sure the center hole is fitted in the peg properly

Correspondingly fit the other pad color inwards the cover recess guiding it hooking the tip of the spring into the hook in the slot of that pad.

Line up the cover to the threads. Careless fitting of the two bolts into theses threads here is the major cause of stripping the caliper threads rendering the bolts useless. Screw the bolts carefully dead straight with only fingers. Never force them with the spanner if they feel a bit tight. Carefully withdraw and jiggle the cover a bit so the bolts can finger screw with out any grinding tight feel freedom of movement.

The final tighten of the bolts is another area will strip the calliper threads. Don't wrench thinking maximum tightness. A light tug they can't and no more.

Adjust the brake arm the brake pads close with one hand sliding the brake arm up the inner wire cable while holding onto the tail of the inner wire cable adjusting the distance of the brake rubbers of rim brake bikes. In the case of a disc brake bike is a rather hit an miss a friar but can be judged pretty closely by eye eyeing down between the crack of the caliper the disc runs between. You will feel a bit of a struggle against the spring  tension witch inevitably makes things difficult. Keep a firm tension on the brake arm.

Once you have the brake pads close enough you need to hold pretty steady against the spring tension or you will loose the adjustment because the brakes springs tend to spread creating to much slack in the inner cable when you tighten the nut. You will be back to square one with spongy brakes. Make sure the tension of the spring doesn't do that. One trick helps compensate.

Adjust the brake arm a little more closer up. By the time you tighten the anchor bolt enough you can let go and the spring tension will move apart slightly in compensation and you can tighten the nut.

A bend in the inner wire cable at the anchor point on the caliper lever can cause spongy braking. If this is the case the cable has to be disassembled and repositioned so the cable is going straight into the cable adjuster.