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Entrance off Howard Hunter Avenue, St Johns

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Grease/Lube Parts
|The Drive Train | Nuts and Bolts| Tuning And Adjusting  | Buying A Bike 
         
Bike Bits
        

 


Has your rider grown out of their current bike and you don't know what to look for?

Well click on this link and have a read Buying And Setting Up A Bike


Bike Mainteance
    

It's no secret that having a well maintained bike helps your riding. If you've got loose parts, or bearings that haven't
seen grease in years, your bike isn't going to ride nearly as well as it could if you spent some time on it. There are
five steps in all but hey! you will need to stay tuned for them all.

Check For Wear

It sounds basic, but a lot of people have found cracks in their frame or forks just through cleaning their bike. If it's
been awhile, go over it with a rag and check around the welds. And don't think a pair of cracked forks will hold
up for one "more run" - they never do.
                                                        
Check the tires and especially the sidewalls. If you can see the tire's threads, you're long over due for some new rubber.
Get to your local shop and replace the tire before you spend money replacing both the tyre and tube.
If you're planning on hitting a race, check the grip ends, If you can see the handlebar poking through, you're either due
for new grips, or at least a set of bar-ends.

Check out your brake cable - if the end of the cable is frayed, cut it above the frayed part and cap it off with a spoke
nipple. Your ankles will thank you for that. 

Grease/Lube Parts                                        Top

You can save yourself a lot of headaches and increase performance if you take the time to lube your chain and the nuts
and bolts that come in contact with other metal parts. For instance, take your stem bolts out, clean them and apply a
little grease before screwing them back into your stem. They'll thread in easier and won't rust - that alone should be
incentive enough.  Don't forget to lube the pedal spindles where they thread into the crank arms. Not only will they
thread in easier, but like the stem bolts, they'll be way easier to get off.  Take time to lube the insides of your axle bolts.
This will actually prolong the axle's life, keeping it from stripping.  If you have a sealed headset or a sealed bottom bracket,
you probably don't need to re-lube it, but if either one is un-sealed and it's been over three months, you probably need to.
Take your time. We're not going anyway. And by the way, do this more than a few days before a race.

Checking Out The Drive Train                           Top

First, check out the sprocket. If it's not straight, you're running the risk of having your chain fall off, and losing a chain sucks.
Also, if any teeth are bent or show excessive wear, you need to start thinking about a new one.  Next check out your
freewheel. If you're starting to hear noises, or it's beginning to skip (where you start pedaling and it doesn't automatically catch),
replace it quick. Both are signs that it's ready to blow.  Chain tightness is an important thing to check. The chain should be
loose enough so that the cranks can spin, but not so loose that you can de-rail the chain with your fingers. Also, while
you're checking the chain's tension, check the links and make sure none are bent or about to break. When a chain
snaps, it's not pretty.

Check Nut And Bolt Tightness                          Top

Take a second and go over all the nuts and bolts on your bike. it won't take more than five minutes, and if you find a
loose bolt, you potentially just saved yourself a lot of pain. Don't forget the micro-adjust bolts under your seat, the
crank arm bolts, and the brake lever. All of them should be tightened to the point where you can't move any of the
parts they hold.  Spoke tension is also important, that's what keeps your wheels straight. If your spokes are loose
take a spoke wrench and give each one a half-turn. Turning them equally is the key to keeping your rim straight.

Fine Tuning And Adjusting                                  Top

Once everything has been cleaned, greased, and tightened, the bike should feel solid. The bars should feel
comfortable and the seat should be low and out of the way.  Now is the time to air up the tires. When you
get to the track it only takes a second to let air out, so put enough in so that they roll as fast as possible
Last but not least, give the brakes a squeeze. If they are mushy, take the inner wire out of the cable housing and
lube it so that it slides back and forth freely. also, bending the tabs behind the brake arms will add some new spring
to your arms.  The only think left now is the test ride. Give it some good, hard cranks to see if anything moves.
If not you're reading to go. Have fun.

Buying And Setting Up A Bike Correctly                     Top

                 
        
The following is a general guide to the buying of a bike If you are buying a new bike, make sure you are getting
a BMX race bike...Many shops have heavier freestyle bikes and salesman are only interested in making a sale.  
Two retail shops where staff know about BMX are Hot Cycles, St Heliers (Roger Stephens) and Bikes Direct
Papatoetoe.
If you are buying second hand at the track, it is the old story of buyer beware. Check out the machine and pay
particular attention to the bottom bracket bearings and the wheel hubs. Estimate how much it might cost to repair
things that are wearing out.  If you are at all unsure of anything, then please make use of the wealth of knowledge
that is in the club.

Frame Sizes                                         Top

  • Riders on big frames are not going to perform
  • More weight means less speed
  • Bike frames are like clothes, they have got to fit the wearer
  • Steel frames are too heavy alternatives are chromyl or the dearer alloy. There are a few very expensive titanium
     frames around, but from observation a good rider on an alloy frame performs just as well.
    • Suggested frame sizes for ages are:
      • 6 & under Minikin
      • 6 to 8 Mini
      • 8 to 10 Junior
      • 10 to 13 Expert
      • 13 and over Pro frame, which themselves come in different sizes


    Fast growing kids might need to go up a frame size earlier, while scrawny weeds will be able to stay on a smaller bike longer.
    Once the riders knees start hitting the handlebars it is time to get a new frame. Short-term measure to finish the
    season, a longer headset can be fitted to put the handlebars further forward.

    Crank Sizes                                       Top

    Long cranks might produce a lot of power once they are wound up. But BMX is all about sprinting and the quicker the
    rider's legs can spin around the better they will perform, so shorter cranks are the answer.

  • Suggested crank sizes for ages are:
    • 6 & under 155mm or less
    • 7 to 8 160mm to 165mm
    • 8 to 10 165mm
    • 10 up 170mm
    • 175mm are only required by a full gown adult and only the very tall and very long legged adults will advance
      to 180 mm cranks


    Handlebars                                   Top

  • Rule of thumb is that the bars should be about level with the rider's belly button
  • Lower bars mean there is too much weight transferred over the front of the bike
  • Higher bars make the bike more difficult to maneuver
  • Bars should be mounted parallel with the front forks or straight up vertical.
  • If pulled back too far or pushed too far forward the rider will have minimal control

    Gearing & Tyres                         Top

    Young riders should not be pushing anymore than about an overall gearing of 54.0. 
    Common set up for the six and unders on the skinny 1 and 1/8 inch tyres is a 16 tooth rear sprocket and a 43 tooth
    front chain ring which equals 53.8.
      
    BMX is all about acceleration out of the start gate, from one obstacle to the next or out of each corner. High gearing
    is fine for a high top speed, but your rider doesn't get the chance to wind it up on a BMX track.  There is one vital
    ingredient with these lower "spinner" gearings, the rider still has to be prepared to pedal as hard as possible.  The club's
    teenage riders achieved success on other Auckland tracks on gearings of around 54.0, which is also suitable for all the
    other tracks in the top half of the North Island, apart from North Harbour, where you can go up one tooth on the front
    chain ring, to say 16 X 44 in the example.

    Hamilton Indoor meeting also needs a gearing change, with the very short straights and hairpin corners, which need
    even more acceleration. If the bike has a flip flop rear hub where you can change the rear sprocket size and also fit a
    14 or 15 tooth rear sprocket, more combinations are available.

    Staying with a gearing around 54.0 to 54.5 right through to 13 or 14 years is recommended. 
    Some of us, who like playing with bikes fit a lower "spinner" gearing of low 53s for club nights and minor meetings to
    help promote more leg speed and as a training exercise. Then the "race" gearing is only fitted for the major meetings.

    Watch Scott Hosking, Waiuku and Shaun Thompson, Cambridge. Both riders pedal furiously on spinner gears with
    very good results.

    The following gearing examples are all for 1 and 1.8 inch rear tyres, which should be used on all frames up to a junior frame.  
        
    15 X 40  = 53.3
    16 X 43  = 53.8
    14 X 38  = 54.3
    15 X 41   = 54.7
    16 X 44  = 55.0
    14 X 39  = 55.7
    1 and 3/8 inch tyres        
    15 X 39  = 53.3
    16 X 42  = 53.8
    14 X 37  = 54.2
    15 X 40  = 54.7
    16 X 43  = 55.1
    14 X 38  = 55.6



     As you can see, different sized tyres mean different overall gearing. If you have a bike with 19 inch sew up tyres,
    the gearing is different again, as is the case with the wider tyres from 1.5 inches upward used on the Pro sized frames.

    Wider tyres create more drag and less speed. Changing to bigger tyres is only necessary when the current ones start
    to slide out. If the rider is getting a lack of traction, make sure the tyre has a good tread first, rather than simply getting
    a wider tyre.  You will probably find the need to fit a wider tyre on the front of the bike first, for better turn into corners
    and to stop the front end sliding or washing out.

    Tyres should be pumped up as hard as possible with a hand pump. Do not pump to the maximum recommended
    pressure, because once they heat up, they tend to explode and blow out! A good hard tyre and tube should not
    puncture. Always look for two nicks in the tube where it has been pinched against the rim!

    Cruiser                                               Top

    If you get into this class, the overall philosophy is to set up the bike just like a 20 inch. Same gearing same crank
    size, because the same legs, heart and lungs are powering the bike.

    Cruiser bikes tend to be a bit heavier and not as maneuverable, so the idea is to make them as "small" and light
    as possible.
                   

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