OzVMX Forum
Clubroom => Tech Talk => Topic started by: Ji Gantor on April 29, 2009, 04:30:21 pm
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This topic is to show how I put an MX tyre on a rim.
Before I do anything else I place the new tyre to be fitted out in the sun and leave it there for about an hour.
This warms up the rubber and makes it more supple and easier to work onto the rim.
Ji
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I then assemble all the tools required for a day playing with tyres.
Ji
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Check to see if your tyre has a direction indicator on it. If it does like this one now is the time to make sure that the wheel and the tyre will be rotating in the same direction. If you get this wrong you will have to remove the tyre and remount correctly.
Ji
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Now is the time to lubricate the tyre.
I use Windex because it drys fast and is not water based.
Ji
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Take the wheel in one hand and the tyre in the other and push the rim into the tyre where the rim lock is.
Make sure that the rim lock is inside the tyre beads.
Ji
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Place the wheel on top of your tyre changer or bin and with the heel of your hand push the opposite bead of the tyre onto the rim.
This sounds hard but with the tyre warmed up and the Windex this is easy.
Ji
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Remove the valve cap and the top securing nut from the tube. Leave the lower nut as this protects the tube from any sharp edges around the rim valve hole.
Ji
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Pump about 5psi of compressed air into the tube or just enough to form a crease when hung over your finger. This inflation prevents the tube from laying around inside the tyre when mounting and getting pinched between the rim and a tyre lever. It also helps when installing the tube into the rim.
Ji
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Sprinkle baby powder onto the tube and rub into the rubber. This helps with installation and cuts down friction and heat when the bike is being ridden.
Ji
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Place the tube into the tyre, valve first. Gently lift the bead up and poke the tube in all the way around making sure that the tube is on top of the rim lock. To check this push the rim lock threaded rod into the tyre and it should spring back when you remove your finger.
Ji
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When the tube is in and the valve is perpendicular to the rim place the retaining nut onto the valve stem one or two turns.
Ji
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Starting at the rim lock use the heel of your hand again and push the bead onto the rim. Work the bead on as far as you can, this is usually about half way with out to much trouble. Check to see that the rim lock is inside the beads. To check this push the rim lock in and again it should spring back when released.
Ji
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To retain the bead and free up one hand place a Bead Buddy onto the rim. This stops the bead from creeping off the rim as you work the tyre on.
Ji
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With one hand push the rim lock all the way in and force the tyre down into the well of the rim. Hold this in until you take up the tension with a tyre lever.
Ji
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With two tyre levers or spoons work the opposite side of the tyre towards the Bead Buddy. When you are within 8 inches of the Bead Buddy the tyre should roll onto the rim.
Ji
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Now the tyre is on check both the rim lock and valve by pressing in. They should both spring back when released.
Ji
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If every thing is cool pump the tyre up to about 20psi to seat the beads.
Bounce the tyre up and down on the ground to help all the components find their new homes.
After the beads are seated reduce the tyre pressure down to 15psi and screw a quality metal valve cap onto the valve. Tighten the rim lock nut to specification.
Job done !
Ji
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Top job , JI . Whats your next project ?
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The rear tyre.
Ji
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Why didnt I think of that ? :D
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YOU RIDE A UNICYCLE THATS WHY :P
PS JI WHEN ARE YOU DOING THE ENGINE THAT THE BIT IM WAITING FOR
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The engine was already done before I got it. I posted images of the bore in topic "New Parts"
The frame goes off to the powder coater next week. This means that the next job is to polish the engine because it is the first thing to go onto the frame when it gets back.
Ji
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OK I WILL HAVE A LOOK ;D
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THAT BIKE SAT AROUND FOR ALONG TIME JI, IF YOU WANT I CAN ASK THE ORIGINAL OWNER HOW LONG DO YOU REALLY THINK ITS WISE NOT TO STRIP ENGINE AND AT LEAST DO BEARINGS AND SEALS AND CHECK CRANK /ROD ,
IT IS NO USE TALKING A PREETY GIRL OUT IF SHE CARNT PRODUCE THE GOODS
IM GOING TO ASK THE ORIGINAL OWNER HOW LONG AND WHAT HE KNOWS,NOT THE GUY YOU GOT IT OFF BUT THE PREVIOUS ONE
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this is what he said so it looks like its been sitting for 12 to 13 years .since you got it id be checking it out ,if it was mine
The '73 was a bike I picked up down the South Coast about 10 to 12 years back. It was chased heavily by over 100 people from as far as New Zealand. As far as the motor is concerned I was sure the previous owner said it was rebuilt and had a new piston and had not been run. I never fired it up as you know now bloody noisy the bikes can be in surburbia!! It was my honest impression it was rebuilt.
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Thanks paul.
Can you ask the guy when he is going to send the missing shock and gear shift lever and any other parts he has to Edgar so Edgar can send them to me so the deal can be finished.
Thanks for all your help.
Ji
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is that what edgar said he was doing because there was no mention of any other parts but i will ask
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Edgar told me that the old owner had just moved into a hew home and all his stuff was in boxes including the missing shock and gear shift lever. I was told that the old owner took a quick look into some easy to get to boxes but the stuff was not there. I was promised that when the old owner gets settled he will forward the gear to Edgar and Edgar will send like onto me.
Ji
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ji ive sent him a email and i'll wait for a reply thats the best i can do
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Thank you Paul
Ji
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Rear tyre done the same way.
Job done !
Ji
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With the rear tyre on we can now check to see if it complies with rule
18.5.0.6
a) ii) Pre-1965, Pre-1970, Pre-1975- 5" (127mm).
Yep it looks pretty good to me I hope the scrutineers use the same tape measure.
Ji
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If your tube does not have enough pressure or your rim lock is loose you may notice that your valve stem looks like this after a ride.
If the valve stem looks like this it is an indication that the tube or the tyre has rotated on the rim. If you continue to ride with the valve stem like this it may tear the valve stem off the tube.
The best thing to do is to remove the tyre and relocate the tube before it leaves you flat.
Ji
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The best thing to do is to remove the tyre and relocate the tube before it leaves you flat.
Ji
You don't have to dismount the tyre, just deflate, release rim lock/s and rotate. Re-inflate to s higher pressure. I've always run 12-15psi. Some like to run lower pressures but each to they own.