OzVMX Forum
Clubroom => Tech Talk => Topic started by: Ji Gantor on February 21, 2009, 01:23:14 pm
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This is the method I use to remove a motocross tyre, If you have a better way or have had an experience that may help please post your constructive comments.
This is the off off technique, because you lever the tyre bead off on both sides.
If you have time place the wheel out in the sun for an hour or so. The heat from the sun will soften the rubber and make it easier to handle. Next place the wheel on top of your tyre changer. This can be a purchased one like mine, home made one or a stiff bucket.
Ji
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Step two,
Assemble all the tools required.
I use a combo spanner to remove the rim lock and tube valve stem nut,
Tube valve remover,
Window cleaner,
Rubber mallet
3 Spoon tyre levers and a
Tyre opener lever
Ji
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Step Three,
Remove the tube valve and the valve stem nut.
Ji
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Step four,
Loosen the rim lock nut and push the rim lock bolt in towards the tube. Some times the rim lock is rusted in place so I give the bolt a tap with a rubber mallet to free it up.
Ji
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Step five,
Use a bead breaker or a tyre iron and work your way around the tyre breaking the bead. Then flip the wheel over and do the other side. When finished place the wheel back on top of the tyre changer with the sprocket side down.
Ji
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Step six,
Using some kind of lubricant, I use a window cleaner, lube the tyre on both sides.
Ji
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Step seven,
Place three tyre levers under the tyre's bead at 180 degs from the rim lock.
Ji
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Step eight,
Starting with the middle tyre lever pull back towards the hub, while using your hand try and push the tyre into the well of the rim on the opposing side. This is not easy to do when the tyre has been on for years.
The reason I use three levers is because when you have popped the bead over the rim the middle lever falls out without scratching the rim. Using the free tyre lever (the middle one that just came out) work the bead off the rim all the way around. Never use a screw driver as a tyre lever, it will puncture your tube and scratch your rim.
Ji
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Step nine,
Flip the wheel over and repeat steps seven and eight on the other side
Ji
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Step ten,
Using your hand (I like using my tyre opener lever) pry open the tyre and remove the tube.
Ji
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Step eleven,
Take the wheel off your tyre changer and with your foot or hand push the rim into the tyre. This should form a gap between the tyre and the rim on one side.
Ji
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This is what the rim looks like when it is pushed into the tyre.
Ji
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Step twelve,
Take the wheel off your tyre changer and place on the ground with the rim in tyre side down.
Get a good hold of the tyre at the top and push it off the rim.
Ji
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Now that the tyre is off the rim the real work begins.
I now have to clean the internal parts of the rim and give it a couple of coats of paint. It is always a good time to spray CRC around your spoke nipples and turn them left and right. This will remove some of the dirt on the threads and make them easier to turn when truing the wheel.
Ji
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Well, you could have provided a little more deetail than that!... :D
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Hi E74,
I can only do my best.
I had to remove two tyres this morning so why not take time out to photograph the procedure.
I hope those that do not know how to remove a tyre will gain some confidence from this topic. Once I have sorted out the hub, rim and spokes I will post a new topic, How To Put A Tyre On.
I have just started cleaning the rim of 30 years of neglect.
Ji
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Hi CST,
Thanks for your kind words.
Ji
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All of the above plus I use rim protectors
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Hi oldfart,
I use rim protectors too, but only on polished or near new rims.
Great addition to my postings.
Ji
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Hi E74,
I can only do my best.
I had to remove two tyres this morning so why not take time out to photograph the procedure.
I hope those that do not know how to remove a tyre will gain some confidence from this topic. Once I have sorted out the hub, rim and spokes I will post a new topic, How To Put A Tyre On.
I have just started cleaning the rim of 30 years of neglect.
Ji
( just taking the piss Ji), Great effort with heaps of detail!
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Hi E74,
Thanks for the kind words.
Keep well.
Ji
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Great work Ji. It shows a real passion for helping others in this sport ????/hobby ????/disease of ours ;D ;D ;D My hat is off to you ;)
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Hi PEZBerg,
Thanks for your support.
I used to scratch rims and rupture beads before someone showed me how to change a tyre properly.
I really appreciated that act of kindness and I hope I have helped others as I was helped.
It is such an easy thing to do but most of us put it off thinking it is to hard. It is simple and only takes 5 minutes once you have all the tools assembled.
Keep well.
Ji
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Good stuff Ji. My one tip for removing tyres is, leave both the old tyre and the replacement tyre in the sun for about an hour before you attempt the work. It's surprising how much easier a sun warmed tyre is to remove or replace compared to a cold tyre ;) :D ;D.
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Whooops, just noticed you said that ::). I use WD40 as a lube. It dries into the tyre and won't promote rust inside the rim ;) :).
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Hi mx250,
You are so right.
I find it very hard to open an old tyre enough to remove the tube with my hand if it has not sat in the sun for a while. I have found the force used to turn the bead over the rim the first time on a cold tyre must be nearly twice that of a warm tyre. Put it in the sun, a simple trick that really pays off.
I have used CRC as a tyre fitment lube before and it works great. I feel it evaporates all most as fast as the window cleaner but there is always those that will say that it is a petroleum product and thus will damage the rubber in the tyre and tube. If you replace your tyres once a year I can not see it doing any harm. The window cleaner is an alcohol and evaporates completely.
The lube used in some tyre fitment shops is water based. This lube can promote corrosion of the rim and rim lock. This lube looks a bit like Vaseline and is not recommended for same day racing use. The lube takes a while to dry and there is a possibility that the tyre may rotate on the rim. This rotation may tear the tube and deflate the tyre.
This is great,
This is a forum.
Thanks Ji.
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With an anodised or polished rim-I had to take to the fitment shop-auto "no touch" changer ( about $ US10-20). Besides, anyone else notice that the tires today have stiffer sidewalls than say 15 years ago or more....or maybe I'm just getting older.
Last tire I changed in a hurry was on a 74 KTM 250 at a 45 min GP around 94-95. I had lots of help and got it done in under 10 min. Thing is, at that speed I was leary of it being on right etc. I put some Pirellis on the RM250a last year or so.
The rims were soft( I actually remembered that the stock RM rims were soft)-so I did everything you did, plus continually heated the tire. The tire on it were some name i've never heard of-and the hardest tires I ever removed, including ones I've cut off.
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Hi Maicojames,
Thanks for sharing your experiances with tyre fitment.
I have seen a few times with dirt bikes but mainly quads where the old tyre has been cut off rather than spending the time to lever them off. When a tyre is old it hardens and it take twice the effort to remove than a new one.
Ji
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Another important thing about changing or maintaining a tyre is the tube valve.
The valve in the tube which is also the valve in gas and compressed air shocks and forks were designed in 1891 by old man Schrader, and that is where the valve got its name. The thing that not too many people know, but may have noticed is that the Schrader valve was designed as a delivery system not a retention system.
Ji
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The Schrader valve does hold in the compressed gas or air to a certain extent but take a look at that expensive pair of gas shocks or forks you own. The valve is covered by a metal cap. This cap is actually the retention device. To prevent deflation I run good quality steel caps with a rubber seal and not the plastic cap that comes with the tube.
Ji
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Another component that is very important but constantly over looked is the rim lock.
I have not been able to use any rim locks that have come with the bikes I have purchased. I can not even show you a picture of my original Maico rim locks because they disintegrated on removal.
Rim locks suffer from corrosion, stripped threads, bent threaded rod shafts, loss of rubber buffer.......
New rim locks only cost about $17.00 and I feel it is not worth the risk.
Ji
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This cap is actually the retention device.
That is a curious thing to say. This is a simple poppet-valve and spring affair, that has worked fine for >100 years. The CAP is a cap to keep gunk out so that the spring-loaded poppet-valve remains seated correctly and doesn't leak. The cap is not and has never been the retention device in any way for Schrader valves.
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Some members think they know everything.
Check out what Wikipedia states
Metal valve caps usually have, in addition to a handy deflating tool, a small rubber insert to permit a good seal against the valve body; a cap of this kind also helps to prevent air escaping from a slightly leaking valve. However, the vast majority of Schrader valves used for tires are fitted with plain black plastic caps which effectively serve only to keep contaminants out of the valve stem.
I have also dealt with Rema Tip Top the tyre fitment supply company for many years and two of their technicians one of which used to be the tyre tech at the Moto GP have both told me that the cap serves as an air retention device as most Schrader valves leak.
And last but not least Works Performance shock Tech last year told me to keep the metal cap on the Scharder valve as it is the retention device.
But don't believe me or any of these other people believe what ever you want.
Ji
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the cap on the valve does indeed serve both as a seal against dirt ingress and as a seal. some of us will remember in the mid sixties an acu official was checking all bikes entered for the bathurst road racing event as part of the scrutineering to ensure that metal valve caps were fitted in acordance with the then current g.c.r's. apparently it had been found that at high speed the centrifugal force developed was sufficient to move the valve slightly off its seat and leak air! my favourite tyre story...i bought a No of tyres which included an unused nobbly which was as hard as a rock, i decided to fit to a spare rear wheel for my rt1. i put it in the sun and since it wouln't fit in the car tyre changer i fitted it with tyre levers it was so bloody hard it took about two hours to get it on [including tea breaks] so i pumped it up pleased with myself saying this will never wear out and watched it go FLAT! so i left it there for a couple of weeks and then thought maybe it will fit the tyre machine ...you guessed it it fitted straight in ..had it fixed in 20 minutes including tea break! one more tip you may or may not like to use..i never use the nut on the base of the valve stem except as an aid for assembly, this way you can see if the tyre is slipping on the rim BEFORE the valve rips out! cheers wally.
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Hi wally cox,
Thanks for that tyre fitment story.
Thanks for the tip about the valve stem retaining nut.
But most of all thanks for your constructive comments.
Keep well.
Ji
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I think there may be some truth to the fact that the tyres have stiffer side walls now.
In the past the tyres were made of lets say 100% rubber.
Now that rubber is becoming expensive most tyre manufacturers use lets say 50% rubber and 50% synthetic.
Another factor may be that the jumps are now huge and the tyres provide lets say 10% of the shock absorption.
These and many more factors may have spurred the tyre manufacturers to increase side wall stiffness.
The old tyres needing to be removed that have been on the rims for 20 years have hardened with time.
But I do remember that the tyres in the seventies came off without to much effort in comparison to today's beasties.
Ji
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Sorry Alison,
I did not mean to offend those members that actually do know everything.
The comment was based on those that only think they know every thing.
Keep well.
Ji
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1st post quote = Some members think they know everything.
quote= But don't believe me or any of these other people believe what ever you want.
I don't think those two lines where called for, I myself know everything and I believe what I want to believe. ;D
alison
2nd post Cool bananas,
just got to look after each other- as there isn't many Legends or older vmxer's left on here....
someones gotta keep you in line ;) :D
alison
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Hi Alison,
After seeing the images of the work coming out of your shed I believe that you do know everything. I also feel some of us could benefit from a workshop or two at your place.
Your husband is a lucky man.
Ji
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An old trick to eliminate rimlocks and bead creep is slip a couple of 50mm wide strips cut from an old inner tube in under the rim tape and tube and have a little protrude out each side which can be trimmed off neatly when the tyre is inflated. I've used this method in the past for running extremely low pressures on an open capacity MXer and it works. Normally I check my tyre pressure before each ride and adjust accordingly after the first few laps but rarely does the pressure exceed 8-14lbs which gives little time or concern for leakdown. For most parts the larger black plastic caps are easier to remove and refit while wearing gloves (remember the steel caps should be fitted tightly and they offer little in the way of grip for gloves or tired sore fingers) so it's the plastic caps I prefer for ease of use under actual conditions. I use larger 10mm hex steel caps for my forks which also offer accessability without the need to remove the gloves ;) This isn't an argument of any type but simply another perspective ;)
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Hi Doc,
That is a great addition to my posting.
I run 8 pounds of air in my rear tyre when riding on cow paddock tracks. This allows more grip I feel when cornering on flat turns. The rim lock substitute is not something I have ever heard about and if I get the chance I must try it. I usually remove my gloves when working on my bike just encase I get oil on them which may prevent grip when riding the bike.
A very good constructive posting, I look forward to your input in future
Ji
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Wow !!!
Do you take all that stuff with you when you go racing or trail riding - I'm impressed !!!
Makes my two old Metzeler levers look pretty shabby :'(
Dave Mac :D
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Hi maicomc490t,
Do you mean the tyre changing tools?
Yes, I do take them to a race day.
Ji
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G'day Ji, I used to cart along the pucture repair kit/levers and tubes also but I've changed my ways of late and instead bring along a ready to bolt in spare wheels. I worked it so near all my 100's/125's share the same wheels and all my 250/400/500's have the interchangable wheels as well ;) much easier and faster than fixing a flat on race day but ironically I've not had a flat since using this method..than again I've barely ridden them so that too decreases the odds ::)
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Hi Doc,
I have been trying to buy extra wheels for my bikes as well so I can take different tyres to the races. I am placing soft and intermediate tyres on them so I can match the conditions. If I get a flat I will just change the wheel not the tyre.
Ji
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Hey Doc your the man,
i was just about to post the same thing. I run 4 strips of inner tube under across the rim ( or should i say thread it across when the tyre is on before i bead it. As the dirt bikes use Tubes your not so worried about the seal, but stopping the rim spining and taking out the valve.
Used my spare wheel with soft tyre on TM last year, Learned that lesson to do it to them all, race one in Tassie Nats, ripped the valve right out but it stayed in place and went down by the last lap. Only Rim without the tapes and only one to spin out a valve in over 10 years.
I use 4 inch strips now but cut them off so they dont flap about and have never had a rim spin, as the rim moves it tries to roll up the rubber stip in the bead and locks in, i have heard of some of the speedway guys go one better and use spray adhesive.
Another one i have tried and works is to assemble with hair spray, when it dry's out it goes tacky and sticks forming a adhesive seal between the rim and the bead, seen that work on a 500 single on a flat track runing 6psi, so i know it works for sure. ;D
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Great input Freakshow
Ji
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CLICK THIS (http://www.youtube.com/watch?v=CW_TYS_Gv9k) to find out how you inflate a tyre and pop the bead in a hurry ;D
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Hi Lozza,
I have seen lighter fuel used like that to inflate quad tyres.
Very dangerous.
Don't try that at home.
Ji
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Local Bike shop.... ;)
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yer tim im with you local bike shop ;D too easy. and i just take a spare bike on race day saves changing a spare wheel just undo 2 tie downs :D
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that sounds interesting putting rubber strips across the rim .thats new to me ...and it really works? another old speedway trick is to punch a hole through the side wall of the tyre and stick the valve out through that hole! looks crude but if the tyre slips on the rim it has nothing to stop the tube going with it.... i was riding at young in 1960 something and it was a very wet and slippery track after rain and young jim airey was pitted next to us merrylands boys. he was riding his very fast payne framed BSA [B31 i think] he came in from practice ,ripped of the back wheel and tyre ,got a big hammer and chisel and formed spurs on the inside edge of the rim about every inch around the wheel!...looked a bit unsutle to me but apparently it worked! cheers wally.
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Wally, that tip about the strips of rubber came from the speedway sidecar legend Bill Sewell. He mentioned it when a good friend purchased his old Lubi-Tech speedway outfit in the late 80's. We fitted a GS1000S motor and proceeded straight to roost heaven without passing go..never did the tyre creep even though it was bloody enormous! :o ;)
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kool doc!
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I am really looking forward to trying the rubber strips now.
Ji
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Dunlop's advice or taking the tyre off.
I like it. I'll have to try it next time. Doing the opposite fitting the tyre might be a good thing as well.
http://www.youtube.com/watch?v=TVKzoaL8qaI&feature=channel_page
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And to put it on..........
http://www.youtube.com/watch?v=IMYQ6L2jKKQ&feature=related
This looks so easy I think I'll rush out side and whip off and on a few tyres just for the fun of it ::).
But first I'll get me one of those neat ratchet spanners, one of those trick 'hold bead in place' special tools and some funky gloves for that professional look and to protect my delicate little pinkies ;D.
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Hi mx250,
They are great videos of how to get the job done.
Great reply.
Ji
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There are torque spanners to set the tension on your spokes.
They come in a set and work great.
They don't cost as much as a Snap On but look like the same quality.
Ji
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Don't throw away your old tubes, with a wad punch you can turn them into washers or muffler mounts. If they are still not to bad repair any holes and keep them as a spare.
Ji