How To Remove A Tyre

[Ji Gantor]

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

[lukeb1961]

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.

[Ji Gantor]

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

[pancho]

 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.

[Ji Gantor]

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

[Ji Gantor]

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

[Ji Gantor]

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

[VMX247]

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. 
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   
alison

[Ji Gantor]

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

[Doc]

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    

[Ji Gantor]

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

[maicomc490t]

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 

[Ji Gantor]

Hi maicomc490t,
Do you mean the tyre changing tools?
Yes, I do take them to a race day.

Ji

[Doc]

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

[Ji Gantor]

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