Thread: DIY Run flat trolley wheels.

I'm after a road report too on this one to please Ray.
As I've had exactly the same problem so this could be interesting.
I use the same brand of foam regularly it skins over quite quickly but I find it takes about 24 hours to cure fully all the way through.

Matt

Originally Posted by Michael G

When I worked at Holdens to fill the brake system of a commodore they would pull a high vacuum on the complete system at the reservoir and then introduce the fluid - no bleeding required. Perhaps something along these lines to fill the tube - pull a vacuum on the tube and then pump the foam (or fluid) into the tyre once there is no air in it.

Slightly OT; I do that to fill the cooling system in my car. This avoids air locks in the alloy heads - something Subaru boxer heads are notorious for. No burping or stuffing about required. I use a Airlift Uview system. Works perfectly every time.

A mate of mine did this on his wheel barrow and a bottle trolley about 2 years ago.
The wheel barrow is still going strong, but in saying that doesn't get used all that much, and
really doesn't have to handle loads much heavier than a bit of fire wood.
The trolley on the other hand was going great guns, with very heavy loads as you might imagine
being a large bottle trolley.
Anyways, like I said all was well, but at some stage the trolley was left outside in a puddle of water for
what I assume was a few weeks. And upon putting a load on it the wheels turned to mush....
So the moral of this story is not to let a lot of water near the wheels...

Originally Posted by Simplicity

I'm after a road report too on this one to please Ray.

swmbo can tell you they - run flat tyres- work just fine on her beemer
they are standard, as the useless car doesnt have a spare....not even a space saver

But my guess is that filling them with foam Uerathane wont work as it will crush when under load

I use:
http://www.truebluegoo.net/page/page/7153432.htm

I find with those smaller tyres such as wheelbarrows they have lots of very small holes in them. Add some blue goo, inflate and it stays filled.

Using single pack PU foam in a can in an enclosed chamber is fail - found thi sout when trying to use it inside a plastic bag to take a mould of a volume so I could build a carbon fibre airbox.
The single pack PUs are moisture cure - they rely on the moisture in the air to cure - put it in a tyre, or plastic bag, completely filling the space, and there's no moisture left for the curing process. Because it doesn't cure, the bubbles collapse, and you wind up with a sticky mess in the bottom of a bag. You'd be much, much better off getting 2 part PU foam from Whitworths Marine or whoever (well, i guess Blackwoods could order it in for you?) and injecting the 2 parts in separately, then shaking the wheel to mix it.

Originally Posted by Gammaboy

Using single pack PU foam in a can in an enclosed chamber is fail - found thi sout when trying to use it inside a plastic bag to take a mould of a volume so I could build a carbon fibre airbox.
The single pack PUs are moisture cure - they rely on the moisture in the air to cure - put it in a tyre, or plastic bag, completely filling the space, and there's no moisture left for the curing process. Because it doesn't cure, the bubbles collapse, and you wind up with a sticky mess in the bottom of a bag. You'd be much, much better off getting 2 part PU foam from Whitworths Marine or whoever (well, i guess Blackwoods could order it in for you?) and injecting the 2 parts in separately, then shaking the wheel to mix it.

Yes that's exactly what I've found, I thought it might harden up overnight, but no such luck the tyres are still soft. I might squirt a bit of water into the tyre and give it another go, nothing to lose

If that fails I'll see if there is a 2 pack polyurethane foam that has some resilience, so that it's more "rubbery"

Round 2:

I see that Selleys have a flexible expanding polyurethane foam. http://www.selleys.com.au/fillers/fo...space-invader/ that might be a more durable choice, now it just depends on if it will expand properly in and enclosed space.

Did I hear someone mumble, sucker for punishment..

Had a look at that link, Ray. I'll be VERY interested how you go with that. If it requires moisture to cure, then maybe wetting the inside of the tyre or tube before injecting might help....?

Gee whizz Raymond;

By now I would have been quicker and cheaper to have bought the semi solid replacements.

I recently bought a pair locally and replaced my trolley wheels. Happy with the result.

Ken

Originally Posted by Toggy

Gee whizz Raymond;

By now I would have been quicker and cheaper to have bought the semi solid replacements.

I recently bought a pair locally and replaced my trolley wheels. Happy with the result.

Ken

Where's your sense of adventure and experimentation? If the selleys stuff works, I'll be ahead, if not I'll have learnt something. ( And others will have learnt it for free )

I have another smaller trolley from SCA that has flat free wheels, this one has bigger 13" wheels.

Originally Posted by RayG

Did I hear someone mumble, sucker for punishment..

No we didnt

Looks a bit messy, but the flexible foam seems to have worked. I'll know for sure after I let it cure for a couple of days.

FoamFiller.jpg

Heh, I tried without an prior research to do this a couple of months back.
With the best intentions but no real thought, I removed the little valve screw, and fed in the foam. Didn't put a hole on the opposing end did I
Suffice to say, that wheel isn't terribly useful at the moment


Part of me is loathe to make an air release hole on the tyre, so my (eventual, slowly but maybe-ly!) plan is to finish off converting an old fridge compressor into a little vacuum pump, then make a small doohickey with one collection to the tyre valve, one to the can of foam, and one to the vacuum. Remove the air from the tyre, then send in the foam!