Classic cars forum & vehicle restoration.

[D4B]

Bought a set of very good (but used) tyres for my Honda TN7 project, as the tyres it came with are very cracked and perished, which is to be expected as it was last on the road in 1992....

After spending most of yesterday removing the old tyres and disassembling the split rims (they were very difficult to break the bead and were rusted in place too, today has been spent cleaning the rims and repainting them, and then restoring the 32 nuts and bolts that hold the rims together!

So anyway, finally I am at the point where I am ready to fit the new(ish) tyres (and now I know why two different tyre fitting centres weren't keen on doing the job) the new tyres seem to almost fall onto the rims! Should I be concerned, or will they lock in place when I inflate them? I have visions of doing 6000rpm and going no where

Any advice happily received (apart from scrap it) ??

[colwyn500]

"I have visions of doing 6000rpm and going no where"

As opposed to going somewhere, but very, very slowly?

Sorry I can't help with the rims. They presumably can't be tubeless? I'm sure they'll be OK when inflated.

[roverdriver]

I assume that what you are dealing with are 'split ring' rims. If that is the case be very very careful. Having said that, they are not difficult to handle if you use common sense.

The tyre and slightly inflated tube will just drop into place on the rim. Poke the valve stem through its hole, wriggle the tyre so it is fitting nicely against the non-split side of the rim, then start inserting the split ring. It might need a little help with some gentle hammer taps to get it into place, but if at all possible, get the ring into its groove by levering.

Now- inspect the ring and make sure it is seating properly within its groove. Stand the wheel up and bounce the tyre on the ground a few times. this should bring the bead in good contact with the ring.

Check again that the ring is properly bedded in its groove, then lay the wheel, ring side down and inflate a little- say 10 psi. Stand the wheel up and again inspect. If all is well, then continue to inflate ring side down and keep well clear as it inflates. Strictly speaking, inflation should be done with the wheel in a cage.

Terrible accidents have happened- decapitation even- when fitting these split ring arrangements, hence legally it should be done with the cage. It is possible for the ring to 'let go' and the pressure to make it fly in the air, taking with it any body parts that are in its way.

I have done many of these, before cages were needed, and I must say, I was very cautious and careful, but never had any problems.

It is imperative that the ring is a good fit into the groove in the rim. It is important that the bead of the tyre is engaged with the rim BEFORE any real air pressure is applied. The tyre bead helps to keep the ring in place, but if the bead is not in contact with the ring, and full pressure pumped in, the sudden movement of the tyre's bead against the ring, can dislodge the ring with dire consequences.

Even of you follow all that I have said, be sure to keep well clear of the wheel during inflation- just in case!
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Dane- roverdriver but not a Viking.

[colwyn500]

Roverdriver, that's a brilliant explanation.
Steve....I'm scared!

[petermeachem]

I used to know a guy who did mobile lorry tyre replacement. He said with split rims he always put them under the lorry to inflate them. Then if it blew it went straight up through the lorry. He was very very cautious with them.
Always nice to hear a positive story I think

[D4B]

Thanks for all the replies!

Roverdriver ~ Many thanks for taking the time to explain, I am feeling a little guilty now as I may have given an incorrect description of these rims.

I am sure they are not "split ring" type, but the rims do unbolt and you are left with 2 halves. Pictures say a thousand words:







I showed a restored rim half and the new tyre to a tyre fitter today and he said that with air in it it will grip tight to the outside of the rim, so hopefully I was worrying for no reason.

Will let you know what happens!

Thanks Steve.

[roverdriver]

Steve, I am sorry that I wrote about split ring wheels in error. Unfortunately I don't know the correct nomenclature for your wheels, but they are the same in principle to many found on the likes of Chinese made wheelbarrows and some makes of ride-on lawnmowers.

If you think about it the base of the rim needs to be slightly smaller than the inside diameter of the tyre, no matter what design of rim or wheel is being considered. Yours would be the simplest and easiest style for fitting the tyres. Simply lightly inflate the tube (so it is round with no kinks or folds), after first setting it within the tyre. Then simply put the tyre/tube onto the larger of the wheel halves, make sure that the tube is still within the tyre and cannot be pinched when the other half of the wheel is set into place for bolting up. Once the bolts are tight, inflate to full pressure.

The pressure of the bead of the tyre against the edge of the rim is what creates the friction to keep it in place.

There have been so many different styles of tyre and rim over the years, and probably worth a story in itself. 'Beaded Edge' (or as the Americans call them 'Clincher') would be among the earliest wherein the edge of the rim folds inwards and the edge of the tyre goes under that fold. They can be somewhat difficult to manage, but remember that motorists of the day did not have a spare wheel, they had to change the tyre with the wheel in situ, and then had to reinflate them to 50 or 65 psi with a hand pump before driving off again. One of the easiest to manage is the well-based wheel as on the Model A Ford. One might need tyre irons for removal but they usually go back on without any tools at all.

Perhaps Rick will explain about the true 'split rims' that are on his Dodge.

Dane.
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Dane- roverdriver but not a Viking.

[D4B]

Thanks Dane you have been a great help Steve

[Roger-hatchy]

http://www.youtube.com/watch?v=b47CJsqFmSM

A friend of mine knows how dangerous split rims can be out on the road as well.
He had the roof of his car sliced open by one on the M1 motorway when a Lorry had a blow out, the ring also ripped the top off of the passengers seat

[Roger-hatchy]

the frightening danger
OK it's and advert but shows why to use cages

http://www.youtube.com/watch?v=dKlJJqHFfoQ

[D4B]

Thanks Roger now I know what a split ring type is Frightening that M1 incident

My replacement tyres went on easily in the end. Turn out that all the hard work was in the removal and cleaning up.....

Before:


After:


Thanks Steve

[kevin2306]

they look superb!

[baconsdozen]

I had split rings on my old bedford truck,a pal helped me change the tyres and they were inflated ring side down under the truck. He took a lot of care in cleaning the rims and checking they were seated because he'd seen what happens when they 'let go'.
Does anyone remember seeing the picture of a mark in the ceiling made by a mechanic who was killed bending over a tyre and wheel that had been left on an airline with no pressure release valve on it?. It was a few years ago,in germany I seem to recall.
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Thirty years selling imperial hand tools for old machinery(Now happily retired).

[Rosco663]

Excellent work D4B Those wheels and tyres look fantastic and certainly did promote some fertile discussion.

Decades ago when I worked in the Ozzy desert split rims were the height of good cheap fashion on many of the service vehicles of the day. I remember seeing a safety poster of the unfortunate fellow that left his imprint on the ceiling of a tyre fitting bay. It was a very poignent reminder to always inflate the tyre inside the tyre cage to avoid the potential for a life threatening injury.

The good thing about the split rim was they were very easy to change in the field - only thing then was not everyone carried an inflation cage with them. A popular method was to weave a chain around the assembled tyre/wheel (leaving sufficient room for expansion) and then inflate.

A good method our employer insisted we adopted was routine maintenance on the rims themselves - especially with vehicles that did not see a lot of field service, as these did tend to exibit more corrosion than the rest of the fleet. Corrosion led to poor engagement of the split rim on the other part of the wheel which in turn increased the possibilty of the rim dislodging under pressure. This routine servicing involved deflation and removal of the tyre/tube from the wheel. A good wirebrushing using a wire wheel on an electric grinder on the mating surfaces then a good lick of the trusty red oxide primer. No fancy top coats were required

The last tyre I changed on a split rim was over 15 years ago but the anticipation of hearing the tyre bead seating under the increased air pressure wassomething else - especially the larger truck sizes - after having one let go a few years before

Stay safe out there,

Cheers
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Rosco

[D4B]

Cheers Rosco, they are all on the (little) truck now