My recent experience has prompted me to reopen the discussion about old tyres.

One of the front tyres on RM2213 has worn evenly to the extent that there is slightly less than 2mm of tread left. This was quite rightly pointed out to me at a recent safety inspection and recorded on the report. On buses the tread must have a depth of at least 1mm to comply with the law.

The tyre is a Dunlop, made in Germany on the 36th week of 2002. It has not been re-grooved. Re-cutting it would cost £25.00.

I have changed the wheels on all my Routemasters to fit 10x22.5 tyres, thinking they were more likely to be available quickly if I had a tyre failure and easily to change as they don't have split rims.

I was surprised to find that my usual supplier decided about two years ago not to stock 10x22.5 tyres as there is little demand for them any more. He is able to get them easily but this took two days. He says 10x22.5 is regarded as rather an old tyre size now.

The only affordable replacement tyres easily available to my supplier were a Triangle at £150.00 and a Double Coin at £200.00. Both are Chinese manufacturers.

I made a decision as to what I would do after some discussion with the tyre fitter who is sensible and likes heritage vehicles. He is perfectly happy working with the split rim wheels on my GS. I'll post what I did in a few day's time when there has been some discussion and comment. All prices mentioned include fitting but exclude VAT.

My bus number (if any): RMs 238, 471. 2213 & GS17

One thing I don't know is what tyre sizes are fitted to other buses
Ie DMS. Metro/Titan and current types. Some have a wider rim and some a different diameter but is this the case for every modern bus?

The split rim wheel is perfectly good if in good condition and given a bit of TLC when a tyre is changed.
For example a good clean up and internal repaint/corrosion protection. The wheel and the boots they have should last very well.
As a spare has to be carried, it would be unfortunate to have a double puncture, but it can happen.

Carrying a couple of good spare inner tubes can be a low volume spare as a get you home. So if a Tyre recovery cannot replace a tyre at least it can be repaired - unless of course, its a serious failure.

The modern wheels are good but not much of a gain if the tyre size is an issue.

One of the preservationist whose vehicle we looked after from time to time had a very good policy.
He had a set of 'Storage' wheels and tyres. These were a worn but still legal set of tyres that were used whenever the bus was laid up ie over winter but legal and safe to use if the bus had to be moved or was required at short notice.
Then he had a set of 'running' tyres. A set of new top condition tyres on very good condition wheels.

The advantage of this rotation was that the good tyres remained in good shape when not in use as there was no load on them.
The older tyres nearing the end of their road life took the weight of the bus and thus risked flatting from long term storage but at least made the bus instantly moveable.

Jacking up wheels on is the alternative but each time the bus is moved makes that a rather tedious task.

When the old set of tyres are finally past it they were replaced with new but not in a hurry, the wheels were refurbished and rebooted but the old 'new' set then becomes the worn set.
In 20 years I think the bus is only recently on the second set now.

This could also be done with a set of prime quality tyres and a set of cheaper tyres. But one thing applies. Storage space.

I had a call from a customer in Germany a few weeks ago with a Bristol K5G with 900x20 wheels. His wheels had failed TuV because they were too corroded and the tyre fitter refused to deal with them or fit new tyres.

As it is almost impossible to get replacement split rim wheels, I got a price for a new set of metric wheels following a thread on here. In the end he took alternative advice given on here: get the old wheels needle gunned, shot blasted and coated. He did and the tyre fitter was quite happy to fit a new set of 900 x 20 tyres!

Most operators in Europe have to have 2 sets of wheels anyway, as "snow" tyres are obligatory in many countries in winter.

My bus number (if any): RML2532

Indeed, I think that's where the second set idea came from as the owner worked for an ND subsidary in the Savoie many years back.

You could think about 11 x 22.5 which would increase the vehicle's height slightly - the tyre company will have the rolling diameter and all other relevant information.The height difference is, I think, about one inch. You would need to check the clearance on full lock and at the rear between the inner and the B frame and allow for body sway. Also any tachograph would need to be recalibrated. Nominally a 10 x 20 is virtually the same as an 11 x 22.5. RML 898 has 10x20 front tyres with no problems about clearances.
You could also investigate low profile tyres: 275/80 or 75 x 22.5 with the same checks made.

You're lucky that you don't have to try to find any of the old 40 x 8s.

http://www.flickr.com/photos/21437618@N02/3575620617/in/set-72157617146227348

recut yre, if still retaining a reasonable profile then retain on front, if squaring off then pair up with another very similar and cascade to rear and get Double Coin tyre for front.
bristol RE buses were generally on 10x22.5
dishes on RM not really wide enough at bead to take 11R22,5 especially at rearand as has beeen pointed out raises height slightly although on rear woukd give slightly higher top speed but remember they are still 80 percent aspect like the 10's.

Mark

My bus number (if any): rm1414 sort of

Thanks for the advice. In the end I bought the Triangle tyre and put it on the front. I haven't re-cut the Dunlop tyre but have decided to store it. It could be re-cut in the future if I decide to use it on a back wheel.

I've decided to ensure the front tyres on all my buses are less than 10 years old. I suspect that eventually all tyres will need to be less than 10 years old. At present this is just a recommendation.

It would be helpful if the date codes were marked on both sides of the tyre. I think this should be made a requirement.

It is tough on heritage vehicle owners as their tyres are unlikely to be worn out in 10 years use. But safety is paramount.

My bus number (if any): RMs 238, 471. 2213 & GS17

https://www.gov.uk/government/publications/public-service-vehicles-tyre-age-recommendation

My bus number (if any): RML2532

Seems a sensible recommendation and is particularly relevant to heritage bus owners.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/266915/dft-tyre-guidance.pdf

It is going to be expensive. At least it is easier to check the dates on the front tyres. Most of my rear tyres are fitted with the date markings hidden from view.

My bus number (if any): RMs 238, 471. 2213 & GS17

Modern buses have metric size wheels eg 1000R225, the equivalent of 900R20.

The wheel rim diameter is different, but the outer diameter of the tyre is the same, so the 2 can be used on the same axle.

BEWARE-do not mix conical fixing wheels with the more modern type! (can't remember the correct term, not used to modern things)...

My bus number (if any): RML2532