Ifor Williams 505 tyre sizing

patchwork puzzle

patchwork puzzle

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So it turns out that my 505 has car tyres on, not trailer specific ones so I'm obviously getting them changed now that I know. The trailer was renovated by the guy I bought it from and the tyres on it are 165/70/13's and I've been told that the garage can't source trailer tyres in that size but can do 155/70/13's. Does anyone know if the slightly narrower tyre will be a problem or will these be ok? They have said they can get 165/80/13's but the 70 only just fits in the spare so I'm not sure they would work.
Any ideas or information appreciated greatly 🙂
 
Have a look on ebay. They have specific trailer tyres on there. Mine had 155/80 13s but I was advised to go for the 165/70s or something like that anyway. I've forgotten the specific size now. If you look at my previous posts the info will be there. The important bit is that they are specific trailer tyres. I think mine are rated for 550kgs each tyre. The amount they are rated for is the maximum weight of the trailer and contents.
 
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The sum of the tyre maximum loads must be at least equal to the maximum trailer weight shown on the manufacturers plate. So if for example it says 3500kg each tyre MUST be capable of carrying 875 kg . Anything lower is illegal.
 
I bought new tyres for my 505 last year - Event ML605 is the make and model, they are commercial tyres so have the necessary load rating. The size I got was 165/80R13 94R.

I got them from a a online tyre place, they came out and fitted them.
 
stick with 165/70R13C tyres and make sure they're trailer ones. They shouldn't be big money (around £50 each) and will then last years and years.
not to put too fine a point on it - don't be fobbed off with "we can't get them". 165/70R13C trailer tyres are probably the most common trailer tyre there is. my suspicion is that the garage have some 155s they aren't able to shift and thought that maybe you'd be a likely candidate!.. ;)
 
Thanks Tiddlypom, but I can't see that these are 70's (maybe I'm missing it 🙂) we can get 165/80's which appears to be the common trailer size and that which is usually used on the 505 but that just brings me back round to my original question lol
 
Thank you for the links but is anyone able to answer my question as to whether the other size is ok and if not why not? Whilst I appreciate the links elsewhere I can get this other size and actually at this stage just wanted to know if they would be ok?
 
patchwork puzzle said:
Thank you for the links but is anyone able to answer my question as to whether the other size is ok and if not why not? Whilst I appreciate the links elsewhere I can get this other size and actually at this stage just wanted to know if they would be ok?
Click to expand...

To understand the tyres and what they mean.... 165 is the width of the tyre tread, 70 is the aspect ratio meaning the depth or sidewall of the tyre looking sideways on is 70% of the tread width.... the 13 relates to the diameter in inches of the wheel it will fit.

So in answer to your question all of the tyres will physically fit. However a trailer tyre has severe loads imposed on, especially with the weight of a valuable horse on it. The most important thing to ask regarding the tyre is its ply rating... this relates the number of layers used to make the carcass of the tyre. I.e it's sidewall thickness and strength.... ideally you don't want to fit anything less than an 8 ply tyre to a trailer... they are thicker and stronger than a normal car tyre as the sidewall has to endure a lot more stress.

So in final answer to your question .... they will fit but only if you replace all five at the same time... the 155 tyre has a slightly smaller width of tread... therefore a slightly smaller amount of contact the tyre has on the road.... the 165/80 has a higher sidewall which means more sideways flex.....

Would I do it? No I would fit the correct size 8 ply tyre.. they are easily available from most tyre retailers...I know I've just bought some.... please don't scrimp on tyres...it's not worth going for cheap ones! :)
 
The spare will fit on the bracket ... you may have to stretch the tyre cover a bit more... because it is an 80 it means that the sidewall height is 80% of the tread width so the tyre itself will have a 10% larger diameter and rolling radius... make sure they are definitely 8 ply!!
Because the sidewall is taller there will be more flex therefore the carcass needs to be stronger....

As an aside having thicker sidewalls also makes them less prone to blow outs!
 
Thank you once again Farmer Chalk, your advice is really helpful 🙂 Im only unsure as to whether it would fit as the 165/70 car tyre that's on the bracket is extremely snug so worried that the 165/80 would be tighter still (or not fit st all) I guess the bracket may be able to lift higher if need be though. Thanks Once again 🙂
 
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