Afternoon all


Recently bought a 500 that I need to register in this country as it's currently sat on NOVA.....


It will need 4 new tyres for it's MOT but at the moment not sure what wheels are going to be fitted but need to fit some new rubber to the standard rims so...........


Has anyone ever fitted any 145/80/SR12's to standard rims or know of a size that will fit standard rims that are basically really cheap....


Thanks in Advance


Rob

That is two sizes larger than standard 125 width which may not be a good idea. You should also be aware that the standard steel rims are not designed to take tubeless tyres.

Yeah, the size difference on a wheel with an 80 profile side wall is not massive to be honest, do you know what the profile is on a standard tyre?


Tubing a tubeless tyre is possible as long as you remove any sharp/rough moulding inside the tyres as they are not initially finished to take tubes and any stickers of course. To be fair its not something I would do on a vehicle that has weight/power or would be used for significant long term use and mileage.

Standard tyres are 125R x 12 and sit in a 3.5" well. Because the original tyres are sometimes hard to get and expensive quite a few guys run 135R x 12 tyres as fitted to the Fiat 126. I know it gets done but I think I read that tubes in tubeless tyres is regarded as illegal and therefore cancels out your insurance as well if something goes wrong.

Do you have a link to the 135's?

Van der Laan has 135s for 44 eu vs 125 pirellis at 62.50. Shame about the exchange rate at the moment but they're still generally the cheapest https://www.fiat500vdlaan.nl/en/webshop.php?CategoryID=17

I have been running 145 R12's with tubes without issue, but only for about 30 years. (Currently I have /70 profile, I can't remember if I have uses /80 profile)

You may find the wider tyre rubs inside the wheel well at full lock. This is not an issue for me, I believe that in OZ an extra leaf was included in the front spring that gives the small amount of additional clearance needed.

There have been other posts about tyre sizes that you can search for that will give you some wider ranging opinions.

Joe R

Hi

I have a full set of almost new 125 tyres. They are on rims with stainless steel trims. I'm looking to shift them on complete. See the photo when they were fitted to my car. Let me know if you are interested?

I have the alloys fitted now with 145 / 70R 12 Falkens fitted.

Cheers
Hugh Jarce

I had 135 tyres on before and they rubbed the arches when turning the wheels, so they were removed and replaced with the old 125s.
This is on a D, which may have a slightly smaller arch and so is less forgiving?


Can I jump in with a related question on the tubed vs tubeless - what makes a tyre need to be tubed?

I have 125 x 12s on mine and one is leaking very very slowly. I took it to the tyre experts and they said it is leaking around the rim, and there's no tube in there.

Do I need a tube in there and is there any way of telling if the other three tyres do have tubes?

In the UK it is legal to use a tube in a tubeless tyres, but it needs to be the correct size tube. I researched this when I replaced the tyres on my Alfa 1750 GTV.

Wheels designed for tubeless tyres have a different bead profile to a wheel designed for a tubeless tyre. The tube ensures that the tyre bead is located correctly on the rim.

Tubeless rims and tyres have a bead profile that securely locates the tyre to the rim. This is done for improved safety, so that if the tyre deflates whilst driving the deflated tyre will, in most cases, stay on the rim. If you use a tubeless tyre on a rim designed for tubed tyres it must be fitted with a tube. Tubes aren't available in many different profiles so your choice of tyres will be limited. A tyre fitting depot should be able to offer advice and fit the tyre and tube correctly to ensure that safety isn't compromised.

Don't forget not to buy a wider tyre as a spare as it will not fit under the hood.
! think 135 will fit but its very tight.

Fair comment, my spare is a 125 on an original steel rim, only thing that fits the boot space.

I do have two spare sets of alloys here plus a variety of steel rims just in case

BambinoClassic said:

Can I jump in with a related question on the tubed vs tubeless - what makes a tyre need to be tubed?

I have 125 x 12s on mine and one is leaking very very slowly. I took it to the tyre experts and they said it is leaking around the rim, and there's no tube in there.

Do I need a tube in there and is there any way of telling if the other three tyres do have tubes?

Click to expand...

If I may I'll add a little to what Hobo1960 has said.

There are specifications for wheel/rim design. One source of info is in the various series of 'Automotive Handbooks' published by Bosch, Germany.
You might find one in a larger bookshop or library.

When tubeless tyres were introduced, the wheel rim design was changed to include a safety 'hump' This is visible on the outside of steel wheels, on the outer and inner flat sections of the rim as a slight depression or groove running all around the rim. On alloy wheels you'd need to remove the tyre to see the 'safety' hump.

There is also typically a 2.5 degree taper to the bead seat. (this angle can vary depending on application).

Tubeless tyres also have a layer of softer rubber at the beads to help sealing at the bead seat. Iirc, this layer of softer rubber may also moulded into the entire inner surface of the tyre to help seal around anything that penetrates the tyre and so avoid/slow deflation.

As Hobo1960 has said it's permissible to fit a tube of the correct size in a tubeless tyre if fitting to a tube- type wheel. You need to use French/tyre chalk and ensure no air pockets exist between tube and tyre inner. This isn't likely to cause any problems on a Fiat 500 but is a concern on cars driven at high sustained speed. As someone else has said you need to remove any labels and any moulded ribs/ridges etc. inside the tyre. If left in place, these will abrade the tube causing deflation. I found this out the hard way in the past, only took less than a couple of 1000 mls to happen.

Remember that you won't be getting the full safety benefits of a tubeless tyre if fitted to a tube-type rim - no safety hump to retain bead in place if tyre deflates, possibly no taper angle on the bead seat. Bear this in mind if running tyres at low pressure, think Fiat 500 front tyres!!

Fitting a tubeless tyre to a tube-type rim without using an inner tube? I've never heard of anyone doing this. I'd imagine it's not a good idea....

How to tell if a tube is fitted? Look at the valve stem, if it's a plain taper from where it exits the rim up to the valve cap then it's a tube that's fitted. If the valve stem has a slight bulge where it exits the rim then reduces in diameter before tapering to where the valve cap is fitted, then it's a tubeless valve (no tube).

As an aside, Am I correct in thinking that the Fiat 126 was available fitted with Dunlop Denovo Run-Flat tyres and used possibly a split rim design?
(or is my memory concocting fiction again!).

Al.

Thank you Al!
By the looks of it mine are all tubeless, based on that valve. Which makes me think the rims are suited for them, as they all seem to fit nicely. (Except the one odd one out)

All very interesting, who knew tyres were so complex

If you have standard 500 wheels, these were NOT designed to have tubeless tyres fitted, even if some muppet has fitted them (and, of course, tubeless type valves)--as 'Hobo' and Al have pointed out both the tyre construction and wheel design for tubed vis-a-vie tubeless are different. The 126 models, even the early 594cc engine versions had wheels designed for radial tyres, which if I remember correctly, have always been tubeless. Incidentally, the early 126s had 4.0inch wide wheels (as against the 500s 3.5in wheels), still with the 190pcd wheel-bolt pattern. using these wheels will allow you to use the 135, or even 145 specification wheels with advantage (better grip and very slightly better gear-box final-ratio). however, as wisely pointed out, you will need to retain a 125 section tyre for your spare.

Yes I am a newish Fiat owner and had 135 tyres fitted to all 5 wheels without tubes. Neither I nor the garage fitting them knew they had to be tubed .They held pressure for about two days before I went back and had tubes fitted. I still had a 135 section spare which I have let down to 15 psi to get it in it's well.Anyway I know now . Thanks Bryan

BambinoClassic said:

Thank you Al!
By the looks of it mine are all tubeless, based on that valve. Which makes me think the rims are suited for them, as they all seem to fit nicely. (Except the one odd one out)

All very interesting, who knew tyres were so complex

Click to expand...

I didn't even scratch the surface as regards the amount of info available on tyres, wheels etc. Just check out some of the tyre websites.
e.g. www.tirerack.com www.longstonetyres.co.uk www.vintagetyres.com
Both of these UK companies list tyres for the Fiat 500.

I forgot to mention - look at the markings on the tyre sidewall.

If the tyre has an 'R' in the size e.g. 135/80R13 then it's a radial tyre.

If it's tubeless then this will be marked on the sidewall also.

Idk if tube-type tyres are marked as such on the sidewall but I think they may be.

It's good practice to replace tubeless valve assemblies whenever a tyre is removed but at least keep an eye on their condition, they can perish/crack at their bases. Make sure you get the correct length, they vary, you don't want them protruding beyond the rim edge nor do you want to have difficulty removing/refitting valve caps, especially if you have wheel trims fitted. Always use a valve cap, it prevents dust being injected into the tyre when inflating the tyre, this dust can get trapped in the valve core seal leading to a leak. The cap also acts as a secondary seal should the valve core start leaking. This is important on wheels that might spin extremely fast, centrifugal force at high rotational speed can open the valve core. Schrader?used to supply valve cores with a stronger spring (denoted by a red sealing ring iirc).

On some old car wheels, the valve hole was a larger size than normal. There are plastic cup washers available to reduce this down to where a tube with a normal neck size can be used.

I was trying to recall an American tire (!) website that I used to consult. Had lots of info and a facility where you could input a vehicle model and then see what the effect of changing wheel size, rim offset, tyre aspect ratio (profile) etc and how the tyre to body/suspension clearance would be affected. I doubt it covered any classic Fiat models but might be useful to those of you guys/gals with modern cars who want to change tyres/wheels. I'd imagine most aftermarket wheel sellers have a similar facility. If I find this site, I'll post it up.

Anyway, enough of my rambling (for the moment, I'll be back!)

Arnie,

I mean Al.

the hobbler said:

If you have standard 500 wheels, these were NOT designed to have tubeless tyres fitted, even if some muppet has fitted them (and, of course, tubeless type valves)--as 'Hobo' and Al have pointed out both the tyre construction and wheel design for tubed vis-a-vie tubeless are different. The 126 models, even the early 594cc engine versions had wheels designed for radial tyres, which if I remember correctly, have always been tubeless. Incidentally, the early 126s had 4.0inch wide wheels (as against the 500s 3.5in wheels), still with the 190pcd wheel-bolt pattern. using these wheels will allow you to use the 135, or even 145 specification wheels with advantage (better grip and very slightly better gear-box final-ratio). however, as wisely pointed out, you will need to retain a 125 section tyre for your spare.

Click to expand...

Hi Tom,

There were some tube type radial tyres in the early days. Vintage Tyres still list a 165R13 Michelin XAS radial which is tube type! Iirc, Citroen were one of the first major manufacturers to fit radial ply tyres and these were tube-type, remember the original Michelin X (it's now being remade - check out Vintage Tyres or Longstone Tyres. I think tubeless radial ply tyres started appearing around the late '70's on new cars.

Regards,

Al.

Hugh Jarce said:

Fair comment, my spare is a 125 on an original steel rim, only thing that fits the boot space.

Click to expand...

Perhaps anyone doing a restoration involving fitting new front panels could usefully consider enlarging the spare wheel well while they're at it.?

Or you could always mount the spare on the bonnet, Landrover did that for years. Rover had a kit to mount it on the bootlid on the P6 model...

Al.