Tyres what size ??

[sigi]

Hi there I was wondering which modern size tyres people have fitted to there dafs, my 44 has 135sr 14 and I have only managed to find one. I was wondering what does not look to different as I need four

[Nick the man with a daf....]

got 165/70/14's on mine with no clearance issues, BUT my car is a 46 and I dont know if the wheel offset is the same as a 44

[dafix]

Hi, I am thinking about replacing the tyres of my 46. She is now equipped with original Kleber 135SR14 (eq. to 135/70R14) at the front and 145/70R14 at the back. I would like to start with the front tyres, hoping it can improve the grip and stability (I still have vibration problems after wheel balancing and toe-in adjustment). Although is is the original size, 135/70R14 tyres look too narrow and are hard to find (and expensive when found). 165/70R14 could be an option but I am not sure they can fit on the original rims. Would 155/70R14 be fine ? I guess (but I may be wrong) that tubes are mandatory for these rims (even if the new tyres are tubeless).

[andrew]

I've had a good rummage around the internet, to check availability and prices in the United Kingdom (I appreciate you're in Brittany, but it's only "just across the water"). 135 & 145/70R14 appear impossible to find anywhere, regardless of which manufacturer you choose. I DID manage to find 155/70R14 tyres, from Continental (a good brand and high quality tyres) which ought to fit onto the car. However, you ought to bear in mind that although these tyres may fit on the wheels and not cause any rubbing problems on the car's bodywork, they might make the speedometer read incorrectly and could put an extra strain on the car's driveshafts.

As regards tubeless and tubes, Your Daf 46's wheels should accept tubeless tyres, so don't worry too much about fitting tubes. Although not illegal (in the U.K.) the fitting of tubes to tubeless tyres is not recommended, as a tubeless tyre has a rougher inside surface that a tyre designed to accept a tube, which could cause a tube to burst prematurely. Another factor to consider is that most tyre fitting companies (in the UK at least!) will no longer know how to fit tubes anyway! My 1972 Daf 33 has just been re-shod with 4 new tubeless Firestone 135/70R13 tyres, and it feels much better.

[dafix]

Hi Andrew, thank you for your comments. There is an online tyre store in France which sells Hankook 155/70R14 for EUR 43.40 a piece (as well as Continental with the same size which are a little more expensive but probably better). I am not sure to understand your point regarding the speedometer: don't 135/70R14 and 155/70R14 have the same circumference ? Regarding tubes, I had some years ago a Peugeot 404 with original tube-type rims but without tubes (I discovered that later). I had basically to re-inflate the tyres every month and the problem was solved when, replacing the tyres, I had tubes installed inside. From this experience and because the rims of my DAF 46 are slightly dented on the edges, I fear they won't probably not be airtight enough to be used without tubes. On the other hand, I may have troubles at the next CT (equivalent of your MOT) if they find I have tubeless tyres (tube-type tyres for cars are almost impossible to find now) with tubes inside (which is forbidden). So it is not that easy...

[daydoodler]

Hi I fitted a set of 155/70-14 Continental tyres to Dolly my 44. No problems with clearance or rubbing. 155/70-14 is a straight swop for 135/80-14. To keep the same profile that is the same rolling radius which is the radius of the tyre when compressed under the weight of the car you go up two sizes So 165/70 is actually bigger than sizes 135 and 135/70 and 145/70 is actually smaller than 13/80-14. Hope this makes sense
I ordered mine through Tyreshopper the price includes valves balance and old casing disposal and can be fitted at any branch of National Tyre and Autocare

[dafix]

Hi daydoodler, thank you for your reply. By the way, do you use tubes with your new tyres, and if not is it OK on your 44 (no air loss) ?
andrew : I realize I was wrong regarding the speedometer issue: indeed 135/70R14 and 155/70R14 don't have the same circumference (because the second number is the tyre height expressed in percentage of the width, which is the first number) ! However, I am not sure that the original tyres (135SR14) are equivalent to 135/70R14. I will measure them.

[mtjm]

Apr 20, 2019 17:31:34 GMT dafix said:

However, I am not sure that the original tyres (135SR14) are equivalent to 135/70R14. I will measure them.

I believe that if a tyre doesn't display an aspect ratio (e.g. the 70) then the default is 80, so 135SR14 would be 135/80R14. See here: www.vintagetyres.com/tools/

[dafix]

Hi,

Yes you're right, I have checked it: 135SR14 is equivalent to 135/80R14. Now, I am still puzzled about the tube vs. tubeless issue. Ideally, I would prefer to use tubeless tyres with no tube fitted inside, but I have still doubts about the compatibility of the DAF 46 rims (they look like similar on the DAF 66): I notice there is only one hump (groove seen from outside) which is on the outer side of the rim, although in theory (from what I have read) there should be another one on the inner side, if the rim accepts tubeless tyres. Also, the space around the hole seems very narrow to have a valve for tubeless tyre installed.

[daydoodler]

Hi I fitted my four tyres tubeless in 2016 and have had no pressure loss. Do not fit tubes, tubeless tyres have ridges inside the casing which will chafe the tubes and you will have a sudden deflation. Your local tyre shop may have a Michelin or similar data book that will give you details such as rolling radius and revs per mile handy if you want to work out final gearing. Hope this helps

[andrew]

If a tyre doesn't have a profile percentage then it is 83% or more (this was the case when I was in the motor trade, but it was 35 years ago!) As to tyre size and speedometer readings, remember that speedometers are allowed a 10% error and factors such as over or under inflation will affect accuracy, probably more than differences in tyre size and profile. Although I've never owned a Daf 46, given they were manufactured in the mid 1970s I therefore am of the opinion that they should only be fitted with TUBELESS tyres and that these tyres should NOT be fitted with tubes, for the reasons already outlined in earlier posts.