20" Tyre Advice - sizing / brand / pressure

[Keaney]

I've now picked the alloys and dimensions but what tyre brand are people using on 20’s

Been quoted on accelera which was really cheap and may go down this route initially but normally stick to main brands, yoko, Pirelli and Michelin etc

 

[MrT6]

I'm running Uniroyal Rainsport 3 275/40R20 106Y - cost around £120 per tyre

 

[YellowHound]

Personally I would not buy tyres on price (alone).
All of the loads generated in driving are transmitted through the tyre contact patch - roughly the size of your palm.
They have a huge influence on both the way a vehicle drives and its safety.
Just my 2p

 

[Keaney]

Yeah I know what you mean, it’s understanding where the line is though.

I’m considering nankang and uniroyal

 

[_GB_]

I'm using Kumho Ecsta . Pretty impressed with them but there only rated 102.

 

[Chriswhit]

Just changed to continental contact sport 6 after having gone through three sets of Uniroyal rainsport 3 . Rate the Uniroyals for the price but the continentals feel more sure footed and the steering feels sharper too , should do at £220.00 each . Be interesting to see if I'll get 14K like the Uniroyals .

 

[T6 dork]

try them Keaney honestly you will never spend daft money on tyres again...
i use them on every car I've had and have just fitted 4 to my Audi A8
275/35R20 ACCELERA PHI-2 102Y XL = £280
less than £300 for a set of 4 ?? no brainer

 

[Fidget]

yeah, I'm sure you've heard it all before from another newbie, sorry about this.

It's time to change the rubber, the van came with a new set of tyres that turned out to be just better than crap. They've been on there or 6 months and are done already. Wheels were new, it's not been curbed or off road so no real reason to be knackered.

So now they are just BLOODY NOISY.

I need to change them ASAP but don't want to go done the route of low profiles. The van has been lowered 50mm so like the way it looks with the higher profile, it's running 275/40ZR20 106W XL rubber atm. Haida 'racing' hd921 tyres, whatever they are.

I'm looking for something quiet, tend to do a fair bit of running around as it's a day to day vehicle so don't need tons of road noise.

Are you in the know able to provide me with some options please? If this was motorbike tyres i'd be fine, but cars and vans confuse the hell out of me.

thanks for your help.

 

[T6180]

I ran 265/40/20s on mine, they were Goodyear eagle f1s costly but worth it
plus they were 103y load rated

 

[Jamie2.0]

So I finally took the plunge and got some 20" wheels, went staggered 8.5/10, offset 37/38.

Van is a T30 Kombi for family use and not lowered (yet). After reading around various threads I'm thinking of going with the following tyre sizes: -

Front 255/45/20
Rear 275/45/20

I have found some tyres in these sizes, however the load and speed rating is different, larger ones are 110 Y, smaller are 105 W. Should I have any concerns over these differences?

Finally the van will be lowered at some point but I'm not sure by how much, no more than 50mm, want a stance where there is a nice even clearance between the tyre and arch upfront and maybe marginally higher on the rear. Could I run into trouble with these sizes?

 

[chriscroft]

Those rear tyres are way too big imo. Unless you have lifted suspension; and a 250hp/400lb/ft engine or reduced gearing it will be a pig imo

Can you find the tyres in: 245/45/20 Front
275/40/20 rear
Avon ZX7
275/40 R20 Y (106)

This tyre is available in 245/45/20 as well

 

[Jamie2.0]

Thanks, is it just the side profiles that are too big on the rears?

I've just gone away and read up on the aspect ratio, think I see what you're saying now!

Am I better to stick with the same side profile all round or does it not matter because it's calculated on the width?

 

[Depron Donkey]

Enter your existing tyre size in to willtheyfit.com (link below). You can then play with the tyre sizes, ideally as close to the original overall diameter/circumference as you can. Some tyres are not available in all the load ratings, check your maximum axle rating and divide by two to find your minimum load rating, it’s 103 for a T32 but don’t know what it is for a T30.
Will They Fit - Online Wheel and Tyre Fitment Calculator

 

[Kramsdog]

I run those ZX7 275/40/20 on my T5 with B12 shocks with 40mm H&R springs, very impressive tyres so quiet and comfortable ride.

 

[chriscroft]

Thanks, is it just the side profiles that are too big on the rears?

I've just gone away and read up on the aspect ratio, think I see what you're saying now!

Am I better to stick with the same side profile all round or does it not matter because it's calculated on the width?

So I would guess that you would like a similar diameter/rolling radius front/rear; but a larger section width on the rear to get the staggered look.

so to calculate the side wall depth you need to multiply the section width by the aspect ratio (expressed as a %)
so fronts = 245 * 45/100= 110mm of side wall rubber
rears = 275 * 40/100 = 110mm of side wall rubber............da da the same

now if you look at tyre size comparison web page such as this

Tire Size Comparison

and tick the mm box, you can see how these tyres compare to say a 235/55/17 standard vw t6 size.

If you put the standard vw tyre in" size 1" & either of the other two tyres in "size 2", you will see that these tyres are 5.5% larger in diameter and rolling radius; so you will be effectively up gearing the van/speedo reading by 5.5%. This is significant, and you will notice it driving the van in terms of gear selection for a certain speed/ acceleration etc; but you will get used to it. What power engine have you got?, if it was the smaller engine; and you were fully loaded; with a roof rack; towing a trailer; in a mountainous region; you may want a remap or two or reconsider up sizing your tyres.

The rear should fit OK, but if they just rub on the plastic wheel arch liner you may need a wheel spacer; and or re mould the liner with a heat gun; but I think you'll be OK.

In terms of lowering, I think you might be OK at 50mm; but if you get adjustable coil-overs you can adjust to suite, certainly 30mm/40mm lowering should defiantly work, as long as you aren't carrying very heavy loads.

The new sizes would have an increased diameter of 38mm = 19mm radius; so the van will sit 19mm higher over all with 19mm more ground clearance (without altering the suspension), and you would loose 19mm of the gap between the arches & tyres all the way around.

275/45/20 would be 63mm larger in dia = 32mm in radius ; and 9.2% increase in gearing/rolling radius/diameter. I don't think they would even go in the gap

 

[Jamie2.0]

Thanks for your help guys. A bit more science to when I last got tyres for a project, I think I just went, got these 15 x 10s, what's the fattest BF Goodrich you can fit on there before it looks silly!


Van will remain as a kombi, no camper conversions, extra roofs or roof bars are planned, rear spoiler has put pay to a bike rack and no chance of towing anything, so should be ok. Remap does sound tempting may have to plan for this later

Whilst the kids are small at the moment it's a very rare occasion anything heavier than a double buggy goes in the back so we should be ok there to.

I'll get on those websites in the morning

 

[Jamie2.0]

Thanks for your help, results are in...

Existing tyres are 205/65/16c 107/105T - engine is 150ps.

Using the comparison website if I go for the following: -
Fronts
245/40/r20 4.5% bigger
or
245/45/r20 8.3% bigger

Rears
275/40/r20 8.3% bigger

40 profiles all round?

The will they fit calculator looks ok too.

 

[Skyliner33]

Those sizes would give you a bigger sidewall on the rear than the front.

 

[Jamie2.0]

Noted, since looking at the above 45 on the front and 40 on the rear. This is only a 0.5mm size difference between the two, however it does mean a much larger set up on the front than existing tyres.

I've had a search on here to see what others are using, keep coming back to this thread with Richard f's van. In terms of looks I think it looks spot on.

View attachment 26220 View attachment 26221
Just went and measured my tyres 245/45/20 103 front on 8.5rims and 275/40/20 106 rear on 10 in”rims and they are the same height and roll in profile

 

[RattyMcClelland]

275/35/20 will be fine on a t30.