Hello from newb and question on tyre size ?

[M 80NGO]

Hi i'm a newbe i sold my vw type 3 earlier this year and invested in a bongo, since owning it i have done a 7 country trip round europe with my mate as a 40th birthday prezzie to ourselves, no wives or kids just me, dan the bongo and the open road, just recently i have been down to limoges in southern france to see an old friend and the bongo never missed a beat on either trip.

I do have just one querie my van has 18" wheels with 225 / 40 tyres these must be wrong for the van as acccording to satnav the speedo is 6mph out its reading 70mph when mrs satnav is showing 64mph so do any of you nice people know what the correct size tyres are for 18" rims

[daveblueozzie]

The bongo was originally made for 15 inch wheels so any larger wheel is going to put the sat nav out slightly, Ive got 17 inch wheels and my sat nav is out by 3mph.

[mikexgough]

The bongo was originally made for 15 inch wheels so any larger wheel is going to put the sat nav out slightly, Ive got 17 inch wheels and my sat nav is out by 3mph.

mine is the same Dave....but then we have the same tyres.... I guess 67 mph at 70 mph on the clock means we are not going to get nicked...

[umbongocat]

, just recently i have been down to limoges

Were you in Ahun in La Creuse on Thursday afternoon? Saw a white bongo, still not posted about it yet...

[daveblueozzie]

The bongo was originally made for 15 inch wheels so any larger wheel is going to put the sat nav out slightly, Ive got 17 inch wheels and my sat nav is out by 3mph.

mine is the same Dave....but then we have the same tyres.... I guess 67 mph at 70 mph on the clock means we are not going to get nicked...

70 mph can the bongo go that slow

[M 80NGO]

, just recently i have been down to limoges

Were you in Ahun in La Creuse on Thursday afternoon? Saw a white bongo, still not posted about it yet...

Thanx for the swift replys guys but i really want to get the right rolling radius sorted cos my vans gonna show more miles on the clock than its actually done.

We were around the jalaneix area and my bongo is green and silver

[mister munkey]

Thanx for the swift replys guys but i really want to get the right rolling radius sorted cos my vans gonna show more miles on the clock than its actually done.

So for every ten thousand miles you do, it'll read 800 miles more. Negligable really & can be adjusted in 15 mins.

Easiest option is to ignore the speedo & just use the satnav speed, or if satnav is off, subtract 6mph.

A set of correctly load rated tyres for 18"s ain't gonna be cheap.

[The Great Pretender]

Wasn't there a post or thread about removing the needle and resetting to sat nav speed?
I have 225.55.17 and the speedo is 1mph fast at 70.

[David Edwards]

I have 215 x 15's all round and mine is 5 out to on sat nav a good help re speed traps so I have left it alone.

[scanner]

I do have just one querie my van has 18" wheels with 225 / 40 tyres these must be wrong for the van as acccording to satnav the speedo is 6mph out its reading 70mph when mrs satnav is showing 64mph so do any of you nice people know what the correct size tyres are for 18" rims

225/40-18 ?? What load index are they? I can only find that size in either 88 or 92 load index and 92 isn't enough for the rear and 88 isn't anywhere near enough on either axle.

If they are they you really ought to change them in any case - even 225/45-18 will only give you a max of 95 which still isn't really enough on the back axle, so you really ought to go up to 235/45-18 which should give you enough load index and cut down the over read on the speedo a bit.

[Sharkojoints]

Thanx for the swift replys guys but i really want to get the right rolling radius sorted cos my vans gonna show more miles on the clock than its actually done.

So for every ten thousand miles you do, it'll read 800 miles more. Negligable really & can be adjusted in 15 mins.

Easiest option is to ignore the speedo & just use the satnav speed, or if satnav is off, subtract 6mph.

A set of correctly load rated tyres for 18"s ain't gonna be cheap.

I junked my 18"s and changed to 16"s for just this reason - decent brand, correctly rated tyres in 18" cost a fortune!

How do you adjust the speedo? Mine's been changed from kph to mph, and it would be nice if the odo read something like the correct mileage.

[mister munkey]

Look around the scrappers for a 626 or MX6 dash. (93 - 99)

They have an identical (in mph though) speedo with GA5R stamped on the botton.

Four screws for a direct replacement that reads in good old Blighty units.

[Sharkojoints]

Look around the scrappers for a 626 or MX6 dash. (93 - 99)

They have an identical (in mph though) speedo with GA5R stamped on the botton.

Four screws for a direct replacement that reads in good old Blighty units.

Ah - I thought you meant you could adjust the odo reading. Useful to know that an MX-6 one fits too: I've got no kph markings on mine at the mo, as it's chipped.

[tricky]

The bongo was originally made for 15 inch wheels so any larger wheel is going to put the sat nav out slightly, Ive got 17 inch wheels and my sat nav is out by 3mph.

The size of the wheel is immaterial. The speedo is calibrated for a given diameter of wheel + tyre. The std 215/65 * 15 has a diameter of 660.5 mm. The 195/70 * 15 used on the front of some models (4WD IIRC) has a diameter of 654mm. The OP's combination has a diameter of 637.2mm which is 3.53% undersized which gives an over-read on the speedo (increased over-read really as the std combination over-reads anyway).

As suggested there are alternative 18" tyres which will correct the diameter to match the spec much more closely.

Looking at http://www.blackcircles.com I can see 245/40 * 18 tyres with a load rating of 97 available at £73.44 each. These will increase the diameter to 653.2mm which is near as dammit the same as the 195/70 * 15 fitted to the front of the 4WD models. I have their 245/45 * 17 W 99 rated tyres fitted to my bongo (replacing the undersized 235s that were previously fitted).

Selecting 245/40 * 18 woud be a lot cheaper option than changing all the wheels and tyres. The 245 width is not a proble wrt fouling.

[M 80NGO]

The bongo was originally made for 15 inch wheels so any larger wheel is going to put the sat nav out slightly, Ive got 17 inch wheels and my sat nav is out by 3mph.

The size of the wheel is immaterial. The speedo is calibrated for a given diameter of wheel + tyre. The std 215/65 * 15 has a diameter of 660.5 mm. The 195/70 * 15 used on the front of some models (4WD IIRC) has a diameter of 654mm. The OP's combination has a diameter of 637.2mm which is 3.53% undersized which gives an over-read on the speedo (increased over-read really as the std combination over-reads anyway).

As suggested there are alternative 18" tyres which will correct the diameter to match the spec much more closely.

Looking at http://www.blackcircles.com I can see 245/40 * 18 tyres with a load rating of 97 available at £73.44 each. These will increase the diameter to 653.2mm which is near as dammit the same as the 195/70 * 15 fitted to the front of the 4WD models. I have their 245/45 * 17 W 99 rated tyres fitted to my bongo (replacing the undersized 235s that were previously fitted).

Selecting 245/40 * 18 woud be a lot cheaper option than changing all the wheels and tyres. The 245 width is not a proble wrt fouling.

Thanx for the info Tricky its exactly what i'm after and tbh what i'm gonna look into is trading my tyres as they're only just over 3 months old for some good partworns in the correct size to keep costs down.