Tyre sizes and wobble at 70mph

[bongolou]

I was just wondering what size tyres should be on my bongo. The dealer replaced all four with new ones for me inc a full size spare. But they are the same size on all four and i have heard people saying the fronts are different to the backs. Is this a problem if they arnt. I have a 2002 V6 Petrol non 4 x 4 if that makes a difference.
I have a slight wobble/shake at 70mph dont tend to do 70 very often normally at 60mph but im guessing it shouldnt shake when i do?? Could it just be a balancing problem.
Not sure about where to take it who will know about tracking etc on bongos.

[Poohbear]

You don't need different tyres front to back on a two wheel drive so no worries there. You do need to make sure that the tyres fitted have the same rolling radius as the originals because otherwise your speedo will be out by a bigger margin. The wobble is probably wheel balance (were the wheels balanced when the new tyres were fitted?) or if it has aftermarket alloys it could be that they need spigot rings fitted because you can't rely on the bolts to centre the wheel on the hub.

[bongolou]

I don't know if they got balanced when they changed them will try and find out. It does have alloys but think they been in it for years. What is the standard size tyre for a v6 petrol 2002 mode? on the car there is a silver plate with two sizes mentioned this confused me like front to back should be different.

[mikeWalsall]

Originaly compared to the back .. it would have slightly thinner tyres on the front (mine still has) ..

But on the rear wheel drive petrols it is not an issue anyway .. It is more crucial to the front wheel drive transfer box / Morse drive chain on the 4WD ..

[bongolou]

This is the sticker my bongo has the 215 70 size all round. A garage told me that its cheaper when i come to replace these to go for 215 65 instead as there a huge price difference between the 70 and 65's.

[mikeWalsall]

The '65' and '75' bit is the 'profile' of the tyre .. in simple terms how high the tyre is in % terms from the road to the rim .. compared with the width of the tyre .. (the 215mm bit) ..

You see some cars with very low profile tyres where it looks like an inch of rubber from the road to the rim ..

Others with higher profile tyres with loadsa rubber like Shoguns .. LandRovers etc: ..

To confuse it .. the bigger the diameter rim you change to (say changing from from 15" to 16" .. 17" .. !8") the lower the profile of the tyre needs to be to keep the 'rolling radius' ( the total diameter of rim and wheel) the same as the original wheels .. in particular to keep the speedo reading legal ..

[Poohbear]

You can compare tyre radii and circumferences with this tool: -

http://www.miata.net/garage/tirecalc.html

This gives the following results: -

195/80-R15 Radius 13.4" Circumference 85.7", Revs per mile 739
215/70-15 Radius 13.6" Circumference 84.4", Revs per mile 751
215/65-15 Radius 13" Circumference 81.7", Revs per mile 776

[MountainGoat]

The problem with sticking to the original tyre size recommendations is to decide what size you should use for the spare wheel once you have thrown out the useless skinny. Even the Japanese Bongo owners ignored Mazda's tyre size recommendations and fitted the same size all round. Mine was one of the Bongos that came over from Japan with 215 alloys fitted all round.

Tony

[bongolou]

Mine has got a full size spare that the dealer put under the car as there wasn't one.

[Jaws]

What size and rating is written on the tyre wall of the ones you have fitted? e.g. 215/70 R15 98R
Then somebody can give more precise advice

[helen&tony]

Hi
Nobody's mentioned that the correct size is 215/65/15, and load rating of 96 or over
217/70/15 will under-read on the speedo
Cheers
Helen

[bongolou]

My bongo says 215 70 15 on the sticker and that's what it has on it allans in Plymouth said 65 are cheaper so when need replacing change to that. My speedo pretty much matches the sat navigation same as my seat ibiza does and Audi I had so think it's accurate will try upload the sticker

[rita]

The problem with sticking to the original tyre size recommendations is to decide what size you should use for the spare wheel once you have thrown out the useless skinny. Even the Japanese Bongo owners ignored Mazda's tyre size recommendations and fitted the same size all round. Mine was one of the Bongos that came over from Japan with 215 alloys fitted all round.

Tony

Do you mean Tyres,if so was your vehicle 2Wd or 4Wd ??

[bongolou]

Yes tyres 2wd v6 petrol.

[rita]

Yes tyres 2wd v6 petrol.

I was talking to Mountaingoat,the guy with the Beard