Tyres on RX8 Alloys

[Mark Norton]

Have some nice RX8 alloys and am looking for tyres. Seen Bongo's with 245/45/18's on, I would like a deeper profile and am considering 245/50/18's that I can get a good price on. Thats a 6.7% increase in diameter over standard and about 4% bigger than the 245/45/18's. My speedo is overreading by 5mph and this size should give me a 4mph gain meaning the speedo will still be legal. Also it seems about the biggest size I could fit before I would have to start sawing off part of the front bumper for clearance.
Any comments appreciated.

[mister munkey]

Not sure if thats an economical or practical solution to sorting a speedo discrepancy Mark.

245/45s are expensive enough, assuming you can source some 96+ load rated ones & if your speedo reads 5mph over (which is not illegal), a careful tweak of the needle on the shaft will probably sort that.

I have a set of RX8s in the shed as they took a bit of a hammering over the winter months & now need a refurb. I love the look, like the ride quality but resent the cost of rubber.

Although rumour has it that suitable 245s are available at around £50 a corner which is the way I'm heading shortly. My last pair of 235s were £115 each.

PM me if you need any info on that front.

[Mark Norton]

Yes 245/45's at £110 for http://www.tyres-pneus-online.co.uk/car ... ,H,XL.html. Seen Maxxis 245/50/18's 100+ load rated at £74 each.
Nice to hear the ride quality was good on your last 235's what profile were they?

[waycar8]

is yours a 4x4?.... if so, you need to get as near to the origional rolling circumference as possible, as it will knack up the auto box

hence the reason why its either 245 x 40 or 225 x 45 that most people go for

http://www.alloywheels.com/tyrecalc.asp a tyre calculater that will help

[madmile]

is yours a 4x4?.... if so, you need to get as near to the origional rolling circumference as possible, as it will knack up the auto box

hence the reason why its either 245 x 40 or 225 x 45 that most people go for

http://www.alloywheels.com/tyrecalc.asp a tyre calculater that will help

I am no diff expert, but I understood it was different circumferences on each axel that messed up the diff, same size all round even if bigger should make little difference.
Personally I have 245/45's on my 18's . They are accellera, rated at 101 and were around £75 each from memory. With standard suspension the ride is fine, with lowered suspension on the van I had them on last year, the ride was grim to say the least. If I am honest, I have noticed a bit of splitting on the edges, but this is quite possibly due to them being on a lowered van for over a year wher the side walls were taking up a lot of the suspensions work.
As MM says, its pretty easy to recalibrate your speedo whatever tyres you have on.

[waycar8]

Its to do with the viscous coupling in the autobox for the 4wd system, the diff will knack if you put different size wheels on the axels.

I am sure Dandy will be along to explain further as hes up on the whole viscous coupling info.
Or do a search I am sure theres loads of info already on here

[mikexgough]

Its to do with the viscous coupling in the autobox for the 4wd system, the diff will knack if you put different size wheels on the axels.

I am sure Dandy will be along to explain further as hes up on the whole viscous coupling info.
Or do a search I am sure theres loads of info already on here

Not an expert but your right about the VC..... Tyre fitter told me years ago on a Full Time 4x4 you should have same size tyres all round.... He does Landies and 4x4 in the main...... Wheelquick fitted same size Tyres all round on my "new" 17" Wheels last week and if anyone should know...

[Mark Norton]

Sorry, not sure if I understand, I thought that as long as all 4 tyres were the same size it didn't matter if they were bigger or smaller. Does this mean that anything other than the standard size + or - 2.5% will cause dammage on a 4x4 even if all tyre sizes are the same?

[mikexgough]

Sorry, not sure if I understand, I thought that as long as all 4 tyres were the same size it didn't matter if they were bigger or smaller. Does this mean that anything other than the standard size + or - 2.5% will cause dammage on a 4x4 even if all tyre sizes are the same?

As long as all the tyres are the same size...... obviously size dictates any speedo errors.....