Tyre sizes - help please

[A911DOM]

Having made a fairly expensive mistake with a set of 888's that are too small for the Teledials I have on my 944, I now need to get some more tyres in readiness for the weather to sort itself out and getting the first track day of the year sorted.

Currently the car ('88 944) has 215/60/15 Conti Sports on. But, Im worndering if I should be looking to put slightly wider on the rear than the front - and as Im wholely confused by what sizes I can and cant put on - I need some help.

Im thinking I could put 215/60/15 on the front - and put a pair of 225/60/15 on the rear (have I got this right to put slightly wider tyres in the rear)?

As its a track tool - should I be considering dropping the profile slightly - eg: 215/55/15 fronts & 225/55/15 rears?

I hate not having a clue

[Nurburgsingh]

I wouldnt worry too much about what size conti's you're currently wearing. You need to know what width the wheel is, then have a look at the R888 spec sheet and it'll give you permited tyre widths to fit the wheel correctly.

Wouldnt bother trying to get a wider rear on a 944, they understeer a bit when you're really pushing on so what you're ideally looking for is the same size tyre all round.

[A911DOM]

Nurburgsingh said:

I wouldnt worry too much about what size conti's you're currently wearing. You need to know what width the wheel is, then have a look at the R888 spec sheet and it'll give you permited tyre widths to fit the wheel correctly.

Wouldnt bother trying to get a wider rear on a 944, they understeer a bit when you're really pushing on so what you're ideally looking for is the same size tyre all round.

Cheers NS,

I believe they are standard, and should be 7J front AND rear according to a spec sheet I also found whilst surfing around for info - the car isnt here for me to inspect unfortunately, otherwise I'd be laughing.

So you reckon to keep same width on front and rear then, that'll make my ordering process easier (which is important following the balls up I made of it last time )

Camskill only list the following sizes in 888's (which wouldnt be smaller than my current tyre) - hence my wanting to make sure this time:
R15" - 215/50/15, 215/50 R15
R15" - 225/45/15, 225/45 R15
R15" - 225/50/15, 225/50 R15
R15" - 225/55/15, 225/55 R15
R15" - 225/60/15, 225/60 R15
R15" - 235/50/15, 235/50 R15

[swtmerce]

IIRC a 7 inch rim should be matched to a 215 R888. Go for the lower profile which will reduce the circumference and improve the equivalent power at the wheels.

[A911DOM]

swtmerce said:

IIRC a 7 inch rim should be matched to a 215 R888. Go for the lower profile which will reduce the circumference and improve the equivalent power at the wheels.

Thats very interesting - where did you get the info from?

[Nurburgsingh]

thats odd... I looked at the toyo website and found this


http://www.toyo.co.uk/productdetail.php?identity=p...

But as you say Camskill have a larger size range and no permitted wheel widths showing....

If I were you, I'd ask someone that races a 924. The 888 is their control tyre and I'm guessing tha they'll all be running 15's....

[A911DOM]

Nurburgsingh said:

thats odd... I looked at the toyo website and found this


http://www.toyo.co.uk/productdetail.php?identity=p...

But as you say Camskill have a larger size range and no permitted wheel widths showing....

If I were you, I'd ask someone that races a 924. The 888 is their control tyre and I'm guessing tha they'll all be running 15's....

Thats a handy link too NS - Cheers

[A911DOM]

NS - Ive got a set of 195/50/15's - and according to that Toyo link you gave above, they'll go on the 15' rims ive got. My mechanic seemed to think they were going to be a bit stretched on there and not be appropriate.

Whats the opinions on that? Am I stretching the tyres too much to be useful on track at those dimensions?

[iguana]

195/50/15 are not stretched at all on a 7j rim, thousands of Golfs, Mx5s, 924s, E30 Bmws run that set up, is prerry much the most popular size track tyre in the older & smaller cars.

[swtmerce]

What iguana says

Track tyres generally take wider rims than road tyres for the same section size. There´s a Toyo webpage that states the range of rim for the tyre sizes plus it gives a recommended rim size too. I just can´t find it at the moment.

[A911DOM]

iguana said:

195/50/15 are not stretched at all on a 7j rim, thousands of Golfs, Mx5s, 924s, E30 Bmws run that set up, is prerry much the most popular size track tyre in the older & smaller cars.

Im seriously questioning why my mechanic has told me these are too small now - not having the tyres OR the car here is proving to be somewhat of a PITA!!!

If I dont need to rush and buy another set of rubber that'd be great - but I dont want to go and stretch a new tyre onto the rims if Im not going to use them and then have trouble selling them on...

Im wondering why he's adjudged them to be too small now... Am I going to need spacers to fill out the rear arches at this size perhaps?

Wholely confused.

[iguana]

A911DOM said:

I hate not having a clue

Think you need to learn a bit really fella. Why did you buy the 195s then??

Ok 195 is fine on 7j, as I said above literally is the most popular tyres size.

But but but they may indeed look lost in a 944s arches- think trolly wheels & the circumference will be less so car will accelerate noticably quicker, & lose out in top whack- (not noticable on uk tracks with car/power)


205/50/15 is a tad better size.

On both the speedo will over read by quite a margin tho 10% & 8%

Nearest treack rubber size to what you have would be 205/60/15 circumference is very close to standard size speedo under 2% out

[A911DOM]

iguana said:

Think you need to learn a bit really fella. Why did you buy the 195s then??

A very valid point, and one which bugs the tits off me!!!

I ended up ordering these tyres from a scribbled note I'd written myself which I took to be the current tyre size - sadly that was written on another scrappy note which got lost/overlooked.

I was in a hurry to get the things ordered as I was coming back to the UK to collect them over a weekend and needed to make sure Camskill had enough time to get them to me. Its all a learning curve I guess.

Thanks for the helpful advice, Im gonna pick the tyres up from the mechanic and take them to the car (at the bodyshop) and see how things tally up.

[swtmerce]

OK here´s the page I referred to that lists the rim ranges PLUS the recommended rim size. Unfortunately it´s old so it doesn´t list the 195 and other sizes.

http://www.toyor888.net/racing/index.htm

Anyway, Toyo technical are only a phone call away

Edited by swtmerce on Thursday 14th January 06:19

[Mr Monza]

Forget the Porsche and get a Dolly old boy. Meh Meh.

[A911DOM]

Mr Monza said:

Forget the Porsche and get a Dolly old boy. Meh Meh.

Ahhh, but the dollys dont like the speed humps much do they fella

Good to see you've finally seen sense and joined the Pistonhead ranks! At least it'll give you something to while away those long days at home (and you can see where I spend most of my 'working' life. Welcome aboard ol'boy!

Edited by A911DOM on Thursday 14th January 10:30

[Mr Monza]

Quite so, especially when you are driving matey! My beloved Dolomite was nearly airbourne with you behind the controls!!!

[A911DOM]

Mr Monza said:

Quite so, especially when you are driving matey! My beloved Dolomite was nearly airbourne with you behind the controls!!!

Sounds quite impressive until you realise it was simply to demonstrate how your own car sounds 'driving away from you' "Watch this, rev rev, vroom, crunch" - Oops

Although the 0-60 tests round the old country lanes were far more impressive!

I seem to remember you getting a touch edgey with my spirited driving (of the old Alfa Sud) on a back road trip to the folks

[Mr Monza]

I fear the phrase is 'shi@@ing ones y-fronts'. I am surprised that I am the one that ended up still having hair!

I concede that the old bus did sound rather impressive........

I got that Monza by the way.....for absolute peanuts. Then find that the previous owner spend upward of £10k having it rebuilt. The engine looks (and sounds) amazing. It pulls like a train & I have finally rejoined the ranks of having something with a touch of thrust!

The 3500s is (well, should be) MoT'd and on the road in weeks! Can't wait to be behind the mighty Rover V8!!!!

There is also talk of a garaged Dolly Sprint, untouched for 10 years that could be coming up for £100! I would have 1st refusal........

God dammit I'm a loose cannon.......

[A911DOM]

Mr Monza said:

I fear the phrase is 'shi@@ing ones y-fronts'. I am surprised that I am the one that ended up still having hair!

I concede that the old bus did sound rather impressive........

I got that Monza by the way.....for absolute peanuts. Then find that the previous owner spend upward of £10k having it rebuilt. The engine looks (and sounds) amazing. It pulls like a train & I have finally rejoined the ranks of having something with a touch of thrust!

The 3500s is (well, should be) MoT'd and on the road in weeks! Can't wait to be behind the mighty Rover V8!!!!

There is also talk of a garaged Dolly Sprint, untouched for 10 years that could be coming up for £100! I would have 1st refusal........

God dammit I'm a loose cannon.......

Dear god, yet more motors! Good work!

I contacted your 'chap' to look out for some extra rims for me for the track project and he responded via his ebay account

Fingers crossed for the Dolly, 100 notes sounds like a bargain if its a nice timewarp barnfind type example! Dont worry I wont tell your Mrs (or ya mum more to the point)

So judging by your profile you just have the 'TEN' cars at the moment then!?

I thought I was doing well adding a fourth to my fleet. Speaking of which, I have finally got the Toyo track tyres back from the mechanic and based on a few bits of advice gleened from the wise folk of Pistonheads, I'll be taking them along to the guy who has the 944 at the moment and getting him to stick them on for me.

I also ordered a race battery last night - The cost of a normal battery over here was about the same, so I thought I'd go for it and lose a few more KG's off the overall weight into the bargain. (I may also have ordered a battery cage, some racing roundels that you stick your numbers on when on circuit and some other bits and bobs too )

I look forward to having a cruise in the Rover, and Im quite intriqued by this Monza too (Im assuming this one is road legal is it?)