Tyre options & ride height

[bobbybo]

Bought my car with Toyo 205/55/R15 tyres, have fitted new gaz Gold shocks (photo's coming soon)which can be adjusted but the ride height could be better, its sitting approx 175mm from corner plate of front outrigger to ground & 190mm at back, which seems to be about standard from past threads, but im no expert

According to tyre section on the Steve Heath manual the 205/55/15's should have a diameter of 606.5mm, mine are around 590mm measuring accross horizontal,

the one's the car came with should be 205/60/15 at 627mm diameter
and 215/60/15's have a 639 diameter,

so if i went with the 215's that should lift the car an inch approx?

page 222 on Steve Heath book has an interesting paragraph on handling, regarding fitting low profiles he says 'several owners blah blah, the anticipated extra grip doesnt happen, blah, at odds with Chims, wedges etc, trailing arm suspension on S's relies on higher profile tyres to compensate for changes in the suspension & wheel geometry.

Probably safer to stick with original 205/60/15 but appreciate any views

Robert

My question's are would 215's fit?, has anyone used them? would they be ok for more relaxed driving trips with wife?

[phillpot]

Wider tyres could make the steering even heavier at low speed

[tozerman]

215/60/15's will raise the car slightly and also alter the gearing so the speedo under reads !
On my S3c my 205 section tyres are very close the trailing arms on their inner edge so be care full about this.If you haven't already seen this website then it is a good way of checking what effects different size tyres have on the car http://www.alloywheels.com/tyrecalc.asp Good luck
Cheers.....Tony..

[bobbybo]

Thanks for replies, appreciate it, thats a great link for tyre calculations Tony have saved that one, ta

ill have a chat with my local tyre place & see what the difference looks like, suppose the two options would be 215/60/15 at 639mm diameter, or 205/65/15 at 647mm , (compared to stock 205/60 at 627mm)

guess there where no speed bumps back in late eighties early nineties when these where built ;-)

[GreenV8S]

bobbybo said:

Bought my car with Toyo 205/55/R15 tyres, have fitted new gaz Gold shocks (photo's coming soon)which can be adjusted but the ride height could be better, its sitting approx 175mm from corner plate of front outrigger to ground & 190mm at back, which seems to be about standard from past threads, but im no expert

According to tyre section on the Steve Heath manual the 205/55/15's should have a diameter of 606.5mm, mine are around 590mm measuring accross horizontal,

the one's the car came with should be 205/60/15 at 627mm diameter
and 215/60/15's have a 639 diameter,

so if i went with the 215's that should lift the car an inch approx?

page 222 on Steve Heath book has an interesting paragraph on handling, regarding fitting low profiles he says 'several owners blah blah, the anticipated extra grip doesnt happen, blah, at odds with Chims, wedges etc, trailing arm suspension on S's relies on higher profile tyres to compensate for changes in the suspension & wheel geometry.

Probably safer to stick with original 205/60/15 but appreciate any views

Robert

My question's are would 215's fit?, has anyone used them? would they be ok for more relaxed driving trips with wife?

205 tyres are the right size for those rims, 215 will fit but are on the wide side and may not be well behaved under hard cornering.

Playing with tyre sizes is not a good way to try to tweak the ride height. You've got adjustable spring seats, use them. But be aware that as you change the ride height you also affect the geometry and weight transfer at the back and can have subtle effects on the car's handling. Since the exhaust is relatively low, you're never going to have a lot of ground clearance so it would imo be a mistake to go to extremes on the rear suspension trying to obtain it.

[bobbybo]

points taken, ive gone off the 215 idea, too heavy steering etc as people have said,

anyone used 205/65/15's? or think they might work?

[GreenV8S]

Is it just ground clearance you're interested in? Have you checked where it's grounding and made sure the exhaust is mounted as high as it will go at that point? If it's grounding at the clamps, have you got the low profile Supra T-bolt clamps instead of the traditional U bolts?