Quick Tyre size question for 13"

[The Shermanator.]

Quick sizing question from recent newbie.

I have 13" wheels x 8" rear, 6" front

Currently have CR500 205x55 and 175x55 (these look in fantastic condition but are 11years old.. so a bit worried they've probably gone off a bit..!)

So looking to put Toyo 888's on. Question is, the 888's only come in 60 profile and no 175 width so would 185 be fine on the 6" fronts and 60 profile instead of 55 all round?

 

Many thanks.

 

[Geoff Brown]

Originally I had CR500 13" 175/55 & 205/55.

Upgraded with no problems to 13" 185/55 & 215/55 ZZS. The fitter did say that they were a pig to get over the rim due to very stiff side walls.

Just one thing to remember is that the 60 profile means that the tyre wall will be higher creating a possible problem of interference with the cycle wing stay or wing. Or both.

As I found out after investigation change in profile requires the speedo to be recalibrated & more than likely the ride height/rake adjusted.

 

[ScottR400D]

I would agree with Geoff having done the same thing. It did require a check of the ride height etc after the change and the speedo. As he says the 60 profile will n mm are things close.

 Nominal sidewall heights:

175/55 - 96.25mm

185/55 - 101.75mm

185/60 - 111mm

So you'd be adding almost 15mm to the height of the tyre under the wing. 

My ZZRs just fit under the cycle wings but have to be tilted under the edge of the wing when offering up, where the CRs went straight on. Some have found that the wings can rub the bigger tyres which is corrected by 'adjusting' the stay. 

I fitted a set of ZZS a few weeks ago to a mate's 420. They go on the rim OK but can be a sod to get the beads to seat. The ones we did had to be inflated to 60psi to seat them. Avon say up to 90psi is acceptable to seat. 

[aerobod - near CYYC]

The R888Rs on 13x6" wheels are ideal in 185/60-13 size for the front tyres. The other two sizes available are 205/60-13 and 225/45-13. The 205 width are only recommended to be used on 5.5 to 7.5" wheels, so 13x6" would work for the rear tyres with them (although they are both too large in diameter and too wide to clear standard wing stays on the front). The 225 width is recommended for 7.0 to 8.5" wheels, so is better suited to 13x8" rear wheels.

In either case the suspension rake likely needs adjusting due to the 185/60-13 tyres having 552mm nominal diameter, 205/60-13 576mm dia and 225/45-13 532mm dia. I'm running Nankang AR-1 tyres in 185/60-13 front and 235/45-13 rear, so very similar to the R888R tyres, I've increased the rear suspension height by the appropriate amount to keep rake at 15mm.

[Golf Juliet Tango]

ELEVEN!    

[Geoff Brown]

Re change in ride height after calculation the nominal change in ride height for my tyre change was 5mm. Even with that small change in ride height the car appeared to be 'on sticks'.

Thank goodness for adjustable platforms.