Rear Tyre - Size Advice

[johnnyfartpants]

Just a quick question. I'm looking to replace the rear tyre soon and have found a good price on a Dunlop Roadsmart. My problem is that the tyre size is 160/60ZR18, and the current one is the usual 160/60ZR17.

Am I right in thinking that the ZR17 bit is the speed rating, rather than anything to do with the size of the tyre. If correct does it make any difference if you run a higher rated tyre to the recommended one?

[peterco]

The last 2 digits is the size of the rim.

http://www.moto-tyres.co.uk/seitenwandbeschriftungen.html

[mikerj]

The 17 refers to the wheel diameter; you will have some serious air leakage issues if you try to fit an 18 inch tyre to a 17 inch rim!

[johnnyfartpants]

Cheers for the replies.

I'll keep on looking, but this time with a bit more knowledge.

[Daveog]

:mrgreen: I'd thought similiar. The 17 refers to the wheel diameter; you will have some serious air leakage issues if you try to fit an 18 inch tyre to a 17 inch rim!

[yorkie_chris]

160/60ZR17

160, width of tyre in mm
/60 height of profile as %age of width so 160 x 0.6 = 96mm
Z speed rating
R radial construction
17 = 17" rim

Play about with any of those dimensions you want except for the 17" part. You can fit 180/55 if you want but it handles a bit odd.


I have seen a few people caught out with cheap 18" tyres :smt082

[johnnyfartpants]

OK, so after trying to save a few pennies on Flea-bay, I was recommended Dave Clark Motorcycles in Oxford. Popped down at lunchtime and after some good advice and a nice chat, have ordered the correct size Dunlop Roadsmart. They're gonna fit it for free, and whilst the caliper is off swap the rear pads. So all in all, I'm happy, Dave has a new customer, and Flea-bay can find some other numpty to flog their tat to.

Thanks again for the prompt advice.

[beabert]

The 17 refers to the wheel diameter; you will have some serious air leakage issues if you try to fit an 18 inch tyre to a 17 inch rim!

lol, :smt040