tires

didn't want to clutter up the other threads.

Can someone explain tire sizes to me?
Heres my sizes 120/90 18 and 80/100 21

Looking at the IRC GP-1 tires and they are listed like 4.10-18 WTH?

ahhhh....metric and inches. Did people know this??


*anyway..what tire size for the front?

**Still researching and still confused. Is there an out and inner limit and anything in between will fit?

Metric tire sizes are very straight forward. 120/90-18: 120mm tread width, 90 section width (the sidewall height is 90% of the tread width, in this case 120 x 0.9 = 108mm. 80 would be 80%, 100 100%, etc), 18" rim.

Inch tire sizes are less straight forward. I usually go by the manufacturer's spec charts and find something close to the size of the metric tire I'm replacing. I haven't been able to find an actual spec chart showing what each standard inch size is supposed to represent in terms of height and width.

FWIW, here's a new 4.60x18 Shinko 244 next to a worn out stock 120/80-18 TW302.

I was reading about those. Very interested.

right now it's between the Kenda K760's and those.

*the shinko's look like a good winter tire, but I have one big ride comeing up this month and a snow ride a little later...Having a tough time.

I'd probably get the 5.10x18 shinko if I do it again, should be closer to the 120/90-18 size I prefer running. I deeply disliked the K760II trakmaster I had this summer unless it was snotty and muddy out without big rocks or roots i.e. not the typical east coast riding I end up in. Assuming you meant to refer to the shinko's comparable Kenda, the 270, the shinko's are cheaper and supposively ride better and wear long, ymmv. Then again, if I wasn't commuting so much I'd be running a MT43 and be done with it...

Dunno how much I'd consider it a winter tire, I'm using it as a 50/50 tire to get me through my nearly all pavement/fire road winter riding and I'm doing my best to avoid snow this year.

And sizing across brands isn't always consistent, so lots of times we just make a choice and hope for the best. Thanks skierd, I'm happy to see those Shinkos are nice and short.

Sarah

OK, I sold earth mover tires for Michelin for a number of years and here is what they taught me. The first number is tread width, second is an aspect ratio of the width, and of course the last is rim size. So a 120/80-18 means the tread width is 120 mm, the second number means the tire height is 80 % of the width so the height of the tire from the rim to the top of the tread is 96 mm or so at least that is what I learned in tire school but who knows perhaps Micheline is incorrect. wilburj Wow my number of posts and my age are the same