tyre size for a 125

[Nipper]

I am looking for a tyre for a RM 125b, and i am a bit confused with tyre sizing. The suzuki manual tells me that the rear tyre for this bike is a 4.10 x 18. But i am having trouble finding the "metric equivalent". To make selection a little easier for me what size tyres is everyone else running on their 125's ?

[mick25]

110 tire is a 4.10 I think

[Nathan S]

3.50 is 80/100
4.00 is 100/100
4.50 is 110/100
Etc.

But 4.10 is actually smaller than a 100/100 - its a lower profile tyre, so more like 100/90.
Same is true for a 4.60 - they're about a 110/80.

Nobody makes 100/90x18s (AFAIK).

In reality, you'll probably find that a 3.50 looks closer to a 4.10 than a 100/100, basically because you spend a lot more time looking at the side of the bike than the back.
I don't know of any good 3.50x18s out there. They only seem to be cheap, non-performance tyres nowdays - if it's a race bike, I'd go for a 100/100.

[John Orchard]

I use a Mitroc Fortune M896 4.00 x 18 on my 125B, mainly because I love the retro look ...

http://www.proaccessories.com.au/products/mitroc_fortune/tyres.htm

As far as I seen, the 4.10, 4.60, 5.10 & 5.60 are all 10% lower profile tyres (as stated above) ...

4.10 = 100/90
4.60 = 110/90
5.10 = 120/90
5.60 = 130/90

[Montynut]

You need to be careful of sizes with Michelins. They measure their tyre width across the tyre including knobs while almost all others measure width across the carcass of the tyre. Basically 120 Michelin is a 110 in other brands.