Question about rim sizes (27.5)

s1mples

Things have changed a lot since I last bought a mountain bike: )

Just thinking about 27.5 wheel sets, would I have to be careful in rim choice depending on what size of tyre I want to fit?

Are there standard sizes in internal rim width that I should look out for/avoid?

Sorry if this is a dumb question... it explains a lot about me: )

steve_sordy

Here is a very good link to internal rim sizes and tyre widths.
https://www.wtb.com/pages/tire-rim-fit-chart

Page down a bit until you get to the charts, one for hybrid bikes and one for mtb. My first proper mtb (2008 Kona Kula hardtail)) had an internal rim width of 17mm on a 26er and I went up to 2.3" wide tyre and that was stretching it a bit. When I fitted a lightweight 2.4", (too far), the front tyre folded when cornering and down I went! Successive bikes had internal rims that were steadily wider (19, 21, 25, 30) to cope with the wider tyres that were becoming more popular. My last regular mtb (2016 Whyte T130) had 30mm rims. I fitted 2.2" wide tyres to them. I could easily have gone wider but I didn't need or want to do so. The wider rims gave the tyres a squarer profile that suited the tyres very well.
Now I have an emtb also with 30mm rims. The original tyres were a lightly treaded 2.6" but I now have a heavier duty 2.5" tyres on and they suit the bike very well.

If I was to start again, knowing what I know now, I would not go below 25mm and not go above 30mm for a mountain bike.

s1mples

Thanks Steve, that's very helpful!