Originally Posted by
HyBr1D
I chose 26mm to allow slower transition upon using the side knobs being that I am a novice at trails the bike already has soft and responsive steering, finding the line and maintaining it will be difficult for a nub like myself. So, having 29mm+ rims with increase the engaging rate of the 2.5" tire faster and may cause me to not react fast enough to the already fast and smooth steering on top of that the frame is very nimble and light so, it will change directions that much faster on a well-rounding tire to rim setup. 26mm will allow a more squishy feel and slower interaction with my user input maintaining control. If I need to change this on the fly I can add or remove tire pressure which can simulate more grip (or less, depending on feel) but there is no direct substitute to correct sized hardware.
In the future when experience is gained, I will run a wide rim (29/30mm) probably keep the front at 2.5, maybe even go up to a 2.6 (the frame won't clear anything wider) and the rear I might bring it down to 2.35 reducing the grip a bit at the tail for more whipping fun
Well first I should say that you are ultimately going to be fine with this setup, and what follows below is really just discussing the finer points....
I understand what you are thinking, here, and it makes sense in theory. Running some tires on overly wide rims can lead to abrupt and aggressive transition to the side knobs that can hook up when you don't want them to.... But I am not sure if you are aware of how that plays out with the specific tire and rim combo you have there.
The whole idea of the "WT" versions is that the tread profile is more rounded, so that 30+mm rims do NOT square-off the profile too much and cause the side knobs to dig in prematurely. In other words, they are designed to avoid what you are concerned about, but on 30mm+ rims.
A standard (non-WT) 2.5 DHF on a 26mm rim would not be overly squared off. It would actually be just about right for that tire.
It is also worth noting that tires like the DHF have a relatively wide and dead transition zone to begin with. As a result, it actually takes a concerted effort to get the side knobs to dig in. You have to actively lean the bike in turns to get them to hook up (but then they REALLY hook up). In other words, a tire like the DHF already addresses your concern pretty well, even on the proper sized rim (which for the WT version is 30mm+).
Running a WT version on a undersized 26mm rim makes the tread profile even rounder than intended, and thus it widens the dead transition zone. So now you need to lean the bike over even farther to get the side knobs to dig in. It is certainly doable, but this is not the most beginner friendly setup.
I guess my point is that I understand wanting to avoid having an abrupt and aggressive transition to the side knobs, but between the tire (which already has a wide transition in the tread pattern), and WT profile combined with a narrow rim, it is being taken to an extreme, and you may find that you have a hard time getting the side knobs to hook up when you want them to, such as in corners or getting traction on off-camber terrain.
I guess these are pretty fine points, though. You are going to learn to work with whatever tire and rim combo you ride just fine. It is hard to go wrong if you are on a mountain bike. And that is a sweet one for sure.