27.5 + front conversion, keep 29 rear, rigid geared MTB

[Erik_A]

I have a fully rigid, geared steel MTB (Singular Swift). Would it help to switch to a 27.5 + front only conversion, but keep 29 rear (due to clearances)? My goal would be to get a bit more "pneumatic suspension' from the 27.5 WTB scrapper rims and 27.5 x 2.8 WTB Trailblazer tire. If needed I have another steel fork that is 15mm longer that I could use to keep the BB height about the same (my bike also has an EBB).

What is your experience and/ or advice?

[p nut]

I'd go 29+ instead. Better cush, no significant weight gain vs 27.5+, slackens the angles a bit on the Swift (good thing, in my opinion). 27.5+ will steepen the angles too much, especially with the WTB Trailblazer tire, which is heavily undersized than indicated.

[bmeryman]

What's the outer diameter of your standard 29er wheel/tire combo? My 27+ built up with Scrapers and 27.5x2.8 Rocket Rons comes in at 725mm.

For what it's worth I ran 29+ for a season and 27+ for a couple seasons now. The 27+ wheels are noticeably quicker to spin up and corner in any sort of technical riding. That being said, 29+ rolls extremely well and would be a great option for less technical riding or bikepacking/camping applications.

[ColonelJLloyd]

I've been running a 29x2.35 Ikon on an i29 rim rear and a 29x3.0 WTB Ranger on an i45 rim front. This is a Ti hardtail with Whisky 9 fork. I like it, but I'm considering replacing the front rim to match the rear (same ERD; nice!) and building a second 27.5+ front wheel because the overall size of the 29x3.0 is pretty friggin' tall and I feel like the same tire feel in a slightly smaller diameter would be better in some of the technical stuff.

Thoughts from anyone who is using a ~2.3" rear with a plus front setup?

And can anyone recommend a 27.5+ tire that measures an actual 79-80mm on an ~i45 rim? So many of these plus tires are often very undersized.

[GRAVELBIKE]

I'm considering doing the same thing on a Jeff Jones. I've ridden it with a 29 x 3.00 WTB Ranger front tire but that seemed less voluminous than the 27.5 x 3.00 Maxxis and Kenda combos I've used (on other bikes). Jones' fork uses 135mm spacing so I can't just swap wheels, unfortunately.

[JAGI410]

The Trailblazer is a joke as a plus tire, it's more like a 2.55" and its overall diameter is at or below 28", so it would be odd to have a larger diameter tire in the rear. If you can't fit a proper 27.5x3.0, don't waste your time. Geometry will suffer! Like mentioned above, go 29+ instead. Or even 29x2.6 (Schwalbe Nobby Nic).