Any advantage of 27.5+ over 29 for Bikepacking?

[ElectricalGuy]

I'm considering using a 27.5+ hardtail for bikepacking and wondering what the advantages are over using a 29 hardtail?  I have a good variety of 29er tires from 1.9-2.35 inches and has served me well.  Would there be any improvements in moving to a 2.8 or 3.0 inch 27.5 tire?

[RonK]

I don't think there are any. Perhaps a wider 27.5 in tire will fit your frame.

Depends what surfaces you expect to ride.

27.5er are usually adopted for nimbler handling but the smoother rolling 29er probably aces them for bikepacking.

[Spec44]

- Overall tire diameter will be similar, dependent on on the tire size, of course.
- Having a suspension fork makes the low pressure high volume of the 27.5+ cancel out, though the low pressure will help absorb some small bumps.
- Being able to use a larger tire on the back at lower pressure will provide some cushion over the smaller 29er.
- the wider, low volume tires of the 27.5+ are beneficial adding some "float" in soft soils like the thick sand we have in Florida, and can also provide additional traction on roots and rocks.
- the smaller contact patch of the 29 will probably be a little faster/roll easier (depending on the tire pressure, tread pattern, etc.)

[ElectricalGuy]

So it sounds like under some conditions a bit more float and traction depending on where I am riding.  Perhaps in a perfect world should choose depending on terrain.  I will have access to both types in the near future but will probably stick with my 29er set up as some of the newer tires feel pretty good to me and probably don't need any more resistance or rotating mass than is necessary.

[Smithhammer]

Definitely can be some advantages to 27+ over 29, depending on terrain.

[pavementgraveldirt]

You should try a bike with low pressure 27.5+ if you are interested in the small bump compliance and the extra traction.  Also might look at 29+ as well. 

They are slower on pavement. The bigger tires also take more time and energy to get going in start stop techy positions over a thin and light 29er.

To be fair I've really liked my 27.5 everything.

[offroute]

Right now I'd guess there's a wider availability of 29er tires than 275+ at shops in general. Better chance of getting something suitable if you have a problem on tour.

If room in your frame: More 2.6" 29er tires are coming out all the time.

Optimal setup really does depend on the route and the bike. Still, every setup will feel like a compromise at some point in hundreds or thousands of miles.

[wahday]

Definitely slower on pavement, but my 27.5+ has great traction and the bump compliance makes a difference over long distances (my ride is rigid). I converted an El Mariachi from 29 to 27.5+ which lowered the BB a little. It isn't a problem, but makes the bike much more stable which is a bonus when loaded down. Hard to tell if it is the tire width or the lower center of gravity, but it is a really great bikepacker now (was already a champ)

[ElectricalGuy]

That's interesting.  I didn't know an El Mariachi could take 27.5+ tires.  I have one but mine is a 2011.  I will see if the tires fit.

[wahday]

To be clear on the El Mariachi conversion, 2.8 is the biggest you can fit in the rear. I originally had a WTB Trailblazer back there and could run with the dropouts all the way in. I now have a Specialized Slaughter 2.8 which is a little wider (front is a WTB Bridger 3.0 on a steel Firestarter fork). Now the dropouts are all the way back, but clearance is good (yes, it is tight, but I have never had issues, though I do live in a dry climate). It is slightly less nimble but not overly noticeable. This is my bikepacking and commuter rig so I am not so concerned. It still performs wonderfully on a day ride, though it doesn't see as much of that kind of action since I have other bikes as well.

Wheelset = Velocity Blunt35s. The rim width will have some impact on ultimate tire width, FYI.

[ElectricalGuy]

Yes I did hear that on "traditional" non-boost 29ers the i35 rim is recommended and most of them won't take anything bigger than a 2.8 in the rear.  My El Mar has the fixed dropouts so it might not work at all.  But I am running the latest Firestarter carbon fork up front which has tons of clearance.

[Boon]

I swapped my 27.5+ for 29ers. The former was cush, but I simply felt I was working too hard over longer distances. So for more technical trails, I'd probably swap back, but for the gravel and dirt roads I ride, I prefer the 29ers.