It really depends on who's making the tires, but I'd say 2.1 - 2.2 would be the max I feel comfortable running. I'm running Kenda Nev 2.1 on the rear and a 2.35 of the front. The 2.35 actually fit but there isn't much breathing room. The Nev's are a true 2.1 tire. I'm pretty happy with them.
There was another thread a while back and someone tested a bunch of tires. I'll try to dig it up later tonight.
The rim also has a great influence on the actual tyre width.
I have done some experiments with my ZION 660EBB frame; see the attached pics. There might be some difference between the regular 660 and the 660EBB frame on this....
Details:
Schwalbe Albert, nominal 26x2,25 in. ETRTO 559-57, with a ZAC 19 rim with about 1 in. /26 mm width. The max. tyre width is about 56 mm /2.2 in. There is about 1/10 in./ 2mm clearance; which I consider insufficient
Schwalbe Big Jim UST, nominal 26x 2,25", ETRTO 559-57; with a MAVIC XM819 UST rim. Max. Tyre width is about 2.09 in./53 mm - This results in about 1/6 in. / 3 to 4 mm clearance; which seems marginally ok to me
I ended up with some Schwalbe LITTLE ALBERT UST 26 x 2.10 SnakeSkin, nominal size 26 x 2.10 in (54-559) - which turns out to be about 2.05 in. / 52mm wide.
UST tubeless allows very low pressure rides even for a 175 pounds guy like me; I like the additional comfort.
I have also been given recommendations on a MAXXIS Larsen 2.3 in; but have not tried this...
As posted earlier, I consider the tyre clearance as a weakness of the ZION frames; and have sent an email to Jenson about this. So, fatties do not fit at all
Thanks for the pics. Yeah, that's a huge weakness of the frame. I've gotten to really like my Kenda Kinetics 2.35 and wouldn't bother buying a frame that wouldn't fit them. In fact, the wider the better, and 2.1 isn't enough in my opinion. I guess I'll keep focused on the On One 456 instead.
Good point, never gave rim width much thought. But I can see how that would effect over all tire width.
The tire clearance issue has been around on the Zion frames since before the 660, it turns a lot of people away from the frame. I'd love to be able to run 2.35 Kenda nev's on the rear. --Mark
Originally Posted by schlappmacher
The rim also has a great influence on the actual tyre width.
I have done some experiments with my ZION 660EBB frame; see the attached pics. There might be some difference between the regular 660 and the 660EBB frame on this....
As posted earlier, I consider the tyre clearance as a weakness of the ZION frames; and have sent an email to Jenson about this. So, fatties do not fit at all