UKH

So, in a bid to reduce a bit of weight compared to my cube EX21 rims and have a 2nd set available for summer/winter tyres, I've decided I'll treat myself to a set of DT Swiss 1900s.  Yes, I know they don't have the nice 350 hubs, but I'm not at the level to justify the cost.

I was planning on 25mm internal width to reduce rear tyre squirm (which I get a lot at the rear with my required pressures and riding style), but thought it wouldn't hurt to ask if I shouldn't consider 30mm.  Only 50g more, but I get the feeling 30mm will make my tyres too square, especially with the Ralphs where the grip drops off a cliff edge at high angles.

Its a Cube Reaction XC bike; in the summer I run 2.25" Racing Ralphs at 1.7-1.85 bar, and in the winter 2.25" Rocket Rons with 1.6-1.75 bar, conditions depending.

Also, as I'm around 95kg (sometimes more.  Ahem), should I consider the M1900 instead of the X1900?  Only 100g more but a bit stronger.  Any thoughts or experiences appreciated.

I’m 80kg and have been running a 2.25” RR on a 25mm inner width rim for years it works so much better than my old 19mm rims, I tried a 2.4” but there wasn’t enough clearance. I wouldn’t want to go any wider on the  rim, StansNoTubes say 26mm rim is the max for a 2.25” tyre.

At  95kg I’d be considering 2.4” tyres  and 30mm rims for extra float if the frame allowed.

Surely, if you go for a piss before you go riding you've covered the 50g difference?

I wasn't worried about the weight remotely   My question was about the grip.

Thanks Jon.  I don't really need float on my local tracks to be honest; only a few deep mud patches in the winter.  Cornering grip and fast rolling is my goal.  Also, my Rons stop at 2.25" and the Ralphs at 2.35"... and definitely don't need more float on my summer tyres.

Glad to hear that the wider rim worked well for you!  I have indeed noticed that manufacturers often state that 30mm would be too wide, but some magazine reviews seem to love 30mm for that tyre size (moving to 35mm for 2.4 or 2.6).  But they all tend to run more aggressive tyres than I do.

Given everything you've said, stick with 25mm F&R.

Any reasoning behind that?

They're lighter :0

Must remember to inhale helium before setting off!

I run 30mm m1900 with 2.5 maxxis tires on my trail/enduro bike, 14.5kg bike 80kg rider. So they go through a pounding. I feel the x1900 will be plenty strong knowing the limitations of a pair of rocket Ron's.

Your posts answer your own question:

Thanks for the feedback Matt.  With the trails here, I'm not really doing any drop offs or anything like that, that would damage rims, but I do like to crash often (my 21mm cube rims do get bent out of shape occasionally).

I speculated based on zero experience of running anything wider than 21... but I prefer answers based on actual experience   Hence asking.

I already gave you my answer based on my experience and your needs.  That's why I said stick with 25mm F&R.

Why would you consider the need to run 2.25" tyres on a 30mm rim! Until the wide rim fad came in we were riding 2.1" tyres on 17mm XC rims no bother and pounding them. Admittedly going low pressure on tubeless means you need a bit more width so for 2.25" inch tubeless me and a number of friends went up to a 21mm rim.  You are being sucked into marketing drivel designed to sell more rims, 21-25mm more than fine

And people were hammering downhill on 100mm travel 26ers all those years ago.  Lol.  Looking back on forums from a decade or two ago, the same arguement was put about larger wheels... just a marketing fad.  Now see how many pros chose 29ers. 

Why would you assume this has to do with marketing?  I haven't seen any manufacturer marketing on rim width.  What I see is an evolution to wider rims over time, so the question is what is the optimum stopping point, and here i was looking to see if anyone had experience of both 25mm and 30mm rims on XC tyres.  Obviously your experience stops at 21mm, which is fine   In motorsport where tyre width is constrained but rim width is free, better grip is always had with wider rims due to sidewall stiffness.  The principles of sidewall stiffness aren't worlds apart.