Can someone school me on Wheelset selection?
 

I've spent most of my time on these forums in the C&V section, so I'm a bit of a noob with CX/gravel.

What exactly sets apart a road wheelset from a gravel/cx set? In other words, what's the 'minimum' rim requirements to accommodate gravel tires (32mm+)? I've seen some marketed that had an inside width of 21mm, some as large as 25, etc, etc.

I'd like 700c clincher wheelset with rim braking surface.

I bought a used cx bike that has a tubular wheelset (I hadn't realized there was a difference between tubular and tubeless.. rookie) and I don't love the idea of not being able to easily fix a flat tire if I intend on doing some serious gravel riding. I've done hundreds of miles on a clincher wheelset on gravel, with rarely a pinch flat, so I'm totally good with clincer (or tubeless ready).

The trend is wider for wider rims, but people have been putting 33mm + tires on road rims forever. I have been racing this season two sets of road clinchers: Mavic Ksyrium SSC and Shimano R-500. These are both under 20mm internal width. I even set up the Shimanos as tubeless with a WTB 37mm Riddler tire and they've worked flawlessly.

I tired to put a 32mm CX tire on an older rim this year, and it just seemed too "tight" trying to squeeze the tube and the tire beads into the rim. Is that just perhaps because it was older (90's) and the internal rim was likely narrower? Would I be able to put the same 32mm tire on this wheelset, for example?

Tubeless-compatible tires* are known to fit a little tighter. You might try thinner tubeless tape in your older rims, and make sure the tube has a little bit of air in it when installing. That helps it to get out of the way.

*I'm making an assumption there, but it seems like most CX clinchers are tubeless these days. ;)

I'm sure it would be fine. I will note that if you're trying to mount tubeless ready tires, they tend to be a lot stiffer at the bead and can be tougher to mount. Warming the tire and lubing the rim with some soapy water can help.

I think my rims are 19mm internal. My old ones were 17.5mm and they handled a true 40mm tire perfectly fine.

A modern rim thats 23mm - 25mm external will be good.

OP, where are you in Pennsylvania? If you are a gravel noob, and want a new wheelset, it might be best to go to a good shop and get some advice - and maybe get a custom-built wheelset. (Unless you build your own.)

The best wheelsets I've owned have all been handbuilt. Costs a little more, but worth it.

are you familiar with Bucknell University? Right around there. It's home to an event called UnPAved, which, attending this year piqued my interests a bit in the gravel realm.

not sure I want to shell out the dough for a custom built set, having upgraded my roadie this spring and the new purchase of a gravel bike. I've got a decent set of Rovals on my Tricross, which I had considered swapping over, but I plan to re-sell the tricross to a friend, and don't think they'd like the tubulars.

ok,so this chart has been useful to me. Not sure why I didn't just check with Sheldon Brown first, anyway..

https://i.stack.imgur.com/EwkOp.png

I suppose that still begs the question, is there anything else that distinguishes a CX wheelset from a road wheelset? Spoke count, etc

None that I can see.

That chart looks a little off to me. For example, Bontrager (Trek) released the Aeolus Pro 3V which is aimed at the "high volume road and gravel tire" market (not MTB) and it's a 25mm internal width. If that chart is accurate it says 44c-57c...but most gravel frames max out around 45c or 50c for 700c tires. I just chatted with Trek CSR (because seeing that chart made me nervous since I just bought the 3V) and their official tire size support for the 3V is 32c - 64c.

The chart is just about what width tire is safe to use on a given width rim. It doesn't take into account frame or fork clearances. That's a separate consideration.

The chart is at least 12 years old, and represents older thinking on rim and tire recommendations. That people would someday run relatively skinny tires on really wide rims didn't occur to them, because the wide rims of the day tended to be much heavier.

Yeah it's misleading as well as old. Because it's implying "safety" issues and so in my case, on a 25mm internal rim, Trek says I can run a 32c on it, but according to that it's "unsafe" to run anything less than 44c! That's such a huge discrepancy.

I had a 700c wheelset custom built for me by Colorado Cyclist. I choose the DT470 rim because it has a 20mm inner width which I think is versatile to run 30-45mm tires. CX wheelsets may be on the narrower side as they're primary designed to run 33mm tires AFAIK. WTB has a chart that represents what combinations of tires/rim width they recommend: https://www.wtb.com/pages/tire-rim-fit-chart#

Beyond width CX wheelsets may have fewer spokes in order to maximize performance/weight rather than durability. There are many opinions on this but i think most all agree that you'll be unlikely to have issues with a well built 28 or 32 spoke wheelset.

We were running 2.5” mt. bike tires on what are now considered really narrow rims, maybe 19-20 mm wide ? and at 35 psi.

Did that for a few decades with nobody thinking it was not a good idea, cause it was fine.

A cx wheelset will usually be 135mm or 142mm in the back.
A road wheelset will usually be 130mm or 142mm in the back.

Thanks all for the info. I was able to put a 32mm cx tire on my road wheelset rims, no problem. I think the tube I used prior was too much (32-42mm). Tried a 28/32 today, fit just fine.

Gererally for gravel, most folks want at least 19 mm internal width and the closer to 25mm internal the better for a 700c rim. Even wider if riding 650bs.

The new Shimano GRX wheelset is excellent with 21.6mm internal width, 1625 grams weight for the set and cost $419. They have CUP AND CONE bearings too (thank goodness!). The new FSA gravel wheelset is pretty goood too at about the same price as the Shimano and just a few grams heavier but a bit wider and has sealed bearings. HuntMason X is comparable to the FSA set. Hunt is newer but good, about the same price though they ship from England unless you find a local shop like SweetWater Bikes in PA that stocks Hunt in the shop. Sometimes you can get hit with the new import Tarriff though when you import Hunt wheels from UK so be wary if you go that route.

Between these three I'd buy the Shimano myself as they are excellent quality and as light as many $1,000+ carbon wheelsets. As a matter of fact I am buying a set of Shimano wheels this week! The Shimano wheels do not get much attention with all of the botique wheelsets available out there, but if anything like the road wheels they build they should be outstanding, they have been building wheelsets for decades and do not put out any sub standard stuff. Shimano has great warranty backing and are easily serviceable by anyone without need for special sealed bearings.

I currently own a set of the FSAs and two sets of the Hunts mentioned above by the way so I can speak with firsthand experience with each.

That is a neat wheelset. I looked at it a few months ago when reading about the group and considering a wheelset for the frame I was building up at the time.
The weight was reported as 1720g to 1800g though, at least from what I read on Shimano's site and one of the larger online reviews.
Its a good price for sure. 24h rims simply scare me away due to not wanting to chance breaking and spending more money, even if the profile is designed to support me.

Does your shop have them in stock?...vendors online seem to be out for the most part.

FWIW running 21mm internal width Stans Crest with 33m tubeless for cyclocross and they've been fine. The rim is more likely to impact roots and ruts etc, mine have quite a bit of superficial damage and require semifrequent truing run at ~25psi with a 180lb rider. They handle the 36-40mm gravel tires much better in the summer when I switch modes

Are you sure about the 1625 gram weight on the GRX wheels? Performance bike has them listed at 1815 grams, Shimano says 951 for the rear and 769 for the front, making it 1720 for the set.

The last review I read has them at 1650 g, sorry, not 1625. I was off a bit. Still a great value however. Be sure you are loking at the GRX RX570 set. https://www.cxmagazine.com/shimano-g...10-rx812-rx570 Will be placing an order in a few days... Funny that the weights are seeming to vary so much from source to source... Will have to weigh them myself when they come in...

thatd be good to see actual weights. Shimano's website shows them as 1720g.
agreed that it's odd how much they vary online.