GoodRoadRunner

I have a Specialized Sirrus bicycle, presently with 700 x 23c tires on Alexrims s500 rims. The rims are labeled "6061H-T6 622 x 14", and are 19mm wide (outside dimension) at the circumference. Next month I plan on riding the Katy Trail in Missouri, which is packed gravel. What is the widest tire that I can put on these rims?
I also have a Wellington 1.0 bicycle with Alexrims RP15F rims, labeled "6061-T6 622 x 16" which are 23mm wide at the circumference. What is the widest tire that I can put on these rims?
Thanks for your assistance.

ThermionicScott 

Those rims have inner widths of 14mm and 16mm, respectively. The old rule of thumb was to double that number for the widest tire you could run, but there is some wiggle room on that.

Maelochs

I have no clue ... but I have a keyboard and an internet connection.

For a while the trend in mountain bikes was to run skinny little rims and gigantically wide tires ... and it worked, but I guess not at the lower pressures people tend to favor nowadays. I would bet you could Safely run 28s on either rim, but I would keep the tires pretty firm ... watch to see if they slop back and forth in the corners, let a little air out, repeat until it gets sketchy, then add five pounds and go.

I would definitely want to use the wider rims, unless they were significantly weaker or heavier ... but really, 2 mm isn't likely to kill you. Buy some really cheap 28s and see what happens.

DiabloScott

622x14 means the inside width is 14mm - this is a narrow/medium width - you might have some un-nerving squirminess in the corners if you go wider than 28mm.

622x16 means the inside width is 16mm - you should be able to fit 37mms on there with no problem.

Your limitation might be on the bike frame though - wider tires are taller tires and might rub on the brake bridge or the chain stays. Try before you buy.

canklecat

You probably won't be doing any fast cornering on gravel while riding a road bike so any tires that physically fit without the bead blowing off the rim are probably okay.

I've ridden our local gravel trails, which are mostly crushed limestone chat trails - probably like the Katy Trails -- not really rough gravel. My 700x23 Vittoria Zaffiro tires were fine for that. The Zaffiros have nominal tread, mostly cosmetic, but still a bit grippier than the slicks I'm riding now. Only thing I'd do differently would be to reduce the pressure a bit, closer to 80-90 psi (I weigh 160 lbs, FWIW). Can't say I enjoyed riding the chat trails on skinny road bike tires, but it was tolerable. I'd prefer my flat bar hybrid with 700x42 Conti Speed Rides.

My road bike has old Araya CTL-370 rims, the lightest commercially available at the time and nominally 14mm wide. The bike was originally supplied with 700x18 tires. I've run two sets of 700x23 and might, maybe, go up to 700x25 with the right tire. But I wouldn't want any splashy, squishy feeling tires on fast cornering, so I wouldn't go as wide as 700x28 even if they fit (which they probably wouldn't -- even 700x25 would be a tight squeeze on my bike).

If I planned to ride more gravel I'd stick with 700x23 or 25 and get some tough training type road tires.

PepeM

As wide as your frame allows.

Johnny Mullet

I have ran wider tires on 700c road bike rims with no issues.

Psimet2001 

Geez...how quickly we all forget.

Before the latest iteration of wide rims we raced cyclocross on 19mm rims and 34mm tires. It was and still is glorious.

People really overthink most of this stuff. OP - you're going to run out of frame and brake clearance before you're going to outclass the rim. Period.

Iride01 

These two posts contain all you really need to know. Well maybe not. But they are pretty concise.

I'll just add that the common rules of tire to rim sizing are all about tires made back in the 70's. IMO, At least the ones I've heard. Tires are built much better now.

Some manufacturer websites will give you their suggested rim sizes if you dig deep enough in their documentation. But it's only suggested.

PepeM

Also worth noting that the Katy Trail is hard-packed gravel. Very wide tires are not really needed. 32s at low pressures should be more than enough.

JerrySTL

I concur. I've done the entire Katy the last 7 years on 700x32s and I weigh around 215 lbs. There are places where things can get a little squishy after some heavy rains but not all that bad. I ridden on the Katy with 700x25s for shorter distances when it's dry; however, for a long tour of it, 700x28s would be the smallest that I'd go with.