Symox

I have a bike with Mavic Open Pros that have space all around the front tire (between the tire and the frame/fork/caliper brake using hex wrenches) of 4mm and 3mm for the rear using 28mm GP5000s. I'm thinking of getting 30mm GP5000 for the front since theoretically it would add 1mm per side (not sure about the top of the tire). I'm hesitant to try it with the rear as I've read its a good idea to have at least 2mm and not sure if the 1mm per side would truly leave me with that room.

My questions are:
1) Is it ok to use 30mm with Open Pros? Their website recommends 19-28mm whereas the rims themselves show 23-32mm - see pic below)
2) Do you think I would end up with the recommended 2mm clearance with both the front and rear tires?

Thanks

Koyote

I would not be comfortable with only 1-2mm of clearance, esp with the rear -- since the wheel might flex slightly under power. And if you hit a pothole and knock the rim even slightly out-of-true, you're making the 'call of shame' to get home.

Polaris OBark

As long as you can get a credit card in between the tire and the chain stay, you are golden. If you are worried, get those Peaty's valve caps that double as spoke wrenches.

79pmooney

I've used bigger than 32c with Open Pros. I've run closer than 2mm but I carry a spoke wrench when I do and I've built a few wheels. I've also run bigger tires in front for situations exactly like yours. Panaracer Paselas, 38 in front and 35 in back on Open Pros. Worked just fine on both pavement and gravel. (A little heavy and slow on pavement but Paselas never were a "fast" tire, just a good all-arounder for its width.)

A consideration - your weight and riding style. I am relatively light and easy on wheels. (155, tall and skinny.) If you weigh more or are a wheel thrasher, run narrower tires with more pressure to 1) have more margin on clearance so the tires clear with less than perfectly straight rims and 2) more pressure to save rims from bottoming out damage and pinch flats (if you are running tubes).

Symox

I'm 155lbs and like to ride hills a lot.

The more I think about it, I'm not sure I want to sacrifice clearance especially on the rear. I guess I'll just stick with 28mm, its a more standard size anyway.

Symox

I had to replace the fork and the front again has 4mm clearance, but it seems to have more margin. I might try 30mm only on the front when it comes time to replace the 28mm rear (I'll swap the 28mm front for the rear and put the 30mm on the front).

Thoughts?

WhyFi

Manufacturers generally recommend 4mm of space on all sides to accommodate for wheel flex, debris clearance, etc. I personally wouldn't bother to push that margin of error just to move to a 30mm from a 28mm - it's not going to be life changing. Frankly, I liked 28s more than 30s on narrower rims, anyway. On wide rims, where the tire cross section is less bulbous and floppy, I'd be more inclined to go up that half size.

Sy Reene

Potentially also a downside to going a bit wider, will you have any hassles removing or installing wheel with tires inflated? Ie. would your brake's release open up enough to accommodate the differential between the rim and inflated tire widths?