I'm sorry if this isn't the right forum...I'm trying here first though. My moutain bike is on its way out (everything is failing on it and it's a cheap box store bike more than 15 years old). I have a nice touring bike that I ride on the roads. But I occasionally like to ride on a gravel trail. Can you mount wider tires on the same rim or do you have to buy a new rim?

Tiff

To a degree, yes. Also consider fork space. A skinny fork may be the limiting factor.

How wide a tire is on there now and how wide do you want to go? I ride gravel on 32mm tires with no problem. A touring bike would likely have clearance for those at least. Most recent road rims would accept a 32.

[QUOTE=dogontour;10768967Can you mount wider tires on the same rim or do you have to buy a new rim?[/QUOTE]

The rim you have will (almost certainly) accept wider tires.

The rim on the touring bike is probably not a particularly narrow one.

https://sheldonbrown.com/tire-sizing.html

Scroll down for "width considerations".

This should help. It's a rule-of thumb guide for tire size vs rim width.

https://www.sheldonbrown.com/tire-sizing.html#width

Edit: Kayaker beat me to it, but my link is better

Also consider if you want to put fenders on it which take a little bit of space, but like the other posters said, if its a touring bike, then it should be designed for that sort of thing.

If you want to turn a road bike into a commuter, the only real option is 650B. That allows one to install fenders and good medium width tires.

I have 32mm tires on right now. I can, and have ridden on gravel but the tires just don't give enough cushion and after 10 miles everything was sore and I still had 20 miles to get home so it's not worth repeating in my book. I was looking at my bike last night as I rode though and I have fenders and a front rack with a narrow profile on it and while I could get away with slightly wider tires it wouldn't allow for much wider. I'll have to take my bike to a shop with me and see what fits in my fenders. Thanks for your help!

Tiff

Tiff, you might see if you can get away with less pressure in your tires to smooth things out without buying fatties. If you're currently running max or near max pressure, you likely have leeway to let pressure out.

I run my 32's with around 90 psi, and I weigh 220 lbs and currently rock a 30 lb bike with a 30+ lb additional load. This gives me a little squish but no pinch flats.

I run mine at 70-80 PSI. I weigh 150, my bike is 40 lbs and I usually have 5-10 lbs on the bike. What should I run it at on gravel without risking a pinch flat?

Trial and error. Every tire/rim/bicycle/person combination will produce different results.

You could likely get away with a bit less pressure, especially if your tire has thicker sidewalls. I run my thin 700x28 tires at 70-75psi most of the time and never pinch. I am also 150lbs. Maybe try 60 in the front and 65 in the rear.

If you were 10 miles out, couldn't you have turned around and been just 10 miles from home?

Well, I could have turned around on gone on gravel for 10 miles or 20 moiles on pavement....I would have chosen 40 miles on pavement over the 10 miles on gravel! I'm wimpy like that.

try a few bumpy miles with 55 in the back and 50 up front (if this isn't below the manufacturer's stated minimum pressure).

better yet - run a few miles out in the gravel as they are, then let some air out (aided by an accurate gauge) and compare the ride home. you might be surprised.