[cbman]

So these Continental Diesel tires are just right for the kind of trails I ride, however I'm wondering if they're too wide for my bike. I ride a Trek 4300(2009). My normal tires are 26x1.75", these tires are 26x2.5". Is this too radical of a size difference? And just one other question do I HAVE to run wider tubes or are 1.5-1.75 fine?

Continental Bicycle -Diesel

[Industry_Hack]

Measure your fork and stays. And yes, you'll need new tubes.

[Sickmont]

I run 27x2.25s on my 09' Trek 4300 disc and i have a mile of clearance left over with them. And yeah, like Mr. hack says, you need new tubes.

[cbman]

Cool dudes, thanks for the info!

[hophead]

1.75" tubes are too small, but don't worry about finding tubes that are rated for 2.5" tires. 2.2-2.35" are fine. Most 2.5" tubes are made for downhill and are heavy and expensive.

[cbman]

So instead of the Diesels I went with Bontrager XR4's. They were what I was looking for, and defiantly fit my bike. The awesome owner of my LBS showed me the actual with of the diesels and it turns out you only have a 1/4 inch of clearance, which is not enough for pedaling. Plus, the XR4's are much lighter, the diesels would have added 4 pounds!!! So it worked out for the best that I went up there. I posted some old, new tire comparison photos.