Trek "commuter" bike, 26x1.5 tires- accept wider tires?
 

If I've posted this in the wrong section, please let me know or move it. I have a line on an unusually nice condition Trek SU200 "urban-commuter" bike(intro'd 2005?), I believe this has now morphed into the SU 2.0. It seems to me pretty much a mountain bike, but with solid front fork, slightly higher gearing(48-38-28t front, 11-30t rear), disk brakes(!), and 26x1.5" street tires. The rims are spec'd as Bontrager Rangers, no width given. Owner says bike has spent its life being ridden only a little, rest of time stored inside apartment or office after those rare commutes- to a downtown big city! These were priced ~$500 or more new, this one's in near-new condition with a extras(headlight, talilight, rear rack with removable slide-off basket) for ~$150. I checked the specs, its 18" frame should be right for me. Seems a good deal for me to begin riding a bike again after 40 years, especially since at first I'll stick to the streets & side roads. But sometime later on I'd like to try a local network of old dirt roads.

Is there any reason why the 1.5" wide factory tires can't be replaced in the future with something wider & more appropriate for riding old dirt roads nearby? Assuming the rims, front fork & rear frame are wide enough wouldn't tires up to 2" or 2.125" mount & work OK? I could find nothing on the Trek site about this. Any & all help appreciated.

For the definative answer you almost have to trial fit some larger tires. Be sure that you have the front derailleur in the granny gear position because that's where you sometimes get interference. If I was going to guess I'd say you should be able to fit 1.9" tires on that bike but it's just a guess.

If you stay on hard packed dirt, the current tires should be fine.

The rims won't be a problem. I've run tires from 700x21 to 41 and 26x1.0 to 2.3 on the same sets of rims on several bikes with no trouble at all.
I don't know that specific bike, but I'd be surprised if you didn't have space to go up at least two or three sizes. You should be able to eyeball it with a fair degree of accuracy. Typical trouble spots are under the brake arms (no problem if it has canti or V brakes; perhaps an issue with sidepulls) and between the fork blades in front. If the existing tires have ample clearance, you can go up.

I dood it- bopught the Trek SU200!
 

Thanks for the help, guys. Yesterday I drove all the way to Dallas to see the Trek SU200- long trip(gas $$!), on I-30 just west of Sulfur Springs went through one of the worst rainstorms I ever drove through- & I've driven through some. Even *I* finally had to stop for a while- heck, even the *trucks* were stopping!

Figured it was a jinxed trip, but when I finally saw the bike, my luck had changed. I was delighted! It's as close to new as any used bike can be- looks like only the middle front sprocket was ever used, the other two fronts seem to have no wear whatever to the black finish. The rear sprockets look like pristine polished chrome. Chain still has the factory lube on it. The Bontrager Satellite Plus 26x1.50 tires- center of tread is near-slick by design, they still have the little mold ridge all around the circumference, couldn't have been ridden more than a few miles. Topeak Explorer disc brake mount rear rack plus Topeak MTX basket that slides onto rack & locks in place look new- basket is surprisingly large, & checking internet prices this combo wil run over $50 plus shipping, owner probably paid bike store price for it. Has cute little clamp-on headlight & taillight, he added a kickstand to the bike too. Got a Giro helmet with it- maybe a cheapie, but still saves a few more $. He even threw in the home model air pump with built-in gauge(RavX?) that he advertised separately at $25, said I'd earned it for the long drive.

The rims are kind of narrow, according to a sticker on them they're 559mm dia x 18mm bead width. Should probably max out at about what the tires are now(26x1.5) or maybe stretch it to ~1.75- but I've about decided that until I wear these tires out al I'm gonna do is get a more comfortable seat, & maybe a set of fenders. I'm really tickled with this. All those extras add up to $100 or a little more, on a bike that was ~$490 plus tax new. All that like new goodness for $150- can't beat it with a stick! And now the great bike hunt is over- exept for finding a decent cheap mtn bike to ride on the dirt roads behind the water tower! I've decided that in the long run it'll be more cost effective to get another bike for ~$100 & have an instant choice of civilization or boonies.

My Safari has 17mm rims. I've run 1.5-2" tires on them with no probs. Won't go past 2.1" because they wouldn't fit under my fenders. I think your bike's clearance will be more of a limiting factor than the rims.