I recently got my first tri bike (QR PRfive) and was thinking about converting my Roubaix SL4 Disc Comp to a gravel bike...really, just changing the tires out. It's a great bike, strong CF frame, but I'm wondering if it could handle the abuse of non-paved roads. Does anyone have any similar experience with this bike or other road bikes going to gravel?

Frame only has clearance for 33mm tires. That's going to be really limiting for gravel applications.

you could do it. but my crystal ball says that most of you will be buying, if you buy new, gravel bikes with tires between 47mm and 57mm in width, mounted on 27.5" wheels. this means a pretty different frame than a roubaix.

That seems to make more sense, the more reading I'm doing on the subject. Guess I'll have to just get another bike! ;)

you could do it. but my crystal ball says that most of you will be buying, if you buy new, gravel bikes with tires between 47mm and 57mm in width, mounted on 27.5" wheels. this means a pretty different frame than a roubaix.

I ride more gravel than anything else these days. Some of it rocky, some single track almost MTB stuff, some deep sandy.... and I still don't know why anyone needs to go that wide unless you are bikepacking. Maybe it's because I'm only 64kg, but 38c is more than enough width for me.

folks who travel around with their gravel bikes know that gravel biking is like open water swimming: it's a very different experience swimming in a lake in minnesota versus starting and ending your swim on a beach in southern california with pumping surf. in fact, maybe that's it. it's the west coast thing. we're weird out here. everything has to be different for us.

i have taken to referring to "west coast gravel" lately. remember that 5-day gravel stage race last year? oregon trail gravel grinder? i wasn't there, but what i heard was the enterprising rider changed to 650b and fatty tires for 1 or 2 stages, and that helped the eventual winner to victory.

on the west coast we have a lot of batholithic and sedimentary soil. granite. quartz. breaks down into boulders, then river rock, then sandy soil. we roll over a lot of rock and we get bogged down in sand... unless we have wider tires to roll over it! in much of america's midwest it's more of a clay-dominant loam and you don't even need to pave it. subdivisions, housing tracts, are built and the roads are sometimes just groomed, but not paved. you don't need 53mm tires on your gravel bike for that. 35mm or even 30mm tires might be fine.

That seems to make more sense, the more reading I'm doing on the subject. Guess I'll have to just get another bike! ;)

i have taken to referring to "west coast gravel" lately. remember that 5-day gravel stage race last year? oregon trail gravel grinder? i wasn't there, but what i heard was the enterprising rider changed to 650b and fatty tires for 1 or 2 stages, and that helped the eventual winner to victory.

That race had slightly more difficult than typical OR gravel and/or contained a shitload of very loose and relatively deep sand (like 30-40 miles total for the whole race). At least in OR, stuff that would pass for single track in many places is common in both gravel and CX racing.

And as far as how the race was won (the winning time gap actually happened on stage one, Barry Wicks and Carl Decker got like a 10 minute gap) was Carl Decker was running 50mm tires. He told me he had to hand trim the side knobs so he could get adequate frame clearance. But that stage included about 5-6 miles of true sand (not kidding, imagine about the worst sand pit you have seen in CX, but it lasts for 5 miles) and then about 2 miles of rocky, steep single track and those tires made the difference. At least the good part was that in a 300 mile race, the first 30 miles were the hardest.

But to your original point, I was glad to have 650Bs for that race and because the wider tires aren't really slower on easier stuff, but can make you stupidly faster in some knarl, they are totally the way to go. As more people figure this out, as you say, we are going to see frames set up to run 50mm as a normal setup and anyone getting a bike now should get ahead of that and make sure they can fit tires at least up to the high 40s.