When you mention the band Van Halen, you immediately bifurcate any group as they argue the merits of David Lee Roth vs Sammy Hagar as the lead singer. Most things in cycling are that way too - always two camps. 26 vs 29 inch mountain bike wheels, 700 vs 650 road wheels and fat vs skinny . And that is just wheels and tires.
We were having one of these either/or discussions in the shop regarding using road tires on dirt for an upcoming Gran Fondo. I was of the camp that unless the dirt is super loose and rocky that tread or lack thereof really did not make much difference and would roll better on the paved parts of the route. The other camp was you needed some tread and the more the better to handle the dirt.
We really did not get very far in the discussion before we lost interest and moved on to other topics. I had forgotten the discussion until riding out on the Palouse this morning and remembered that there was about a 5 mile section of dirt on Jackson Road that runs between Hwy 27 and Valley Chapel Road.
As I approached Freeman I thought it was time to put my money where my mouth is and ride that 5 mile dirt section on my "skinny" tires with no tread The road is paved in Freeman and for about a mile thereafter.
|Junction of Hwy 27 and Jackson Rd at Freeman|
Since I was road riding I was on 700 x 23 Bontrager Hard-Case
tires inflated to about 110 psi to handle the sand and glass still on the shoulders of the road. These tires are tough and very flat resistant. I also like that they are only 330 grams so they do not feel overly sluggish. The bike was an aluminum Klein Reve with carbon forks and seat stays.
The road appears to have been graded recently, so there was probably more rock on the surface than you might normally encounter, but no washboards whatsoever. It still had some moisture from the rain and snow this week so dust was not an issue.
After a couple of miles of rolling along the Palouse you start descending toward Latah Creek and into some trees. Top speed was around 29 mph and the tires seemed perfectly at home on the dirt at that speed - braking and cornering were not an issue.
After the descent the road follows Latah Creek for awhile and starts the climb back up to Valley Chapel.
Climb-out was pretty non-eventful and traction good both sitting and standing back up to the paved road. I was very happy to be running 700 x 23 tires back on the road and found them quite well mannered on the dirt portion of the ride. I would consider running more volume like a 25 or 28 if riding a route that had a lot of dirt, just to be able to run a little lower tire pressure and get a more compliant and less hoppy ride.
Traction on dirt with semi slick or slick road tires will most likely not be an issue unless it is deep, loose or muddy - then, no amount of road-type tread pattern is going to be any help - so I say tire tread is not critical and riding road tires on reasonably compact dirt and rock should be fine otherwise.
Finally, I say Sammy Hagar. He had a much broader vocal range and was far less obnoxious and had a long and varied career - can anyone say Montrose?