base2 

So I checked the WSDOT website and aside from an exclusion from Hwy 161 in Federal Way to Hwy 181 (the West Valley Hwy (to what looks about 1000 feet adjacent & West of Hwy 167)) Highway 18 looks as if it is legal to ride on from basically the Highway 167 interchange and Eastward towards Preston & into Snoqualmie.

I am trying to find a route around the Southern side of Tiger Mountain. I know about the Northern routes. Preston-Fall City Road to High Point down into Issaquah from there. And of course May Valley Road and Cedar Grove Roads to connect Maple Valley to Renton.
But going around the South side of the mountain seems like it would make a nice pleasingly large round shape on the map.

The Strava Global heatmap does not inspire confidence in that any trace on the map would be more than an a Garmin unit left on while someone is driving home.

So, though it is legal to ride on Hwy 18 does anybody actually do it? Any road reports any one can add?

Seattle Forrest

I wouldn't.

It's rare for me to be on 18, but I don't remember it as being even remotely bike friendly.

phtomita

I did recently twice on the section that is double lanes to explore some new places.
From Redmond went to Issaquah-Hobart Rd. SE and took SR-18 to SE 304th St close to Auburn and back - it gives me 60 mi ride free of stops.
Didn't go further because the bridge over Green River doesn't have much shoulder when coming back.
If you are super adventurous there is a crossing between southbound and northbound right before Green River, for cops and construction crew...?

First time, I went to SR-169 in Maple Valley and was going to Renton on the trail when a patrol officer asked me to ride on the shoulder instead since the mup is closed due to the pandemic.

I would like to, but won't try the Issaquah to Preston section. That is a busy section and without much shoulder to ride safely.

base2 

Ok, you guys. Thanks. This is definitely something to think about.

Maybe a weekday, away from commute times and the reverse of commute direction...if I feel brave. But maybe not at all as well.

Certainly not during the Friday evening rush.

I appreciate the feedback.
Base2

Carbonfiberboy 

I rode it a couple times maybe 25 years ago from Auburn to I-90. The section climbing over the shoulder of Tiger Mt. was a bit terrifying. Big trucks doing 60, me up against a guard rail, no room.

droppedandlost 

Please don't ride 18 over Tiger Mtn, it's dangerous enough in a car. That section has one of the highest traffic fatality rates in the state.

akropilot

Last fall I attempted to ride from Issaquah-Hobart road up over the section of Highway 18 to link up with the Tiger Mountain trailhead.
Hwy 18 is essentially a freeway with fairly heavy truck traffic. The shoulder goes absolutely to zero. It's 6 inches from right elbow to steel guardrail, 6 inches from left elbow to semi-truck. As soon as I hit that section I bailed out. You should be able to see this on Street View about 1 mile north of Issaquah-Hobart.
It's much safer to ride on Highway 90 than Highway 18 in my opinion.

The other south-to-north option is to head east on 208th street, and you can link up to Rattlesnake Road on gravel/logging roads. Again, requires something with fatter tires.

base2 

So I took this to heart & figured I'd give it a shot. I brought up the heatmap & the tiniest faint trace shows there is indeed a route. Parts of which show "Private" roads according to USGS Topo scans. Nevertheless, an easement is an easement & I set about setting a route.

RidewithGPS really took some effort & I couldn't figure out quite why it was making things difficult with 40 & 80 mile detours.
It turns out that at Lat/Long N 47.44432, W 121.85435 there is a wooden bridge that is rotten. It's probably plenty fine for bicycles though.

It was at that point I figured it was time for a lunch break & confident it went through, I turned around to head home & that's when my chain blew apart. I pulled a few links in-situ by using a rock to seperate the masterlink & discarding the bad link. I reconnected the master link & gingerly made it home being sure to stay out of the bigger end of the cassette.
Check out my activity on Strava: https://strava.app.link/xJ2OHuwf06

I'm probably going to do it again. I've got a new chain, a new crankset (Schlumpf speed drive) & a new 11-46 cassette.

Thanks for making me take a second look at the heatmap.

Aaron

SlowPokeRandy

A safer option is to follow dirt roads from SE 104th ST off HWY-18 (47.5045238,-121.8836374) to Hobart -- google maps "bike mode" will give you routing info for the roads to take if you give an intermediate point of 47.44045238,-121.8636374

FWIW: The west bound shouldler of HWY-18 west of the summit to the Issaquah Horbart road is very narrow and motor vehicle traffic is typically going 10 over.

akropilot

I rode it on the 24th (https://www.strava.com/activities/3506521197). The wooden bridge is blown out from truck traffic, but I walked across it just fine. It's a really burly timber bridge built for trucks. Just don't step in the potholes. It's a good thing you turned around though since the climb on the other side wouldn't have worked with a blown-out chain...it's pretty tough.

I also was foiled again trying to find a rideable connector through Taylor Mountain to the Tiger Mountain trailhead. I rode to the end of road K, but the traverse that continues from there is a cobbled 15% mess from erosion and horse traffic. It's a 0.4mi push-a-bike section which I wasn't interested in, but I *think* above that you could ride the rest of the way through. I already discovered Road A to be an overgrown cesspool of mud and horse-poop.

The biggest challenge for this ride turned out to be water. With Starbucks closed in Snoqualmie you need 3 bottles, or fill from a stream, or find a hose on some house. Or skip the PooPoo climb.