truthseeker14

I'm thinking about converting a Soma Double Cross DC so it's more suited for light trail riding. It's currently set up as a road bike with 700c wheels, 24 spoke (Bontrager Select Disc). Even if I keep the same wheel size, the wheels I have have a reputation for being weak, so I'd imagine I would need new wheels. It's a 48 cm frame, and though I'm not all that familiar with 650b wheels, they sound like a good option. The spec sheet says it can fit 700c x 38 mm tires, but if I go with 650b or 26", I can fit wider tires, which I would like to do. Any advice? 700c, 650b, or 26"? For the 650b and 26", what are the widest tires I could use? I'll likely lose the rack and fenders. I was tentatively planning on keeping everything else the same, but other ideas are welcome. Specs on frame are below.



The frame has been retired, but here are the specs:

https://www.somafab.com/archives/pro...ouble-cross-dc
- Tange Prestige heat-treated CrMo front triangle; butted CrMo rear end
- Clearance for 700x38c tires with fenders
- Rear spacing is 132.5 and fits road or mtn hubs.
- Matching straight blade IRD disc only fork
- Disc mount: v.2 has disc mounts on the chainstay which allows you to put almost any rack or fender on it. Rear disc mounts fits 160mm rotors only
- 1-1/8" size headtube - w/ extra height so you use less spacers.
- 48 cm frame
- 4.3 lbs
- Color: Slick Black

t2p

me ?

appears to be cool bike in it’s current form and I would not go to great lengths / hassle / expense to convert it for light trail riding

there is a decent supply of affordable bikes suited for light trail riding - from vintage rigid MTBs to more contemporary MTBs … and some hybrids might also suit your needs

mstateglfr 

I doubt anyone here will know what size 650b you can fit on an old model DCD. Thats from when...like 2016 when they did both canti mounts and disc tabs?

Anyways, Just measure the width of spacing between the chainstays where a 650b tire would be, subtract 8mm for 4mm of tire clearance on each side, and get some new wheels and tires.

mstateglfr 

Well look at that, someone had the frame and did exactly what you are looking to do with it!
Wild.

truthseeker14

Thanks! I was hoping some one did the same thing. But just to make sure, my frame was one of the many retired Soma Double Cross frames. Yours was the one that could do both disc brakes and cantilevers?

Fentuz

1st google click says - Clearance for 700x42c tires (38c w/fenders)
https://www.somafab.com/archives/pro...-disc-archived

Most of gravel that specify this tyre size to go for the classic 47-584 tyre for 650b. (often see WTB sendero 47-584 on these bike). Note that the BB will be lowered by ~ 15mm/ [1/2"and a bit]

truthseeker14

Thanks, I have an older double cross that has clearance for 700c x 38

Fentuz

As a rule of thumb, I tend to go for 5-7mm wider with 650b than what's allowed with 700c

BikeBellevue

FWIW, I am running 26x1.95 tires on my DC, and love the feel. It feels more nimble than when I use 700cx38 setup. Given the drop in bottom bracket, i went from 175mm cranks to 170mm.
In the pic below, I am running as a single speed but have since configured to 1x9.

truthseeker14

thanks, that looks like a newer DC than mine, (mine can do either cantilever or disc brakes) but 26" wheels are tempting, especially since it looks like 650b tires and wheels are less common and more expensive. I'm away from my bike, but I might have 165 mm crank arms.