Ritchey Outback fender compatibility
700 x 48mm or 650 x 2" (50.8mm) (depending on tire/rim manufacturer)
Frame max spacing 58mm; Fork max spacing 60mm
Ritchey Outback Measurements
Hub to crown race = 393mm
Crown race to top of 60mm clearance = 44.2
Hub to top of 60mm clearance = 348.8 (calculation: 393 - 44.2 = 348.8)
650b x 48mm tire radius: 340mm
Top of tire to top of 60mm clearance = 8.8mm
Rules of thumb for clearances
Rules of thumb from Ritchey
Max tire clearance in a fendered bike is 10mm narrower than what the frame is designed for without fenders. The Outback is designed for 50.8mm, so: 41mm.
You might find that you can get away with a 650b x 45mm tire and fenders.
Rule of thumb from Velo Orange
The fender should be at least 8mm wider than the tire; 10-12 mm is better.
A fender's width is measured on the outside, not inside.
Rules of thumb from others
Fenders should be at least 10mm wider than the widest tire you're going to ride.
Rene Herse: 42 mm tires are best used with 58-60 mm-wide fenders.
Portland Design Works
Ca Heo: [FB post]. PWD 650b x 48 fenders + 47mm tires. I'm using 650bx42 tires. 47mm Rutland tires was excellent and trusted on bumpy wet road. It is Rutland 47mm fit perfectly with Portland Design Works fender (650b x 48).
Craig Smith: (Facebook post). PDW 55 with 650b X 50 and 700 X 47. These are PDW Full Metal Fenders. In the photo they’re on 650b wheels with 50mm tyres, but they’re also fine with my 700c wheels and 47mms. ; PDW Full Metal Fenders on 700c x 47mm rubber. Solid as a rock... I use Portland Design Works ‘Full Metal Fenders’. Not the lightest, but solid and no rattling. They also fit my 47mm-50mm tyres... I use these - https://ridepdw.com/products/full-metal-fenders-700x55. They work well, don't break easily like the plastic SKS ones, fit wider tire widths. The fit around my 700 x 47mm Teravails is tight, but still does just fine in heavy mud.
Kevin Kwan: Portland Design Works 55mm fenders. 700c x 40c tires.
Tariq Bayjoo: Portland Design Works 45mm Full Length Fender with 700x33mm tyres. Crucial to getting the fitment right is to get the radius of the fender near the rear chainstay mount correct due on the length of the chainstays, otherwise it will result in a big gap with rear tyre there.
SKS
Gene Ronchetto: SKS Edge 56 with Maxxis Rambler 40mm
Karl Brats: SKS Bluemels Stingray 45, 40-622 tires.
Kris la Gasse: Sks Bluemels 65: Pirelli Cinturato Gravel M 650Bx50 on 24mm inner rims. The tires measure slightly wider, I think about 52mm. Wouldn’t go ant wider for frame clearance. Clearance tire vs fender is no issue. Fenders are too wide for the frame and fork so you have to modify them a little to not make them rub the paint off.
Terence Burgers: SKS Velo cross 55 fenders protecting my Outback. I ride on schwalbe 2.0 inch wide tyres mounted on Hunt 650b wheels.https://www.facebook.com/photo.php?fbid=10160654672116896&set=p.10160654672116896&type=3
Cooper Gavin: SKS edge aluminium; will just about take 50 mm tyres; Cooper Gavin; but they are not the best they rattle quite a bit, I use gaffer tape to stop them rattling
Alexis Gosselin: VO 650b Smooth Fenders, 58mm. Tires are Goodyear Connector Ultimate 50mm and the clearance is very good. I like the fenders and the protection but I will probably add an extra U stay connecting the front part of the front fender to the middle eyelet of the fork for extra stability. Question: Did you have any difficulty fitting them into the frame or into the fork? How much clearance do you have between the fender and the tire? Would you say it is 8mm (58mm - 50mm) or a bit less? Alexis Gosselin: clearance is good it's around 5mm between the widest part of the tire and the fender. I had to slightly form the fender at the seat stay tube location. I did that to improve clearance and get a consistent fender line.
Dachlan Sutijono nice looking with good size tires
Ole Erik Løvold - 700c; 55mm Pelago aluminium fenders with 42mm Ultradynamico Cava Race tyres Pelago aluminium fenders, 55mm wide, with 42mm tyres. Can fit up to 45mm.
Clay Hackett I’ve got 48x650b gravel king slicks on mine. They measure 51 on GRX wheels and there is about 5 mm on each side of the chain stays. Scott that’s what I’ve got on my 650 wheels now! Although my rims must be narrower (25 internal I think?) because they left lots of room on both sides. My 2.1s were knobby Vittoria Barzos so maybe that had something to do with it too
Brandon Souba: Thanks for all of the comments and the push to keep 650x48 — I ended up getting an Ultradynamico Rose JFF front tire which fixed the unpredictable steering issue.